Prevalence and antibiotic resistance profiles of Gram negative bacilli associated with urinary tract infections (UTIs) in Karachi, Pakistan

Abstract

The aim of this investigation was to determine the prevalence and antibiotic resistance profiles of Gram negative bacilli (GNB) responsible for urinary tract infections (UTIs). Urine specimens were cultured on Cysteine Lactose Electrolyte Deficient Agar (CLED) medium and pathogenic GNB were identified by conventional biochemical methods and automated profile index (API) system and further subjected to antibiotic sensitivity testing by disk diffusion method. Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii were encountered as most frequent GNB in sequence. Among them E. coli (71%) was the most prevalent GNB. About 77% E. coli isolates of indoor patients and 59% of outdoor patients were found resistant to Cefotaxime. Kleb. pneumoniae were 100% resistant to Ampicillin. Higher resistance in Ps. aeruginosa was noticed in isolates of indoor patients i.e. Ciprofloxacin (76%), Cefoperazone-sulbactam (60%), Ceftazidime (59%), Piperacillin-tazobactam (53%), Imipenem (49%) and Amikacin (39%) in contrast to that of outdoor patients. Slightly lower resistance in Acinetobacter baumannii against Ampicillin (86%), Nitrofurantoin (81%) and Fosfomycin (12%) was witnessed in indoor patients’ urine specimens compared to outdoor patients’ urine. Polymyxin B, Imipenem, Fosfomycin, Piperacillin-tazobactam, Cefoperazone-sulbactam, Amikacin and Nitrofurantoin were most effective in GNB induced UTIs. This study revealed elevated resistance profiles in GNB against Ampicillin, Amoxicillin-clavulanate, Cefotaxime, Aztreonam, Ciprofloxacin,Nalidixic acid and Trimethoprim/sulfamethoxazole. Emergence of antibiotic resistant GNB was due to the frequent use and misuse of antibiotics in our region.