Sensitivity of extended spectrum of β-lactamase producing Escherichia coli and Klebsiella species to Fosfomycin

Abstract

Objective: To investigate extended spectrum beta-lactamase production and Fosfomycin resistance rates of Escherichia coli and Klebsiella species isolates from patients' urine culture. Methods: Chromogenic agar was used to identify Escherichia coli and Klebsiella species strains. All antibiogram processing was carried out on a fully automated VITEK 2 identification and antibiogram system. The results obtained between January 2015 and December 2018 were retrospectively screened. Results: Escherichia coli and Klebsiella species were isolated from total 2868 urine cultures. Thus, 844 (34.9%) of 2418 Escherichia coli and 305 (67.8%) of 450 Klebsiella species producted ESBL. Sensitivity rate of ESBL producing Escherichia coli to Fosfomycin was 96.5%, and 98.8% for ESBL negative Escherichia coli. Sensitivity rate of ESBL producing Klebsiella pneumoniae to Fosfomycin was 70.5%, and 53.1% for ESBL negative Klebsiella pneumoniae. None of the three ESBL producing Klebsiella oxytoca strains were found to be resistant to Fosfomycin, though five of 15 ESBL negative strains were found to be resistant to Fosfomycin. Conclusion: Taking into consideration the advantages of low resistant rate, it is concluded that Fosfomycin may be a good alternative for first step empirical treatment in urinary tract infections, especially in Escherichia coli positive cases. However, the rate of resistance identified in Klebsiella strains informs the onset of resistance problems in Fosfomycin.