Carbapenem-resistant Gram-negative bacteria associated with catheter-related bloodstream infections in three intensive care units in Egypt

Eur J Clin Microbiol Infect Dis. 2018 Sep;37(9):1647-1652. doi: 10.1007/s10096-018-3294-7. Epub 2018 Jun 23.

Abstract

We aimed to identify the carbapenem-resistant Gram-negative bacteria (GNB) causing catheter-related bloodstream infections (CRBSI) in intensive care units (ICU) in a tertiary care Egyptian hospital, to study their resistance mechanisms by phenotypic and genetic tests, and to use ERIC-PCR for assessing their relatedness. The study was conducted over 2 years in three ICUs in a tertiary care hospital in Egypt during 2015-2016. We identified 194 bloodstream infections (BSIs); 130 (67.01%) were caused by GNB, of which 57 were isolated from CRBSI patients (73.84%). Identification of isolates was performed using conventional methods and MALDI-TOF MS. Antimicrobial susceptibility testing (AST) was done by disc diffusion following CLSI guidelines. Phenotypic detection of carbapenemases enzymes activity was by modified Hodge test and the Carba-NP method. Isolates were investigated for the most common carbapenemases encoding genes blaKPC, blaNDM, and blaOXA-48 using multiplex PCR. Molecular typing of carbapenem-resistant isolates was done by ERIC-PCR followed by sequencing of common resistance genes. The overall rate of CRBSI in our study was 3.6 per 1000 central venous catheter (CVC) days. Among 57 Gram-negative CRBSI isolates, Klebsiella pneumoniae (K. pneumoniae) was the most frequently isolated (27/57; 47.4%), of which more than 70% were resistant to Meropenem. Phenotypic tests for carbapenemases showed that 37.9% of isolates were positive by modified Hodge test and 63.8% by Carba-NP detection. Multiplex PCR assay detected the blaNDM in 28.6% of the isolates and blaKPC in 26.8%, blaNDM and blaKPC were detected together in the same isolate in 5.6%, while blaOXA-48-like were not detected. ERIC-PCR detected limited genetic relatedness between K. pneumoniae isolates. Elevated resistance rates were observed to all antibiotics including carbapenems among K. pneumoniae isolates causing CRBSI. ERIC-PCR showed that the resistant isolates were mainly polyclonal. Our results call for reinforcement of antimicrobial stewardship and measures to prevent CRBSI.

Keywords: Carbapenem resistance; Catheter-related bloodstream infections; ERIC-PCR; Gram-negative bacteria.

Publication types

  • Multicenter Study

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Bacteremia / epidemiology
  • Bacteremia / microbiology*
  • Bacterial Proteins / analysis
  • Bacterial Proteins / genetics
  • Carbapenems / pharmacology*
  • Catheter-Related Infections / epidemiology
  • Catheter-Related Infections / microbiology*
  • Cluster Analysis
  • Drug Resistance, Bacterial* / genetics
  • Egypt / epidemiology
  • Gram-Negative Bacteria / physiology*
  • Humans
  • Intensive Care Units / statistics & numerical data*
  • Microbial Sensitivity Tests
  • Molecular Typing
  • beta-Lactamases / analysis
  • beta-Lactamases / genetics

Substances

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