Distribution and Antimicrobial Susceptibility Pattern of Gram Negative Bacteria Causing Urinary Tract Infection (UTI) and Detection New Delhi Metallo-beta-lactamase-1 (NDM-1) Producing Isolates in Ahwaz

Urinary tract infection (UTI) is the commonest bacterial infectious disease in worldwide (especially in developing countries) with a high rate of morbidity and financial cost. The management of UTI infections has been jeopardized by increase in immergence of antimicrobial drug resistance. Knowledge of the local bacterial etiology and susceptibility patterns is required to trace any change that might have occurred in time so that updated recommendation for optimal empirical therapy of UTI can be made. The aim of this investigation was distribution and antimicrobial susceptibility pattern of gram negative bacteria causing urinary tract infection (UTI) and detection NDM-1 (new-delhi-metallo-beta-lactamase-1) producing isolates in Ahwaz.
This cross-sectional study was done during a period of one year from April 2013 to March 2014. Clean catch midstream urine samples were collected from suspected patients to UTI. The isolates were identified based on morphological and biochemical testes. Culture was performed on routine microbiological media. Susceptibility testing was performed according CLSI (2013) guidelines. Detection of carbapenemase producing isolates was performed by modified hodge test (MHT). Metallo-beta-lactamase isolates were detected by imipenem-EDTA combined disc test (CDT).
In this study 708 gram negative organisms were isolated from urine samples. E.coli was the most common isolated bacteria (67%) followed by Klebsiella spp. (26.5%) and Enterobacter spp. (2.5%). In antibiotic susceptibility testing more than 90% of isolates were sensitive to tetracycline, ceftazidime, meropenem, amikacin, cefotaxime, imipenem, and cefepime. Isolates were more resistant to cephalothin (32%), co-trimoxazol (30.5%), and nalidixic acid (25%).
In our results isolated organisms from outpatients showed very high sensitivity to common antibiotics. Continuous and regular monitoring of susceptibility pattern of community isolated strains is necessary. Antimicrobial susceptibility is important to guide effective antibiotic therapy.