Multiple Vibrio vulnificus strains in oysters as demonstrated by clamped homogeneous electric field gel electrophoresis

Abstract

Clamped homogeneous electric field gel electrophoresis and a computer program for managing electrophoresis banding patterns (ELBAMAP) were used to analyze genomic DNA of 118 Vibrio vulnificus strains, isolated from three oysters by direct plating. Analysis with SfiI resulted in 60 restriction endonuclease digestion profiles (REDP), while analysis with SrfI produced 53 different REDP. Similarities between REDP ranged from 7 to 93%. Principal-component analysis showed that the strains were heterogeneous. Vibrio vulnificus is an estuarine organism that occurs naturally in temperate and tropical climates. It is commonly found in seawater and sediment and is associated with various marine life forms (10, 16, 18, 19, 24, 26). It is considered one of the most invasive and rapidly lethal human bacterial pathogens known today. Human disease can occur from ingestion of raw seafood, mainly raw oysters (2, 13), or by infection of skin lesions. V. vulnificus poses the greatest risk to persons who are compromised, especially those with liver dysfunctions (2, 13, 23). The fatality rate is greater than 50% for individuals with primary septicemia (15). Because this at-risk population is ever growing, food safety precautions for such opportunistic pathogens are increasingly important. Although much is known of

Cluster analysis of AP-PCR generated DNA fingerprints of Vibrio vulnificus isolates from patients fatally infected after consumption of raw oysters

“…Examination of the DNA ¢ngerprints from the clinical isolates used in this study (all of which caused fatality after consumption of raw oysters) using gel analysis and cluster analysis, revealed signi¢cant genetic diversity among these strains known to be fatal in susceptible human individuals. This result is consistent with data from several other studies (Aznar et al 1993;Buchrieser et al 1995;Tamplin et al 1996;Vickery et al 1996Vickery et al , 1998 which demonstrated that V. vulni¢cus strains isolated from environmental samples had a diverse genomic organization. To the best of our knowledge, this is the ¢rst study to examine AP-PCR DNA ¢ngerprints produced only from strains of V. vulni¢cus con¢rmed to be virulent in humans.…”

“…Arbitrarily primed polymerase chain reaction (AP-PCR) (Welsh and McClelland 1990) DNA ¢ngerprinting has been optimized previously, primarily for environmental isolates of this micro-organism (Aznar et al 1993;Buchrieser et al 1995;Smith et al 1996;Tamplin et al1996;Vickery et al 1996Vickery et al , 1998. However, this methodology thus far has not been applied exclusively for clinical isolates of this pathogen.…”

Genetic and quantitative assessment of Vibrio vulnificus populations in oyster (Crassostrea virginica) tissues

“…Mean Shannon-Weiner indices ranged from 3.41 to 3.62 for each tissue within a treatment group with average indices of 4.27 and 4.15 for untreated and PHP-treated oysters respectively (Table 2). Similarly high diversity was also observed in freshly harvested oysters using pulsed-field gel electrophoresis (Buchrieser et al, 1995).…”

“…Vibrio vulnificus is an autochthonous inhabitant of estuarine environments that is found at high population densities and diversities in oysters (Buchrieser et al, 1995;Tamplin et al, 1996;Jackson et al, 1997). This opportunistic pathogen is the leading cause of reported deaths associated with shellfish consumption (Hlady et al, 1993;DePaola et al, 2003), and it caused approximately 14.5% of the Vibrio infections reported by Foodborne Diseases Active Surveillance Network.…”

Virulence factors and pathogenicity of Vibrio vulnificus strains isolated from seafood

“…Tison et al (1984) reported that, in relation to phenotypic characteristics, DNA homology, DNA base pair composition and virulence to mice, there is no difference between clinical and environmental strains from different geographic areas. Buchrieser et al (1995), using the PFGE technique, concluded that there is an enormous genetic diversity for this bacteria even among strains coming from the same oyster.…”