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Background: Fusobacterium nucleatum (F. nucleatum) is an integral component of supra‐ and subgingival biofilms, especially more prevalent in subgingival areas during both periodontal health and disease. Aims: In this review, we explore the physical, metabolic, and genetic interactions that influence the role of F. nucleatum in the formation of mixed oral biofilms. The role of F. nucleatum in antibiotic resistance in oral biofilms was discussed and some therapeutic strategies were proposed. Methods: PubMed, Scopus, Google Scholar, and the Web of Science were extensively searched for English‐language reports. Results: F. nucleatum‐derived proteins such as RadD, Fap2, FomA, and CmpA are involved in direct interactions contributing to biofilm formation, while autoinducer‐2 and putrescine are involved in metabolic interactions. Both groups are essential for the formation and persistence of oral biofilms. This study highlights the clinical relevance of targeted interactions of F. nucleatum in supra‐ and subgingival oral biofilms. Conclusions: By focusing on these interactions, researchers and clinicians can develop more effective strategies to prevent biofilm‐related disease and reduce the spread of antibiotic resistance. Further research in this area is warranted to explore the potential therapeutic interventions that can be derived from understanding the interactions of F. nucleatum in oral biofilm dynamics. [ABSTRACT FROM AUTHOR]

Background and Aims: Multidrug and extensive drug‐resistant Pseudomonas aeruginosa was extracted from burn patients referring to burn centers in southwest Iran so that biofilm generation and antibiotic resistance could be investigated. Methods: A specific primer was used to confirm all our considered 110 P. aeruginosa culture‐positive reports on 345 burn patients. The resistance of P. aeruginosa to seven antibiotics and Colistin with minimum inhibitory concentration (MIC) was assessed. Biofilm formation was assessed by the phenotypic study of specimens under Congo red agar and microtiter plate assays. Results: One hundred and 10 clinical P. aeruginosa isolates taken from burn wound infections were validated. Among P. aeruginosa isolates, Piperacillin, Ceftazidime, Maeropenem, Gentamycin, and Gatifloacin had the highest resistance to antibiotics, while Ticarcillin‐Clavulanic acid and Ceftolozane‐Tazobactam showed the least resistance. MICs were then evaluated via the E test. Seven isolates were resistant to colistin. Colistin reference MICs for multidrug‐resistant P. aeruginosa prevalence was 38%, while it was 22% for extensively drug‐resistant (XDR) P. aeruginosa. One P. aeruginosa was pandrug‐resistant (PDR). Under Congo red agar test, 66 isolates (67%) formed biofilms and black colonies, whereas 44 isolates (50%) had red colonies. In MTP, 76% formed biofilm. 40%, 32%, 21% of the isolates were strong, moderate, and weak biofilm formers, respectively, while 43% did not form biofilms. Conclusion: The P. aeruginosa resistance to antimicrobial agents has largely challenged the control of the infection. Accordingly, a higher resistance occurred when the isolates were transferred to the patients. Less than 50% P. aeruginosa samples generated strong biofilms. Consequently, hygienic measurements are essential to inhibit P. aeruginosa transmission to hospitalized patients. [ABSTRACT FROM AUTHOR]

Background and Objectives: Klebsiella pneumoniae is an opportunistic pathogen responsible for causing nosocomial and community-acquired infections. Its pathogenicity is associated with a variety of virulence factors and antibiotic resistance. The aim of the present study was to compare virulence attributes between ESBL and non-ESBL producing isolates. Materials and Methods: A total of 113 K. pneumoniae including 56 ESBL and 57 non ESBL-producers were collected in Bushehr province, Iran, from November 2017 to February 2019. Enzymatic profile, hypermucoviscosity and biofilm formation were investigated phenotypically. In addition, the presence of rmpA, aerobactin, kfu, allS, mrkD, ybtS, entB, iutA, fimH, wabG, wcaG, K1 and K2 genes were detected by PCR and sequencing. Results: There was no statistically significant difference in enzymatic profile between ESBL and non-ESBL producers. The prevalence of the hypermocoviscosity was lower among ESBL compared to non-ESBL producers but the intensity of biofilm was higher in the ESBL producers. Among the virulence genes, K1, rmpA, iutA, and aero were observed only in non-ESBLs. Moreover, the carriage of allS, K, K2, rmpA, iutA and aero genes was higher in hypermucoviscous in comparison with non hypermucoviscous isolates. Conclusion: The identification of potentially pathogenic isolates plays an important role in preventing their spread as well as the success of their treatment. [ABSTRACT FROM AUTHOR]

Background: Denture stomatitis (DS) is a chronic mucosa inflammation that supports removable dentures. Candida albicans is the most critical factor in the pathogenesis of DS. Systemic antifungal drugs such as nystatin are effective in people with acute candidiasis. Yet, in cases of predisposing factors such as a denture, nystatin cannot completely control the infection, andrecurrences are common. Objectives: In this study, the resistance and sensitivity of oral C. albicans species to nystatin were evaluated, and the effect of silver nanoparticles (AgNPs) was investigated on the nystatin-resistant specimens. Methods: This in vitro study was performed on 20 C. albicans specimens isolated from patients with denture stomatitis. After confirmation of C. albicans and in vitro biofilm preparation, nystatin was applied to the biofilm. The results were recorded as minimum growth inhibitory concentration (MIC) using Clinical & Laboratory Standards Institute (CLSI) standard protocol, and the specimens with MIC of more than 1 g/mL were categorized as resistant. Then, biofilms were re-formed for nystatin-resistant specimens exposed to AgNPs, and MIC results were reported. Results: This study revealed that 8 C. albicans specimens (40%) represented a MIC of more than 1 g/mL when exposed to nystatin. The results of AgNPs exposure to this group showed significantly higher efficiency of AgNPs than nystatin (P < 0.05). AgNPs can reduce the MIC of 6 nystatin-resistant specimens (75% of all resistant specimens). Conclusions: Both nystatin and AgNPs are effective against Candida biofilms formed on denture surfaces. However, AgNPs seem more effective in the case of resistant species. [ABSTRACT FROM AUTHOR]

The prevalence of Streptococcus agalactiae infections in adult populations is increasing. The current study aimed to characterize the genetic features of S. agalactiae strains responsible for different infections. A cross-sectional study was performed on 65 S. agalactiae strains (30 invasive and 35 noninvasive) isolated from non-pregnant women. All S. agalactiae isolates were confirmed by atr and dltS PCR assays. Antibiotic susceptibility patterns were determined using the disk diffusion method. Biofilm production was investigated by microtiter plate assay. PCR was done to detect resistance determinants. Isolates were characterized using the multilocus sequence typing (MLST) method. cMLSB, iMLSB, and M phenotypes accounted for 47.7%, 30.8%, and 6.2%, respectively. MDR was detected in 15.4% of noninvasive and 44.6% of invasive isolates. MtP assay indicated that 80% of isolates were biofilm producers. Biofilm formation was common among noninvasive compared with invasive strains (94.3% versus 66.7%). tet (M) (46.2%) and erm (B) (69.2%) were the most prevalent tetracycline and macrolide-resistance genes. The most prevalent serotype was type III (50.8%), followed by Ia (18.4%), II (15.4%), V (12.3%), and IV (3.1%). The frequency of serotype III among biofilm producer strains (81.8%) was found to be significantly higher than that of non-producer isolates (18.2%) (P < 0.05). S. agalactiae was resolved within four clonal complexes, including CC19 (46.2%; in both invasive and noninvasive), followed by CC23 (30.8%; only noninvasive isolates), CC1 (15.4%; only noninvasive isolates) and CC17 (7.6%; only invasive isolates). The main sequence types (STs) found were ST19 (27.7%), ST17 (7.7%), ST27 (6.2%), and ST28 (4.6%) linked with invasive infections and ST23 (18.4%), ST933 (12.3%), ST644 (9.2%), ST19 (7.7%), ST1 (6.2%) found in noninvasive infections. The high prevalence of CC19 and CC23 clones among S. agalactiae strains reflects the emergence of these lineages as successful clones in Iran. [ABSTRACT FROM AUTHOR]

Background and Objectives: Antibiotic resistance is an indicator of the passively acquired and circulating resistance genes. Salmonella Gallinarum significantly affects the poultry food industry. The present study is the first study of the S. Gallinarum biofilm in Iran, which is focused on the characterization of the S. Gallinarum serovars and their acquired antibiotic resistance genes circulating in poultry fields in central and northwestern Iran. Materials and Methods: Sixty isolates of S. Gallinarum serovar were collected from feces of live poultry. The bacteria were isolated using biochemical tests and confirmed by Multiplex PCR. Biofilm formation ability and the antibacterial resistance were evaluated using both phenotypic and genotypic methods. The data were analyzed using SPSS software. Results: According to Multiplex PCR for ratA, SteB, and rhs genes, all 60 S. Gallinarum serovars were Gallinarum biovars. In our study, the antibiotic resistance rate among isolated strains was as follows: Penicillin (100%), nitrofurantoin (80%), nalidixic acid (45%), cefoxitin (35%), neomycin sulfate (30%), chloramphenicol (20%), and ciprofloxacin (5%). All isolates were susceptible to imipenem, ertapenem, ceftriaxone, ceftazidime, and ceftazidime+clavulanic acid. All sixty isolates did not express the resistance genes IMP, VIM, NDM, DHA, blaOXA48, and qnrA. On the other hand, they expressed GES (85%), OXA48 qnrB (75%), Fox M (70%), SHV (60%), CITM (20%), KPC (15%), FOX (10%), MOXM (5%), and qnrS (5%). All S. Gallinarum isolates formed biofilm and expressed sdiA gene. Conclusion: Considering that the presence of this bacteria is equal to the death penalty to the herd, the distribution of resistance genes could be a critical alarm for pathogen monitoring programs in the region. This study showed a positive correlation between biofilm formation and 50% of tested resistance genes. Also, it was found that the most common circulating S. gallinarum biovars are multidrug-resistant. [ABSTRACT FROM AUTHOR]

