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 Urinary Tract Infections (henceforth, 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. Then, 250 samples were cultured, as suspected of having UTI, of which 193 samples (77.2 %) showed positive culture, while 57 samples (22.8 %) were negative cultures. Gram-positive bacteria were the predominant cause of UTI as represented by (66.7%), while Gram-negative species were found in (33.3%). Staphyloccus spp. bacteria were the predominant Gram-positive genus to isolate from UTI patients, while E. coli was the predominant species among Gram-negative bacteria. The isolates were tested for antibiotic susceptibility and biofilm formation. The most effective antibiotics tested on the Gram-positive isolates were Nitrofurantoin followed by Chloramphenicol (with resistance of 19% and 20%, respectively), whereas the least effective one was Azithromycin (with 64% resistance). As for the most effective antibiotic tested on the Gram-egative isolates, it was Amikacin (having only 8% resistance), while the least effective one was Erythromycin (with 98% resistance). Biofilm detection was performed by employing Congo red agar (CRA) method and microtiter plate (MTP) assay. The results showed that by using CRA method, about 81.3% of isolates were biofilm formers. While 96.7% of isolates were detected as biofilm formers by using MTP assay. Generally, biofilm formation was more predominant among Gram-positive isolates than Gram-negative ones.