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Routine blood culture is used for the detection of bloodstream infections by aerobic and anaerobic bacteria and by common pathogenic yeasts. A retrospective study was conducted in a public hospital in Maceió-AL, by collecting data of all medical records with positive blood cultures. Out of the 2,107 blood cultures performed, 17% were positive with Staphylococcus coagulase negative (51.14%), followed by Staphylococcus aureus (11.21%) and Klebsiella pneumoniae (6.32%). Gram-positive bacteria predominated among positive blood cultures, highlighting the group of Staphylococcus coagulase-negative. While Gram-negative bacteria had a higher number of species among positive blood cultures. Resumo A cultura sanguínea de rotina é usada para a detecção de infecções na corrente sanguínea por bactérias aeróbias e anaeróbias e por leveduras patogênicas comuns. Estudo retrospectivo realizado em hospital público de Maceió-AL, por meio da coleta de dados de todos os prontuários com culturas sanguíneas positivas. Das 2.107 culturas sanguíneas realizadas, 17% foram positivas com Staphylococcus coagulase negativo (51,14%), seguido por Staphylococcus aureus (11,21%) e Klebsiella pneumoniae (6,32%). As bactérias Gram-positiva predominaram entre as culturas de sangue positivas, destacando-se o grupo das Staphylococcus coagulase-negativo. Enquanto as bactérias Gram-negativas apresentaram um número maior de espécies entre as culturas de sangue positivas.

• Owing to their cutaneous, immunologic, and renal immaturity, newborns (especially premature neonates) are at increased risk of infection. • As a group of potentially life-threatening but often treatable diseases, infections must always be considered in a newborn with skin lesions. • Prompt diagnosis and initiation of therapy are crucial to prevent devastating long-term sequelae, particularly in instances of disseminated disease. • Staphylococcus aureus, Streptococcus species, Candida albicans, and herpes simplex virus are the most common causes of skin infections in the neonate.

Під час розвитку маститу у корів формування біоплівки збудником захворювання є ефективним способом його збереження в мікрооточенні молочної залози. Біоплівкові інфекції важко піддаються лікуванню антимікробними засобами, порівняно з тим, що спостерігається при вирощуванні в планктонних умовах. Мета роботи – визначити та порівняти вплив антимікробних препаратів та бактеріофагу Phage SAvB14 при знищенні біоплівок сформованих S. aureus var. bovis. За результатами дослідження встановлено, що антибіотики згубно впливали на кількість бактерій у складі біоплівки, проте знищували її, в середньому, на 60%. 100% ефективність проявляв лише один антибіотик фторхінолонового ряду – енрофлоксацин - ймовірно, через його низьку молекулярну масу. При дослідженні впливу бактеріофагу Phage SAvB14 на життєздатність S. aureus var. bovis у складі біоплівки встановлено, що фаг впродовж 24 годин повністю руйнував сформовану біоплвку. Отже, отримані результати вказують на перспективність ефективного використання стафілококового бактеріофагу Phage SAvB14 для руйнування біоплівки, сформованої S. aureus var. bovis – при маститі корів.

This research was directed to understand the bactericidal effect of epidermal mucus of two Asian cat fish species viz. Clarias batrachus and Heteropneustes fossilis. Epidermal mucus extracts (raw and diluted) of both cat fish species were tested against several Gram negative (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia, A. hydrophila) and Gram positive bacterial strains (Bacillius cereus, Staphylococcus aureus, S. epidermidis) and antibacterial results were also compared with two standard antibiotics viz. amikacin and chloramphenicol used as positive control. An A. hydrophila challenge experiment was also performed on all selected test fish species to examine the change in the amount of mucus production and its bactericidal impact.. Both epidermal mucus extracts (raw and diluted) of all selected normal and bacterial challenged test objects showed potent bactericidal effect against all pathogenic bacterial strains taken under study. However, former was more effective than later. Also raw epidermal mucus extracts of both normal and bacterial challenged cat fish species exhibited significantly higher ZOI values against all selected microbial strains than diluted mucus extracts and antibiotic chloramphenicol. Hence, these outcomes have clearly revealed that this cost effective natural product acquired from fishes is the key component of their defensive system. Therefore, it could be utilized as a novel ‘antimicrobial’ in human as well as veterinary sector for combating against several bacterial diseases.

Background Patients with invasive infections caused by methicillin-resistant Staphylococcus aureus (MRSA), especially those with an elevated minimal inhibitory concentration (MIC) of vancomycin (VA), are likely to have treatment failure and poor outcomes. The aim of this study was to delineate and correlate the genotypes and phenotypes of clinical VA-intermediate S. aureus (VISA) from invasive infections in Taiwan. Methods Between 2006 and 2010, a total of 670 non-duplicate MRSA isolates were collected from patients with invasive infections, mostly from blood, as part of a nationwide antimicrobial surveillance program named Tigecycline in vitro Surveillance in Taiwan. Among them, 10 (1.5%) VISA (VA MIC = 4 mg/L) isolates were identified. Molecular typing with staphylococcal cassette chromosome mec (SCCmec), multilocus sequence typing, staphylococcal protein A (spa), mec-associated hypervariable region (dru), accessory gene regulator (agr), and pulse-field gel electrophoresis, and phenotypic analysis including antibiotic susceptibility testing, gene encoding Panton-Valentine leukocidin (pvl), and superantigenic toxin profiles, were analyzed. Results All but one isolate was defined as molecular health-care-associated MRSA: 6 as SCCmecIII-ST239-spa t037-agrI-dru7 (1 isolate) and dru14 (5 isolates), 2 as SCCmecII-ST5-spa t586-agrII-dru4, and one as SCCmecII-ST89-spa t3520-agrIII-dru7. One isolate was defined as SCCmecIV-ST59-spa t437-agrI-dru8, which was categorized as molecular community-associated MRSA. Five pulsotypes were identified; only one had a positive D-test and 3 were insusceptible to daptomycin (MIC ≧1 mg/L). Five isolates possessed sea-selk-selq, among them 4 belonged to SCCmecIII-ST239-spa t037-agrI. Conclusion In this study, VISA was rarely isolated from invasive MRSA infections, and most cases harbored limited genotypes and corresponding phenotypes.

Methicillin-resistant Staphylococcus aureus (MRSA), biofilms, and persisters are three major factors leading to recurrent and recalcitrant implant infections. Although antibiotics are still the primary treatment for chronic implant infections in clinical, only few drugs are effective in clearing persisters and formed biofilms. Here, felodipine, a dihydropyridine calcium channel blocker, was reported for the first time to have antibacterial effects against MRSA, biofilm, and persisters. Even after continuous exposure to sub-lethal concentrations of felodipine, bacteria are less likely to develop resistance. Besides, low doses of felodipine enhances the antibacterial activity of gentamicin by inhibiting the expression of protein associated with aminoglycoside resistance (aacA-aphD). Next, biofilm eradication test and persisters killing assay suggested felodipine has an excellent bactericidal effect against formed biofilms and persisters. Furthermore, the result of protein profiling, and quantitative metabonomics analysis indicated felodipine reduce MRSA virulence (agrABC), biofilm formation and TCA cycle. Then, molecular docking showed felodipine inhibit the growth of persisters by binding to the H pocket of ClpP protease, which could lead to substantial protein degradation. Furthermore, murine infection models suggested felodipine in combination with gentamicin alleviate bacterial burden and inflammatory response. In conclusion, low dose of felodipine might be a promising agent for biomaterial delivery to enhance aminoglycosides efficacy against implant infections caused by MRSA, biofilm, and persisters.