Objectives. Today, Stenotrophomonas maltophilia (S. maltophilia) is a major opportunistic pathogen among hospitalized or immunocompromised patients. Antibiotic-resistant clinical isolates are increasing in several parts of the world. Various antibiotic-resistance and biofilm-forming genes are identified in this bacterium. Its capacity to form biofilms is an important virulence factor that may impact antibiotic-resistance patterns. In the current study, we evaluated the biofilm-formation capacity, antibiotic-resistance profile, and prevalence of biofilm-forming genes as well as antibiotic resistance genes among S. maltophilia isolates. Materials and Methods. In this cross-sectional study, 94 clinical S. maltophilia isolates were recovered from four tertiary-care hospitals in Iran between 2021 and 2022. The presence of the selected antibiotic-resistance genes and biofilm-forming genes was examined by polymerase chain reaction (PCR). The ability of biofilm formation was examined by microtiter plate assay. The Kirby–Bauer disc diffusion method was used to evaluate the trimethoprim-sulfamethoxazole (TMP-SMX), levofloxacin, and minocycline resistance. Results. S. maltophilia is mainly isolated from bloodstream infections. Notably, 98.93% of isolates were biofilm producers, of which 19.35%, 60.22%, and 20.43% produced strong, moderate, and weak biofilm, respectively. The frequency of biofilm genes was 100%, 97.88%, 96.80%, and 75.53% for spgM, rmlA, smf-1, and rpfF, respectively. Isolates with the genotype of smf-1+/rmlA+/spgM+/rpfF+ were mostly strong biofilm producers. Among the antibiotic-resistance genes, the Smqnr, L1, and sul1 had the highest prevalence (76.59%, 72.34%, and 64.89), respectively. Antimicrobial susceptibility evaluation showed 1.06%, 3.19%, and 6.3% resistance to minocycline, TMP-SMX, and levofloxacin. Conclusion. The results of the current study demonstrated that S. maltophilia isolates differ in biofilm-forming ability. Moreover, smf-1, rmlA, and spgM genes were presented in all strong biofilm producers. Although the overall resistance rate to the evaluated antibiotics was high, there was no statistically significant relation between antibiotic resistance and the type of biofilm. [ABSTRACT FROM AUTHOR]

Background & Aims: Staphylococcus aureus is one of the human pathogens that causes a wide range of diseases such as endocarditis, blood, bone, skin and soft tissue infections (1). One of the resistant strains of this bacterium is methicillin-resistant strains of Staphylococcus aureus (MRSA), which has been reported as a serious risk by the Centers for Disease Control and Prevention. One of the pathogenic mechanisms and antibiotic resistance of this bacterium is the formation of biofilm, which causes this bacterium to bind to different surfaces (2). Biofilm-forming strains have become resistant to many antibiotics, so that biofilm-forming strains form extracellular matrices that are immune to the immune system and antibiotics. Various genes are involved in biofilm production, one of which is the icaB gene, which plays a key role in the production of poly N-acetyl glucose amine and biofilm production. The design of new antimicrobial drugs for the treatment of this bacterium is important, so finding a suitable treatment option for the treatment of infections caused by this bacterium is one of the challenges of researchers (3). Recent advances in nanotechnology have suggested alternative solutions, such as drug delivery systems, that increase drug specificity and efficiency (4). One of these drug delivery systems is nanosystems, which are composed of bilayer nonionic surfactants. Due to the importance of nanosystems, the aim of this study was to synthesize nanoparticles containing naproxen, to investigate their physicochemical properties and their antimicrobial and antifouling effects against Staphylococcus aureus strains. Methods: Nanosomes containing naproxen were synthesized by thin layer hydration method. The confinement efficiency is indicative of the drug encapsulated in the nanosystem structure relative to the drug used. For this purpose, the nanonosomal formulation was first centrifuged at 4 ° C at 14000 g for 45 minutes. The nanosystem containing the drug precipitates and the free drug remains in the supernatant. The absorbance of the supernatant sample at 270 nm was read by a spectrophotometer and the amount of free drug was calculated from the initial value. The Physico-chemical characteristics of prepared nanoniosome encapsulated naproxen was determined using scanning electron microscopy (SEM), Dynamic light scattering (DLS). The in vitro drug release study was done using dialysis bag (6). The Staphylococcus aureus strains were recovered from 100 clinical samples and their antibiotic resistance patterns were studied using disk diffusion method. The antibacterial activity of nanoniosome loaded naproxen and free naproxen were investigated using well diffusion and micro-dilution methods (7). The icaB biofilm gene expression analysis in S. aureus isolates which are treated with nanoniosome loaded naproxen and free naproxen were examined using Real Time PCR methods (8). Draw diagrams and Statistical analysis was performed by GraphPad Prism software version 7 and SPSS version 23, and one-way analysis of variance was used for statistical analysis and p <0.05 was considered significant. Results: In this study, using different molar ratios of surfactant, cholesterol and drug, different formulations of nanosystems containing naproxen were synthesized. The optimal niosome size synthesis was measured by DLS method. The results of electron microscopy (SEM) show that the synthesized nanonosomes have a spherical structure. In this study, the dialysis bag method was used to evaluate the drug release pattern. Figure 2 shows the pattern of naproxen release from nanosystems and free naproxen over 72 hours. Out of 100 clinical specimens, 15 specimens of Staphylococcus aureus were isolated and identified using microbiological methods. The results of antibiotic resistance profile test showed that out of 15 strains, 10 strains were methicillin resistant (MRSA). The antibacterial activity of nanoniosome encapsulated naproxen and free naproxen showed that the MIC was reduced by 2 to 4 times. The results of the well diffusion method showed that nanoniosomes containing naproxen had more significant antimicrobial power than free naproxen, so that the diameter of the growth inhibition zone increased with increasing nanosystem concentration. Real-Time PCR was used to evaluate the effect of nanoniosoms containing naproxen and free naproxen on icaB biofilm gene expression in Staphylococcus aureus strains. Also, after treating Staphylococcus aureus strains with naproxen-containing nanosystem sub-inhibitory concentration, it was shown that the expression of icaB gene was significantly reduced compared to the 16S rRNA reference gene (p <0.05). Conclusion: In this study, naproxen was encapsulated as a drug compound in the nanoniosome structure and its physical and chemical properties including size, morphology, drug enclosure percentage and drug release were studied. The results of this study showed that the synthesized nanoniosome in the optimal formulation had a spherical shape, the average size was 125.3 nm with a confinement percentage of 66.84%. Drug release results also showed that naproxen in the formulated form in nanonosomes has a much slower release pattern than free naproxen, which is a suitable feature of a drug delivery system. The results of the antimicrobial test showed that naproxen-containing nanoniosome had more significant antimicrobial effects than free naproxen compared to free naproxen, reducing the MIC by 2 to 4 times. One of the antimicrobial mechanisms of nanoniosome containing naproxen is the fusion of nanoniosome with bacterial cell membranes, which can deliberately release the drug into the cytoplasm of the cell and cause bacterial cell death (10). The results of this study showed that nanoparticles containing naproxen have more significant anti-biofilm effects than free naproxen compared to free naproxen and can significantly reduce the expression of biofilm gene (11). One of the reasons for the anti-biofilm effects of naproxen-containing nanosystems is the greater penetration of naproxen-containing nanosystems into the biofilm structure, which can cause the death of bacteria, a decrease in the number of bacteria, and the conversion of biofilms into planktonic cells (12). [ABSTRACT FROM AUTHOR]

Background: Dental caries is an infectious disease caused by bacterial colonization and biofilm formation. Streptococcus mutans (S. mutans) is mainly responsible for dental caries development. Considering the side effects of synthetic antibacterial agents, attempts are ongoing to find antimicrobial agents with minimal or no side effects for preventing dental caries. Based on the reported antibacterial activity of chitosan, this in vitro study aimed to assess the antibacterial and anti-biofilm effects of chitosan nanoparticles on S. mutans clinical isolates. Methods: S. mutans isolates were isolated from supragingival plaque and carious lesions of patients by standard biochemical tests and Polymerase Chain Reaction (PCR) of the gtfB gene. The antibacterial activity and Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) of chitosan nanoparticles against S. mutans was evaluated by the agar well-plate and broth micro-dilution test, respectively. Also, the effect of chitosan nanoparticles on biofilm formation was evaluated using micro-titer plate method. Data were analyzed using ANOVA. Results: Fifteen S. mutans isolates were collected from patients. The chitosan nanoparticles synthesized had a diameter of 20–30 nm. The chitosan nanoparticles showed antibacterial activity against S. mutans isolates. MICs and MBCs ranged from 0.625-2.5 µg/ml and 1.25-5 µg/ml, respectively. All isolates evaluated in this study were biofilm-forming and 5 of these produced a strong biofilm. The chitosan nanoparticles inhibited biofilm formation at 0.75 µg/ml concentration. Conclusion: Chitosan nanoparticles had antibacterial and antibiofilm activity on S. mutans clinical isolates. This study suggests the potential of chitosan nanoparticles as antimicrobial agents against cariogenic Streptococci. [ABSTRACT FROM AUTHOR]

Background. The present study is aimed at surveying the antibiotics resistance profile, biofilm formation ability, staphylococcal cassette chromosome mec (SCCmec) types, and molecular epidemiology of Staphylococcus epidermidis and Staphylococcus haemolyticus isolated from hospitalized patients and healthcare workers in four teaching hospitals in Iran. Methods. In total, 43 Staphylococcus epidermidis and 12 Staphylococcus haemolyticus were isolated from hospitalized patients, and 19 Staphylococcus epidermidis and 7 Staphylococcus haemolyticus isolated from healthcare workers were included in the present study. The antimicrobial resistance profile of isolates was determined using the disk diffusion method. Moreover, the resistance of isolates to methicillin was identified using the cefoxitin disk diffusion test. The microtiter-plate test was used for quantifying biofilm formation. Moreover, the frequency of icaA and icaD genes was determined using PCR assay. The molecular epidemiology of methicillin-resistant isolates was determined using SCCmec typing and pulsed-field gel electrophoresis methods. Results. Among all coagulase-negative staphylococci isolates, the highest resistance rate (81.5%) was seen for cefoxitin and cotrimoxazole. All of the isolates were susceptible to linezolid. Out of the 66 mecA-positive isolates, the most common SCCmec type was the type I (n = 23 ; 34.8%) followed by type IV (n = 13 ; 19.7%). Using pulsed-field gel electrophoresis (PFGE) assay, 27 PFGE types including 14 common types and 13 singletons were obtained among 51 methicillin-resistant S. epidermidis (MRSE) isolates. Moreover, among 12 methicillin-resistant S. haemolyticus (MRSH) isolates, 8 PFGE types were detected, of which 5 PFGE types were singletons. Conclusion. The high rate of resistance to antibiotics as well as the possibility of cross-infection shows the importance of a pattern shift in the management and controlling programs of coagulase-negative staphylococci, especially in healthcare centers. Clinical trial registration. The present study is not a clinical trial study. Thus, a registration number is not required. [ABSTRACT FROM AUTHOR]

