In Vitro Activities of Ceftazidime-Avibactam and Comparator Antimicrobial Agents Tested against ESBL Producing Urinary E. coli Isolates

Objectives: Urinary tract infections (UTIs) remain one of the most common infections for antibiotic prescription. Increased resistance to antibiotics currently used to treat these infections may lead to significant problems. Extended spectrum beta-lactamase (ESBL) production in organisms causing UTIs are often responsible for the increase in resistance. The aim of this study was to investigate the in vitro antimicrobial susceptibility of ESBL producing community acquired urinary E. coli isolates to Ceftazidime/Avibactam (CAZ/AVI) and other antimicrobial agents using disk diffusion method. Methods: Between 2016 and 2017, a total of 100 ESBL producing E. coli urine isolates were collected from outpatients who had no history of hospitalization in the last three months in Akdeniz University Hospital. All isolates were tested for in vitro susceptibility to the CAZ/AVI and other antimicrobial agents using disk diffusion method. Results: No CAZ/AVI and carbapenem resistance were observed. Resistance rates to other antimicrobial agents were as follows: ampicillin 100%, amoxicillin/clavulanate 85%, cefotaxime 98%, ceftazidime 89%, cefepime 82%, gentamicin 41%, ciprofloxacin 65%, levofloxacin 39%, fosfomycin 3%, nitrofurantoin 2%, trimethoprim/sulfamethoxazole 72% and Piperacillin/Tazobactam 41%. Conclusions: Our results showed that ceftazidime / avibactam, carbapenems, nitrofurantoin and fosfomycin may be among the first line treatment options in the empirical therapy. In selected patients, CAZ/AVI could be an option for the treatment of UTI caused by ESBL producing E.coli which may reduce the use of carbapenems. J Microbiol Infect Dis 2019; 9(2):112-115.