Oral treatment options for patients with urinary tract infections caused by extended spectrum βeta-lactamase (ESBL) producing Enterobacteriaceae.

Introduction: Frequent use of different antibiotics to treat urinary tract infections (UTIs) exerts a variety of selective pressure on pathogens which ultimately lead to the antimicrobial resistance. Extended Spectrum βeta-Lactamase (ESBL) producing Enterobacteriacae causing UTIs, which are usually multidrug resistant organisms, pose a great therapeutic treatment challenge. Rediscovery of forgotten antibiotics such as pivmecillinam, fosfomycin, and nitrofurantoin may be helpful in this situation until the discovery of new agents. The main aim of present study was to determine the prevalence of ESBL producing Enterobacteriacae causing UTIs and their sensitivity profile to determine alternate effective oral treatment options.

Methods: This retrospective study was conducted to determine the prevalence of ESBL producing Enterobacteriacae from urine samples and their sensitivity profile (pivmecillinam, fosfomycin, nitrofurantoin, trimethoprim and ciprofloxacin) from September 2015 to September 2017.

Results: A total of 986 organisms were isolated from the urine samples of 680 patients. Approximately 77% isolates were obtained from female patients (526). Of 986 organisms, Escherichia coli was the most common isolated organism (889, 90%); followed by Klebsiella species (71, 7%) and other Enterobacteriacae (26, 3%). Of 889 E. coli, approximately 98%, 96%, and 93% were found to be sensitive to fosfomycin, pivmecillinam and nitrofurantoin respectively. On the other hand pivmecillinam was most effective against Klebsiella species (83%, 59); followed by fosfomycin (62%, 44) and nitrofurantoin (42%, 30). Of 26 other Enterobacteriacae, 23 (88%), and 22 (85%) were sensitive to pivmecillinam and fosfomycin while lower sensitivity rate (15%, 4) was noted against nitrofurantoin. More than 95% of all ESBL producing Enterobacteriacae were sensitive to pivmecillinam, fosfomycin and nitrofurantoin. Trimethoprim and ciprofloxacin were least effective.

Conclusion: The emergence of multidrug resistant ESBL producing Enterobacteriacae restricts significantly the therapeutic options. This study shows higher sensitivity rates to pivmecillinam, fosfomycin and nitrofurantoin. We recommend their use to treat uncomplicated UTIs due to ESBL producing Enterobacteriacae.