Background: Acne is a serious skin problem that affects mostly adolescents. The topical and systematic therapies are effective but could lead to several side effects and the emergence of antibacterial resistance of the acne-causing bacteria. Plant resources have been used as traditional medicine for centuries and can be the alternative therapies for acne treatment. Antioxidants are compounds that can prevent or delay the oxidation of substrates when present in low concentrations. Antioxidants are usually involved in several mechanisms of action, including the inhibition of free radical generation, enhancement of the scavenging capacity against free radicals, and reducing power. Methods: In this study, three antioxidant assays, DPPH, ABTS, and FRAP were used to evaluate the antioxidant properties of the ethanolic extracts of five plant extracts (A. bilimbi, M. nigra, O. stamineus, P. granatum, and E. longifolia). Furthermore, the study aimed to identify the most potent plant extracts and their combination which could provide better antibacterial activities against acnecausing bacteria. Ethanolic extracts of A. bilimbi, O. stamineus, M. nigra, P. granatum, and E. longifolia were prepared by the Ultrasound-Assisted Extraction (UAE) technique. Their phytochemical contents were screened using several biochemical tests and GC-MS analysis. Results: The study found that only the extracts of P. granatum and O. stamineus exhibited good antioxidant activity using DPPH assay (82.37% and 81.72% μg/mL respectively) and in ABTS assay (87.25% and 88.85% μg/mL respectively); their observed FRAP values were 115.1667 ± 5.6182 and 41.3860 ± 2.4583 μg/mL, respectively. The preliminary antibacterial screening using the disc diffusion method showed that P. granatum and O. stamineus were the most potent extracts; hence, both extracts were combined at the ratios of 1:1, 1:2, and 2:1 to a total concentration of 400 mg/mL. Discussion: The antibacterial efficacy of the mixture was studied using the disc diffusion method and the MIC value was determined. Both S. aureus and S. epidermidis were sensitive to all the individual and combined extracts but C. acnes was resistant to all of them. Conclusion: The antibacterial activity of the combined extracts against S. aureus showed a synergistic effect at the ratio of 2:1 with the inhibitory zone diameter of 18.00 ± 1.00 mm and MIC value of 12.5 mg/mL; however, antagonistic effects were observed against S. epidermidis while no effect was noted against C. acnes. Therefore, all the selected plant extracts exhibited antibacterial activities against certain bacteria and their effects may be enhanced by combining the plant extracts.

Open wounds are prone to infection and difficult to heal, which even threatens the life of patients because bacterial infections can induce other lethal complications without prompt treatment. The commonly used antibiotics treatment for bacterial infections has been reported to cause globally bacterial resistance and even the occurrence of superbacteria. The highly effective and antibiotic-independent therapeutic strategies are urgently needed for treating various kinds of bacteria-infected diseases. In this work, we synthesized an eco-friendly nanohybrid material (ZnDMZ) consisting of a kind of biodegradable metal organic framework (MOF, ZIF-8) combined with Zn-doped MoS2 (Zn–MoS2) nanosheets, which exhibited great ability to kill bacteria and promote the healing of bacteria-infected wounds under 660 nm light irradiation. The underlying mechanism is that besides the local hyperthermia, the nanohybrid material exhibits enhanced photocatalytic performance than single component in it, i.e., it can also be excited by 660 nm light to produce more oxygen radical species (ROS) due to the following factors. On one hand, the Zn doping can reduce the work function and the band gap of MoS2, which promotes the movement of photoexcited electrons to the surface of the material. On the other hand, the combination between Zn–MoS2 and MOF induces the formation of a built-in electric field due to their work function difference, thus accelerating the separation of photoexcited electron-hole pairs. Because of the synergy of photocatalytic effect, photothermal effect and the released Zn ions, the synthesized ZnDMZ possessed a highly effective antibacterial efficacy of 99.9% against Staphylococcus aureus under 660 nm light irradiation for 20 min without cytotoxicity. In vivo tests showed that this nanohybrid material promoted the wound healing due to the released Zn ions. This nanohybrid will be promising for rapid and portable treatment of bacteria-infected open wounds in pathogenic bacteria contaminated environments.

Introduction : Clinical use of mobile phones have increased exponentially. Whilst evidence of contamination is documented, a key factor when determining potential risks of contamination, is establishing the duration the organism remains viable on the device. If pathogens are found to persist for extended duration, healthcare mobile phones may become fomites for cross departmental transmission. Aim : Determine the duration pathogenic bacteria, Acinetobacter baumannii, Escherichia coli, two Pseudomonas sp. Bacillus cereus, Enterococcus faecalis susceptible and resistant to vancomycin (VSE and VRE) Staphylococcus aureus susceptible and resistant to methicillin (MSSA and MRSA), and a coagulase negative Staphylococcus (CoNs) can remain viable on a mobile phone under controlled conditions. Method : Phones were inoculated with 106 – 107 of each bacterium. The duration of viability was measured from the point the inoculum had dried and CFUs retrieved at timed intervals over 28 days. Results : The mean percentage of bacteria viable at each time point was significantly different (20mins, p=0.004, 1hour p=0.014, 6hours p = 0.006, 24hours p=0.004, 7 days p = 0.007, 14 days p = 0.003, 21 days p = 0.002- and 28-days p =0.004). Gram-positive bacteria remained viable longer than gram-negative bacteria (p=0.010). MSSA declined faster than MRSA within the first 6 hours (p=0.036). Conclusion : The extended duration of bacterial viability indicates the ability for pathogens to persist on a device and remain viable long enough to be transmitted to new areas both within the hospital and out to the community. Mobile phone decontamination should occur in combination of hand hygiene.

We aimed in this work to detect bacterial pathogens causing infection of the vascular accesses in hemodialysis patients and demonstration of important genes responsible for virulence and biofilm formation in Staphylococcus aureus isolates namely; spa, mecA, PVL, γ-hemolysin, and icaA genes. The study was conducted from March 2018 to September 2020 and included 90 patients with infected hemodialysis accesses. Blood samples were collected for blood culture. Distal catheter end was cut and placed in brain heart infusion broth. Total bacterial isolates were 234. Samples were identified by conventional bacteriological methods. Virulent genes In Staph. aureus were detected by PCR. Staph. aureus was the most common isolated microorganism. Fifty (96.25%) of the 52 Staph. aureus isolates were mecA gene positive. The most common spa genotype was at S3 followed by S2. Forty of 52 (76.90 %) Staph. aureus isolates were icaA positive. Only 2(3.85%) Staph. aureus isolates were gamma-hemolysin positive. All 52 isolates of Staph. aureus were negative for Panton-Valentine leukocidin gene.

