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J Hosp Infect. 2017 Mar;95(3):318-323. doi: 10.1016/j.jhin.2016.12.004. Epub 2016 Dec 10.

Reduction in chlorhexidine efficacy against multi-drug-resistant Acinetobacter baumannii international clone II.

Author information

1
Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Aichi, Japan.
2
Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Aichi, Japan. Electronic address: kumiko@met.nagoya-u.ac.jp.
3
Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo, Japan.
4
Department of Bacteriology, Nagoya University Graduate School of Medicine, Aichi, Japan.

Abstract

BACKGROUND:

Nosocomial infections caused by Acinetobacter baumannii international clone II (IC II) can cause severe clinical outcomes.

AIM:

Differential evaluation of bactericidal efficacy of chlorhexidine gluconate (CHX) and benzethonium chloride (BZT) disinfectants against IC II and non-IC II isolates.

METHODS:

Minimum inhibitory concentrations (MICs) of CHX and BZT were determined for 137 A. baumannii IC II, 99 non-IC II and 69 non-baumannii isolates, further classified according to MIC values into disinfectant-reduced susceptible (DRS) and disinfectant-susceptible (DS) groups. Time-kill curves and minimum bactericidal concentrations (MBCs) were evaluated for representative isolates in each group.

RESULTS:

CHX and BZT MIC90s for IC II isolates were 100 and 175mg/L, respectively, but those for non-IC II and non-baumannii isolates were <100mg/L. Nevertheless, time-kill curves indicated that CHX and BZT reduced live bacterial cell number by 5 log10 for IC II and non-IC II isolates within 30s when used at 1000mg/L, comparable to practical use concentrations. CHX MBC at 30s was 1000mg/L for IC II and non-IC II isolates, and was not influenced by addition of 3% bovine serum albumin (BSA); BZT MBC at 30s was 100mg/L without BSA and increased up to 500mg/L upon addition of BSA. No significant differences in BSA were found between DRS and DS isolates.

CONCLUSION:

CHX and BZT were effective against Acinetobacter spp. including IC II at a concentration of 1000mg/L and exposure for at least 30s, but their concentrations should be considered carefully to ensure sufficient effects in both clinical and healthcare settings.

KEYWORDS:

Acinetobacter baumannii; Benzethonium chloride; Chlorhexidine gluconate; Disinfection; International clone II

PMID:
28159381
DOI:
10.1016/j.jhin.2016.12.004
[Indexed for MEDLINE]

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