Molecular characterization and antibiotic resistance of Acinetobacter baumannii in cerebrospinal fluid and blood

PLoS One. 2021 Feb 22;16(2):e0247418. doi: 10.1371/journal.pone.0247418. eCollection 2021.

Abstract

The increasing prevalence of carbapenem-resistant Acinetobacter baumannii (CRAB) caused nosocomial infections generate significant comorbidity and can cause death among patients. Current treatment options are limited. These infections pose great difficulties for infection control and clinical treatment. To identify the antimicrobial resistance, carbapenemases and genetic relatedness of Acinetobacter baumannii isolates from cerebrospinal fluid (CSF) and blood, a total of 50 nonrepetitive CSF isolates and 44 blood isolates were collected. The resistance phenotypes were determined, and polymerase chain reaction (PCR) was performed to examine the mechanisms of carbapenem resistance. Finally, multilocus sequence typing (MLST) was conducted to determine the genetic relatedness of these isolates. It was observed that 88 of the 94 collected isolates were resistant to imipenem or meropenem. Among them, the blaOXA-23 gene was the most prevalent carbapenemase gene, with an observed detection rate of 91.5% (86/94), followed by the blaOXA-24 gene with a 2.1% detection rate (2/94). Among all carbapenem-resistant Acinetobacter baumannii (CRAB) observations, isolates with the blaOXA-23 gene were resistant to both imipenem and meropenem. Interestingly, isolates positive for the blaOXA-24 gene but negative for the blaOXA-23 gene showed an imipenem-sensitive but meropenem-resistant phenotype. The MLST analysis identified 21 different sequence types (STs), with ST195, ST540 and ST208 most frequently detected (25.5%, 12.8% and 11.7%, respectively). 80 of the 94 isolates (85.1%) were clustered into CC92 which showed a carbapenem resistance phenotype (except AB13). Five novel STs were detected, and most of them belong to CRAB. In conclusion, these findings provide additional observations and epidemiological data of CSF and blood A. baumannii strains, which may improve future infection-control measures and aid in potential clinical treatments in hospitals and other clinical settings.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acinetobacter Infections / drug therapy*
  • Acinetobacter baumannii / drug effects*
  • Acinetobacter baumannii / genetics
  • Anti-Bacterial Agents / therapeutic use*
  • Bacterial Proteins / genetics
  • Blood / microbiology*
  • Carbapenems / therapeutic use
  • Cerebrospinal Fluid / microbiology*
  • Drug Resistance, Multiple, Bacterial / genetics*
  • Humans
  • Imipenem / therapeutic use
  • Meropenem / therapeutic use
  • Microbial Sensitivity Tests / methods
  • beta-Lactamases / genetics

Substances

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

Grants and funding

This work was supported by the National Sci-Tech Key Project (2018ZX10713-003-002, 2018ZX10713-001-002). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.