Determination of intravenous phosphomic resistance in clinical insulations of klebsiella pneumoniae and investigation of the synergist effect with meropenem, imipenem, amikacin antibiotics

In this study, fosfomycin disodium resistance status and synergistic effect with amikacin, meropenem, imipenem antibiotics were investigated by agar dilution method of carbapenem-resistant K. pneumoniae isolates grown in various samples of patients hospitalized in the intensive care unit and clinic. Thus, it is aimed to establish the most effective empirical treatment models for invasive infections caused by carbapenem resistant K. pneumoniae strains. 71 K. pneumoniae isolates grown in various patient samples sent from intensive care units and clinics to Dicle University Faculty of Medicine, Department of Medical Microbiology, Bacteriology Laboratory Unit between 20.03.2021 and 31.12.2021 were included in the study. Strains were identified by MALDI-TOF MS (bioMerieux, France). Antimicrobial susceptibility tests of the isolates were performed with the BD Phoenix 100 (Becton Dickinson, USA) automated system system using the Phoenix NMIC-400/ID panel. Carbapenem resistance of isolates detected as resistant to carbapenem in the automated system was confirmed by using ertapenem, meropenem and imipenem antibiotic discs and disc diffusion method. Strains with carbapenem resistance in the disc diffusion method were included in the study. The fosfomycin disodium resistance status of carbapenem-resistant K. pneumoniae isolates and the synergistic effect of fosfomycin with amikacin, meropenem, imipenem antibiotics were investigated by agar dilution method. As a result of the agar dilution method, 97,2% of the isolates were resistant to fosfomycin, 69% to amikacin, 84.5% to meropenem and 94,4% to imipenem. The combination of fosfomycin-amikacin in 25,35% of the isolates, fosfomycin-meropenem in 45,07% and fosfomycin-imipenem in 21.12% showed a synergistic effect. In all isolates and all combinations, antagonism was detected in the fosfomycin-amikacin combination in only one strain. Fosfomycin disodium can be used in combination with amikacin, meropenem and imipenem against invasive infections caused by multidrug rezistans (MDR) and carbapenem resistant K. pneumoniae strains.