Reproducibility of Polymerase Chain Reaction (PCR) for characterizing the virulence gene vcgC in known and unknown Vibrio vulnificus isolates from the Coastal Bend region of Texas
Abstract: Vibrio vulnificus is a Gram-negative bacterium found in estuarine and marine waters, and the tissues of shellfish and the skin of finfish. Vibrio vulnificus is known to cause gastroenteritis, necrotizing fasciitis, and primary septicemia; mortality can be high (~60%) with the latter two conditions. The bacterium contains a virulence correlated gene locus, vcg, whose function is unknown, and consists of two different alleles: vcgC, or clinical (disease-causing) isolates, and vcgE, or environmental isolates. This study used the Polymerase Chain Reaction (PCR) assay to determine if vcgC would be seen in 24 of 44 isolates of Vibrio vulnificus taken from local waters of the Coastal Bend region of south Texas. We predicted that isolates shown to have the vcgC amplicon from previous work would have that same amplicon. Four isolates (BS 0607-5, CB 0407-5, CB 0407-15 and CB 0407-18) tested in 2013 and 2014 had the 428 bp amplicon of the vcgC locus, indicating that PCR was reproducible. Nine untested Vibrio vulnificus isolates also revealed the 428 bp amplicon, demonstrating that PCR can consistently detect the vcgC allele in unknown Vibrio vulnificus isolates. Future experiments will test the remaining 30 unknown isolates for both vcgC and vcgE loci.
LarReshia Brumfield* and Dr. Gregory Buck
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