BACKGROUNDNasopharyngeal carriage of pathogenic bacteria precedes invasive disease and higher rates are found in low socioeconomic-status (SES) settings. Local immune responses are important for controlling colonization, but whether SES affects these responses is currently unknown.OBJECTIVEExamining bacterial colonization and cytokine response in nasal mucosa of children from high and low SES.METHODSTwenty-five cytokines were measured in nasal fluid. qPCR was performed to determine carriage and density of Haemophilus influenzae (H. influenzae), Streptococcus pneumoniae (S. pneumoniae), Moraxella catarrhalis (M. catarrhalis) and Staphylococcus aureus (S. aureus).RESULTSThe densities of H. influenzae and S. pneumoniae were increased in low compared to the high SES (p=0.006, p=0.026), with respectively 6 and 67 times higher median densities. Densities of H. influenzae and S. pneumoniae were positively associated with levels of IL-1beta (p=0.002, p=0.008) and IL-6 (pp=0.006). After correcting for bacterial density, IL-6 levels were increased in colonized children from high compared to low SES for both H. influenzae and S. pneumoniae (both p=0.039).CONCLUSIONIncreased density of H. influenzae and S. pneumoniae was observed in low SES children, while IL-6 levels associated with colonization were reduced in these children, indicating that immune responses to bacterial colonization were altered by SES.

Introduction Metagenomic next-generation sequencing (mNGS) assay for detecting infectious agents is now in the stage of being translated into clinical practice. With no approved approaches or guidelines available, laboratories adopt customized mNGS assays to detect clinical samples. However, the accuracy, reliability, and problems of these routinely implemented assays are not clear. Objectives To evaluate the performance of 90 mNGS laboratories under routine testing conditions through analyzing identical samples. Methods Eleven microbial communities were generated using 15 quantitative microbial suspensions. They were used as reference materials to evaluate the false negatives and false positives of participating mNGS protocols, as well as the ability to distinguish genetically similar organisms and to identify true pathogens from other microbes based on fictitious case reports. Results High interlaboratory variability was found in the identification and the quantitative reads per million reads (RPM) values of each microbe in the samples, especially when testing microbes present at low concentrations (1 × 103 cell/ml or less). 42.2% (38/90) of the laboratories reported unexpected microbes (i.e. false positive problem). Only 56.7% (51/90) to 83.3% (75/90) of the laboratories showed a sufficient ability to obtain clear etiological diagnoses for three simulated cases combined with patient information. The analysis of the performance of mNGS in distinguishing genetically similar organisms in three samples revealed that only 56.6% to 63.0% of the laboratories recovered RPM ratios (RPMS. aureus/RPMS. epidermidis) within the range of a 2-fold change of the initial input ratios (indicating a relatively low level of bias). Conclusion The high interlaboratory variability found in both identifying microbes and distinguishing true pathogens emphasizes the urgent need for improving the accuracy and comparability of the results generated across different mNGS laboratories, especially in the detection of low-microbial-biomass samples.

Resumen Se estudió la actividad in vitro de delafloxacina, ciprofloxacina y levofloxacina por los métodos epsilométrico y de difusión por discos frente a 181 aislamientos clínicos de infecciones de piel y osteoarticulares. Se incluyeron 40 Staphylococcus aureus resistentes a meticilina (SARM), 44 S. aureus sensibles a meticilina (SASM), 46 estafilococos coagulasa negativos (ECN), 23 Klebsiella pneumoniae y 28 Pseudomonas aeruginosa. Las CIM50/CIM90 (mg/l) de delafloxacina, ciprofloxacina y levofloxacina respectivamente fueron 0,004/0,064, 0,25/16 y 0,125/4 frente a SARM; 0,002/0,004, 0,125/0,25 y 0,125/0,25 frente a SASM; 0,008/0,25, 0,125/>32 y 0,25/>32 frente a ECN; 4/>32,>32/>32 y 16/>32 frente a K. pneumoniae y 1/>32, 0,5/>32 y 4/>32 frente a P. aeruginosa. La proporción de aislamientos sensibles a delafloxacina, ciprofloxacina y levofloxacina fue la siguiente: SARM, 97,5%; 82,5% y 82,5%; SASM, 97,7%; 95,5% y 95,5%; ECN, 93,5%; 63,0% y 60,9%; K. pneumoniae, 21,7%; 26,1% y 43,5%; P. aeruginosa, 35,7%; 53,6% y 42,8%. La concordancia categórica del método de difusión por discos y el método epsilométrico para evaluar la actividad in vitro de la delafloxacina fue del 98,8% en S. aureus y del 91,3% en ECN. Abstract In vitro activities of delafloxacin, ciprofloxacin and levofloxacin were evaluated by epsilometric and disk diffusion methods against 181 bacterial isolates recovered from bone and skin infections. Isolates included were 84 Staphylococcus aureus (40 MRSA and 44 MSSA), 46 coagulase-negative staphylococci (CNS), 23 Klebsiella pneumoniae and 28 Pseudomonas aeruginosa. The MIC50/MIC90 (mg/l) for delafloxacin, ciprofloxacin and levofloxacin, respectively, were: MRSA, 0.004/0.064, 0.25/16 and 0.125/4; MSSA, 0.002/0.004, 0.125/0.25 and 0.125/0.25; CNS, 0.008/0.25, 0.125/>32 and 0.25/>32; K. pneumoniae, 4/>32,>32/>32 and 16/>32; P. aeruginosa, 1/>32, 0,5/>32 and 4/>32. Susceptibilities for delafloxacin, ciprofloxacin and levofloxacin, respectively, were: MRSA, 97.5%, 82.5% and 82.5%; MSSA, 97.7%, 95.5% and 95.5%; CNS, 93.5%, 63.0% and 60.9%; K. pneumoniae, 21.7%, 26.1% and 43.5%; P aeruginosa, 35.7%, 53.6% and 42.8%. The disk diffusion and epsilometric methods were concordant for evaluating in vitro susceptibility in staphylococci (categorical concordance of 98.8% for S. aureus and 91.3% for CNS).

Antibacterial activities of essential oils (EOs) of three widely used herbal elements of cinnamon (Cinnamomum verum J.Presl), eucalyptus (Eucalyptus camaldulensis Dehnh.), and thyme (Zataria multiflora Boiss.), whose antimicrobial effects are indirectly described in the old literature of Persian medicine as antiseptic agents and treatments of diseases caused by Havaye Vabaee (e.g., air-borne infectious diseases), were investigated. Antibacterial activities of the EOs were evaluated against some important Zoonosis and medicine pathogenic gram-negative (Escherichia coli, Klebsiella pneumonia, Listeria monocytogenes, and Pseudomonas aeruginosa) and gram-positive (Staphylococcus aureus, S. epidermidis, and Streptococcus pyogenes) bacteria. These pathogens cause disease in animals and humans.To this end, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and double-diffusion assay (DDA) tests were utilized using a microdilution method. While MIC values for cinnamon, eucalyptus, and thyme ranged between 0.25-1, 8-64, and 0.5-16 μg mL-1, respectively, the range of MBC values were 1-4, 32-256, and 2-64 μg mL-1. In DDA tests, a concentration of 0.5 μg mL-1 of the three EOs induced inhibition zones ranging between 20-35, 9-25, and 0-35 mm in diameter in the culture media of the above bacteria. Antibacterial effects of double combinations of the EOs against E. coli and S. aureus were also investigated by checkerboard test and fractional inhibitory concentration (FIC) index. Combinations of the EOs resulted in FIC index values of 1.06-2, indicating no interaction between most of the compounds combined. Our study also suggested the use of thyme oil with caution in combination with cinnamon or eucalyptus oils against E. coli because of their possible antagonistic effects (FIC index = 4).

