Influence of whole-body washing of critically ill patients with chlorhexidine on Acinetobacter baumannii isolates

Am J Infect Control. 2014 Aug;42(8):874-8. doi: 10.1016/j.ajic.2014.04.009. Epub 2014 Jun 7.

Abstract

Background: Acinetobacter baumannii is 1 of the most important nosocomial pathogens and the causative agent of numerous types of infections, especially in intensive care units (ICUs). Our aim was to evaluate the effect of 2% chlorhexidine gluconate (CHG) whole-body washing of ICU patients on A baumannii in a tertiary care hospital.

Methods: During the 6-month intervention period, 327 patients were subjected to whole-body bath with 2% CHG-impregnated wipes. blaIMP (active on imipenem), blaVIM (Verona integron-encoded metallo-ß-lactamase), and blaoxacillinase (OXA) of A baumannii were typed. Isolates were genotyped by pulsed-field gel electrophoresis. Minimum inhibitory concentrations (MIC) to CHG were determined by the agar dilution method and drug susceptibility determined using the broth microdilution method. Biofilm formation was determined by crystal violet staining.

Results: We analyzed 80 isolates during the baseline period and 69 isolates during the intervention period. There was a decrease in the MIC₅₀ and MIC₉₀ values for CHG for isolates (8 mg/L and 16 mg/L, respectively). All isolates typed positive for OXA₅₁-like and 86% typed positive for OXA₂₄-like pulsed-field gel electrophoresis identified 2 main clone types. During the intervention period the frequency of clone A decreased and that of clone B increased. Both clones were OXA₂₄-like positive.

Conclusions: The A baumannii isolates recovered from patients who received body washing with 2% CHG presented with a significant decrease in CHG MIC values associated with a change in clonality correlating with increased biofilm production.

Keywords: Disinfectant; IMP (active on imipenem); Oxacillinase; Pulsed-field gel electrophoresis; VIM (Verona integron-encoded metallo-ß-lactamase).

MeSH terms

  • Acinetobacter Infections / epidemiology*
  • Acinetobacter Infections / microbiology
  • Acinetobacter Infections / prevention & control*
  • Acinetobacter baumannii / classification
  • Acinetobacter baumannii / enzymology
  • Acinetobacter baumannii / genetics
  • Acinetobacter baumannii / isolation & purification*
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents / pharmacology
  • Anti-Infective Agents, Local / therapeutic use*
  • Chlorhexidine / therapeutic use*
  • Critical Illness*
  • Electrophoresis, Gel, Pulsed-Field
  • Female
  • Humans
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Molecular Typing
  • Tertiary Care Centers
  • Young Adult
  • beta-Lactamases / classification
  • beta-Lactamases / genetics

Substances

  • Anti-Bacterial Agents
  • Anti-Infective Agents, Local
  • beta-Lactamases
  • Chlorhexidine