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OCCURRENCE OF VIRULENCE FACTOR ACTIVITY RELATIONSHIP (VFAR) IN ESCHERICHIA COLI ISOLATED FROM MUNICIPAL WASTEWATER EFFLUENTS
Citation:
Boczek*, L A., E. W. Rice, AND B. K. Kinkle. OCCURRENCE OF VIRULENCE FACTOR ACTIVITY RELATIONSHIP (VFAR) IN ESCHERICHIA COLI ISOLATED FROM MUNICIPAL WASTEWATER EFFLUENTS. Presented at NRMRL Peer Review, Cincinnati, OH, August 25, 2004.
Impact/Purpose:
To inform the public.
Description:
Escherichia coli O157:H7 has been linked to waterborne outbreaks in the United States and abroad. Methods employed to detect this pathogen typically are cultural based and take advantage of phenotypic traits that are specific for this serotype, including slow sorbitol fermentation and negative -glucuronidase activity. The main concern with using these techniques is that other enterohemorrhagic E. coli (EHEC) strains, some of them implicated in disease, do not produce the same phenotypic characteristics as strain E. coli O157. As a result potential strains of pathogenic E. coli may go undetected. This study incorporated virulence factor activity relationships (VFAR) to detect EHEC organisms in wastewater effluents. VFAR is a research tool that is currently under review as a way to detect such waterborne pathogens. EHEC organisms produce specific virulence factors, including enterohemolysin, intimin and one or more Shiga-like toxins I and II (SXTI, SXTII). Molecular probing for one or more of these virulence factors could be a powerful tool for examining waterborne EHEC outbreaks. These results show that domestic sewage in the U.S. is not a significant source of EHEC.
Seven municipal wastewater treatment plants from across the United States were surveyed. Each sample was screened for organisms producing the virulence factor enterohemolysin. The resulting 338 isolates of E. coli that produced enterohemolysin were stereotyped and analyzed for presence of SXT I, SXTII, EAE, and intimin protein A. Stereotyping analysis revealed several serotypes, none of which were E. coli O157 H:7. Two samples were positive for the virulence factor intimin gamma, encoded by the EAE gene. None of the enterohemolysin positive strains were positive for presence of SXT I, SXTII, or intimin alpha. Probing for VFAR in municipal wastewater effluents allowed for the detection of enterohemolysin positive E. coli.