ARS | Publication request: Antibiotic and disinfectant susceptibility profiles of vancomycin-resistant Enterococcus faecium (VRE) isolated from community wastewater in Texas

Submitted to: Bulletin of Environmental Contamination and Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 18, 2007
Publication Date: March 14, 2008
Citation: Beier, R.C., Duke, S.E., Ziprin, R.L., Harvey, R.B., Hume, M.E., Poole, T.L., Scott, H.M., Highfield, L.D., Alali, W.Q., Andrews, K., Anderson, R.C., Nisbet, D.J. 2008. Antibiotic and disinfectant susceptibility profiles of vancomycin-resistant Enterococcus faecium (VRE) isolated from community wastewater in Texas. Bulletin of Environmental Contamination and Toxicology. 80(3):188-194.

Interpretive Summary: Many different kinds of disinfectants are in common use on farms, in food processing plants, and in hospitals. In each of these places there is also widespread use of a variety of antibiotics. Little is known about the impact of disinfectant use on the spread of antibiotic resistance. Certain bacteria named VREs are a major health hazard for hospitalized patients. Hospitals are environments in which both disinfectants and antibiotics are heavily utilized. We found that many VREs isolated from wastewater are resistant to disinfectants and to antibiotics. This double resistance is probably due to certain pieces of genetic material present in VREs. This information is important to understanding the way antibiotic resistant bacteria are spread through our environment and our finding has practical application in hospital infection control programs.

Technical Abstract: Vancomycin-resistant Enterococcus faecium (VRE) previously isolated from human wastewater effluents in a nonclinical semiclosed agri-food system in Texas were characterized for susceptibility to antibiotics and disinfectants. The 50 VRE were resistant to eight fluoroquinolones and to 10 of 17 National Antimicrobial Resistance Monitoring System (NARMS) 2005 Gram-positive antibiotics. The VRE were only susceptible to quinupristin/dalfopristin and linezolid. Lack of the genomic fragment IS1251 correlated with VRE susceptibility to streptomycin and gentamicin at P < 0.0001 and P = 0.033, respectively. An association was observed between pulsed-field gel electrophoresis type 3 and type 4 and susceptibility to streptomycin at P = 0.0006. VRE susceptibility for nine disinfectants and five disinfectant components is shown. Ninety-two percent of the isolates had a susceptibility to triclosan at greater than or equal to 2 ppm. Triclosan minimum inhibitory concentrations (MICs) for many of the VRE were well over expected product application levels. No cross-resistance or co-resistance was observed between antibiotic resistance and disinfectant susceptibility in these VRE.