Staphylococcus aureus is the second leading pathogenic cause of nosocomial infections and plays an important role in the development of food poisoning and purulent, systemic and nosocomial infections. This bacterium is responsible for infections such as abscess, food poisoning, third grade burns, traumatic ulcers, surgical incisions, bed sores or atrophic ulcers. Long-term use of antibiotics has led to the emergence of multi-drug resistant strains in infectious diseases. Due to increased resistance of bacteria to chemical drugs and the few side effects of medicinal plants, medicinal plants have nowadays attracted much more attention of researchers. In this regard, studies have been done on the effectiveness of medicinal plants against infectious agents such as S. aureus and methicillin-resistant S. aureus. Therefore, in this review study, native Iranian herbs that are effective on S. aureus were reported. In this review study, search terms including Staphylococcus aureus, herbs, extracts and essential oils were used to retrieve articles indexed in databases such as the Institute for Scientific Information, PubMed, Scopus, Scientific Information Database, Magiran, and Google Scholar. Garlic, pomegranate, Anethum graveolens, coriander, eucalyptus, Lawsonia inermis, Descurainia sophia, Figworts, artemisia, thyme, etc. are some of the most important anti-staphylococcal herbs.

Aim During several local COVID-19 outbreaks in China in 2020, SARS-CoV-2 or its RNA was isolated or detected from frozen food or packages, revealing the lack of effective disinfection measures in the frozen food chain and risk of transmission. We explored the possibility that disinfectant plus antifreeze could be delivered as thermal fog to realize effective disinfection at subzero temperatures. Methods and Results We selected two disinfectant-antifreeze combinations, didecyl dimethyl ammonium bromide (DDAB) – propylene glycol (PPG) and peracetic acid (PAA) – triethylene glycol (TEG), and each combination is used with a custom-optimized thermal fogging machine. The two fogs were tested in −20°C freezer warehouses for their disinfection efficacy against a coronavirus porcine epidemic diarrhoea virus (PEDV) field strain, a swine influenza virus (SIV) field strain, and three indicator bacteria, Escherichia coli, Staphylococcus aureus and Bacillus subtilis endospores. At −20°C, the DDAB-PPG or PAA-TEG thermal fogs settle within 3.5 to 4.5 h and effectively inactivated PEDV with median tissue culture infective dose of 10−3.5 0.1 ml−1 and SIV-H1N1 with hemagglutination titre of 26 ml−1 within 15–60 min. DDAB-PPG could inactivate S. aureus and E. coli vegetative cells (106 cfu ml−1) within 15–60 min but not effective on B. subtilis spores, while PAA-TEG could disinfect B. subtilis spores more effectively than for S. aureus and E. coli. Conclusions We showed that a practical subzero temperature disinfection technology was effective in killing enveloped viruses and vegetative bacteria or bacterial spores. DDAB-PPG or PAA-TEG thermal fogging may be a practical technology for cold-chain disinfection. Significance and Impact of the Study This subzero temperature disinfection technology could help to meet the urgent public health need of environmental disinfection in frozen food logistics against pandemic and other potential pathogens and to enhance national and international biosecurity.

Infectious diseases become one of the leading causes of human death. Traditional treatment based on classical antibiotics could not provide enough antibacterial activity to combat bacterial infections due to low bioavailability, even leading to antibiotic resistance. In recent years, biomimetic delivery systems have been developed to improve drug therapy for various diseases, such as malignant tumor and cardiovascular disease. In this work, we designed virus-inspired nanodrugs (VNDs) through co-assembly of amphiphilic lipopeptide dendrons and poly(lactic-co-glycolic acid) polymers for high-efficiency antibiotic delivery. These VNDs had well-defined and stable nanostructures for tetracycline encapsulation and delivery. The VNDs were capable of promoting antibiotic internalization and enhancing their antibacterial effects against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Additionally, no obvious cytotoxicity of VNDs was observed to human cell lines. This work successfully demonstrated the virus-mimetic nanoparticles served as promising and applicable antibiotic delivery platform for antibacterial treatment.

To search for a new eco-friendly therapy for infectious disease caused by Escherichia coli, Staphylococcus aureus or Klebsiella oxytoca, we collected the vaginal swabs from healthy women, screened for Lactobacillus and found a strain repressing the growth of pathogenic bacteria. The new isolate was identified as L. gasseri by the colony morphology, Gram staining, biochemical reactions and confirmed by the 16S rDNA sequencing. The HMV18 strain inhibited the growth of food-borne pathogens such as E. coli, S. aureus and K. oxytoca. The HMV18 strain was sensitive to penicillin, ampicillin, erythromycin, tetracycline and chloramphenicol. The HMV18 strain produced α-hemolysis. Pathological histology of the mice ileum showed that the mucosa, villi, lamina propria and crypt depth remained intact and there was no inflammation or hyperemia in the L. gasseri HMV18 gavaged group. L. gasseri HMV18 could not up-regulate inflammatory cytokines level of plasma. All the results suggested L. gasseri HMV18 is a candidate probiotic to be an additive for food preservation or drug to prevent food-borne diseases.

The antibacterial effects of combined extracts of Punica granatum L. and Areca nut (P.A) against resistant bacteria, a gram-positive bacterium, Staphylococcus aureus and three gram-negative bacteria, Escherichia coli, Salmonella, and Enterobacter aerogenes, in individual and biofilm forms was studied. Antibacterial activity was studied using disk diffusion method, microbroth dilution, and microtiter plate methods. Given the disc diffusion test (Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC)), the extracts had inhibitory effects on the individual forms of bacteria. However, the ethanolic extract had greater effectiveness than the methanolic extract. Generally, ethanol efficiently extracts flavonoids and their glycosides, catechol and tannins. This fact due to the ethanol polarity that is equal 0.654. The results indicated that the ability of extracts in inhibiting the formation of biofilms, destruction of biofilms, and prevention of metabolic activity of bacteria had a direct relationship with concentration and the highest inhibitory was seen on Staphylococcus aureus (98.98%), Staphylococcus aureus (94.98%), and Enterobacter aerogenes (88.55%). Based on the results, the P.A. combined extract can be used as an alternative combination with the ability to inhibit antibiotic-resistant bacteria in single and biofilm forms.

Introducción. La creciente resistencia bacteriana a los antibióticos representa una amenaza mundial de salud pública. Las excreciones y secreciones larvarias derivadas de moscas necrófagas de la familia Calliphoridae podrían configurar una fuente promisoria para contrarrestar sus efectos.Objetivo. Comparar la actividad antimicrobiana de las excreciones y secreciones larvarias nativas, y de las mayores y menores de 10 kDa de Calliphora vicina y Sarconesiopsis magellanica (Diptera: Calliphoridae).Materiales y métodos. El bioensayo se hizo a partir de la técnica de turbidimetría y en el caso de las excreciones y secreciones menores de 10 kDa se determinó la concentración inhibitoria mínima (CIM).Resultados. Las excreciones y secreciones nativas y las menores de 10 kDa de C. vicina y S. magellanica, evidenciaron una potente actividad antibacteriana contra tres cepas de Staphylococcus aureus y cuatro bacterias Gram negativas, siendo las menores de 10 kDa más efectivas que las nativas en las dos especies de moscas evaluadas. Además, las menores de 10 kDa presentaron la misma efectividad, aunque en las pruebas de CIM se observó que las de S. magellanica fueron más potentes en todas las bacterias evaluadas, excepto contra la cepa de S. aureus ATCC 25923. Las mayores de 10 kDa no inhibieron el crecimiento bacteriano.Conclusión. Los resultados validaron, en general, que estas sustancias son fuente importante para el aislamiento y la caracterización de agentes antimicrobianos.

