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Background and Objectives: Salmonella species (spp) are the most prevalent zoonotic pathogens that cause outbreaks of gastroenteritis worldwide. Therefore evaluation of the profile of antibiotic resistance, virulence factors, and plasmid replicon types in these bacteria is necessary to control and prevent the spread of potentially pathogenic and drug-resistant strains., Materials and Methods: This study was performed on 39 Salmonella spp. The antibacterial susceptibility of isolates to various antibiotic agents was determined using disk diffusion test. β-lactamases ( bla ) including ESBLs, AmpC, MBLs, and virulence genes were detected by PCR methods. Plasmid incompatibility groups among the isolates were identified using PCR-based replicon typing (PBRT)., Results: The most prevalent virulent gene was phoP/Q (84.6%). slyA, sopB , and stn were identified in 79.4% (n=31), 69.2% (n=27), and 2.5% (n=1) of the isolates, respectively. The antibiotic susceptibility testing showed that 30.7% of the isolates were ESBL-producing. bla TEM (41%; n=16) was the most frequent β-lactamase gene among the isolates followed by bla NDM-1 (15.4%; n=6), bla DHA (7.7%; n=3), and bla CTX-M (1.5%; n=1). Six different plasmid replicon types, including IncP (n=9; 23%), IncFIC (n=3; 7.70%), IncY (n=3; 7.70%), IncI1-Iγ (n=2; 5.12%), IncFIIAs (n=1; 2.56%), and IncN (n=1; 2.56%) were observed among the isolates., Conclusion: Our study showed the emergence of carbapenem-resistant and bla NDM-1 among Salmonella spp. for the first time in Kerman, Iran. Since Salmonella spp. plays an important role in the transmission of resistance genes in livestock and humans in the food chains, so more stringent control policies are recommended to prevent the circulation of drug-resistant and potentially pathogenic strains from animals to humans., (Copyright© 2024 The Authors. Published by Tehran University of Medical Sciences.)

Background and Objectives: Candida albicans complex species are well known as the main cause of candidiasis, particularly among susceptible individuals. In this study, we report the genetic diversity of Candida spp. and the antifungal susceptibility pattern of the cryptic C. albicans complex isolates in Kerman, Iran., Materials and Methods: A total of 112 yeast isolates were obtained from different clinical samples, and molecular identification was performed. All C. albicans complex isolates were tested for susceptibility of them to amphotericin B, fluconazole, and itraconazole., Results: The majority of clinical isolates were C. albicans complex (n=48) followed by C. glabrata complex (n=34), C. parapsilosis complex (n=21), and C. krusei (n=9). Among C. albicans complex, 45 isolates were C. albicans (94%), 2 isolates were C. dubliniensis (4%), and 1 isolate was C. africana (2%). Amphotericin B was the most active antifungal, whereas 8.9% and 6.7% of the isolates were resistant to fluconazole and itraconazole, respectively., Conclusion: Regarding the high incidence of Candida infections particularly in susceptible populations and the emergence of an infrequent yeast species with elevated MICs, which is indistinguishable with conventional methods, developing accurate molecular methods for laboratory diagnosis should be considered in the clinical setting., (Copyright © 2022 The Authors. Published by Tehran University of Medical Sciences.)

Background and Objectives: It is well known that Staphylococcus aureus biofilm plays an important role in adenoiditis and biofilm resistance frequently results in failure of therapy. The goal of this study was to evaluate the biofilm production of S. aureus isolates obtained from adenoid specimens and assess the relationship between biofilm formation ability and ica operon genes., Materials and Methods: A total of 112 adenoid samples were obtained from patients under 15 years old with adenoid hypertrophy. All S. aureus isolates were initially identified by standard microbiological tests and amplification of nuc by polymerase chain reaction (PCR) technique. Biofilm formation of S. aureus isolates was evaluated and icaADBC genes were detected by PCR technique., Results: There were 46 isolates (41%) identified as S. aureus . The ability to produce biofilm was detected among total S. aureus isolates. Molecular study of ica operon revealed that 2 (6.3%) and 19 (59.4%) isolates carried icaA and icaD , respectively. The prevalence of icaA + icaD was seen among 11 (34.4%) S. aureus isolates, while icaC and icaB were not detected., Conclusion: Our findings indicated that icaABCD operon are associated with biofilm formation in S. aureus isolates, however the absence of these genes may not necessarily exclude this property., (Copyright © 2021 The Authors. Published by Tehran University of Medical Sciences.)