Background and Aim: The ability to form biofilms is an effective way for Acinetobacter baumannii to survive in stressful conditions. The aim of this study was to investigate the prevalence, antimicrobial susceptibility, and distribution of virulence genes involved in biofilm formation in multidrug-resistant Acinetobacter baumannii isolated from Shahrekord medical centers in Chaharmahal and Bakhtiari Province, Iran. Materials and Methods: In this study, 150 samples from Shahrekord medical centers in Chaharmahal and Bakhtiari Province were isolated and identified using biochemical tests. Then, the antimicrobial susceptibility of A. baumannii isolates was determined using these antibiotics, Ampicillin/Sulbactam, Doxycycline, Ceftazidime, Ciprofloxacin, Erythromycin, Trimethoprim/ Sulfamethoxazole, Gentamicin, Colistin, Imipenem, and Amikacin. Finally, the rate of biofilm formation and the frequency of virulence genes associated with biofilm formation (bap, ompA, csuA, csuE, epsA, bfmS, bfmR, pgaA, pgaD, and surA) were evaluated. Results: Out of 150 samples, 90 were identified as A. baumannii. The results of antimicrobial susceptibility testing showed that there was the highest resistance rate to Ciprofloxacin and Imipenem (100%), followed by Ceftazidime (90%) and Ampicillin/ Sulbactam (77.77%). The highest frequency of virulence genes associated with biofilm formation was related to bap (100%), ompA (100%), and pgaA/ pgaD (98%). Conclusion: Biofilm formation significantly reduces susceptibility to antibiotic agents. Evaluation of biofilm formation showed that all isolates could produce biofilm; hence, they are very important for public health. Therefore, it is necessary to determine antibiotic susceptibility, biofilm formation capacity and the frequency of biofilm-related virulence genes in the clinical setting. [ABSTRACT FROM AUTHOR]

Background: and Aim Acinetobacter baumannii causes various nosocomial infections and has a high antibiotic resistance. Probiotics can produce metabolites with antimicrobial properties. This study aims to evaluate the antimicrobial ability of probiotics against nosocomial pathogens by inhibiting the ompA gene expression effective in biofilm formation in Acinetobacter baumannii. Methods & Materials: The antimicrobial properties of probiotics against nosocomial pathogens were evaluated phenotypically. The polymerase chain reaction (PCR) technique was used to identify the ompA gene in Acinetobacter baumannii. After treatment with Bacillus licheniformis supernatant, the ompA gene expression was compared before and after treatment with real-time PCR technique. Ethical Considerations This study was approved by the ethics committee of Islamic Azad University, Qom branch (Code: IR.IAU.QOM.REC.1398.004). Results: Among the study probiotics, Bacillus licheniformis supernatant had the best antimicrobial properties against nosocomial isolates of Acinetobacter baumannii A52, Acinetobacter baumannii ATCC19606, Kelebsiella pneumonia ATCC70063, and Pseudomonas aeruginosa PAO1. Bacillus licheniformis supernatant also significantly reduced the biofilm formation and ompA gene expression in Acinetobacter baumannii. Conclusion: Bacillus licheniformis can produce substances with antimicrobial and antibiofilm properties. It can be used for controlling the causative agents of nosocomial infections. [ABSTRACT FROM AUTHOR]

Pathogenicity of a bacterium is affected by the social characteristics of the population and environmental factors. The ability of biofilm formation among β-lactamase-producing uropathogenic Escherichia coli (UPEC) could facilitate the exchange of antibiotic-resistance genes, which resulted in widespread dissemination of antibacterial drug resistance. We investigated the prevalence of biofilm and β-lactamase producing UPECs among patients with urinary tract infection (UTI) in two cities with different demographics and climates in Iran. A total of 265 E. coli was isolated from patients with UTIs from two referral hospitals (n = 191) and two outpatient clinics (n = 74) in Isfahan and Zahedan, Iran. Production of curli and cellulose, and, biofilm formation was investigated using Congo red agar and microtiter plate methods, respectively. Biofilm producing (BFP) isolates (n = 107) were further characterized using rep-PCR, antimicrobial susceptibility testing and extended-spectrum β-lactamase (ESBL)/AmpC phenotypic production. Isolates were also screened for the presence of carbapenemase, ESBL and AmpC genes using multiplex PCR. High diversity was found among BFP strains in both cities, with 58% strains producing ESBL and 21% producing AmpC. ESBL (98%), AmpC (50%) and carbapenemase genes (40%) were identified in BFP strains with ESBL-positive phenotype, respectively. The prevalence of BFP strains, antibiotic resistance and β-lactamase genes in Zahedan, a low socioeconomic city with a warm climate, was significantly higher than that of Isfahan. High prevalence of biofilm and β-lactamase producing UPEC strains among strains from Zahedan suggests that socioeconomic status and environmental factors might have a role in pathogenicity of the strains. [ABSTRACT FROM AUTHOR]

Ventilator-associated pneumonia (VAP) is a prevalent nosocomial illness in mechanically ventilated patients. Hence, the aim of this study was to investigate the pattern of antibiotic resistance and biofilm formation of bacterial profiles from Endotracheal Tubes of patients hospitalized in an intensive care unit in southwest Iran. According to the standard operating method, the microbiological laboratory conducts bacteria culture and susceptibility testing on endotracheal Tube samples suspected of carrying a bacterial infection. The Clinical and laboratory standards institute (CLSI) techniques are used to determine the Antimicrobial resistance (AMR) of bacterial isolates to antibiotics using the disk diffusion method. The crystal violet staining method was used to assess the biofilm-forming potential of isolates in a 96-well microtiter plate. In total, (51%) GPBs were included in this study. The isolated GPB were coagulase-negative Staphylococcus (16%), S. aureus (14%). In total, (40%) of GNB were included in this study. The isolated GNB were Klebsiella spp. (36%), A. baumannii (22%), P. aeruginosa (35%). (32%) bacterial strains were MDR and (29%) strains were XDR. The results of biofilm formation showed (72%) were biofilm producers. VAP is a common and severe nosocomial infection in mechanically ventilated patients. Controlling biofilm formation, whether on the ET or in the oropharyngeal cavity, is thus an important technique for treating VAP. Colistin and linezolid are antibiotics that are effective against practically all resistant GNB and GPB isolates. [ABSTRACT FROM AUTHOR]

The production of biofilms by S. aureus contributes significantly to treatment failures. The present study aims to establish the relationship between biofilm formation and antibiotic resistance and adhesion genes in Staphylococcus aureus strains isolated from raw cow milk in Shahrekord, Iran. A total of 90 samples of raw cow's milk were collected. Presumptive S. aureus strains were obtained using Baird-Parker plates after enrichment in tryptone soy broth, and final colonies were selected from brain heart infusion. Additional tests such as coagulase were done, and the identification was confirmed by the detection of the aroA gene. Biofilm producing strains were screened using a spectrophotometry method applied to microplates. Crystal violet staining was used to quantify the formation of biofilm. An antibiotic susceptibility test was performed using the Kirby–Bauer disc diffusion method. PCR was used to detect several biofilm and antibiotics resistance related genes. The chi-square test and Fisher's exact test were used to establish a statistically significant relationship between biofilm reaction and antibiotic resistance (p value <0.05). Results show a moderate (38.88%) recovery rate of S. aureus in milk and 65.71% of the isolates were strong biofilm producers. Antibiotic susceptibility tests show an alarming rate of resistance to beta-lactam antibiotics, especially penicillin (100%), ampicillin (91.42%), and oxacillin (71.42%). This finding correlates with antibiotic resistance gene detection, in which the gene blaZ was most found (71.42%), followed by mecA and Aac-D (42.85%). Detection of biofilm-related genes shows that all the genes targeted were found among S. aureus isolates. Statistical tests show a significant correlation between biofilm production and antibiotic resistance in S. aureus. This study revealed that there is a significant correlation between biofilm production and antibiotic resistance in S. aureus isolated from raw milk. These results highlight the need for regular surveillance of the occurrence of S. aureus strains in milk and milk products in Iran. [ABSTRACT FROM AUTHOR]

Thymus daenensis Celak (Lamiaceae family), known as denaian thyme, is an Iranian endemic plant, commonly used for its carminative, expectorant, antibacterial and antifungal properties. Previous studies report the chemical profile of the essential oil of T. daenensis aerial parts, but little is known about its non volatile constituents. Herein, phytochemical and biological investigation of the polar extract of T. daenensis aerial parts to provide further insight into traditional use of this plant has been accomplished. High-performance liquid chromatography coupled to linear ion-trap and orbitrap high-resolution mass spectrometry (LC-ESI/LTQOrbitrap/MS/MS) analysis of MeOH extract was performed to guide the isolation of specialized metabolites and successive characterization by NMR analysis. MeOH extract displayed antioxidant activity evaluated by DPPH (EC 50 = 48.99 ± 1.47 μg/mL) and TEAC assay (1.37 mg/mL). Successively, the biofilm inhibitory activity of extract and isolated compounds against mature biofilms of Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Listeria monocytogenes, and Staphylococcus aureus , and their influence on the metabolism of sessile bacterial cells were evaluated. Two previously unreported thymol derivatives have been identified. The biofilm inhibitory activity of isolated compounds highlighted a promising antimicrobial action for the tested compounds. In particular, vanillic acid, (3 S ,5 R ,6 R ,7E,9 S)-megastigm-7-ene-3,5,6,9-tetrol 3- O -β-D-glucopyranoside, thymoquinol-2- O -β-D-glucopyranoside and the never reported compound daenol resulted capable of exerting inhibitory activity vs all pathogenic strains. All compounds tested at a concentration of 10 μg/mL inhibited the metabolism of the sessile cells of E. coli at a percentage ranging between 37.7% and 77.39%, and of L. monocytogenes at a percentage ranging between 21.79% and 71.17%. [Display omitted] • A LC-MS profile of the MeOH extract of Thymus daenensis aerial parts was carried out. • Two previously undescribed thymol derivatives have been isolated and characterized by NMR analysis. • The inhibitory activity of extract and isolated compounds against mature biofilms of different bacteria has been tested. • The influence of extract and isolated compounds on the metabolism of sessile bacterial cells has also been evaluated. • Some compounds including the undescribed daenol were active in inhibiting mature biofilms of all tested strains. [ABSTRACT FROM AUTHOR]