Early diagnosis of bacterial infection and tracking of treatment effect are of great importance for developing a “sense-and-treat” integrated system. Herein, we developed a bacteria-triggered, portable, wearable and colorimetric film-based band-aid (FBA) for closed-loop monitoring and light-controlled therapy of wound infection. FBA with high photothermal conversion efficiency of 52.56% was prepared by wrapping Bi2S3 nanoflowers (BS NFs) loaded with rhodium nanoparticles (Rh NPs) and bromothymol blue (BTB) into LB agar film, integrating bacteria-triggered color change, photothermal/photodynamic therapy (PTT/PDT) synergistic bactericidal therapy and agar-based band aid in one intelligent system. Initially, FBA effectively simulates the pH sensing mechanism, and monitors the occurrence of bacterial infections within 5 minutes through color changes of Staphylococcus aureus (S. aureus) from blue to yellow and Escherichia coli (E. coli) from yellow to blue. Additionally, the short-term and controlled antibacterial strategy of “one light dual-mode responses” (photothermal and photodynamic responses) was implemented with the introduce of near-infrared (NIR). Ultimately, the effectiveness of FBA was fully validated in the monitoring and treating of S. aureus-infected mouse wounds. Notably, the designed FBA decisively abandoned off-target side effects maximizing the treatment effect and nakedly tracking therapeutic situation in real time, contributing an effective antibacterial alternative strategy for reducing the use of antibiotics. To the best of our knowledge, such integrated system is still unreported on film-fixed model. In view of the advantages of the low cost and convenience of the simple device, the integrated design is expected to provide a solution for the development of a closed-loop biomedical system combining diagnosis and treatment.

Aim This study aimed to identify genotype enterotoxigenic antimicrobial-resistant Staphylococcus aureus species, mainly methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) among commensal rodents. Methods and results A total of 280 samples were collected from nasal and mouth swabs, heart blood, intestinal content and lung tissues of 56 commensal rodents trapped from North Sinai, Egypt. Antimicrobial susceptibility testing was performed to bacteriologically identified S. aureus isolates against 15 antimicrobial agents by disc diffusion method. Detection was conducted for identifying coagulase gene (coA), antimicrobial-resistant genes (mecA and vanA/B), enterotoxigenic and virulence determinant genes (hlg, seb, sed and see) among the MRSA and VRSA isolates. Results Staphylococcus aureus species were isolated from 24 (42.86%) out of 56 rodents. Phenotypic examination revealed that all the isolates were multidrug-resistant, whereas two isolates were multiple antibiotic resistant (MAR). Out of 33 examined isolates, 33 (100%) were resistant to oxacillin and amoxicillin, 31 (93.93%) to cefoxitin and 12 (36.36%) to vancomycin. PCR assay revealed that 24 isolates revealed (100%) positivity to coA gene, 17 (70.83%) to mecA gene and 12 (50%) to vanA/B genes. Enterotoxin genes and haemolysin genes were detected among MRSA and VRSA isolates. There was a strong positive correlation between the tested antimicrobial-resistant genes and virulence genes (p > 0.05). Conclusions This study demonstrated the occurrence of MRSA and VRSA strains among commensal rodents in North Sinai, Egypt. The detection of enterotoxigenic and virulence genes of the isolated MRSA and VRSA strains indicated the health hazards of food contamination and zoonotic infections. Significance and impacts of the study. This study emphasizes the role of commensal rodents in maintaining and disseminating multidrug-resistant MRSA and VRSA strains to the environment, animals and human beings.

Probiotics can effectively modulate host immune responses and prevent gastrointestinal diseases. The objective of this study was to investigate the probiotic characteristics of Lactobacillus brevis KU15152 isolated from kimchi and its protective potential against intestinal inflammation induced by Staphylococcus aureus lipoteichoic acid (aLTA). L. brevis KU15152 exhibited a high survival rate in artificial gastric and bile environments. Additionally, the adhesion capability of the strain to HT-29 cells was higher than that of L. rhamnosus GG. L. brevis KU15152 did not produce harmful enzymes, such as β-glucuronidase, indicating that it could be used as a potential probiotic. The anti-inflammatory potential of L. brevis KU15152 was determined in HT-29 cells. Treatment with L. brevis KU15152 suppressed the production of interleukin-8 without inducing significant cytotoxicity. The downregulatory effects of L. brevis KU15152 were involved in the suppression of nuclear factor-kappa B activation mediated by the extracellular signal-regulated kinase and Akt signaling pathways. Collectively, these data suggest that L. brevis KU15152 can be used in developing therapeutic and prophylactic products to manage and treat aLTA-induced intestinal damage.

Three previously undescribed triquinane type sesquiterpenoids, antrodiellins A‒C (1‒3), together with three known analogues 4‒6, were isolated from wild fungus Antrodiella albocinnamomea. Their structures were elucidated by means of spectroscopic analysis and single crystal X-ray diffraction. Compounds 3 and 4 exhibited weak inhibitions against Staphylococcus aureus with MIC values of 128 and 64 μg/mL, respectively.

Antimicrobial resistance is undoubtedly one of the greatest global health threats. The emergence of multidrug-resistant (MDR) gram-positive pathogens, such as methicillin-resistant Staphylococcus aureus (S. aureus), vancomycin-resistant Enterococcus faecium, and β-lactamase-resistant Streptococcus pneumonia, has severely limited our antibiotic arsenal. Numerous ribosome-targeting antibiotics, especially pleuromutilins, oxazolidinones, and streptogramins, are viewed as promising alternatives against aggressive MDR pathogens. In this study, we identified a new ABC-F family determinant, srpA, in Streptococcus suis (S. suis) by means of a comparative analysis of the whole-genome sequences of tiamulin-resistant and -sensitive bacteria. Functional cloning confirmed that the deduced gene can mediate cross-resistance to pleuromutilins, lincosamides, and streptogramin A in S. suis and S. aureus. A sequence alignment revealed that srpA shares the highest amino acid identity with Vga(E) (36%) and shows canonical characteristics of ABC-F family members. In SrpA-ribosome docked compounds, the extended loop region of SrpA approaches the valnemulin-binding pocket in the ribosome peptidyl-transferase center and competes with bound valnemulin. A detailed mutational analysis of the loop residues confirmed that this domain is crucial for SrpA activity, as substitutions or truncations of this region affect the efficiency and specificity of antibiotic resistance. Intracellular antibiotics accumulation indicated that SrpA does not act as an efflux pump, while a ribosome binding assay supported the protective effects of SrpA on the ribosome by preventing antibiotic binding as well as displacing bound drugs. These findings clarify the mechanisms underlying resistance to ribosomal antibiotics.