Background and Objectives: The new beta-coronavirus, which caused Severe Acute Respiratory Coronavirus-2 Syndrome (SARS-CoV-2), a major respiratory outbreak in Wuhan, China in December 2019, is now prevalent in many countries around the world. Identifying PCR-based viruses is a well-known and relatively stable protocol. Unfortunately, the high mutation rates may lead to widespread changes in viral nucleic acid sequences, and so using specific primers for PCR can be recommended. In this study, we evaluated the power of a conventional RT-PCR to detect SARS-CoV-2 RNA among the five set primer sets., Materials and Methods: The five genomic regions of the Coronavirus SARS-2 virus including Nucleocapsids (N), Envelope (E), RNA depended RNA Polymerase (RdRp), ORF1ab and Spike (S) were selected for primer designing. A conventional RT-PCR was performed to compare sensitivity, specificity and other analytical characteristics of primers designed against two Real Time PCR commercial kits., Results: The result of the comparative analysis showed that the ORF1ab, N and RdRp primers had a sensitivity, specificity and positive predictive value higher than other primers. A significant difference in the analytical sensitivity between the studied primer sets in RT-PCR kits was observed., Conclusion: In this study, the ORF1ab, Nucleocapsid and RdRp regions have the best primers for identifying the SARS-CoV-2 RNA between different genes that have been suggested., (Copyright© 2020 Iranian Neuroscience Society.)

Background and Objectives: Colonization of Pseudomonas aeruginosa in Cystic Fibrosis (CF) patients may lead to severe pulmonary disease and death. Different characteristics of P. aeruginosa from these patients were determined in the present study., Materials and Methods: Antimicrobial susceptibility and AmpC-overproduction were determined. The β-lactamase genes were detected by PCR and the oprD gene was sequenced in some of the carbapenem resistance isolates. Distribution of exo genes was determined by PCR. Cytotoxicity of Exo effector proteins was measured using A549 cells. Biofilm production was determined by microtiter plate assay. Random amplified polymorphic DNA (RAPD) -PCR was performed for molecular analysis., Results: Polymyxin B, piperacillin/tazobactam and meropenem were the most active antibiotics and 9.6% of isolates were ampC overproducers. The prevalence of bla VEB , bla OXA , bla VIM , and bla PER genes were as follow: 22.7%, 3.75%, 6.25% and 3.75%, respectively. A high proportion (83.5%) of isolates was able to produce biofilm. The exoT gene was present in all isolates while exoU was present in about 35% of them. RAPD-PCR revealed 49 patterns among 78 tested isolates in which 34 patterns were detected once., Conclusion: Biofilm formation ability and relatively high frequency of exoS may contribute to the persistence of bacteria within lungs of CF patients. Some characteristics of isolates recovered from a single patient after several sampling procedures were similar, while others lacked resemblance.

Background and Objectives: Oral candidiasis is a serious problem for immunocompromised patients, especially patients with hematological malignancies. After becoming a systemic candidiasis it is difficult to diagnose, control and treat in individuals with hematological malignancies. The aim of this study was to diagnose candidiasis in the oral mucosa of patients with leukemias and lymphomas in a timely manner in order to prevent their progression to systemic candidiasis., Materials and Methods: In this cross sectional study, 50 clinical samples were collected from the mouth of patients with hematological malignancies undergoing chemotherapy from the oncology units of teaching hospitals in Kerman, Iran. Patients were from Kerman, Sistan-Baluchestan and Hormozgan in south-eastern Iran. Sampling was restricted to patients with diagnosed acute lymphoid leukemia (ALL); acute myeloid leukemia (AML); chronic lymphoid leukemia (CLL); chronic myeloid leukemia (CML); Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL). Presumptive species identification of fungi was performed using conventional methods like colony characteristics on CHROMagar Candida medium, germ tube production, and assessing the morphology fungi on corn meal agar. Confirmation of presumptive candida isolates was performed using PCR-RFLP., Results: From a total of 50, 14 patients (28%) had positive oral candidiasis. Candida albicans (57.14%) was the most common species followed by Candida glabrata (14.28%), Candida parapsilosis (14.28%), Candida krusei (7.14%) and Candida kefyr (7.14%). Candida albicans had the highest rate of oral infection in ALL (35.71%) and then NHL (28.57%) patients., Conclusion: The results indicate that oral candidiasis is a prevalent fungal infection in the patients with hematologic malignancies with C. albicans being the main etiological agent. However, other species of Candida cause similar infections in these patients.