Diarrheagenic E. coli (DEC) strains are important causes of gastrointestinal diseases worldwide, especially in developing countries. This study aimed to investigate the presence, antibiotic resistance, and potential biofilm formation in dairy products in Isfahan, Iran. A total of 200 samples, including traditional and pasteurized dairy products, were analyzed. In 200 samples, 54 E. coli isolates, including (48/110) and (6/90) positive samples of traditional and pasteurized dairy products, were detected. Furthermore, pathogenic strains were isolated from 30% of traditional dairy products and 5.55% of pasteurized dairy products. Most isolates were classified as enteropathogenic E. coli (EPEC). Moreover, antibiotic resistance was evaluated using the disk diffusion method for pathogenic E. coli. Overall, 73.68% of contaminated samples by pathogenic strains were resistant to at least one antibiotic. The highest resistance was observed against streptomycin (57.9%), followed by tetracycline (50%). Additionally, all isolates were sensitive to amikacin. For evaluating biofilm formation, the violet crystal assay was applied on a polystyrene microplate well for pathogenic isolates. In total, 68.42% of isolates were able to form biofilms. The presence of E. coli in dairy products indicates potential health risks for Iranian consumers. Serious measures are needed to control and prevent the spread of this pathogen. [ABSTRACT FROM AUTHOR]

Multimicrobial infections caused by pathobionts are called dysbiotic multimicrobial illnesses. Commercial mouthwashes, such as chlorhexidine, have negative side effects that can prevent tooth decay and infection. The present study aimed to determine the antifungal, antibacterial, and cytotoxicity characteristics of the propolis extracts from different areas (Iran). The ethanolic extract of propolis was prepared. GC/MS carried out the characterization to determine the thymol, carvacrol, and menthol extracts, and also, total phenol and flavonoid were assed for all samples. The antimicrobial and antibiofilm effects were evaluated against S. mutans, S. mitis, S. salivarius, L. acidophilus, E. coli, S. aureus, and C. albicans. The cytotoxic effect of extracts was measured on human fibroblast cells by MTT test. The MIC values in mg mL-1 were ranged as follows: S. salivarius (0.003 to 0.048), S. mutans (0.003 to 0.029), S. mitis (0.007 to 0.058), L. acidophilus (0.007 to 0.117), C. albicans (0.014 to 0.234), E. coli (0.007 to 0.058), and S. aureus (0.007 to 0.058), while MBC were, respectively, S. mutans (0.007 to 0.058), S. salivarius (0.007 to 0.117), S. mitis (0.007 to 0.117), L. acidophilus (0.014 to 0.234), C. albicans (0.029 to 0.468), E. coli (0.014 to 0.234), and S. aureus (0.007 to 0.117). Cariogenic bacteria and Candida albicans were demonstrated to be resistant to propolis extracts. Therefore, propolis extracts may make good mouthwashes. [ABSTRACT FROM AUTHOR]

The spread of mupirocin-resistant Staphylococcus aureus strains in hospitals and communities is a universal challenge. Limited data is available on the genetic features of high-level mupirocin resistant- (HLMUPR-) S. aureus isolates in Tehran. In the present research, we investigated 48 high-level mupirocin resistance S. aureus by antimicrobial activity, virulence analysis, biofilm formation, multilocus sequence typing (MLST), and staphylocoagulase (SC) typing. All the HLMUPR strains were positive for mupA gene. The frequency of multidrug resistance was 97.9%. Twenty-one (43.8%) were toxinogenic with 14 producing pvl (29.2%), 5 tst (10.4%), and two eta (4.2%). Among the HLMUPR isolates, biofilm production was detected in 45 (89.6%) isolates with complete dominance clfB, clfA genes, and a noticeably high frequency fnbA (95.8%), followed by fnbB (93.8%), eno and icaD (each 83.3%), sdrC (81.3%), ebps (79.2%), icaA (75%), sdrD (66.7%), fib (60.4%), sdrE (50%), cna (41.7%), and bap (4.2%). Coagulase typing distinguished isolates into four genotypic patterns including III (50%), II (27.1%), and type IVa (22.9%). A total of three clonal complexes (CCs) and 4 sequence types (STs) including CC/ST22 as the most prevalent (52.1%), CC8/ST239 (20.8%), CC/ST8 (16.7%), and CC/ST5 (10.4%) were identified in current work. According to our analysis, nonbiofilm producer isolates belonged to CC8/ST239 (6.3%) and CC/ST8 (4.2%). Fusidic acid-resistant isolates belonged to CC/ST45 (n = 3) and CC8/ST239 (n = 1). Observations highlighted the circulation of the CC/ST22 HLMUPR S. aureus strains with strong biofilm-production ability in our hospitals, indicating the possibility of transmission of this type between community and hospital. [ABSTRACT FROM AUTHOR]

Introduction: Nowadays, due to the increasing resistance of Acinetobacter baumannii to antibiotics, it has been a problematic agent in clinical settings. As a significant nosocomial pathogen, A. baumannii isolates use resistant genes and biofilm development as means of survival. The aim of this study was to determine antimicrobial resistance patterns, aminoglycoside and carbapenems resistance genes, and biofilm formation among clinical isolates of A. baumannii. Materials and Methods: A cross-sectional study was conducted from April 2018 to March 2019. In all, 133 nonduplicated isolates of A. baumannii were isolated from Yasuj and Bandar Abbas, located in Iran. Antimicrobial susceptibility was determined using disk diffusion. Carbapenem- and aminoglycoside-resistant genes were investigated by the polymerase chain reaction method. The ability to generate biofilms was evaluated using the microtiter plate method. Results: In this study, all isolates contained blaOXA-51-like and were confirmed as A. baumannii. High-level resistance was observed for carbapenems and aminoglycosides. The prevalence of oxacillinase genes blaOXA-23-like and blaOXA-24-like was 89 (66.9%) and 46 (34.6%), respectively. Moreover, the co-occurrence of bla-OXA-23-like and bla-OXA-24-like was 10 (7.5%). A total of 73 (54.9%) and 69 (51.9%) were positive for aac (3)-I and aph (3')-I, respectively. Furthermore, the coexistence of two genes was obtained in 55 (41.4%) isolates. The result demonstrates that 129 (97%) of isolated were strong, three (2.3%) moderate, and one (0.8%) weak biofilm producer. Conclusion: Results revealed that bla-OXA-23-like and aac (3)-I genes were the most prevalent resistance genes. Since a vast majority of isolates were drug-resistant with strong biofilms, infection control programs and policies should be frequently upgraded to control the transmission of drugresistant A. baumannii isolates in the future. [ABSTRACT FROM AUTHOR]

Aims: This study aimed to investigate class 1 integrons and biofilm formation in multi-drug resistance (MDR) Uropathogenic Escherichia coli (UPEC) isolated from patients with urinary tract infection (UTI). Materials and Methods: Three hundred and eighty positive cultures were collected from patients with UTI referred to Shohadaye Qom hospital from 2018 to 2019. Suitable tests were done to diagnose UPEC, and confirmed by usp gene polymerase chain reaction (PCR). Antibiotic susceptibility testing was performed using Kirby Bauer disk diffusion. Analysis of biofilm production was conducted using microtiter plate assay. Next, the presence of Class 1 integrons and dfr-17 gene was surveyed by PCR. Data analyzed using Chi-squared and Fisher's exact tests in SPSS software, P < 0.05 was considered statistically significant. Findings: In total, 166 isolates of UPEC were retrieved. Among them, 120 isolates were MDR. The highest resistance of MDRs was observed against ampicillin. Among MDRs, 71, 18, 15, and 16 isolates were negative, weak, moderate, and strong biofilm producers, respectively. Meanwhile, 47.5% of the isolates were positive for int-1 gene and 25.8% of the isolates were positive for dfr-17-gene cassette. Out of 57 int-1 positive MDRs, 15 isolates (26.3%) showed strong biofilm which indicated a significant correlation (P < 0.001). Furthermore, among 31 MDRs with the positive dfr-17, 8 isolates (25.8%) had strong biofilm which statistically was significant (P < 0.001). Conclusion: The present study reported a significant correlation between cassettes genes, Class 1 integrons, and biofilm formation with antibiotic resistance pattern. Hence, continuous screening for antibiotics resistance is vital for infection control and prevention. [ABSTRACT FROM AUTHOR]

Background. Dental caries is known as a multimicrobial disease. Caries are very prevalent in numerous countries, and the incidence is higher in underdeveloped countries than in developed countries. Dental caries is a major public health problem, and it is the most prevalent health problem across the world, affecting 2.4 billion people. Natural mouthwashes can be beneficial in the prevention of dental caries and oral infections without the side effects of synthetic mouthwashes. Aim. The aim of the present study was to investigate the antibacterial, antifungal, and cytotoxicity properties of sea salt from different areas of Iran. Methods and Materials. Sea salts from different areas (Urmia, Qom, and Jarquyeh) of Iran were collected. In order to define the elemental and mineralogical features of different salt samples, X-ray powder diffraction (XRD) was employed. Different concentrations (0.19–50 mg/mL) of sea salt were used in the antimicrobial and antibiofilm tests. The antimicrobial (MIC, MBC, MFC, and DAD tests) and antibiofilm (formation and degradation tests) effects were evaluated against L. acidophilus, S. aureus, E. coli, S. mitis, S. mutans, S. salivarius, and C. albicans. The cytotoxic effect of salts was evaluated on human gingival fibroblasts by the MTT test. Results. The range of MIC values in mg ml−1 was as follows: S. salivarius (50), S. mutans (50), S. mitis (50), L. acidophilus (12.5 to >50), C. albicans (50), E. coli (12.5 to 25), and S. aureus (12.5 to 25), while MBC values were, S. mutans (>50), S. salivarius (>50), S. mitis (>50), L. acidophilus (50 to >50), C. albicans (>50), E. coli (50), and S. aureus (50). MTT results showed that more than 50% of cell viability depends on decreasing the salt concentration (<1.56 mg/ml). Conclusion. Sea salts had significant antimicrobial effects on cariogenic bacteria and C. albicans. Therefore, sea salts can be a suitable candidate for mouthwash. [ABSTRACT FROM AUTHOR]

