A Study of Urinary Tract Infections Prevalence, Antibiotics Resistance, and Biofilm Formation Capability of the Bacterial Causal Agents

Abstract

The aim of this study was to evaluate the incidence of UTI in Salahadin governorate/Iraq, identify the causative agents, their antibiotic sensitivity and their ability to form biofilms; such studies are mandatory to determine the empirical therapy of such cases. A total of 650 urine samples were collected. Two hundred and fifty samples were cultured, as suspected of having UTI, and 193 samples (77.2 %) showed growth (Positive culture), while 57 samples (22.8 %) were negative cultures. Gram-positive bacteria were the predominant cause of UTI (66.7%), while Gram-negative species were found in 33.3%. Staphyloccus spp. were the predominant Gram-positive genus to isolate from UTI patients, while E. coli was the predominant among Gram-negative bacteria. The isolates were tested for antibiotic susceptibility and biofilm formation. The most effective tested antibiotic on the Gram-positive isolates was Nitrofurantoin followed by Chloramphenicol (resistance percentage 19 and 20% respectively), and the least effective one was Azithromycin (64% resistance). While the most effective tested antibiotic on the Gram-egative isolates was Amikacin (only 8% resistance), and the least effective one was erythromycin (98% resistance). Biofilm detection by Congo red agar (CRA) method and microtiter plate (MTP) assay were done; the results showed that by CRA method 81.3% of isolates were biofilm formers. While 96.7% of isolates were detected as biofilm formers by microtiter plat assay. Generally, biofilm formation was more predominant among Gram-positive isolates than Gram-negative ones