Mastitis affects a high proportion of dairy cows and is still one of the greatest challenges faced by the dairy industry. Staphylococcal bacteria remain the most important cause of mastitis worldwide. We investigated how distinct staphylococcal species evade some critical host defense mechanisms, which may dictate the establishment, severity, and persistence of infection and the outcome of possible therapeutic and prevention interventions. Thus, the present study investigated variations among distinct bovine-associated staphylococci in their capability to resist phagocytosis and to trigger respiratory burst activity of blood and milk polymorphonuclear neutrophil leukocytes (PMNL) in dairy cows. To do so, PMNL of 6 primiparous and 6 multiparous dairy cows were used. A collection of 38 non-aureus staphylococci (NAS) and 12 Staphylococcus aureus were included. The phagocytosis and intracellular reactive oxygen species (ROS) production by blood and milk PMNL were analyzed by flow cytometry. Phagocytosis, by both blood and milk PMNL, did not differ between S. aureus and NAS as a group, although within-NAS species differences were observed. Staphylococcus chromogenes (a so-called milk-adapted NAS species) better resisted phagocytosis by blood PMNL than the so-called environmental (i.e., Staphylococcus fleurettii) and opportunistic (i.e., Staphylococcus haemolyticus) NAS species. Otherwise, S. haemolyticus was better phagocytosed by blood PMNL than S. aureus, S. fleurettii, and S. chromogenes. No influence of the origin of the isolates within the staphylococci species in the resistance to phagocytosis by blood and milk PMNL was found. Overall, both S. aureus and NAS did not inhibit intracellular ROS production in blood and milk PMNL. Non-aureus staphylococci induced fewer ROS by milk PMNL than S. aureus, which was not true for blood PMNL, although species-specific differences in the intensity of ROS production were observed. Staphylococcus chromogenes induced more blood PMNL ROS than S. fleurettii and S. haemolyticus, and as much as S. aureus. Conversely, S. chromogenes induced fewer milk PMNL ROS than S. aureus. The origin of the isolates within the staphylococci species did not affect the ROS production by blood and milk PMNL. In conclusion, our study showed differences in staphylococci species in evading phagocytosis and triggering ROS production, which may explain the ability of some staphylococci species (i.e., S. aureus and S. chromogenes) to cause persistent infection and induce inflammation.

Background and Objective:Staphylococcus aureus (S. aureus) is a gram-positive bacterium and one of the major nosocomial pathogen. It has the ability to acquire resistance against almost all available classes of antibiotics; Methicillin-Resistant S. aureus (MRSA) is a well-known antibiotic resistance. S. aureus is a globally distributed pathogen that need in-depth epidemiological and genomic level investigation for proper treatment and prevention.Methods:To explore the genomic epidemiology of S. aureus in-silico Multi Locus Sequence Typing (MLST) was carried out for 355 complete genomes. Diversity within the species was investigated through pan-genome analysis and subtractive genomic approach was employed for identification of core immunogenic targets.Results:Epidemiological study identified 62 different sequence types (STs) of S. aureus distributed worldwide, in which ST-8, ST-5, ST-398, ST-239, and ST-30 are the most dominant STs comprising more than 50% of the isolates. The pan-genome of S. aureus is still open with 7,199 genes and there is a major contribution (80%) of MRSA strains in the S. aureus species pangenome. The core genome (2,025 genes) of S. aureus is almost stable (comprises of 72% of S. aureus genome size) while accessory and unique genes (28% of S. aureus genome size) are gradually increasing. Screening of 2,025 core genes identified putative vaccine candidates. The best scoring and dominant B-cell and T-cell epitopes were predicted out of the selected potential vaccine candidate proteins with the help of a multi-step screening procedure.Conclusion:We believe that the current study will provide insight into the genetic epidemiology and diversity of S. aureus and the predicted epitopes against the pathogen can be tested further for its immunological responses within the host and may provide both humoral and cellular immunity against the disease.

The spread of multidrug-resistant and virulent Staphylococcus aureus among children is a public health concern, but the actual conditions in Myanmar have not been characterized. In this study, a to...

Diseases caused by harmful microorganisms pose a serious threat to human health. Safe and environment-friendly disinfectants are, therefore, essential in preventing and controlling such pathogens. This study aimed to investigate the antimicrobial activity and mechanism of a novel hydrogen peroxide and silver (H 2 O 2 -Ag + ) complex (HSC) in combatting Staphylococcus aureus ATCC 29213, Escherichia coli O157:H7 NCTC 12900 and Salmonella typhimurium SL 1344. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values against S. aureus were found to be 0.014 % H 2 O 2 -3.125 mg/L Ag + , while 0.028 % H 2 O 2 -6.25 mg/L Ag + for both E. coli and S. typhimurium . Results of the growth curve assay and time-kill trial suggest that the HSC could inhibit the growth of the tested bacteria, as 99.9 % of viable cells were killed following treatment at the 1 MIC for 3 h. Compared with Oxytech D10 disinfectant (0.25 % H 2 O 2 -5 mg/L Ag + ), the HSC exhibited better antibacterial efficacy at a lower concentration (0.045 % H 2 O 2 -10 mg/L Ag + ). The mechanism of antibacterial action of HSC was found including the disruption of the bacterial cell membrane, followed by entry into the bacteria cell to reduce intracellular adenosine triphosphate (ATP) concentration, and inhibit the activity of antioxidases, superoxide dismutase (SOD) and catalase (CAT). The enhanced bactericidal effect of hydrogen peroxide combined with silver indicates a potential for its application in environmental disinfection, particularly in the food industry.

In recent years, methicillin-resistant Staphylococcus aureus (MRSA) has gained interest in veterinary medicine due to its zoonotic potential. Currently, little information is available on the genot...

The housekeeping sortase A (SrtA), a membrane-associated cysteine transpeptidase, is responsible for anchoring surface proteins to the cell wall peptidoglycan in Gram-positive bacteria. This process is essential for the regulation of bacterial virulence and pathogenicity. Therefore, SrtA is considered to be an ideal target for antivirulence therapy. In this study, we report that ML346, a compound with a barbituric acid and cinnamaldehyde scaffold, functions as an irreversible inhibitor of Staphylococcus aureus SrtA (SaSrtA) and Streptococcus pyogenes SrtA (SpSrtA) in vitro at low micromolar concentrations. According to our X-ray crystal structure of the SpSrtAΔN81/ML346 complex (Protein Data Bank ID: 7V6K), ML346 covalently modifies the thiol group of Cys208 in the active site of SpSrtA. Importantly, ML346 significantly attenuated the virulence phenotypes of S. aureus and exhibited inhibitory effects on Galleria mellonella larva infection caused by S. aureus. Collectively, our results indicate that ML346 has potential for development as a covalent antivirulence agent for treating S. aureus infections, including methicillin-resistant S. aureus.