Introduction. Patients with acute respiratory distress syndrome caused by coronavirus disease 2019 (COVID-19) are at risk for superadded infections, especially infections caused by multidrug resistant (MDR) pathogens. Before the COVID-19 pandemic, the prevalence of MDR infections, including infections caused by MDR Klebsiella pneumoniae (K. pneumoniae), was very high in Iran. This study is aimed at assessing the genetic diversity, antimicrobial resistance pattern, and biofilm formation in K. pneumoniae isolates obtained from patients with COVID-19 and ventilator-associated pneumonia (VAP) hospitalized in an intensive care unit (ICU) in Iran. Methods. In this cross-sectional study, seventy K. pneumoniae isolates were obtained from seventy patients with COVID-19 hospitalized in the ICU of Shahid Beheshti hospital, Kashan, Iran, from May to September, 2020. K. pneumoniae was detected through the ureD gene. Antimicrobial susceptibility testing was done using the Kirby-Bauer disc diffusion method, and biofilm was detected using the microtiter plate assay method. Genetic diversity was also analyzed through polymerase chain reaction based on enterobacterial repetitive intergenic consensus (ERIC-PCR). The BioNumerics software (v. 8.0, Applied Maths, Belgium) was used for analyzing the data and drawing dendrogram and minimum spanning tree. Findings. K. pneumoniae isolates had varying levels of resistance to antibiotics meropenem (80.4%), cefepime-aztreonam-piperacillin/tazobactam (70%), tobramycin (61.4%), ciprofloxacin (57.7%), gentamicin (55.7%), and imipenem (50%). Around 77.14% of isolates were MDR, and 42.8% of them formed biofilm. Genetic diversity analysis revealed 28 genotypes (E1–E28) and 74.28% of isolates were grouped into ten clusters (i.e., clusters A–J). Clusters were further categorized into three major clusters, i.e., clusters E, H, and J. Antimicrobial resistance to meropenem, tobramycin, gentamicin, and ciprofloxacin in cluster J was significantly higher than cluster H, denoting significant relationship between ERIC clusters and antimicrobial resistance. However, there was no significant difference among major clusters E, H, and J respecting biofilm formation. Conclusion. K. pneumoniae isolates obtained from patients with COVID-19 have high antimicrobial resistance, and 44.2% of them have genetic similarity and can be clustered in three major clusters. There is a significant difference among clusters respecting antimicrobial resistance. [ABSTRACT FROM AUTHOR]

Background: Hospital-acquired pneumonia (HAP) is the second most common nosocomial infection in intensive care units (ICUs). The present study aims to determine the prevalence of pathogenic bacteria, their biofilm formation, and molecular typing from patients with HAP in southwestern Iran.Methods: Fifty-eight patients with HAP participated in this cross-sectional study. Sputum and endotracheal aspirate were collected from each patient for isolation and detection of bacteria. Biofilm formation was evaluated using Congo red agar or Microtiter plate assay. The antimicrobial susceptibility patterns of the isolates were investigated. The multiplex polymerase chain reaction (M-PCR) technique was used to determine the Staphylococcal Cassette Chromosome mec (SCCmec) types of methicillin-resistant Staphylococcus aureus (MRSA) strains. All S. aureus isolates were typed using the agr typing method. A repetitive element sequence-based PCR (rep-PCR) typing method was used for typing of Gram-negative bacteria. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) software version 15 and the chi-square test.Results: Bacteria were isolated in 52 (89.7%) of patients. Acinetobacter baumannii (A. baumannii) was the most prevalent organism (37%), followed by S. aureus, Pseudomonas aeruginosa (P. aeruginosa), and Escherichia coli (E. coli). Using the PCR method, 56 bacteria were detected. A. baumannii was the most prevalent (35.7%) organism. A. baumannii and P. aeruginosa were biofilm-producing. All Gram-negative isolates were colistin-sensitive, and most of the A. baumannii isolates were multidrug-resistant (MDR). MRSA was identified in 12 (80%) S. aureus isolates, and 91.6% of MRSA were SCCmec type III. The agr type III was the most predominant. The rep-PCR analysis showed seven different patterns in 20 A. baumannii, six patterns in 13 P. aeruginosa, and four patterns in 6 E. coli.Conclusion: A. baumannii was more prevalent than S. aureus in ventilator-associated pneumonia (VAP), while S. aureus is a major pathogen in non-ventilator hospital-acquired pneumonia (NV-HAP), possibly due to the tendency of the former to aquatic environments. Based on the rep-PCR typing method, it was concluded that bacteria were transmitted from patients or healthcare workers among different wards. Colistin can be used as a treatment in Gram-negative MDR isolates. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus is an important food pathogen that has the ability to form biofilms. This pathogen has been implicated in foodborne outbreaks associated with the consumption of meat and meat products. Since the role of meat products as reservoirs of antimicrobial resistant S. aureus and biofilm formers has not been studied, this research was conducted to assess the incidence, antimicrobial resistance, and presence of biofilm-forming genes in S. aureus bacteria from meat and meat products. For this purpose, 440 samples of meat and meat products were randomly collected from supermarkets of Shahrekord city, Iran. S. aureus isolates were highlighted and identified through biochemical tests. All S. aureus isolates were profiled for susceptibility to 14 antibiotics and the corresponding resistance genes were searched. The quantification of biofilm formation followed by a screening of biofilm formation encoding genes was done. Of the 440 samples collected, 61 were found to contain S. aureus. The incidence of S. aureus among the beef meat (16/61) was the highest followed by its incidence in sausage (10/61) and lunch meat (9/61). At least one isolate of S. aureus carries one of the following resistance gene blaZ, mecA, tet K, linA, tetM, erm A, ermB, and aac A-D. High distribution of icaA, icaB, icaC, icaD, clfB, and clfA, biofilm formation genes and Enterotoxin encoding genes sea, seb, sec, and sed. The ability of biofilm production and the presence of virulence determinants in the genome of S. aureus can contribute to their pathogenicity. This research demonstrated the roles of meat and meat products as reservoirs of biofilm-forming and antimicrobial-resistant strains of S. aureus. This poses a food safety and public health problem. However, further work needs to be done to better understand the implication of icaABCD biofilm forming genes present in S. aureus from meat and meat products in their resistance. [ABSTRACT FROM AUTHOR]

Aim. Klebsiella pneumoniae (K. pneumoniae) is an encapsulated Gram-negative bacterium that can lead to 14–20% of nosocomial infections. The ability of biofilm formation in this bacterium decreases the host immune response and antibiotic efficacy. This may impose a huge impact on patients and healthcare settings. This study aimed to evaluate the antibiotic resistance pattern and biofilm formation in K. pneumoniae strains isolated from two major Hamadan hospitals, west of Iran. Methods. A total of 83 K. pneumoniae strains were isolated from clinical samples of patients in different wards of Hamadan hospitals from September 2018 to March 2019. Determination of antimicrobial susceptibility was performed using the disk diffusion method. Biofilm formation was evaluated by the crystal violet method. Data were analyzed by the SPSS software and chi-square test. Results. The results showed that clinical samples included 18 urinary tract samples (22%), 6 wound samples (7%), 6 blood samples (7%), 17 tracheal tube aspiration samples (20%), 32 throat cultures (38%), 2 sputum samples (2.5%), and 2 abscess drain cultures (2.5%). High-level resistance to cefotaxime was detected in 92%, and all of isolates were susceptible to colistin. Biofilm formation was seen in 62 (75%) isolates. Strong biofilm formation was observed in 17 (20%) strains. A significant correlation was seen between biofilm formation and antibiotic resistance (P value <0.05). Conclusion. Our findings emphasize the need for proper diagnosis, control, and treatment of infections caused by K. pneumoniae especially in respiratory tract infections due to the strong biofilm formation and high antibiotic resistance in these strains. [ABSTRACT FROM AUTHOR]

Background: Acinetobacter baumannii is an opportunistic pathogen that can cause several kinds of nosocomial infections. Increasing antibiotic resistance as well as identifying genetic diversity and factors associated with pathogenicity and prevalence of this bacterium is important. The aim of this study was the investigation of molecular typing, biofilm production, and detection of carbapenemase genes in multidrug-resistant Acinetobacter baumannii isolated from different infection sites using ERIC-PCR in Iran. Methods: Forty isolates of A. baumannii were obtained from various wards of the central hospital, in the west of Iran. Phenotypic identification and genetic diversity, biofilm production assay, and detection of Carbapenemase genes carried out. Results: Tracheal samples 26 (61.9 %) are the most frequent isolates, and 95 % of isolates were identified as MDR. 32.5 % of all A. baumannii strains were capable to form a strong biofilm. It was founded that antimicrobial resistance patterns had a significant relationship with strong biofilm formation (P = 0.001). Most frequencies of the studied genes were in the order of VIM (81 %), SPM (45.2 %), and IMP (35.7 %) genes. The VIM gene was the most frequent in all isolates which were significant (P = 0.006). 14 different ERIC-types were observed including 7 common types and 7 unique or single types. F type is the largest common type consisting of nine isolates and B, D, and E types contain two isolates separately. Conclusions: ERIC-PCR technique was used to genetically classify A. baumannii isolates as one of the most common microorganisms in nosocomial infections. [ABSTRACT FROM AUTHOR]

Background. Biofilm formation and efflux pumps (EPs) correlation play a critical role in the pathogenicity and antibiotic resistance of Pseudomonas aeruginosa. In this study, biofilm formation and EP's collaborative role in clinical isolates of P. aeruginosa infection were investigated. Methods. Eighty-six (86) P. aeruginosa isolates were collected from different clinical specimens and were confirmed using different biochemical tests. The formation of biofilm was investigated by using a crystal violet assay. Also, EP genes were identified by the PCR method. Results. Based on the results, gentamicin-resistant (n = 50, 66.29%) and ciprofloxacin-resistant (n = 61, 69.66%) strains were the most frequent and colistin (n = 1, 1.12%) and ceftazidime (n = 12, 7.86%) resistant strains were the least prevalent. Furthermore, 22 isolates (31.42%) were MDR, and 11 isolates (12.35%) were XDR strains. Also, 19 isolates (22.47%) were classified as strong biofilm, 29 isolates (21.34%) as moderate biofilm, and 3 (11.23%) isolates as weak biofilm producers. The distribution of the EP genes was as follows: mexA (n = 44, 34.83%), mexB (n = 33, 32.58%), oprM (n = 59, 29.21%), oprD (n = 61, 30.33%), tetA (n = 22, 25.58%), tetR (n = 19, 22.09%), and emrE (n = 21, 24.41%). However, there was a strong significant association between biofilm formation and EPs in P. aeruginosa. Conclusions. In this study, we suggested that the presence of a multidrug resistance efflux pump, MexEF-OprN, significantly reduced P. aeruginosa pathogenicity. In contrast, the presence of the MexAB-OprM and MexCD-OprJ pumps did not affect virulence. [ABSTRACT FROM AUTHOR]

