Sulaiman M I Alotaibi1,2, Alafate Ayibiekea1, Annemette Frøling Pedersen1, Lotte Jakobsen3, Mette Pinholt4, Heidi Gumpert4, Anette M Hammerum3, Henrik Westh4,5, Hanne Ingmer1. 1. Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark. 2. Foodborne Diseases Surveillance Center, Executive Department of Surveillance Centers & Crisis Management, Saudi Food & Drug Authority, Riyadh, Saudi Arabia. 3. Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark. 4. Department of Clinical Microbiology, Hvidovre University Hospital, Hvidovre, Denmark. 5. Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark.
Abstract
PURPOSE: 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. METHODOLOGY: 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. RESULTS: For benzalkonium chloride, 89 % of VRE faecium strains had a minimal inhibitory concentration (MIC) of 8 mg l-1, whereas for VSE faecium, only 25 % of the strains had an MIC of 8 mg l-1. For chlorhexidine, the MIC of 95 % of VRE faecium strains was 4 mg l-1 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. CONCLUSION: 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.
PURPOSE: 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. METHODOLOGY: 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. RESULTS: For benzalkonium chloride, 89 % of VRE faecium strains had a minimal inhibitory concentration (MIC) of 8 mg l-1, whereas for VSE faecium, only 25 % of the strains had an MIC of 8 mg l-1. For chlorhexidine, the MIC of 95 % of VRE faecium strains was 4 mg l-1 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. CONCLUSION: 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.
Authors: Bárbara Duarte; Ana P Pereira; Ana R Freitas; Teresa M Coque; Anette M Hammerum; Henrik Hasman; Patrícia Antunes; Luísa Peixe; Carla Novais Journal: Appl Environ Microbiol Date: 2019-11-14 Impact factor: 4.792
Authors: Nichaela Harbison-Price; Scott A Ferguson; Adam Heikal; George Taiaroa; Kiel Hards; Yoshio Nakatani; David Rennison; Margaret A Brimble; Ibrahim M El-Deeb; Lisa Bohlmann; Christopher A McDevitt; Mark von Itzstein; Mark J Walker; Gregory M Cook Journal: mSphere Date: 2020-03-18 Impact factor: 4.389