Alotaibi Sulaiman M I, Ayibiekea Alafate, Pedersen Annemette Frøling, Jakobsen Lotte, Pinholt Mette, Gumpert Heidi, Hammerum Anette M, Westh Henrik, Ingmer Hanne
Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark.
Foodborne Diseases Surveillance Center, Executive Department of Surveillance Centers & Crisis Management, Saudi Food & Drug Authority, Riyadh, Saudi Arabia.
J Med Microbiol. 2017 Dec;66(12):1744-1751. doi: 10.1099/jmm.0.000642. Epub 2017 Nov 14.
In Danish hospitals, the number of infections caused by vancomycin-resistant Enterococcus faecium (VRE faecium) has dramatically increased in recent years. Hospital disinfectants are essential in eliminating pathogenic microorganisms, and reduced susceptibility may contribute to hospital-associated infections. We have addressed whether clinical VRE faecium display decreased biocide susceptibility when compared to vancomycin-sensitive Enterococcus faecium (VSE faecium) isolates.
In total 12 VSE faecium and 37 VRE faecium isolates obtained from Danish hospitals over an extended time period were tested for susceptibility towards three commonly applied biocides, namely benzalkonium chloride, chlorhexidine and hydrogen peroxide.
For benzalkonium chloride, 89 % of VRE faecium strains had a minimal inhibitory concentration (MIC) of 8 mg l, whereas for VSE faecium, only 25 % of the strains had an MIC of 8 mg l. For chlorhexidine, the MIC of 95 % of VRE faecium strains was 4 mg l or higher, while only 33 % of VSE faecium strains displayed MIC values at the same level. In contrast, both VRE and VSE faecium displayed equal susceptibility to hydrogen peroxide, but a higher minimal bactericidal concentration (MBC) was found for the former. The efflux activity was also assessed, and this was generally higher for the VRE faecium strains compared to VSE faecium.
VRE faecium from Danish hospitals demonstrated decreased susceptibility towards benzalkonium chloride and chlorhexidine compared to VSE faecium, where the use of chlorhexidine is particularly heavy in the hospital environment. These findings suggest that biocide tolerance may characterize VRE faecium isolated in Danish hospitals.
在丹麦医院，近年来耐万古霉素屎肠球菌（VRE粪肠球菌）引起的感染数量急剧增加。医院消毒剂对于消除病原微生物至关重要，而敏感性降低可能会导致医院相关感染。我们研究了与万古霉素敏感的屎肠球菌（VSE粪肠球菌）分离株相比，临床VRE粪肠球菌对杀菌剂的敏感性是否降低。
从丹麦医院在较长时间段内获得的总共12株VSE粪肠球菌和37株VRE粪肠球菌分离株，被检测对三种常用杀菌剂的敏感性，即苯扎氯铵、氯己定和过氧化氢。
对于苯扎氯铵，89%的VRE粪肠球菌菌株的最低抑菌浓度（MIC）为8mg/L，而对于VSE粪肠球菌，只有25%的菌株MIC为8mg/L。对于氯己定，95%的VRE粪肠球菌菌株的MIC为4mg/L或更高，而只有33%的VSE粪肠球菌菌株显示相同水平的MIC值。相比之下，VRE和VSE粪肠球菌对过氧化氢的敏感性相同，但前者的最低杀菌浓度（MBC）更高。还评估了外排活性，与VSE粪肠球菌相比，VRE粪肠球菌菌株的外排活性通常更高。
与VSE粪肠球菌相比，丹麦医院的VRE粪肠球菌对苯扎氯铵和氯己定的敏感性降低，而氯己定在医院环境中的使用尤其频繁。这些发现表明，杀菌剂耐受性可能是丹麦医院分离出的VRE粪肠球菌的特征。