Background: Oral candidiasis is a frequent form of candidiasis, caused by Candida species, in particular, Candida albicans (C. albicans). The transition of C. albicans from yeast to hyphae allows its attachment to epithelial cells, followed by biofilm formation, invasion, and tissue damage. Hence, we investigated the effect of Streptococcus salivarius subspecies thermophilus (S thermophilus) on the growth as well as biofilm and germ-tube formation of C. albicans both in vitro and in vivo in a murine model. Methods: This experimental study was performed in the Department of Medical Mycology and Parasitology, School of Medicine, in collaboration with the Central Research Laboratory and the Comparative Biomedical Center, Shiraz University of Medical Sciences, Shiraz, Iran (2017 to 2018). The inhibitory activity of S. thermophilus against Candida species growth was evaluated using the broth microdilution method, and the inhibition of C. albicans biofilm formation was measured using the XTT assay. The inhibition of C. albicans germ-tube formation by S. thermophilus was evaluated using the plate assay and fluorescence microscopy. The experimental activity of the probiotic bacterium was assessed by culture and histopathological methods in six groups of five mice, comprising those treated with four concentrations of probiotics, fluconazole, and distilled water. The one-way analysis of variance, followed by a Tukey post hoc test, was used and a P value of less than 0.05 was considered significant. Results: S. thermophilus inhibited Candida species growth at concentrations of 16 to 512 ^g/mL. This probiotic inhibited the formation of C. albicans biofilms and germ tubes in a dose-dependent manner. S. thermophilus significantly reduced the colony-forming units in the mice receiving 30 mg/mL of this probiotic treatment compared with the control group (P=0.024). The histopathological analysis showed that Candida colonization was diminished in the mice following the administration of the probiotic. Conclusion: Given the inhibitory activity of S. thermophilus against the growth, transition, and biofilm formation of C. albicans, it could be used in the management of oral candidiasis. [ABSTRACT FROM AUTHOR]

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Background and Aim: Uropathogenic Escherichia coli (UPEC) are the most common cause of urinary tract infections. The binding of these bacteria to epithelial cells and the formation of biofilms cause these bacteria to be further colonized and difficult to remove in the urinary tract. This study aimed to determine the antibiotic resistance and to evaluate the biofilm formation power in Escherichia coli isolated from pregnant women in the city of Karaj, Iran. Materials and Methods: This descriptive-analytical study was performed on 64 isolates of UPEC. Identification of these bacteria was determined using biochemical tests and antibiotic resistance by Kirby – Bauer method and according to the recommendation of the Clinical and Laboratory Standards Institute (CLSI 2017) guideline. The ability to form biofilms, using the microtiter plate method and the presence of papC and sfa genes was examined by Duplex PCR. Results: Based on the results; the highest levels of resistance were related to cotrimoxazole (40.6%), and ampicillin (31.3%). The examination of biofilm formation by the phenotypic method also showed that of the isolates, 48.4% (strongly), 15.6% (moderately) and 21.8% (weakly) have biofilm formation power. Based on the obtained Duplex PCR results, 15 isolates had papC gene, 10 isolates had sfa gene and 9 isolates had both genes simultaneously. 100% of the isolates with both papC and sfa genes were able to produce biofilms. Conclusion: The results showed that most UPEC causing urinary tract infections can form biofilms. Also, the abundance of papC and sfa genes encoding pili in these strains can act as one of the binding factors of this bacterium. [ABSTRACT FROM AUTHOR]

Background: Klebsiella pneumoniae is a common cause of nosocomial infections. Antibiotic resistance and ability to form biofilm, as two key virulence factors of K. pneumoniae, are involved in the persistence of infections. The purpose of this study was to investigate the correlation between antimicrobial resistance and biofilm formation capability among K. pneumoniae strains isolated from hospitalized patients in Iran. Methods: Over a 10-month period, a total of 100 non-duplicate K. pneumoniae strains were collected. Antibiotic susceptibility was determined by Kirby–Bauer disk diffusion method according to CLSI. Biofilm production was assessed by tissue culture plate method. Finally, polymerase chain reaction was conducted to detect four families of carbapenemase: blaIMP, blaVIM, blaNDM, blaOXA−48; biofilm formation associated genes: treC, wza, luxS; and K. pneumoniae confirming gene: rpoB. Results: Most of the isolates were resistant to trimethoprim-sulfamethoxazole (52 %), cefotaxime (51 %), cefepime (43 %), and ceftriaxone (43 %). Among all the 100 isolates, 67 were multidrug-resistant (MDR), and 11 were extensively drug-resistant (XDR). The prevalence of the blaVIM, blaIMP, blaNDM, and blaOXA−48 genes were 7 , 11 , 5 , and 28 %, respectively. The results of biofilm formation in the tissue culture plate assay indicated that 75 (75 %) strains could produce biofilm and only 25 (25 %) isolates were not able to form biofilm. Among these isolates, 25 % formed fully established biofilms, 19 % were categorized as moderately biofilm-producing, 31 % formed weak biofilms, and 25 % were non-biofilm-producers. The antimicrobial resistance among biofilm former strains was found to be significantly higher than that of non-biofilm former strains (p < 0.05). Molecular distribution of biofilm formation genes revealed that 98 , 96 , and 34 % of the isolates carried luxS, treC, and wza genes, respectively. Conclusions: The rise of antibiotic resistance among biofilm-producer strains demonstrates a serious concern about limited treatment options in the hospital settings. All of the data suggest that fundamental actions and introduction of novel strategies for controlling of K. pneumoniae biofilm-related infections is essential. [ABSTRACT FROM AUTHOR]

Legionella pneumophila can be transmitted to people, especially immunocompromised patients, via hospital water pipe systems and cause severe pneumonia. The aim of our study was to investigate the presence of major virulence factor genes, ability of biofilms formation, and correlation between presence of Legionella isolates and temperature, pH, and residual chlorine of water. Hundred water samples were collected from nine hospitals in Tehran, Iran. Temperature, pH, and residual chlorine were determined during sampling. Different virulence genes and the ability to form biofilms were subsequently analyzed among the L. pneumophila isolates. Results showed that 12 (12%) samples were positive in culture method and all of the isolates were positive as L. pneumophila species (mip). A correlation was found between Legionella culture positivity and temperature and pH of water, but there was no significant correlation between residual chlorine of water samples and the presence of Legionella. The isolation of Legionella rate in summer and spring was higher than winter and autumn. Twelve (100%) isolates were positive for mip genes, 9 (75%) for dot genes, 8 (66.66%) for hsp, 6 (50%) for lvh, and 4 (33.33%) for rtx. All of the isolates displayed strong ability for biofilm production every three days. Two of these isolates (16.6%) displayed weak ability to form biofilm on the first day of incubation. This study revealed that water sources in hospitals were colonized by virulent Legionella and should be continuously monitored to avoid elevated concentrations of Legionella with visible biofilm formation., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Natural products are one of the best candidates for controlling drug-resistant pathogens, the advantages of which include low production costs and low side effects. In this study, as potential antimicrobials, the anti-bacterial and antibiofilm activities of several Iranian native medicinal plants were screened., Methods: The antibacterial/antifungal and anti-biofilm activities of 18 medicinal plants including Reseda lutea L., Nepeta sintenisii Bunge., Stachys turcomanica Trautv., Stachys lavandulifolia Vahl, Diarthron antoninae (Pobed.) Kit Tan., Ziziphora clinopodioides Lam., Euphorbia kopetdaghi Prokh, Euphorbia serpens Kunth., Hymenocrater calycinus Benth., Scutellaria pinnatifida A.Ham., Viola tricolor L., Hypericum helianthemoides (Spach) Boiss., Hypericum scabrum L., Convolvulus lineatus L., Scabiosa rotata M.Bieb Greuter & Burdet, Delphinium semibarbatum Bien. Ex Boiss., Glycyrrhiza triphylla Fisch. & C.A.Mey., and Ziziphus jujuba Mill., against two Gram-positive bacteria, Staphylococcus aureus, Bacillus cereus, as well as two Gram-negative bacteria, Pseudomonas aeruginosa, Escherichia coli; and Candida albicans as a fungal strain, were evaluated. The minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) values of the extracts against tested microorganisms were reported and we investigated their effect on the biofilm inhibition of Pseudomonas aeruginosa PAO1, Staphylococcus epidermis, Staphylococcus aureus and Streptococcus mutans. In addition, the effect of the extracts on the eradication of the biofilms of these bacteria was evaluated., Results: In this study, H. scabrum was found to exhibit potentially significant activity against Gram-positive bacteria with the MIC range of 6.25-25 µg/mL. This extract also showed a significant effect on inhibiting the biofilm of S. aureus, S. mutans, and S. epidermidis and eradicating the biofilm of S. epidermidis DSMZ 3270. In addition, Hymenocrater calycinus root extract had moderate antibacterial activity against B. cereus with the MIC and MBC 62.5 µg/mL, respectively., Conclusions: The results of this study showed that the root extracts of two plants, Hypericum scabrum and Hymenocrater calycinus, had antimicrobial and anti-biofilm effects. Based on the observed anti-biofilm effects, these two plants may be considered in future studies to find responsible antimicrobial compounds., (© 2024. The Author(s).)

Introduction. Enterococcus faecalis (E. faecalis) is the most important species in dentistry and plays a significant role in the etiology of persistent apical lesions after root canal treatment. Up to date, the intracanal application of 2% chlorhexidine for 7 days is the best way to eliminate E. faecalis. However, due to the ability of this bacterium to persist and survive in harsh environments, many studies have been directed towards finding an alternative strategy for prevention or eradication of it. This study was conducted to investigate the effect of bismuth nanoparticles on E. faecalis, as an etiologic factor in recurrent root canal infections. Methods. Forty patients, referred to Endodontic Ward of Shiraz University of Medical Science for endodontic pretreatment, provided root canal samples. First, all samples were transferred in Enterococcosel broth and incubated. Then, samples which showed growth were plated on blood agar plates and incubated for further PCR procedure. Nanoparticle powder was dissolved in high-purity water, and the final concentration of bismuth nanoparticles (BiNPs) was measured by the spectrophotometer. Minimum inhibitory concentration (MIC) of BiNPs against E. faecalis was determined by microbroth dilution method according to methods for antimicrobial susceptibility tests. Also, bactericidal assays were conducted in Mueller-Hinton broth medium and reported as the concentration of BiNPs that reduced the viable bacterial count by 99.9%. Results. Of all samples, 77.5% revealed the presence of E. faecalis by PCR. Also, E. faecalis growth inhibition was observed at concentrations ranging from 0.625 μg/ml to 20 μg/ml (geometric mean: 2.337 μg/ml), and the MBC values were between 1.25 μg/ml and 40 μg/ml (geometric mean: 4.781 μg/ml), which in comparison with chlorhexidine, these values were about one-eighth of chlorhexidine. Conclusion. The experimental data suggest that bismuth nanoparticles could be an interesting alternative to combat E. faecalis, which, in view of the advantages mentioned for bismuth nanoparticle like inhibiting Streptococcus mutans biofilm formation and higher antibacterial activity compared to chlorhexidine, can be suggested to be used in different fields of dentistry. [ABSTRACT FROM AUTHOR]

