Majid Eslami, Shahin Najar Peerayeh,
Volume 15, Issue 1 (4-2012)
Abstract
Background: TEM, PER, and VEB are extended-spectrum betalactamase (ESBL) enzymes that are capable of hydrolyzing penicillins, cephalosporins, and aztreonam. The aim of this study was to determine the prevalence of ESBL producing E.coli and molecular evaluation of TEM, PER, and VEB β-lactamases among E.coli strains.
Materials and Methods: A total of 200 clinical strains of E.coli were isolated from clinical specimens and their antibiotic susceptibility was determined by disk diffusion method. ESBL production was determined using the combined disk method with CAZ and CTX with clavulanic acid and alone. Minimum concentration inhibition (MIC) for CAZ and CTX with clavulanic acid and alone was determined by agar dilution method. Finally, PCR with specific primers was used for determining the presence of blaTEM, blaPER, and blaVEB genes.
Results: Combined disk method confirmed 94 strains (47%) to be ESBL producing E.coli. Of the 94 ESBL producing strains, 36 samples had MIC=16, 44 samples had MIC between 32-256, and 10 samples had MIC≥512 for ceftazidime, whereas 8 samples had MIC=16, 68 samples had MIC between 32-256, and 21 samples had MIC≥512 for cefotaxime. The frequency of TEM was 44% however, blaPER and blaVEB genes were not detected by PCR among ESBL producing isolates.
Conclusion:The results indicated that the high percentage of ESBL producing E.coli is 47% and PCR method showed a high frequency of TEM enzyme, but PER and VEB betalactamase were not found among them.
Nader Zarinfar, Majid Akbari, Mojtaba Sharafkhah,
Volume 16, Issue 10 (1-2014)
Abstract
Background: According to the studies, Iran’s per capita antibiotic consumption is remarkable. Since the emergence of Antibiotic Resistant Organisms (AROs) is considered a global problem in the community and hospitals, this study aimed to investigate the pattern of antibiotic resistance in Gram-negative bacteria isolated from patients in an academic and a non-academic hospital in Arak, Iran.
Materials and Methods: This descriptive cross-sectional study included all specimens referred to the microbiology laboratory at Amir Al-Momenin Hospital (academic hospital) and Imam Khomeini Hospital (non-academic hospital) in a one-year period from June 2012 to June 2013. The susceptibility of the isolated Gram-negative bacteria against the important antibiotics used in clinical practice was determined using the disk diffusion method.
Results: A total of 846 specimens were collected from patients in the two hospitals where 520 (61.5%) were Gram-negative bacteria, of which 63.3% were E. coli. The prevalence of Gram-negative organisms in the academic and the non-academic hospital was measured 79.8% and 20.2%, respectively (p=0.097). It was also determined that there is a significant difference between the two hospitals in the prevalence of ESBL (Extended-Spectrum Beta-Lactamase) Gram-negative bacteria (p=0.003).
Conclusion: There was a significant difference between the two hospitals in the prevalence of ESBL Gram-negative bacteria. Therefore, conducting regional surveillance programs to examine the patterns of antibiotic resistance is recommended.
