Isolation of Gram-Negative Organisms Causing Nosocomial Catheter Associated Urinary Tract Infection and Detection of Fosfomycin Effect on Multi-Drug Resistant Strains in Sohag University Hospital

Abstract

Background: CAUTIs are the commonest HAIs and frequently caused by MDR Gram negative organisms, fosfomycin could be potentially used for this infection. Objectives:To isolate, identify Gram negative organisms causing CAUTIs, their antibiotic resistance pattern and to investigate their sensitivity to fosfomycin at Sohag University Hospitals. Methodology: Cross-sectional study included patients with catheter associated urinary tract infections (CAUTIs) admitted in the different Departments of Sohag University Hospitals from December 2019 to December 2022. The study included 310 urine samples from CAUTIs. Urine samples were subjected to routine culture, complete biochemical identification and antibiotic sensitivity testing were done by the BD Phoenix ™ automated identification and susceptibility testing system. ESBL producing organisms were detected by double-disk synergy test (DDST), Carbapenemase production by the modified Hodge test (MHT) and MBL production by EDTA combined disk synergy test (CDST). Fosfomycin sensitivity was detected by the disc diffusion method and minimum inhibitory concentration (MIC) by E-test. Conventional PCR was used to detect FosA, fosA2, fosA3, fosC2 genes. Results: The study group included (180) patients from them Gram negative bacilli were isolated. Their mean age was 52.8±11.7 years. Males were 99 (55%) of all studied patients. Most of them were from ICU. The most common isolated organism was E. coli 75 (41.7%), followed by Klebsiella pneumoniae 39 (21.7%), and Enterobacter cloacae 24 (13.3), 156 (86.6%) were MDR, 67 (43.3%) were ESBL producers by DDST, 49 (27%) Carbapenemase producers by MHT and 40 (22%) were MBL producers by EDTA CDST. One hundred and fifteen strains (66%) were sensitive to fosfomycin by E-test and FosA, A2, A3, C2 genes were detected in 47 (72.3%) of fosfomycin resistant strains. Conclusion: The study revealed that 86% of CAUTI were caused by MDR Gram negative organisms and 59% of them were susceptible to fosfomycin.