Extended-Spectrum β-Lactamase Production Rates and Antibiotic Susceptibilities Among Enterobacteriaceae Isolated From Urine Cultures

Objective: The aim of this study was to investigate the distribution of pathogens in urine cultures with significant bacteriuria from inpatients and outpatients, and to detect extended-spectrum beta-lactamase (ESBL) production rates among Enterobacteriaceae and their antimicrobial susceptibilities in our hospital. Methods: Urine specimens sent from various units to micro-biology laboratory between January 2016 and December 2017 were examined, and urines with pyuria and yielding a significant bacteriuria were included in the study. The identification, susceptibility tests , and ESBL production of the bacteria were determined by the VITEK ® 2 automated system. Results: A total of 4352 urine specimens showed significant bacteriuria. The most commonly isolated microorganisms were Escherichia coli, Klebsiella spp. and Enterococcus spp. ESBL positivity was found in 17.9% of Enterobacteriaceae , and it was detected more frequently in bacteria isolated from males, inpatients and patients over 65 years of age ( p <0.001). In the presence of ESBL positivity, sensitivity rates of nearly all antibiotics except fosfomycin and nitrofurantoin were significantly low. When antibiotic sensitivity rates of E. coli and Klebsiella spp. were compared between the outpatients and inpatients, antibiotic sensitivity rates in inpatients were low. Nitrofurantoin and fosfomycin were the most active antibiotics for both E. coli and Klebsiella spp. in outpatients; whereas amoxicillin-clavulanate, trimethoprim-sulfamethoxazole and ciprofloxacin were the less active ones. The most active parenteral antibiotics against E. coli and Klebsiella spp. were piperacillin-tazobactam, carbapen-ems and aminoglycosides.