Background and Objective: Production of beta-lactamase enzymes is the most common mechanism of bacterial resistance against beta-lactam antibiotics. The aim of this study was to determine the antibiotic resistance pattern and the frequency of AmpC genes in Escherichia coli (E. coli) isolated in outpatients. Methods: In this descriptive-analytical study, 67 isolates of E. coli were investigated from urinary tract infection of outpatients of the largest medical center in Kermanshah, west of Iran. Their susceptibility to ceftriaxone, cefotaxime, ceftazidime, cefoxitin and imipenem antibiotics was determined using disk diffusion. AmpC phenotypic screening was performed using combination disk method (cefoxitin with and without boronic acid). After extraction the bacterial genome, the presence of MOX, CIT, DHA, ACC, EBC and FOX genes were tested by multiplex PCR. Results: The resistance of 67 E. coli isolated to ceftriaxone, cefotaxime, ceftazidime and cefoxitin was 49. 2%, 49. 2%, 37. 3% and 25. 3%, respectively. The 100% of the isolates were sensitive to imipenem. Seventeen (25. 3%) and 9 isolates (13. 4%) were phenotypically and genotypically positive for AmpC, respectively. The prevalence of CIT, MOX, FOX, DHA and EBC genes was 7. 4%, 5. 9%, 4. 4%, 4. 4% and 2. 9%, respectively. However, the ACC gene was not found in isolates. Except for significant correlation between AmpC phenotype and MOX gene (P<0. 05), no significant statistical relationship was found between phenotype and AmpC genotype. There was a significant correlation between AmpC phenotype and ceftazidime antibiotic (P<0. 05). There was a significant correlation between CIT gene and EBC and FOX (P<0. 05). Conclusion: AmpC-producing E. coli isolates cause significant resistance to cephalosporins. One of the current therapeutic options is using of carbapenems. However, the relatively high prevalence and synergistic genes of AmpC in outpatients are a big concern and unfortunately it reflects the fact that these isolates are prevalent in the society.

Objective(s): Drug resistant Acinetobacter baumannii have emerged as a major problem in many hospitals and intensive care units. Various types of extended spectrum beta-lactamases (ESBLs) are responsible for resistance to beta-lactam antibiotics in different parts of the world. The objective of this study was to determine the prevalence of integron class1 (INT 1) and ESBL types PER-1, PER-2 and VEB-1 among A. baumannii strains isolated from Tabriz, North-West of Iran.Material and Methods: A total of 100 A. baumannii isolates collected from different clinical samples were included in the study. Antimicrobial susceptibility profiles were determined using the Kirby Bauer disk diffusion method. Production of ESBL was investigated by testing resistance against ceftazidime, cefotaxime, ceftriaxone and verified by Double Disk Synergy Test. DNA was extracted from the isolates and the frequency of INT 1 and ESBL types PER-1, PER-2 and VEB-1 were determined by PCR using specific primers.Results: Among 100 A. baumannii isolates screened, 80 isolates were multidrug-resistant and 70 isolates were positive for ESBL production. PCR screening revealed that 74 % of the isolates contained class 1 integron, 51% were positive for PER-1 gene, 10% positive for VEB1 whereas none of the isolates were positive for PER2 type gene.Conclusion: This is the first report of ESBL types VEB and PER in A. baumannii from North West of Iran. The results of this study demonstrated high prevalence of PER-1 and VEB-1 type ESBLs among A. baumannii isolates in the study region and reminded the necessity of appropriate infection control strategy to prevent further spread of infection by these organisms.

Background: Since the incidence of infections caused by MBLs producing Enterobacteriaceae is increasing worldwide, the aim of this descriptive study was the detection of MBLs producing in Enterobacteriaceae strains isolated from clinical specimens in Yazd teaching Hospitals using PCR method.Methods: This research was performed on Enterobacteriaceae strains collected from various specimens of in-patients in three teaching hospitals dependent to Shahid Sadoughi university medical sciences from 2011.2.1 until 2012.2.19 in Yazd. All isolates were identified by conventional methods. The antimicrobial susceptibility test was performed by Kirby- Bauer method according to CLSI protocols. MBL production was detected by Hodge test. PCR method using specific primers for blaIMP-1, blaVIM-1 and blaNDM was performed.Results: According to the results, of the 100 Enterobacteriaceae isolated, 26% were resistant to imipenem. Evaluation of Hodge test showed that 7 strains (7%) had Metalo-beta- Lactamases enzyme. 6 of these Metallo-beta-lactamases producing strains was isolated from urine culture and one Metallo- beta-lactamases producing strain was isolated from blood culture. Evaluation of blaIMP-1, blaVIM-1 blaNDM genes showed that among the Metallo-beta-Lactamases producing Enterobacteriaceae strains, 5 E. coli and one Enterobactercloacae strains had blaIMP-1 gene and one Klebsiella strain had bla- VIM-1 gene. None of them had blaNDM gene. All MBL producing isolates were multi drug resistant.Conclusion: The results show the high frequency of imipenem resistance in Enterobacteriaceae strains. In addition, the results show high prevalence of blaIMP-1 gene in MBLs producing Enterobacteriaceae.

The occurrence of extended-spectrum beta-lactamases-producing bacteria is an important public health issue. The aim of this study was to investigate phenotypic and genotypic characteristics regarding the presence of extended spectrum β-lactamase ctx-m, per and ver producing Escherichia coli isolated from raw dairy samples. For this purpose, E. coli were isolated from 247 raw dairy samples (milk and cheese) in Yasooj in 2015-2017, and the isolates were screened for antibiotic resistance, extended spectrum β-lactamase and the presence of ctx-m, per and ver. In total, 200 isolates were selected. The highest frequency of resistance in isolates was against tetracycline (96. 5%) and ampicillin (95. 5%) antibiotics and the lowest against imipenem (12. 5%), In addition, multidrug resistance against four or more antibiotics was observed in some isolates. Extended spectrum β-lactamase resistance was detected in 86 isolates (43%) and ctx-m, per and ver genes were detected in 82, 0 and 7 E. coli isolates, respectively. These findings demonstrated that raw dairy products may be reservoirs for the dissemination of β-lactam antibiotics and that resistance genes could be transmitted to humans through the food chain.