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Background S. aureus seems to play a significant role in the pathogenesis of infection in hospitals setting. This study aimed to the investigation of the prevalence of S. aureus isolates and the determination of antibiotic susceptibility pattern and the different types of SCCmec in MRSA isolates obtained from a clinical sample in Isfahan, Iran. Methods This study was performed during January 2013 to March 2014 at tertiary care hospitals. S. aureus isolates were collected from the clinical samples. Determination of antibiotic susceptibility pattern was done by the disc diffusion method. Also, SCCmec typing was performed by PCR method. Results A total of 150 S. aureus isolates were collected from the different clinical sample. Among them, 41.3% (62/150) isolates were MRSA. The most sensitivity for MRSA isolates was to vancomycin with 90% sensitivity and the high rate of resistance was toward tetracycline in MRSA and MSSA isolates. All of MRSA isolates were MDR. The rate of SCCmec types IV, III, I and II among MRSA isolates were 44.4%, 40.7%, 11.1% and 3.7, respectively. Conclusions The results of the current study showed that S. aureus especially MRSA isolates with a high rate of resistance still remains an important healthcare problem. Majority of the isolates were community-acquired and belonged to Sccmec type.

The emergence of carbapenem resistance among Escherichia coli is a serious threat to public health. The objective of this study was to investigate resistance genes and clonality of carbapenem resistant E. coli in Iran. Between February 2015 and July 2016, a total of 32 non-duplicate E. coli isolates that were ertapenem resistant or intermediate (R/I-ETP) were collected from patient clinical or surveillance cultures (rectal swabs) at two university hospitals. Resistance genes were identified by PCR and sequencing. Conjugation experiments, PCR-based replicon typing, PFGE and multilocus sequence typing (MLST) were performed. PCR assays showed, among the 32 isolates, twenty-nine strains produced carbapenemase genes. The predominant carbapenemase was blaOXA-48 (82.8%), followed by blaNDM-1 (31%), blaNDM-7 (6.9%) and blaOXA-181 (3.4%). Seven of the blaNDM positive isolates co-harbored blaOXA-48 carbapenemases. The blaNDM and blaOXA-48 were found in IncA/C and IncL/M conjugative plasmids, respectively. The blaCTX-M-15, qnrA and intI1 genes were also present in most isolates. The PFGE revealed genetic diversity among the 28 E. coli isolates, which belonged to six minor PFGE clusters and 14 isolates were singletons. The 26 isolates were distributed into 18 STs, of which two were dominant (ST648 and ST167). We identified one blaNDM-1-positive ST131 E. coli isolates that harbor the blaCTX-M-15 and blaTEM genes. Horizontal transfer of IncA/C and IncL/M plasmids has likely facilitated the spread of the blaOXA-48 and blaNDM genes among E. coli. Their clonal diversity and the presence of faecal carriers in isolates suggest an endemic spread of OXA-48 and NDM. Therefore, it emphasizes the critical importance of monitoring and controlling the spread of carbapenem resistant E. coli.

Introduction Due to the important role of integrons and efflux pumps in increasing drug resistance, the aim of this study was to investigate the frequency of integrons and efflux pump in Uropathogenic Escherichia coli (UPEC) isolated from Iranian kidney and non-kidney transplant patients. Materials and methods A case-control study was performed on 111 UPEC isolates obtained from 46 kidney transplant patients (group A) and 65 non-kidney transplant patients (group B) who were diagnosed with a UPEC-associated urinary tract infection between June 2019 to October 2019 in Isfahan, Iran. In our study, isolates were further confirmed as E. coli based on phenotyping and genotyping test. Antimicrobial susceptibility was determined using the disc diffusion method, and the presence of integron and efflux pump genes was detected by polymerase chain reaction. Results In this study, the frequency of integron genes was as follows: 60.9% and 28.3% isolates of group A and 47.7% and 21.6% isolates of group B carried int1 and int2, respectively. In both groups with int1-positive, the highest resistance was to co-trimoxazole with (89.3%) and (67.7%), respectively. The lowest antibiotic resistance rates in groups A and B with int1-positive were seen against piperacillin/tazobactam (14.3%) and nitrofurantoin (9.7%), respectively. There was a significant association between the presence of Class 1 integron and cefixime in group A, and resistance to co-trimoxazole in group B. All three genes acrA, acrB, and tolC were present simultaneously in 68.5% (76/111) isolates, 71.8% (33/46) isolates of group A, and 66.2% (43/65) isolates of group B. Among all isolates a significant correlation between the presence of the tolC gene and the resistance to nalidixic acid, ofloxacin, and piperacillin-tazobactam was observed. Conclusion Our data indicated a significant relationship between the presence of integrons and several antibiotics such as co-trimoxazole and cefixime. Furthermore, RND efflux pumps such as AcrAB-TolC play an important role in gram-negative bacteria in the removal of toxic substances and antibiotics.