Heterogeneity of environmental, retail, and clinical isolates of Vibrio vulnificus as determined by lipopolysaccharide-specific monoclonal antibodies

The opportunistic pathogen Vibrio vulnificus expresses lipopolysaccharide ( LPS) antigens on its outer membrane surface. A serological typing system wa s developed for these antigens, utilizing the discriminatory recognition of monoclonal antibodies (MAb) by ELISA. MAb were used to recognize five uniq ue types of LPS-associated antigens for examination of clinical, environmen tal, and retail isolates of V. vulnificus. The overall serotype profile of the clinical isolates was significantly different (P < 0.05) from that of t he environmental and retail isolates. A higher percentage of clinical isola tes were typable (61%) compared to the environmental isolates (41%) and ret ail isolates (44%). In particular, the percentage of serotype 1/5 among cli nical isolates (33%), compared to that of environmental (9%) and retail (4% ), was highly significant (P < 0.0001). Among the environmental Gulf Coast isolates, there were differences in the prevalence of serotypes 2 and 3 (P < 0.05), depending on whether isolates were obtained from Louisiana or Alab ama harvest sites. There were no statistically significant differences betw een the serotype profiles of Gulf and Atlantic Coast retail isolates despit e the absence of serotype 1/5 from the Atlantic Coast. While some serotype diversity was detected in V. vulnificus isolated during different seasons, from different geographic locations, and at retail versus at harvest, there was no apparent concordance between any of the serotype distributions obta ined from oysters versus that isolated clinically. The heterogeneity of env ironmental isolates and relative homogeneity among clinical isolates sugges t that human risk may not be predicted on quantitative exposure alone.