Location: Produce Safety and Microbiology ResearchTitle: Using MOMP typing as an epidemiological tool to investigate outbreaks caused by milkborne Campylobacter jejuni isolates in California Author
|Miller, William - Bill|
Submitted to: Journal of Clinical Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/24/2012
Publication Date: 10/24/2012
Publication URL: http://doi: 10.11/28/JCM.0845-12
Citation: Jay-Russell, M.T., Mandrell, R.E., Yuan, J., Bates, A.H., Manalac, R., Mohle-Boetani, J., Kimura, A., Lidgard, J., Miller, W.G. 2012. Using MOMP typing as an epidemiological tool to investigate outbreaks caused by milkborne Campylobacter jejuni isolates in California. Journal of Clinical Microbiology. 51(1):195-201. Interpretive Summary: Campylobacter jejuni is a leading cause of bacterial food-borne illness. A major hurdle in the epidemiology of C. jejuni is rapid typing of clinical and food/environmental isolates to establish a point source or sources for a food- or water-related outbreak. The necessity of rapid typing is especially true for milk-related outbreaks. Campylobacters do not survive for long periods in milk and the normal turnover of campylobacters in the cow results in a fairly short window of opportunity to identify the source of a milk-related C. jejuni outbreak. Here we describe the use of a typing method that sequences the gene that codes for a highly variable C. jejuni outer surface protein, called MOMP. Using this method, putative outbreak strains (strains that had MOMP types identical to the clinical isolates) were identified at dairies associated with two separate milk-related outbreaks in California. These strains were confirmed as outbreak strains using additional typing methods. This indicates that the MOMP typing method is useful for rapid analysis of potential source-related strains during outbreak investigations.
Technical Abstract: We describe using major outer membrane protein (MOMP) typing as a screen to compare the C. jejuni porA gene sequences of clinical outbreak strains from human stool with the porA sequences of dairy farm strains isolated during two milkborne campylobacteriosis outbreak investigations in California. The genetic relatedness of clinical and environmental strains with identical or closely-related porA sequences was confirmed by multilocus sequence typing and pulsed-field gel electrophoresis analysis. The first outbreak involved 1,644 C. jejuni infections at 11 state correctional facilities, and was associated with consumption of pasteurized milk supplied by an on-site dairy (Dairy A) at a prison in the central valley. The second outbreak involved eight confirmed and three suspect C. jejuni cases linked to consumption of commercial raw milk and raw chocolate colostrum at another central valley dairy (Dairy B). Both dairies bottled fluid milk on the farm and distributed finished product to off-site locations. Altogether, C. jejuni was isolated from 7 of 15 (46.7%) bovine fecal, 19 of 20 (95%) flush alley water, and 20 of 20 (100%) lagoon samples collected on Dairy A. At Dairy B, C. jejuni was cultured from 9 of 26 (34.6%) bovine fecal samples. Environmental strains indistinguishable from the clinical outbreak strains were found in five flush alley water (Dairy A) and four bovine fecal samples (Dairy B). The findings demonstrate that MOMP typing is a useful tool to triage environmental isolates prior to conducting more labor intensive molecular typing methods.