Molecular Survey of Nalidixic Acid Resistance E.coli Isolated from Patients with Urinary Tract Infection in Baqiyatallah Hospital

Members of the Enterobacteriaceae family are a large group of bacteria widely distributed in nature. Enterobacteriaceae often are labeled as enteric bacteria because of their predilection for intestinal colonization. E.coli is the most common cause of urinary tract infection. The aim of this study was molecular survey of Nalidixic Acid Resistance E.coli isolated from patients with urinary tract infection in Baqiyatallah hospital.

During 5 months (January to June 2005), urine samples of patients referred to clinical laboratory of Baqiyatallah hospital were cultured. Differential tests were done for diagnosis of E.coli. For evaluation of antimicrobial resistance, PCR method was done for positive samples including sensitive and resistant E.coli. Then, MIC test was done and finally sequencing was performed.

In this study, 121 E.coli were isolated from urinary samples. In Nalidixic Acid antibiogram test, 55 cases (45.5%) were sensitive, 63 cases (52%) were resistant and 3 cases (2.5%) were Intermediate. Results of PCR and MIC were similar to antibiogram.

Depending on results of this study and comparison with other studies, trend of resistance of E.coli is increasing. Therefore, we recommend control of antibiotic misusage and application of MIC and PCR tests (if possible) prior to treatment for suitable selection of antibiotic and prevention of microbial resistance.