Background: Cystic fibrosis (CF) is an autosomal recessive disease characterized by respiratory, gastrointestinal, and reproductive tract problems. Patients with CF often suffer from chronic pulmonary infections due to the Pseudomonas aeruginosa, which frequently ends in pulmonary exacerbations. With their anti-inflammatory, anti-virulence, and anti-biofilm properties, macrolides such as azithromycin (AZM) play a beneficial role in the treatment of CF. Objectives: We evaluated the ability of biofilm formation among P. aeruginosa isolates from CF patients and compared the antibacterial and anti-biofilm effect of the AZM on them. Methods: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AZM against 21 P. aeruginosa isolates from Iranian CF patients were determined. Then, we investigated the ability of biofilm formation by P. aeruginosa and also anti-biofilm effect of AZM on biofilm producing P. aeruginosa isolates. Results: The results showed a high level of AZM MIC (≤ 512 µg/mL) and MBC (≤ 2048 µg/mL) against P. aeruginosa isolates. Most isolates (70%) were biofilm producers, 20% being strong producers. The AZM anti-biofilm effect showed that sub-MIC concentration (≤64 µg/mL) could inhibit biofilm production. Conclusions: P. aeruginosa isolated from CF patients showed a high level of MIC and MBC for AZM that indicated aweakanti-bacterial effect of AZM. However, AZM inhibited biofilm formation in low doses; this might lead to dangerous chronic pulmonary infection by P. aeruginosa. [ABSTRACT FROM AUTHOR]

Objectives: dental units are necessary tools for modern dentistry. microbial contamination of dental units is thought to be the result of biofilm formation in various parts of the unit. We aimed to identify the total microbial count in the suction hose of dental units, and detect the presence of Pseudomonas aeruginosa. Methods: random sampling of suction hoses of dental units in Birjand, Iran, was performed in dental clinics on the first (n = 115) and last (n = 115) working days of the week. Total viable counts of bacteria and detection of P. aeruginosa were performed on plate count agar and cetrimide agar, respectively. Plates were incubated at 37 °c for 48 hours. Results: none of the samples were free from bacterial contamination. P. aeruginosa was detected in 22.6% and 18.3% of samples taken on the first and last working days, respectively. Conclusions: Suction hoses were heavily contaminated with bacteria, especially opportunistic pathogens, and current disinfection does not adequately control the contamination. [ABSTRACT FROM AUTHOR]

Background: Staphylococcus aureus is the most important etiological agent of biofilm associatedinfections. It is one of the Gram-positive pathogens causing a wide range of nosocomial infections. Genes involved in biofilm formation is a defensive mechanism of this pathogen to combat the host immune response and remain stable in hostile environment. The aim of this study was to investigate prevalence of biofilm associated genes (BAGs). Methods: Eighty samples of Staphylococcus aureus isolates from human infections were collected. Thirteen BAGs including rbf, sigB, sasG, icaA, sarA, icaR, icaD, clfA, clfB, fib, fnbpB, bap and fnbpA were amplified by PCR assay. Results: The prevalence of genes were as follows: sigB (93.7%) and sarA (90%) were the most prevalent BAGs followed by rbf (83.7%), fib (80%), sasG (78.7%), icaR (78.7%), clfB (78.7%), clfA (78.7%), fnbpA (73.7%), icaD (66.2%), icaA (50%), fnbpB (22.5%). However, bap was not detected in any isolate. Conclusion: This study showed that the sensitivity and specificity of PCR is high in the identification of biofilm associated genes in S. aureus. However, researchers need new molecular methods to improve understanding of the exact role of the genes involved in biofilm formation. [ABSTRACT FROM AUTHOR]

Background: Polyetheretherketone (PEEK) has favorable properties that make it able to be used as a denture base material, but it is also susceptible to the adhesion of microorganisms. In this study, we applied Octafluoropentyl (meth) acrylate (OFPA) coating on the PEEK polymer surface by using plasma spray and investigated the functional groups present on the surface, changes in the surface energy and Candida albicans adhesion. Materials and Methods: In this experimental study, the samples were placed in a control group without surface preparation and three experimental groups that were subjected to plasma spray for 10, 30, and 60 s and then impregnated with degassed Octa fluoropentyl (meth) acrylate (Sigma-Aldrich, USA) monomer. Fourier transform infrared spectroscopy (FTIR) was used to identify the functional groups and new chemical bonds between PEEK and OFPA, and Sessile Drop Method was used to evaluate the surface's wettability. The surface morphology was checked using a LEXT OLS4000 (Olympus®-Japan) microscope, and the inhibition of C. albicans adhesion was also checked by counting the colonies in terms of colony forming unit/mL (CFU/mL). Kurskal–Wallis analysis was conducted to assess Candida adhesion, while wettability was evaluated using analysis of variance and post hoc analyses. The level of statistical significance was set at P < 0.05. Results: FTIR analysis confirmed that a chemical between OFPA and PEEK was established. The samples showed a significant increase in the contact angle after 30 s of plasma application (CA = 88.2 ± 7.3). The contact angle decreased again by increasing the surface modification to 60 s (CA = 64.33 ± 5.5). Examining the surface morphology of the samples shows an increase in surface roughness with increasing plasma time up to 60 s. The number of adherent colonies was the lowest in 30 s group, but it was not statistically significant (P = 0.658). Conclusion: No statistically significant difference in C. albicans CFU/mL count was found between groups. The contact angle of the 30 s group was significantly higher than the control group. [ABSTRACT FROM AUTHOR]

Here, we described the efficacy of colistin sub-minimum inhibitory concentrations (sub-MICs) on biofilm-forming activity, host epithelial cell adherence, and invasion capacity of Acinetobacter baumannii strains collected from children admitted to the Children's Medical Center Hospital. Biofilm formation potency of A. baumannii clinical isolates was measured using a 96-well microtiter plate assay. Distribution of biofilm-related genes, including bap , abaI , ompA , csuE , and bla PER-1 , was detected by PCR. The mRNA expression level of ompA and csuE was measured by qPCR in the presence of ¼ and ½ MICs of colistin. A. baumannii adhesion and invasion to eukaryotic host cells were phenotypically assayed at sub-MICs of colistin. Eighty percent (56/70) and 35.7% (25/70) of A. baumannii isolates were multidrug-resistant (MDR) and extensively drug-resistant (XDR) phenotypes, respectively. The strong, moderate, and weak biofilm producers of A. baumannii were 37.1% (26/70), 32.8%, (23/70), and 22.8% (16/70), respectively. The frequencies of biofilm-associated genes were 100% for abaI , ompA , and csuE , followed by 22.8% (16/70) and 24.3% (17/70) for bap and bla PER-1 , respectively. The downregulation of csuE and ompA expression levels was observed in the sub-MIC of colistin. In vitro cell culture study showed a decreased capability of A. baumannii to adhere to the human epithelial cells at sub-inhibitory doses of colistin; however, none of the isolates could invade HEp-2 cells. Our study showed that the genes encoding biofilm-associated proteins undergo downregulation in expression levels after exposure to sub-MICs of colistin in A. baumannii . Longitudinal in vivo studies are needed to fully understand the clinical aspects of pathogenicity mechanisms and evolutionary dynamics of drug resistance.IMPORTANCESince the toxicity of colistin is dose dependent, there is a focus on strategies that reduce the dose while maintaining the therapeutic effect of the drug. Our findings about sub-inhibitory doses of colistin provide a novel insight into the logical use of colistin to treat and control Acinetobacter baumannii -related infections in clinical practice., Competing Interests: The authors declare no conflict of interest.

Due to high antimicrobial resistance and biofilm-forming ability, Pseudomonas aeruginosa is one of the seriously life-threatening agents causing chronic and nosocomial infections. This study was performed to determine the antibiotic resistance pattern, biofilm formation, and frequency of biofilm-related genes in P. aeruginosa strains. In total, 123 P. aeruginosa isolates were collected from different clinical sources. Antimicrobial susceptibility testing (AST) was performed to detect multidrug-resistant P. aeruginosa (MDRPA) isolates. To evaluate the biofilm-forming isolates, the microtiter plate (MTP) method was carried out. Also, the prevalence of biofilm genotype patterns, including pslA, pslD, pelA, pelF, and algD genes, was detected by polymerases chain reaction (PCR). According to our findings, the highest resistance and susceptibility rates were found in ceftazidime with 74.7% (n = 92) and ciprofloxacin with 42.2% (n = 52), respectively. In our study, the highest level of antibiotic resistance belonged to wound isolates which meropenem had the most antibacterial activity against them. In total, 86.1% (n = 106) P. aeruginosa isolates were determined as MDRPA, of which 61.3% (n = 65) were able to form strong biofilm. The highest and lowest frequency of biofilm-related genes among biofilm producer isolates belonged to pelF with 82.1% (n = 101) and algD with 55.2% (n = 68), respectively. The findings of the conducted study indicate a significant relationship between MDRPA and biofilm genotypic/phenotypic patterns, suggesting the necessity of a careful surveillance program in hospital settings., (© 2023. The Author(s), under exclusive licence to Institute of Plant Genetics Polish Academy of Sciences.)

