Molecular characterization of carbapenemase and extended spectrum beta-lactamase producing Acinetobacter baumannii isolates causing surgical site infections in Ethiopia

BMC Infect Dis. 2024 Apr 30;24(1):459. doi: 10.1186/s12879-024-09362-5.

Abstract

Background: Acinetobacter baumannii is an opportunistic pathogen that can cause a variety of nosocomial infections in humans. This study aimed to molecularly characterize extended-spectrum beta-lactamase (ESBL) producing and carbapenem-resistant Acinetobacter species isolated from surgical site infections (SSI).

Methods: A multicentre cross-sectional study was performed among SSI patients at four hospitals located in Northern, Southern, Southwest, and Central parts of Ethiopia. The isolates were identified by microbiological methods and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antibiotic susceptibility was determined using disk diffusion. The presence of phenotypic ESBL and carbapenemase production was detected by employing standard microbiological tests, including combined disk diffusion (CDT). ESBL and carbapenem resistance determinants genes were studied by polymerase chain reaction (PCR) and sequencing.

Results: A total of 8.7% Acinetobacter species were identified from 493 culture-positive isolates out of 752 SSI wounds. The species identified by MALDI-TOF MS were 88.4% A. baumannii, 4.7% Acinetobacter pittii, 4.7% Acinetobacter soli, and 2.3% Acinetobacter lactucae. Of all isolates 93% were positive for ESBL enzymes according to the CDT. Using whole genome sequencing 62.8% of the A. baumannii harbored one or more beta-lactamase genes, and 46.5% harbored one or more carbapenemase producing genes. The distribution of beta-lactamases among Acinetobacter species by hospitals was 53.8%, 64.3%, 75%, and 75% at JUSH, TASH, DTCSH, and HUCSH respectively. Among ESBL genes, blaCTX-M alleles were detected in 21.4% of isolates; of these 83.3% were blaCTX-M-15. The predominant carbapenemase gene of blaOXA type was detected in 24 carbapenem-resistant A. baumannii followed by blaNDM alleles carried in 12 A. baumannii with blaNDM-1 as the most common.

Conclusions: The frequency of Acinetobacter species that produce metallobetalactamases (MBLs) and ESBLs that were found in this study is extremely scary and calls for strict infection prevention and control procedures in health facilities helps to set effective antibiotics stewardship.

Keywords: A. baumannii; Carbapenemase producing; ESBL; Ethiopia; SSI; Whole-genome sequencing.

Publication types

  • Research Support, Non-U.S. Gov't
  • Multicenter Study

MeSH terms

  • Acinetobacter Infections* / epidemiology
  • Acinetobacter Infections* / microbiology
  • Acinetobacter baumannii* / drug effects
  • Acinetobacter baumannii* / enzymology
  • Acinetobacter baumannii* / genetics
  • Acinetobacter baumannii* / isolation & purification
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents* / pharmacology
  • Bacterial Proteins* / genetics
  • Bacterial Proteins* / metabolism
  • Carbapenems / pharmacology
  • Child
  • Child, Preschool
  • Cross-Sectional Studies
  • Ethiopia / epidemiology
  • Female
  • Humans
  • Infant
  • Male
  • Microbial Sensitivity Tests*
  • Middle Aged
  • Surgical Wound Infection* / epidemiology
  • Surgical Wound Infection* / microbiology
  • Young Adult
  • beta-Lactamases* / genetics
  • beta-Lactamases* / metabolism

Substances

  • beta-Lactamases
  • Bacterial Proteins
  • carbapenemase
  • Anti-Bacterial Agents
  • Carbapenems