A study on the aac-(6(1))-lb-cr gene prevalence among ciprofloxacin-resistant strains of uropathogenic Enterobacteriaceae.

INTRODUCTION: Urinary tract infections (UTIs) are very common. Indiscriminate use of antibiotics has led to the development of resistance to most of the commonly used antibiotics including quinolones.

AIM: This study aimed to find out the prevalence of ciprofloxacin resistance among the uropathogenic Enterobacteriaceae, to determine the virulence factors of these isolates, and to detect the aac-(6(1))-lb-cr gene among those isolates with minimal inhibitory concentrations (MICs) of ciprofloxacin >256 mcg/ml.

MATERIALS AND METHODS: Urine samples reaching the microbiology laboratory were processed, pathogens belonging to the Enterobacteriaceae family were isolated from those with significant bacteriuria, and antibiotic sensitivity testing was performed according to the CLSI guidelines. MIC of ciprofloxacin for the isolates resistant to ciprofloxacin was determined by using the E-test, and virulence factors such as hemagglutination, hemolysis, and mucoid colonies were analyzed. aac-(6(1))-lb-cr gene was analyzed by polymerase chain reaction for those isolates with MIC > 256 mcg/ml.

RESULTS: Escherichia coli was the most common isolate (62%) with the highest ciprofloxacin resistance (68%). Fourteen percent of them had MIC > 256 mcg/ml and all of these isolates harbored the aac-(6(1))-lb-cr gene.

CONCLUSION: Plasmid-mediated drug resistance can rapidly spread and lead to selection of drug-resistant mutants if not controlled.