Background: The ability of bacteria to form biofilm is an essential strategy for creating stable infections. This issue is more critical in Acinetobacter bauamannii as a hospital pathogen. Today, the control of biofilm formation and solutions to prevent or remove biofilm is being developed. Carvacrol has been considered an anti-biofilm compound in significant bacteria. This study investigated the anti-biofilm effect of Carvacrol on biofilm formation in clinical colistin heteroresistant isolates of A. baumannii ., Methods: 22 clinical strains of A. baumannii were collected from Motahari Hospital in Tehran, Iran, in 2019. Biochemical and genotypic methods confirmed these isolates. Colistin heteroresistance was determined by the Standard PAP method. Carvacrol's antibacterial and anti-biofilm activity was determined according to the standard protocol., Results: About 12 isolates were considered strong biofilm producers and were used for analysis. Six isolates had hetero-resistance to colistin. Carvacrol at a 512 g/ml concentration showed the best antibacterial activity against all isolates. The sub-MIC of Carvacrol (256 g/ml) reduced the biofilm formation capacity, which was statistically significant (p < 0.05)., Conclusion: The results of this study showed that sub-MIC of Carvacrol has anti-biofilm effects in clinical A.baumannii colistin hetero-resistance isolates., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Objectives: Antimicrobial resistance and biofilm formation are increasingly significant public health concerns. This study aimed to examine the antibacterial and antibiofilm properties of carbon dots (C-dots) alone and in combination with antibiotics against biofilm-forming isolates of Pseudomonas aeruginosa., Methods: The antibacterial property of C-dots was investigated by broth microdilution method against ATCC PAO1 and P. aeruginosa clinical isolates. The antibacterial effect of the C-dots and ciprofloxacin combination was investigated using the checkerboard method. The antibiofilm effect of the C-dots alone and its combination with ciprofloxacin was evaluated using the microtiter plate method. Subsequently, the toxicity of each agent was tested on L929 fibroblast cells. In the end, the effects of C-dots on the expression levels of pslA, pelA, and ppyR genes were determined using real-time quantitative PCR., Results: The combination of C-dots and ciprofloxacin exhibited a synergistic effect. Additionally, this compound substantially decreased bacterial growth (P < 0.0001) and inhibited biofilm formation at MIC (96 µg/mL) and sub-MIC (48 µg/mL) concentrations (P < 0.0053, P < 0.01). After being exposed to C-dots at a concentration of 1mg/mL for 24 hours, the survival rate of L929 cells was 87.3%. The expression of genes pslA, pelA, and ppyR, associated with biofilm formation in P. aeruginosa, was significantly reduced upon exposure to C-dots (P < 0.0023)., Conclusions: The findings demonstrate a promising new treatment method for infections. Furthermore, reducing the dosage of antibiotics can lead to an improvement in the toxic effects caused by dose-dependent antibiotics and antimicrobial activity., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Chemical analysis of extracts from cultures of the plant pathogenic fungus Cytospora sp. strain CCTU A309 collected in Iran led to the isolation of two previously unreported heptanedioic acid derivatives namely (2 R ,3 S) 2-hydroxy-3-phenyl-4-oxoheptanedioic acid (1) and (2 S ,3 S) 2-hydroxy-3-phenyl-4-oxoheptanedioic acid (2) as diastereomers, four previously undescribed prenylated p -terphenyl quinones 3 – 6 in addition to five known metabolites. Their structures were elucidated on the basis of extensive spectroscopic analysis and high-resolution mass spectrometry. For metabolites 1 and 2 , the absolute configurations at C-2 were deduced from comparison of the 1H NMR difference of their (S)- and (R)-phenylglycine methyl ester derivatives while the relative configurations were tentatively assigned by a J -based analysis and confirmed by comparison of 13C chemical shifts to literature data. The isolated compounds were tested for their cytotoxic, antimicrobial (including biofilm inhibition), antiviral, and nematicidal activities. While only moderate antimicrobial effects were observed, the terphenyl quinone derivatives 3 – 6 and leucomelone (10) exhibited significant cytotoxicity against the mouse fibroblast L929 and cervix carcinoma KB-3-1 cell lines with IC 50 values ranging from 2.4 to 26 μg/mL. Furthermore, metabolites 4–6 showed interesting antiviral activity against hepatitis C virus (HCV). Unlabelled Image [ABSTRACT FROM AUTHOR]

Introduction: Urinary tract infections are the common medical problems in pregnant women and associated bacteria produce biofilm which protects them from antibiotics. Aim of this study was to determine the pattern of antibiotic resistance and biofilm formation by Escherichia coli and Klebsiellapneumoniae isolated from urine of pregnant women in Kerman, Iran. Methods and Materials: 107 urine samples were collected from pregnant women. Identification was performed by biochemical tests. Antibiotic sensitivity by disc diffusion method and minimum inhibitory concentration (MIC) by agar dilution method were performed. The cell surface hydrophobicity (CSH) behavior of those strains and their ability to form biofilm on glass and propylene surfaces was evaluated in static and shake conditions. The effect of antibiotics on biofilm formation ability was also determined on the catheter surface. Results: From 80 positive cases, 35 isolates of Escherichia coli and 15 isolates of Klebsiella pneumoniae were selected for this research. The Maximum resistance and sensitivity of isolates were observed about amoxicillin and imipenem, respectively. All isolates with CSH higher than 70% showed better biofilm formation even though on propylene in shaking state. Treatment of culture with 0.5 MIC (μg/ml) and 0.25 MIC (μg/ml) of selected antibiotics significantly reduced the adhesion ability of isolates. Conclusion: The survey therefore came to the conclusion that similar researches should be continuously repeated in different medical centers to test antimicrobial susceptibility as well as diagnosing and quantifying biofilm infection which surely achieved data help to find appropriate therapeutic way against UTI in pregnancy. [ABSTRACT FROM AUTHOR]

Background and Aim: A variety of bacteria like Staphylococcus aureus utilize quorum sensing to perform their important activities such as biofilm formation and production of virulence factors. Interfering with the bacterial QS will disable the bacteria to perform above-mentioned vital activities. The principal aim of the study was to evaluate the effects of five plant extracts against bacterial Quorum sensing of Staphylococcus aureus. Materials and Methods: Thirteen strains of Staphylococcus aureus were isolated from patients with dental implant infection and identified. The plant species were collected from vicinity gardens of Fars Province and extracted using 96% ethanol. The anti-QS and antimicrobial susceptibility methods were then carried out to evaluate their bactericidal and QS properties with the use of Agrobacterium tumefaciens NTL/PZLR4. Furthermore, the biofilm production of the isolates was evaluated by microtiter plate (MTP) assay. Ethical Considerations: This study with research ethics codes 01-16-1-1959 and 73/118248 has been approved by research ethics committee at Islamic Azad University, Jahrom and research sciences branch, respectively. Findings: The results of the study disclosed that the extract of raspberry blossom possesses significantly (p<0.05) anti-QS property (>21 mm). The anti-QS activity was proved by creating clear halo sides of the wells formed by Agrobacterium tumefaciens NTL/PZLR4. Moreover, the extracts of tarragon, wheat flower, flixweed and basil showed antimicrobial properties. Conclusion: According to the anti-biofilm and anti-QS properties of raspberry blossom extract against the isolates of Staphylococcus aureus, it could be considered as a mouthwash against dental bacterial infection with the identification of active compounds in the raspberry. [ABSTRACT FROM AUTHOR]

Objective: To investigate the relationship between biofilm formation and antibiotic resistance patterns in meticillin-resistant and meticillin-sensitive Staphylococcus aureus, isolated from burns. Methods: In a cross-sectional study, pus/wound swab samples were obtained from burns. Presence of Staphylococcus aureus was confirmed, and biofilm formation-related icaABCDR and eta, etb genes were detected by polymerase chain reaction. Biofilm formation assay was assessed using the microtiter plate method. Antibiotic resistance was performed using the disk diffusion method and minimum inhibitory concentration. Results: A total of 95 patients with burns were recruited. Of the 95 wounds swabbed, Staphylococcus aureus was identified in 50 (62.5%), and 47 (94%) isolates capable of producing biofilm. Biofilm production levels were classed as 'strong' (n=29; 58%), 'moderate' (n=11; 22%), 'weak' (n=7; 14%) and 'non-biofilm forming' (n=3; 6%). There was an almost even split between isolates identified as meticillin-resistant Staphylococcus aureus (MRSA), n=24 (48%), and meticillin-sensitive Staphylococcus aureus (MSSA) n=26 (52%). The prevalence of the icaA, icaB, icaC, icaD and icaR genes among the studied isolates were 96%, 80%, 80%, 96% and 84%, respectively. The prevalence of eta and etb genes in isolates were 84% and 92%, respectively. Conclusion: Biofilm producing isolates of Staphylococcus aureus showed greater multidrug resistance than non-biofilm producers. In our study, a high rate of biofilm formation and antimicrobial drug resistance was seen. Our results highlight the alarming levels of antimicrobial resistance among MRSA strains and important data about the prevalence of eta and etb genes in Staphylococcus aureus strains isolated from burn patients in this study. [ABSTRACT FROM AUTHOR]

Aims: Staphylococcus epidermidis is an important bacterium, also one of the 40 species related to the Staphylococcus family. It can be found in the human normal body flora, commonly on the skin, and less commonly on mucosal flora. Instrument and Methods: In the cross-sectional study, we were isolated samples according to the laboratories standards, and S. epidermidis identification were collected for 1 year, 90 S. epidermidis from urinary tract infections of children were selected from educational hospitals in Isfahan, (Iran). In this way, we use the Kirby–Bauer method. S. epidermidis isolates were collected for determined biofilm producing method, with culturing in (Congo red agar) medium and microplate titration. Results: The results reveal that 45 methicillin resistance S. epidermidis isolates produce biofilm in different levels. The high resistance was for methicillin (50%), erythromycin (43.5%), ciprofloxacin (50.2%), and penicillin (46.9%). The lowest resistance was for linezolid (4%) and nitrofurantoin (5%). Conclusions: The results of our study show the high prevalence of antibiotic-resistant and biofilm producing of S. epidermidis strains, especially, in methicillin resistance S. epidermidis strains in the Isfahan hospitals, which could be a reservoir for antibiotic resistance genes. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to evaluate the susceptibility of catheter-related Klebsiella pneumoniae isolates to two biocides (benzalkonium chloride and Deconex) under biofilm and planktonic conditions. Methods: A total of 85 strains of K. pneumoniae were isolated from catheters of inpatients hospitalized in four hospitals in Kerman, Iran. Susceptibility to antibiotics and biocides under biofilm and planktonic growths was performed using the microdilution method. Antibiofilm activity of the biocides was determined by microtiter assay. Biofilm eradication was carried out at different periods of time. The presence of cepA and qacEΔ1 genes were detected by polymerase chain reaction (PCR). Results: We found that 15% (n = 12) of the isolates showed strong biofilm activity, 40% (n = 35) displayed moderate activity, 30% (n = 26) demonstrated weak activity, and 15% (n = 12) showed no attachment to microtiter wells. Both the biocides had profound inhibitory activities on planktonic cells (average minimum inhibitory concentration [MIC] 0.06 ± 0.2 mg/ml for Deconex and 0.03 ± 0.1 mg/ml for benzalkonium chloride). They exerted the least antibiofilm activity at a sub-MIC concentration of 0.015 mg/ml. The isolates that formed high biofilm also harboured the cepA gene. Furthermore, a considerable increase in MIC to piperacillin/tazobactam, tetracycline, and cefotaxime was observed for cells grown in biofilm conditions for 24 hours, but all the isolates were sensitive to colistin and tigecycline. These differences were statistically significant, with a p-value of < 0.05. Most of the biofilms were eradicated from the microtiter plate within 30 minutes' exposure to these biocides. Conclusions: As the data indicates, benzalkonium chloride and Deconex have good potential as hospital disinfectants for catheter-related infections caused by K. pneumoniae in planktonic conditions. Antimicrobial stewardship programs must be performed weekly in our hospitals to improve the quality of antimicrobial use, reduce the use of antibiotics, and shorten the length of hospital stay without increasing mortality rates. [ABSTRACT FROM AUTHOR]