Detection of CTX beta-lactamase Gene in Escherichia Coli Isolated from Urinary Tract Infection Using Polymerase Chain Reaction

Background and Escherichia Coli is one of the most common pathogens associated with nosocomial infection. Increasing use of beta Lactam Antibiotics in treatment of bacterial infections resulted in increments of drug resistance of such bacteria that is caused due to the production of B-lactamase enzymes. The beta lactamase – producing bacteria especially E.coli which is resistant to beta lactam antibiotics may pose great risks for patients. This study was conducted to determine the prevalence of CTX B-lactamase in E.coli isolates collected from hospitals in sari and Qaemshaher, Iran. In this study, 200 urine samples were collected from nephrology and infection departments in Qaemshaher Razi and Sari Imam Khomeini hospitals. The samples were cultured on EMB agar and incubated at 37oC for 24 hours. E.coli isolates were detected in 120 samples using standard bio chemical tests. ESBL production was determined by combination disk method. Then, the susceptibility of isolates towards antibiotics was determined by standard disk diffusion method. The presence of CTX gene was determined applying PCR. From 120 samples identified as Ecoli 66 (55%) were ESBLs producing strains. PCR showed that from 66 isolates 40 (60%) contained CTX gene. Our study showed high frequency of CTX gene in ESBL producing isolates. This indicates the role of enzyme in resistance to beta lactam containing antibiotics. This issue poses a serious harm to public and all necessary actions should be taken to prevent and control this problem.