Evaluation of the Anti-enterococcal Activity of Disinfectants and Medicated Soaps on Vancomycin-resistant Enterococcus faecalis Strains

Abstract

Background: Enterococcus faecalis has intrinsic resistance which aids its spread in the hospital environment. As a nosocomial pathogen with increasing resistance breaking its route of transmission and spread is therefore imperative. Aims: In this study, six brands of disinfectants and eight medicated soaps commonly used in health care facilities and at homes were investigated for anti-enterococcal activity against eleven strains of E. faecalisten of which are vancomycin-resistant. Place and Duration of Study: This study was carried out in the Department of Microbiology, Ekiti State University, Nigeria between July, 2009 and February, 2010. Methodology: Standard microbiological methods were used to determine the effects of the disinfectant and soap samples on the strains of vancomycin-resistant E. faecalis. Results: Two of the disinfectants, NXD and ZGC completely inhibited the test organisms even at the manufacturers’ recommended in-use concentrations. ZAL followed by VGL had the least anti-enterococcal property. Enterococcus faecalis DMOF 53 and E. faecalis DMOF 47 were the most resistant while E. faecalisDMOF 21 and E. faecalis ATCC 29212 (control) were the least resistant to the disinfectants. Vancomycin-sensitive strain, E. faecalis ATCC 29212 (control) was also resistant to some of the disinfectants. This shows that there is no correlation between resistance to antibiotics, vancomycin in particular and disinfectants. The disinfectants CRT, RBT, TMS and DTA, in that decreasing order, showed anti-enterococcal property while MSF and NVA showed the least effect on the enterococci. Strains recovered from the surface of the bland soap sample had confluent growth pattern which indicated the ability of the organisms to survive on its surface. Survival was least on CRT soap sample followed by DTL soap sample and most of the strains grew very well on the surfaces of most of the soap samples. Conclusion: This study shows that most of the disinfectants are not effective at the manufacturers’ recommended in-use concentrations, and also that pathogens can be transmitted through the common use or sharing of soaps contaminated with the carriers of antimicrobial-resistant pathogens.