No abstract

Vibrio vulnificus causes rare but frequently fatal septicemia associated with raw oyster consumption by persons with underlying hepatic or immune system dysfunction. The virulence potential of environmental reservoirs appears widely distributed, because most strains are virulent in animal models; however, several investigations recently demonstrated genetic divergence among strains from clinical versus environmental origin at independent genetic loci. The present study used PCR to screen DNA polymorphisms in strains from environmental (n ‫؍‬ 35) or clinical (n ‫؍‬ 33) sources, and genomic relationships were determined by repetitive extragenic palindromic DNA PCR (rep-PCR) typing. Significant (P < 0.01) association was observed for typical "clinical" or "environmental" polymorphism profiles based on strain origin. Most oyster isolates (88%), including all of those with the "environmental" profile, also formed a single rep-PCR genogroup. Clinical isolates within this group did not have the typical "clinical" profile. On the other hand, clinical isolates with the typical polymorphism profile were distributed among multiple rep-PCR genogroups, demonstrating greater genetic diversity than was evident by profiling genetic polymorphisms. Wound isolates were genetically distinct from typical blood isolates by all assays. Strains from an outbreak of wound infections in Israel (biotype 3) were closely related to several U.S. strains by rep-PCR, indicating potential reservoirs of emerging disease. Strains genetically related to blood isolates appeared to be relatively rare in oysters, as only one had the "clinical" polymorphism profile or clustered by rep-PCR. However, this study was not an extensive survey, and more sampling using rep-PCR for sensitive genetic discrimination is needed to determine the virulence potential of environmental reservoirs.Vibrio vulnificus is associated with serious wound infections or frequently fatal (mortality rates are generally Ͼ50%) septicemia related to consumption of raw shellfish, particularly oysters (5, 37). The bacterium is indigenous to temperate estuaries, and prevalence in oysters and seawater approaches 100% during warmer months (25,45). Most strains isolated from environmental reservoirs appear to be as virulent as clinical strains in animal models (13,35,36,39). Also, multiple virulence factors have been proposed for V. vulnificus but are generally present in most strains and do not provide predictive value (16,36,39,50). Virulent strains are distinguished by opaque colony morphology (34, 49), which reflects expression of a protective capsular polysaccharide (CPS); however, both clinical and environmental strains are generally encapsulated (45). Thus, appropriate markers to screen the virulence potential of V. vulnificus in environmental reservoirs are not available.Recently, DNA sequence polymorphisms at individual loci discriminated isolates from clinical versus oyster origin in several independent studies. Polymorphic variants generally included two genotypes, such as types ...

The Suwannee River spans the Florida/Georgia border to the Gulf of Mexico, and contributes to regional irrigation and recreational activities. Association of Salmonella enterica with these resources may result in the contamination of produce and disease outbreaks. Therefore, surface water was examined for the distribution of S. enterica at multiple time points from 4 sites on the upper Suwannee River. Isolates were confirmed by detection of the invA gene, and 96% of all samples were positive for the bacterium. Most probable number enumeration ranged from <18 to 5400 MPN/100 mL. Genetic diversity of these isolates (n=110) was compared to other environmental (n=47) or clinical (n=28) strains and to an online library (n=314) using DiversiLab rep-PCR. All strains showed >60% similarity and distributed into 16 rep-PCR genogroups. Most (74%) of the Suwannee River isolates were clustered into two genogroups that were comprised almost exclusively (97%) of just these isolates. Conversely, 85% of the clinical reference strains clustered into other genogroups. However, some Suwannee River isolates (12%) were clustered with these primarily clinically-associated genogroups, supporting the hypothesis that river water can serve as a disease reservoir and that pathogenic strains may persist or possibly originate from environmental sources.

Revised! FSHN-03-1, a 5-page fact sheet by Keith R. Schneider, Renée Goodrich Schneider, Michael A. Hubbard, and Alexandra Chang, discusses the common foodborne pathogen E. coli O157:H7, especially as it concerns food handlers, processors, and retailers. Includes references. Published by the UF Department of Food Science and Human Nutrition, November 2009. FSHN031/FS097: Preventing Foodborne Illness: E. coli O157:H7 (ufl.edu)

FSHN09-01, a 3-page fact sheet by Anita C. Wright, Renée Goodrich Schneider, Michael A. Hubbard, and Keith R. Schneider, describes this bacterium that occurs naturally in coastal waters throughout the world and is linked to illnesses associated with consumption of raw or improperly cooked seafood — type of illness, who is at risk of infection, how common infections are, how they occur, how to receive and store seafood and shellfish, and methods to prevent infection in high-risk individuals. Includes references. Published by the UF Department of Food Science and Human Nutrition, July 2009. FSHN0901/FS146: Preventing Foodborne and Non-foodborne Illness: Vibrio parahaemolyticus (ufl.edu)