Background and Objectives: Staphylococcus aureus is the main Gram-positive bacteria isolated from patients with ocular infections. Herein, we describe the pattern of antibiotic resistance, presence of resistance genes including ermA, ermB, ermC, msrA, mecA and the pvl cytotoxin gene in S. aureus isolates collected from patients with external ocular infection., Materials and Methods: In this study, 8 S. aureus isolates were collected from 81 patients that suffered from eye damage. Antibacterial susceptibility of isolates was determined using the Kirby-Bauer disk diffusion method. Resistance genes including ermA, ermB, ermC, msrA, mecA and the pvl virulence gene were detected by PCR method. Staphylococcal cassette chromosome mec (SCC mec ) in MRSA isolates were detected by the multiplex-PCR method., Results: Three isolates were resistant to cefoxitin which is considered MRSA. The mecA gene was identified in MRSA isolates. SCC mec type IV and the pvl gene were detected in one of the MRSA isolates that was recovered from a diabetic patient., Conclusion: The emergence of S. aureus isolates belonging to SCC mec type IV and pvl gene among patients with ocular infection is very serious; therefore, identify genetic characterization of MRSA isolates for empirical therapy and infection control is very important.

Background and Objectives: The oprD mutation and AmpC overproduction are the main mechanisms of intrinsic resistance to carbapenems such as imipenem and meropenem in Pseudomonas aeruginosa., Materials and Methods: In this study, we investigated intrinsic resistance to carbapenems including mutation of oprD and AmpC overproduction in a carbapenem-resistant P. aeruginosa isolated from a burn patient by phenotypic and molecular methods., Results: In our study, the carbapenem-resistant P. aeruginosa isolate was resistant to imipenem, meropenem, cefepime, gentamicin, ceftriaxone, carbenicillin, aztreonam and ciprofloxacin but was susceptible to ceftazidime and polymyxin B. The minimum inhibitory concentrations (MICs) against imipenem, meropenem and ceftazidime were 64 μg/ml, 16 μg/ml and 2μg/ml, respectively. The isolate was ESBLs and AmpC overproducer. No carbapenemase activity was detected by Modified Hodge test (MHT). This isolate was carrying only bla OXA-10 . PCR amplification and sequencing of oprD performed on isolate resulted in PCR product of 2647bp. Sequence analysis of the 2647bp product revealed insertion of a sequence of 1232 bp at position 8 in coding region of oprD., Conclusion: According to the results of this study, oprD mutation and AmpC overproduction can cause the main mechanism of resistance of P. aeruginosa to carbapenems.

Background and Objectives: Pseudomonas aeruginosa is responsible for devastating nosocomial infections among severely burn patients. Class C of cephalosporinase (AmpC-β-lactamases) is important cause of multiple β-lactam resistance in P. aeruginosa. The aim of this study was to detect the AmpC-β-lactamases producing isolates among carbapenem resistant P. aeruginosa isolated from burn patient., Material and Methods: a total of 100 isolates of carbapenem resistant P. aeruginosa isolates from different burn patients were investigated. Three phenotypic methods were selected for identification of the AmpC-β-lactamases producing isolates., Results: Fifty four isolates were AmpC producer as detected by AmpC disk test. Seventeen isolates were identified as AmpC producer using combined disk method. Fifty two isolates showed a twofold or threefold dilution difference between the minimum inhibitory concentration of imipenem or ceftazidime and the minimum inhibitory concentration of imipenem or ceftazidime plus cloxacillin. One isolate was identified as AmpC producer using three methods. Three isolates produced AmpC as detected by both AmpC disk test and combined disk methods and 19 isolates were found as AmpC producer using both AmpC disk test and minimum inhibitory concentration methods. Six isolates were AmpC producer as shown by the MICs of both imipenem and ceftazidime., Conclusion: According to the results of this study, AmpC- β-lactamase looks to be the main mechanism of resistance of Pseudomonas aeruginosa to cephalosporins and carbapenems in the study hospital.