Background As an opportunistic pathogen, Escherichia coli ( E. coli ) is widely recognized as the main cause of nosocomial infections as well as some disorders especially those associated with urinary tract infections (UTIs). This study, therefore, sets out to determine the extent of antibiotic resistance to quinolones and to measure the frequency of qnr genes (A, B, and S) within extended-spectrum beta-lactamase (ESBL) and non-ESBL-producing strains of E. coli isolated from UTI-diagnosed patients as well as to investigate their antimicrobial susceptibility patterns for some selected antibiotics in southwest Iran. Methods Two hundred E. coli strains were isolated from UTI-diagnosed patients, hospitalized in nine different wards of Ahvaz Golestan Hospital between November 2015 and March 2016. The isolates were confirmed through well-practiced phenotypical methods. Moreover, the antimicrobial susceptibility test was successfully performed using a disk diffusion method. ESBL production among the isolates was screened by double disk synergism test (DDST), and the qnr genes were identified using a multiplex PCR. Results Out of the 200 samples collected, 167 isolates were confirmed to be E. coli strains. Maximum and minimum resistance were reported against nalidixic acid and chloramphenicol with 65.3% and 17.4%, respectively. Most of the isolates were resistant to all three types of quinolones studied in this research. Using multiplex PCR, the qnr genes were found in 100 (59.88%) strains ( qnr A = 10, qnr B = 21, qnr S = 41, qnr B-S = 21, qnr B-A = 1, qnr A-S = 3, qnr A-B-S = 3), 58% of which was found among ESBL-producing isolates. Conclusions Resistance to quinolones antibiotics was highest among ESBL-producing isolates harboring, especially qnr S among other determinants of the qnr gene. There is a need for sensitive antibiotic stewardship especially in hospitals of Ahvaz, Khuzestan province. Further research is needed to ascertain the gravity of quinolones resistance in Iran and to quickly act against its spread among other nosocomial pathogens.

No abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen. We sought to determine the frequency of the different types of SCCmec in MRSA isolates by performing a cross-sectional study. A total of 72 S. aureus isolates were collected from Imam Khomeini and Golestan hospitals and analysed for MRSA and SCCmec typing by multiplex PCR. The pattern of antibiotic resistance among S. aureus isolates was determined by disc diffusion analysis. Of the 72 S. aureus isolates, 29 (40.27%) were recognized as MRSA. SCCmec type III was the most common type, with 55.17% (16/29), followed by type II with 27.58% (8/29); type IV with 10.34% (3/29); and type I with 6.89% (2/29). All 29 MRSA isolates were resistant to chloramphenicol and erythromycin. In addition, resistance to cephalothin, gentamicin, clindamycin, ciprofloxacin, tetracycline and rifampicin was seen in 24 (75%), 26 (63.4%), 17 (94.4%), 27 (71.05%), 10 (71.42%) and 13 (68.42%) MRSA isolates, respectively. A decreased sensitivity of MRSA to the antibiotics used was observed, with type III SCCmec being the predominant isolate.

Background:The rising frequency of methicillin resistant Staphylococcus aureus (MRSA) has led to an increased use of antibiotics such as macrolide, lincosamide, streptogramin B (MLSB) for the treatment of S. aureus infections. Resistance to MLSB in S. aureus is commonly encoded by erm genes, which can be constitutive MLSB (cMLSB) or inducible MLSB (iMLSB). The purpose of this study was to determine the frequency of cMLSB, iMLSB, and MS phenotypes using D-test and polymerase chain reaction (PCR) methods.Materials and Methods:A total of 215 isolates of S. aureus were collected from January 2010 to May 2012 from Al-Zahra Hospital in Isfahan. PCR was performed for detection of mecA gene on all isolates using specific primers. The frequency of MLSB-resistant isolates was determined using D-test, and then a multiplex PCR was performed for detection of ermA, ermB, and ermC genes.Results:Among 215 S. aureus isolates examined, 82 (40.9%) were MRSA, and iMLSB, cMLSB, and MS resistance phenotypes had a frequency of 9 (4.18%), 58 (26.9%), and 11 (5.1%), respectively. Among nine isolates with iMLSB resistance phenotype, four isolates contained ermC gene, two isolates ermB gene, and one isolate ermA gene. Two isolates did not have any erm gene.Conclusion:In the current study, cMLSB was the most frequent phenotype and ermC was the most common gene in iMLSB resistant phenotypes.