In this study, sodium alginate was extracted from Sargassum algae, collected from coastal waters of Bushehr, Persian Gulf, Iran and used as a stabilizing and wrapping agent for CuO nanoparticles. The synthesized nanocomposite was characterized by some spectroscopic and microscopic techniques, such as IR, XRD, Uv–vis, BET, BJH, zeta potential, SEM, TEM, HR-TEM, and XPS. The antibacterial effects of the CuO–alginate nanocomposite against some bacteria, isolated from a burn wound, were evaluated. The results showed that this nanocomposite had better antibacterial effects than its components on Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 12600, Streptococcus pyogenes ATCC 19615, and Staphylococcus epidermidis ATCC 49461. Among these, Staphylococcus aureus ATCC 12600 was the most sensitive one to this nanocomposite, with the lowest minimum inhibitory concentration (2.08 mg mL−1) observed. Moreover, the synthesized nanocomposite showed good catalytic activity in the oxidative coupling of carboxylic acids with N,N-dialkylformamides toward the synthesis of amides.

The objectives of this investigation were a) to isolate bacteria from different foods (dairy products, fruits, and vegetables) and evaluate their probiotic potential and b) to select, identify, and characterize the strain with the highest probiotic potential. From 14 food samples, a total of 117 strains were isolated; however, only 42 (T1 to T42) showed the morphology (gram-positive, coco, and bacillar form) and were catalase- and oxidase-negative to be considered as a presumptive lactic acid bacteria (LAB). The antagonistic activity of the 42 strains was evaluated on Escherichia coli (O157:H7E09), Listeria monocytogenes (ATCC 19115), Staphylococcus aureus (ATCC 25923), and Salmonella enterica serotype Typhimurium (ATCC 14028). The strains with the highest antagonistic activity were nine isolates from the following: pulque (T1), sprouted beans (T26), ranchero cheese (T30, T31, T32, T33, T35, T36), and tenate cheese (T40) with inhibition zones from 17.0 ± 1.2 to 19.3 ± 2.8 mm. Based on the antagonistic activity against pathogenic bacteria and resistance to low pH and bile salts, strain T40 exhibited the highest probiotic potential. Using the 16S rRNA technique, strain T40 was identified as Lacticaseibacillus paracasei (the previous taxonomic nomenclature was Lactobacillus paracasei , prior to the nomenclature change in April 2020); this strain presented no resistance to ampicillin, gentamicin, erythromycin, and tetracycline. The antagonistic activity was evaluated in situ (fresh cheese) against pathogenic bacteria, evidencing the probiotic potential of L. paracasei . Finally, Lacticaseibacillus paracasei isolated from tenate cheese showed characteristics as a probiotic microorganism and high potential in food technology.

Multidrug-resistant (MDR) Staphylococcus aureus biofilms have emerged as a serious threat to human health. Recently, the development of antibiotic replacement therapy has gained much attention due to the potential application of bacteriocin. The present study sought to evaluate the antibacterial effect of bacteriocin XJS01 against MDR S. aureus, a previously reported bacteriocin against S. aureus strain 2612:1606BL1486 (S. aureus_26, an MDR strain demonstrated here), and its potential application as an antibiofilm agent. The minimum bactericide concentration of XJS01 against MDR S. aureus_26 was 33.18 μg/mL. XJS01 exhibited excellent storage stability and resistance against acid and reduced the density of established MDR S. aureus_26 biofilm. The hemolytic and HEK293T cytotoxicity activities of XJS01 and the histological analyses in mice confirmed its safety. Moreover, XJS01 effectively disrupted the MDR S. aureus_26 biofilm established on the skin wound surface and reduced the biofilm-isolated bacteria, thereby decreasing the release of pro-inflammatory cytokines and the proliferation of alternatively activated macrophages. Compared to mupirocin, XJS01 exhibited an excellent therapeutic effect on mice skin wounds, confirming it to be a potential alternative to antibiotics.

Bacterial infections are considered as a critical healthcare concern worldwide. Timely infection detection is crucial to effective antibiotic administration which can reduce the severity of infection and the occurrence of antibiotic resistance. We have developed label–free polydiacetylene (PDA) liposome-based colorimetric biosensor to detect and identify bacterial cultures at the genus and species level with naked eyes by simple color change. We found that among the various liposomal systems, moderate concentration of PDA, phospholipids and cholesterol in liposome assemblies can greatly influence the sensitivity to different bacteria, exhibiting unique chromatic properties of each bacterial strain. The strikingly different chromatic color change was due to the various mechanisms of interactions between bacterial toxins and biomimetic lipid bilayers. Furthermore, increase of cholesterol in liposome assemblies greatly enhanced the sensitivity of bacterial strains related to membrane destruction mediated by pore-formation mechanism such as S. aureus and E.coli, whereas the detection of the two bacterial strains was believed to rely on the specific recognition elements coupled with PDA moiety. As a proof of concept, a colorimetric finger-print array for distinguishing 6 bacterial species was studied. Particularly, the proposed bacterial detection platform is achieved through the interaction between bacterially secreted toxins and liposome bilayers instead of specific recognition of receptors-ligands. The results of both response time and sensitivity of label-free-liposome-based system show superior to previous reports on chromatic bacterial detection assays. By combing these results, the label-free-liposome-based colorimetric sensing platform shows great importance as a bacterial-sensing and discrimination platform.

Cystic fibrosis is characterized by abnormal mucous secretions in the lungs that favor the proliferation of colonizing bacteria, with Pseudomonas aeruginosa and Staphylococcus aureus being the most isolated, however, other less known species could also have an impact on the health of the patient. Here we demonstrate the isolation and antibiotic resistance profiles of Inquilinus limosus, a rarely reported multidrug resistant bacterium, and compare them to a co-infectant strain of Pseudomonas aeruginosa. Likewise, we found that co-infection with both bacteria promotes increased formation of neutrophil extracellular traps, which can have an impact on the disease severity and make treatment difficult.

Bacterial resistance to antibiotics have become one of the most severe threats in global public health, so the development of new-style antimicrobial agents is urgent. In this work, quaternized carbon quantum dots (qCQDs) with broad-spectrum antibacterial activity were synthesized by a simple green “one-pot” method using dimethyl diallyl ammonium chloride and glucose as reaction precursors. The qCQDs displayed satisfactory antibacterial activity against both Gram-positive and gram-negative bacteria. In rat models of wounds infected with mixed bacteria, qCQDs obviously restored the weight of rats, significantly reduced the death of rats from severe infection, and promoted the recovery and healing of infected wounds. Biosafety tests confirmed that qCQDs had no obvious toxic and side effects during the testing stage. The analysis of quantitative proteomics revealed that qCQDs mainly acted on ribosomal proteins in Staphylococcus aureus (Gram-positive bacteria) and significantly down-regulated proteins associated with citrate cycle in Escherichia coli (Gram-negative bacteria). Meanwhile, real-time quantitative PCR confirmed that the variation trend of genes corresponding to the proteins associated with ribosome and citrate cycle was consistent with the proteomic results after treatment of qCQDs, suggesting that qCQDs has a new antibacterial mechanism which is different from the reported carbon quantum dots with antibacterial action. Statement of Significance : With the development of the research on carbon quantum dots, the application of carbon quantum dots in the field of medicine has attracted extensive attention. In this paper, quaternized carbon quantum dots (qCQDs) with antimicrobial activity prepared by specific methods were studied, including antimicrobial spectrum, antimicrobial mechanism and in vivo antimicrobial application. The antimicrobial mechanism of qCQDs was studied by proteomics and RT-qRCR, and the different mechanisms of qCQDs against Gram-positive and Gram-negative bacteria were also found. This study provides a research foundation for the application of carbon quantum dots in antimicrobial field, and also expands the application range of carbon quantum dots in medicine field.

