Background and Objective: Urinary Tract Infections (UTIs) are mostly caused by Escherichia coli. The appropriate therapy demands a current knowledge on the antimicrobial susceptibility pattern amongst these pathogens, as an inappropriate use of antibiotics may lead to complications and treatment failure. The UTIs which are caused by multidrug resistant Extended-Spectrum Beta-Lactamase (ESBL) producing bacteria further pose a severe problem, as the treatment options are limited. The aim of this study was to identify the pattern of multi drug resistance amongst the uropathogenic E. coli (UPEC) isolates which were obtained from hospitalized patients.
Materials and Methods: Forty UPEC were isolated from 200 urine samples of hospitalized patients who were clinically suspected for UTIs. Antimicrobial susceptibility screening was performed by using 16 antibiotics, by the Kirby Bauer disk diffusion technique. The isolates which were resistant to the third generation cephalosporins were subjected to the ESBL confirmatory test by using drug and drug-inhibitor combination disks by following the CLSI guidelines.
Results: All the 40 isolates except three were multidrug resistant. They showed the highest sensitivities for nitrofurantoin (72.5%) and amikacin (70%). A high level of resistance was observed against ampicillin (97.5%), nalidixic acid and cefelexin (95%), amoxicillin (92.5%), cotrimoxazole (82.5%) and ciprofloxacin (80%) respectively. Thirty different antibiotic resistance patterns were observed against the different antibiotics. Twenty-eight out of the 40 isolates were resistant to the third generation cephalosporins. However, the phenotypic test for the ESBL confirmation indicated that eighteen out of the twenty-eight isolates were ESBL producers and that eleven different drug resistance patterns were observed amongst them.
Conclusions: Therefore, this study accounts for the varied multidrug resistance pattern amongst the uropathogenic E. coli which were isolated from hospitalized patients in Kolkata, an eastern region of India. Nitrofurantoin and amikacin should be assigned as potent drugs to treat this infection in this region of the country. These varied resistance patterns present major therapeutic and infection control challenges and they suggest a heterogeneous population of the uropathogenic E. coli isolates which circulate in this sector of India.