Emerging Ciprofloxacin resistant Escherichia coli among urinary tract isolates. Is Ciprofloxacin resistance, a bench marker resistance to other fluoroquinolones?

Introduction: Escherichia coli (E.coli) are the common bacteria causing urinary tract infections (UTIs) worldwide. Ciprofloxacillin, a fluoroquinolone, is the most common empirical drug prescribed for urinary tract infections due to Escherichia coli. Increased use of ciprofloxacin has resulted in its resistance to E.coli and resistance to one generation of fluoroquinolone may also confer resistance to other fluoroquinolones. This study aims to describe the antibiotic susceptibility pattern of E.coli isolates from patients with UTIs. Ciprofloxacin resistant E.coli isolates were analyzed for antibiotic susceptibility to further generation fluoroquinolones. Material and Methods: A total of 248 urine samples which were positive for E.coli were randomly selected for this study. Antibiotic susceptibility testing of the E. coli isolates was done by Kirby Bauer disc diffusion technique in accordance with the National Committee for Clinical Laboratory Standards (NCCLS). 100 ciprofloxacin resistant E.coli isolates were further studied for their antibiogram to levofloxacin, gatifloxcin and moxifloxacin. The clinical and demographic profile of patients was noted. Results: High rates of susceptibility was found to cefoperazone+ sulbactam( n=175, 70.5%), followed by ciprofloxacin (n=144, 58%), cefipime ( n=142, 57.2%), nitrofurantoin (n=142, 57.2%) and amikacin ( n=138, 55.6 %). The lowest susceptibility was to trimethoprim-sulphomethoxazole (n=30, 12%). Among these 100 ciprofloxacin resistant isolates there was only a slight improvement in their susceptibilities even to other fluoroquinolones. Discussion: This study shows emerging ciprofloxacin resistance among urinary tract E.coli isolates. The ciprofloxacin resistant E.coli isolates showed only a slight improvement in their susceptibilities to other fluoroquinolones. Conclusion: Fluoroquinolones may be prescribed following culture and sensitivity results and not as empirical drugs. This study recommends nitrofurantoin for empirical therapy in UTI. It also suggests that ciprofloxacin resistance could be considered as a bench marker for resistance to other fluoroquinolones.