Purpose The prsA and vraTSR regulatory systems play a unique role in methicillin resistance by modifying the peptidoglycan cell wall PBP2 and involving cell wall stress response in Staphylococcus aureus. This study was designed to observe the transcriptional response of prsA and vraTSR system under oxacillin stress in S.aureus. Methods In this study, three clinical isolates of Staphylococcus aureus and a laboratory strain were examined. All the isolates were tested for mecA gene by PCR assay and were also tested for prsA, vraT, vraS and vraR gene. The transcriptional responses of the prsA gene along with the vraTSR regulatory system in these isolates was observed under normal conditions and exposed to 2 ​μg/ml and 4 ​μg/ml of oxacillin stress by quantitative real-time PCR assay. Results The result of transcriptional analysis confirmed that under oxacillin stress, the expressions of vraS and vraT are increased with the increase in the concentration of oxacillin. However, prsA has shown no significant expression under oxacillin stress. Conclusion Although prsA did not show any specific expressional pattern, the study highlights the role of vraS and vraT regulatory system in conferring a methicillin-resistant phenotype when exposed to subinhibitory concentrations of oxacillin, which could act as a potential target for the next-generation antimicrobials.

Lectins are proteins essential for the biological recognition of cells a key factor for killing microbes. Since, legumes are good source, we extracted lectin from Cicerarietinum Black (CiarBL), Prunusdulcis nut raw (PruDuNRL), characterized for its key properties. The protein content of CiarBL was 13.13 ± 4.53, 25.45 ± 3.93, specific activity was 472.97, 243.80HAU/mg protein and for Prunusdulcis nut raw it was 04.60 ± 1.60, 17.84 ± 1.41and specific activity was 365.71, 252.52 HAU/mg protein. The total hemeagglutination activity of both lectin was found to be 512HAU. Blood group specificity analysis showed specificity to O+ and B+ for CiarBL, and for PruDuNRL O+, A+, B+ human erythrocytes both the lectin was specific to goat blood among the animal blood tested. The hemeagglutination inhibition assay showed specificity to glucose, maltose alone for CiarBL. While, PruDuNRL was glucose, sucrose, maltose, xylose specific. Both exhibited good antioxidant activity but erythrocyte membrane stability was higher with CiarBL when compared to PruDuNRL. CiarBL demonstrated promising stability to urea. While, PruDuNRL depicted sensitivity to pH, temperature, urea but both showed stability to salts such as FeCl3, Na2So4, CaCl2. SDS PAGE, authenticate it as low molecular weight i.e. 20, 29 KDa for CiarBL, for PruDuNRL 20 to 60KDa, 115KDa, the molecular weight was ranging from low to high. The antibacterial effect against gram positive oral pathogenic bacteria showed good result for CiarBL against Streptococcus oralis, Streptococcus pyogens at all concentration studied, moderate activity with Propionibacterium acnes, Staphylococcus aureus at 100 µg/ml. For PruDuNRL, the antibacterial activity was found to be decreased in the order of Streptococcus pyogenes

We are developed in the green activity of silver nitrate nanoparticles and are used materials of Mentha (M), Azadirachta indica (A) leaves, and have been implemented as the agent for stabilizing the poly-leaf extracts (LE) / pig liver acetone powder (PL) with complexes. An optimal extract absorption of LE/PL has been used in 500 mg then 200 mg individually, by attraction about 0.841%. Since the PL satisfied with an energetic mediator of the MA leaf extracts are 92.1667 ± 0.3626%. The antibacterial movement on made silver nanoparticles is Escherichia coli, then Staphylococcus aureus. These samples are calculated to additional the antimicrobial movement counter to verified in a pathogenic way in a gram of positive, negative with microbial and fungiform straining. It was made with fast production to Natural Garden Pest Control (non-toxic method) for the mixture of silver nanoparticles are showed hopeful to the movement of all the established microbial straining. The trend is improved through an augmented quantity echelon.

Background: Antimicrobial substances from medicinal plants have been widely applied in many industries, without the concern of side effects. Nonwoven fabric products such as face masks, paper wipes, and wound dressings contain antibacterial substances for reduction of bacterial accumulation. Therefore, the use of bioactive compounds from medicinal plants improves the properties of fabrics. This study used a crude extract from Caesalpinia sappan to perform phytochemical screening and investigate its antibacterial activity, stability, hemolytic activity, and preliminary application in nonwoven fabric products. Results: The alcoholic crude extracts of C. sappan heartwood consisted of alkaloids, anthraquinones, coumarins, flavonoids, saponins, tannins, terpenoids, and cardiac glycosides. The C. sappan extract (CSE) had the highest inhibitory activity against Staphylococcus aureus with inhibition zone of 13.67 ± 1.56 mm in the agar well diffusion assay. The MIC value of CSE was at 1.95, 1.95, and 0.98 mg/ml, while the MBC value was 62.5, 3.91, and 31.25 mg/ml for S. aureus, Bacillus cereus, and Vibrio parahaemolyticus, respectively. The phenolic content was stable at 28 ± 2°C and at pH 4.0 for 12 h (∼95%) and 10 d (>90%), and it had low hemolytic activity on human erythrocytes at 5.04–18.95%. The major chemical component was flavonoids, and brazilein was 1.88% area sum. For the application to antibacterial fabrics, the highest inhibitory activity against S. aureus was found in 2MIC of CSE-coated fabric with 99% for 3 h. Conclusions: The CSE had high inhibitory toward 3 bacterial strains and stability in a wide range of pH and temperature. The CSE-coated nonwoven fabric had efficient inhibition to S. aureus and a possibility to application in a nonwoven product in the future.How to cite: Hemthanon T, Ungcharoenwiwat P. Antibacterial activity, stability, and hemolytic activity of heartwood extract from Caesalpinia sappan for application on nonwoven fabric. Electron J Biotechnol 2022;55. https://doi.org/10.1016/j.ejbt.2021.10.002

Emergence of multi-drug resistant pathogens has fueled the search for alternatives to the existing line of antibiotics that can eradicate pathogens without inducing resistance development. Here, we report the accelerated wound healing and disinfection potential of a non-amphiphilic quaternized fungal exopolysachharide, pullulan, without resistance generation in pathogens. The quaternary ammonium substituted pullulan (CP) derivatives showed excellent bactericidal activity against both Gram negative (MBC90=1.5 µg/mL) and Gram positive (MBC90=0.25 µg/mL) bacteria at very low concentrations without showing any toxicity towards mammalian cells. A combined approach of atomistic molecular dynamics simulation and experimental assays revealed that CP exerts a membrane directed bactericidal action through atypical “non-pore forming” pathway which is not yet established for any known antibacterial polysaccharides. This involves increase in membrane roughness, disorder among anionic lipid tails, formation of localized anionic lipid clusters and membrane depolarization finally leading to physical disruption of membrane integrity. Moreover, CP also displayed biofilm eradication abilities and emerged as an excellent therapeutic material for disinfection & healing of infected wounds. The present work shows the potential of exploiting polysaccharides as next-generation broad-spectrum antimicrobials and provides a platform for further development of rationally designed pullulan-based functional materials for biomedical applications.