TY - JOUR
T1 - Reduced susceptibility to chlorhexidine among extremely-drug-resistant strains of Klebsiella pneumoniae
AU - Naparstek, L.
AU - Carmeli, Y.
AU - Chmelnitsky, I.
AU - Banin, E.
AU - Navon-Venezia, S.
N1 - Funding Information:
This work was supported in part by the European Commission Research Grant FP7 : SATURN – Impact of Specific Antibiotic Therapies on the Prevalence of Human Host Tolerant Bacteria.
PY - 2012/5
Y1 - 2012/5
N2 - Background: Over the last decade, extremely-drug-resistant (XDR) strains of . Klebsiella pneumoniae have emerged worldwide, mainly as a result of patient-to-patient spread. The predominant clone, sequence type 258 (ST258), is associated with high morbidity and mortality, and is a worldwide threat to public health. It was hypothesized that reduced susceptibility to chlorhexidine, the most widely used hospital disinfectant, may contribute to the endemic nature of this strain. Aim: To characterize and compare the susceptibility of the epidemic . K. pneumoniae clone ST258 and non-epidemic . K. pneumoniae clones to chlorhexidine. Methods: The minimum inhibitory concentration (MIC) of chlorhexidine was determined in 126 XDR . K. pneumoniae clinical isolates using agar dilution. Expression of three different efflux pumps - . cepA, . acrA and . kdeA - was investigated in the absence and presence of chlorhexidine using quantitative real-time polymerase chain reaction. Heteroresistance to chlorhexidine was identified using population analysis. Findings: The MIC of chlorhexidine was higher for . K. pneumoniae ST258 (. N = 70) than other . K. pneumoniae sequence types (. N = 56); 99% of ST258 isolates had MICs >32 μg/mL, compared with 52% of other . K. pneumoniae sequence types (. P < 0.0001). Reduced susceptibility to chlorhexidine appeared to be independent of the expression of . cepA, . acrA and . kdeA efflux pumps. Chlorhexidine-resistant subpopulations were observed independent of the bacterial sequence type or the MIC. Conclusions: Reduced susceptibility to chlorhexidine may contribute to the success of XDR . K. pneumoniae as a nosocomial pathogen, and may provide a selective advantage to the international epidemic strain . K. pneumoniae ST258. The heterogeneous nature of chlorhexidine-resistant subpopulations suggests that this phenomenon might not be rendered genetically.
AB - Background: Over the last decade, extremely-drug-resistant (XDR) strains of . Klebsiella pneumoniae have emerged worldwide, mainly as a result of patient-to-patient spread. The predominant clone, sequence type 258 (ST258), is associated with high morbidity and mortality, and is a worldwide threat to public health. It was hypothesized that reduced susceptibility to chlorhexidine, the most widely used hospital disinfectant, may contribute to the endemic nature of this strain. Aim: To characterize and compare the susceptibility of the epidemic . K. pneumoniae clone ST258 and non-epidemic . K. pneumoniae clones to chlorhexidine. Methods: The minimum inhibitory concentration (MIC) of chlorhexidine was determined in 126 XDR . K. pneumoniae clinical isolates using agar dilution. Expression of three different efflux pumps - . cepA, . acrA and . kdeA - was investigated in the absence and presence of chlorhexidine using quantitative real-time polymerase chain reaction. Heteroresistance to chlorhexidine was identified using population analysis. Findings: The MIC of chlorhexidine was higher for . K. pneumoniae ST258 (. N = 70) than other . K. pneumoniae sequence types (. N = 56); 99% of ST258 isolates had MICs >32 μg/mL, compared with 52% of other . K. pneumoniae sequence types (. P < 0.0001). Reduced susceptibility to chlorhexidine appeared to be independent of the expression of . cepA, . acrA and . kdeA efflux pumps. Chlorhexidine-resistant subpopulations were observed independent of the bacterial sequence type or the MIC. Conclusions: Reduced susceptibility to chlorhexidine may contribute to the success of XDR . K. pneumoniae as a nosocomial pathogen, and may provide a selective advantage to the international epidemic strain . K. pneumoniae ST258. The heterogeneous nature of chlorhexidine-resistant subpopulations suggests that this phenomenon might not be rendered genetically.
KW - Chlorhexidine resistance
KW - Efflux pumps
KW - Extremely drug resistant
KW - Heteroresistant subpopulations
KW - ST258
KW - XDR Klebsiella pneumoniae
UR - http://www.scopus.com/inward/record.url?scp=84860332763&partnerID=8YFLogxK
U2 - 10.1016/j.jhin.2012.02.007
DO - 10.1016/j.jhin.2012.02.007
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C2 - 22463977
AN - SCOPUS:84860332763
SN - 0195-6701
VL - 81
SP - 15
EP - 19
JO - Journal of Hospital Infection
JF - Journal of Hospital Infection
IS - 1
ER -