Study of Cases of Bacteremia with Gram-Negative Pathogens with Multiple and Extreme Antibiotic Resistance in Real Clinical Practice

Abstract

Aim:To study cases of bacteremia caused by multidrug-resistant (MDR) and extremely-resistant (XDR) gram-negative bacteria in the departments of a multidisciplinary hospital.Material and Methods.Since 2017, a retrospective epidemiological study has been conducted to investigate cases of infections with bacteremia caused using gram-negative bacteria with multiple or extreme antibiotic resistance. The pathogens were identified using the MALDI-TOF MS method, the sensitivity to antibacterial drugs was determined using the automatic Phoenix system, the beta-lactamase genes were detected using real-time PCR on a GeneXpert analyzer.Results.In 2017, bacteremia caused by MDR and XDR pathogens was detected in 42 and 76 patients, in 2018 — in 57 and 81 patients, in 2019 — in 65 and 111 patients, respectively. During three years of observation, the most frequent XDR microorganisms were, in descending order,Klebsiella pneumoniae,Acinetobacter baumannii,Pseudomonas aeruginosa. In 2019, among 11K.pneumoniaestrains, class D carbapenemase (OXA-48) was detected in 5 cases (45.5%), 3 strains produced NDM metallo-carbapenemase, and 3 strains had a combination of NDM and OXA-48 enzymes. Infections caused by MDR and XDR pathogens were characterized by high mortality. Thus, the relative risk of death in patients with XDR infection was 1.33 times higher than in patients from the MDR group (95% CI 1.04-1.69, PConclusions.K.pneumoniaeandA.baumanniiwith extreme antibiotic resistance are the main causative agents of severe late nosocomial infections in immunosuppressed patients. Nosocomial infections with bacteremia caused by gram-negative bacteria with the XDR phenotype and resistant to carbapenems are characterized by a high mortality rate (from 72 to 80%), and increase the duration of hospitalization by more than 4 times.