Analysis of carbapenemase resistance genes and their homology in multi-drug resistant Acinetobacter baumannii / 中国热带医学

ABSTRACT

@#Abstract: Objective　To analyze the genotype of carbapenemase resistance genes and their genetic homology in multidrug-resistant Acinetobacter baumannii, and to provide a theoretical basis for guiding the rational use of antibiotics and controlling the prevalence of nosocomial infections. Methods A total of 83 multidrug-resistant Acinetobacter baumannii isolated from patients in the intensive care unit (ICU) and environmental specimens in the Sixth People's Hospital of Nantong from July 2020 to December 2021 were collected. The bacteria were identified and subjected to drug sensitivity tests using the BioMérieux DL96-Ⅱ automatic bacterial identification susceptibility system. The carbapenemase-related drug resistance gene types were detected using the polymerase chain reaction (PCR) method, and clones were analyzed by pulsed field gel electrophoresis (PFGE). Results The types of 83 ICU Acinetobacter baumannii specimens include sputum (43 strains), broncholavage fluid (20 strains), and surfaces of objects such as ventilators (20 strains). The resistance rates of all strains to imipenem, tetracycline, gentamicin, amikacin and ciprofloxacin were 100%, 32.5%, 38.6%, 41.0% and 77.1% respecitively, while the resistance rates to others such as ticarcillin and clavulanate were greater than 95%. All strains carried were detected to carry OXA-23 and OXA-51 genes, while OXA-24, OXA-58, IMP-1, VIM, IMP-4, SIM and NDM-1 resistance genes were all negative. PFGE homology analysis confirmed that 83 strains of Acinetobacter baumannii, with counts of 12, 18, 12, 13, 10, 6, 7, 5 respectively, mainly A, B, C, D, E clones, the rest were sporadic clones. Conclusions The carbapenem resistant Acinetobacter baumannii isolated from our ICU are widely drug-resistant to commonly used antimicrobial drugs, with B clone strain being the major prevalent strain. Carrying OXA-23 and OXA-51 genes may be an important reason for the resistance of Acinetobacter baumannii to carbapenem antibiotics in our ICU. Rational use of antimicrobial drugs, enhanced monitoring of bacterial resistance, and effective control of the generation and further spread of drug-resistant strains should be emphasized.