Potentially pathogenic vibrios associated with mussels from a tropical region on the Atlantic coast of Brazil

Abstract

Mussels (Perna perna) harvested on the coast of Ubatuba, in three different stations in the State of São Paulo, Brazil, were examined for Vibrio spp. over a 1 year period. The ranges of most probable number (MPN 100 g-1) were: Vibrio alginolyticus (< 3-24,000), V. parahaemolyticus (< 3-24,000), V. fluvialis (< 3-1100), V. cholerae non-O1 (< 3-23), V. furnissii (< 3-30), V. mimicus (< 3-9) and V. vulnificus (< 3-3). The highest incidence was observed for V. alginolyticus (92-100%), followed by V. parahaemolyticus (67-92%), V. fluvialis (34-67%), V. vulnificus (8-17%), V. furnissii (0-17%), V. mimicus (0-17%) and V. cholerae non-O1 (0-8%). Tests for virulence factors were positive in 34.1% of the vibrios in the rabbit ileal loop and 31.7% in the Dean test. Positive results in the Kanagawa test were obtained with 0.51% of V. parahaemolyticus strains. The mean values (MPN 100 g-1) of faecal coliforms in mussels from the three regions varied from 1100 to 44,000, and seawater collected at the same stations gave average values for faecal coliforms in the range 18-3300 MPN 100 ml-1. These results highlight the potential risks of food poisoning associated with raw or undercooked seafood.

Enzymatic characterization of Vibrio alginolyticus strains isolated from bivalves harvested at Venice Lagoon (Italy) and Guanabara Bay (Brazil)

“…Both in Venice Lagoon and Guanabara Bay, the majority of strains of Vibrio alginolyticus point to increasing virulence characteristics expressed by the presence of three enzymes at the same time while strains with low or null infectivity were minimal or absent in these cities 5 .…”

“…Also, we observed the isolation of Plesiomonas shigelloides an emergent pathogen isolated from aquatic ecosystem including fresh and estuarine water. These pathogens may cause different pathologies especially to immunocompromised patients that are more susceptible to infections 5,7 .…”

“…The inability of some species, like the V. fluvialis, to degrade the components of the conjunctive tissue seems to limit its capacity to cause extra intestinal pathology. The concomitant lack of the keratinases in the majority of Vibrio species, and the ability to degrade the conjunctive tissue is consistent with their condition of opportunists' bacteria which need a primary lesion to invade the derma and hypodermic layers of the skin 3,5,10,11 .…”

“…Otherwise, many species are able to transmit intestinal or extra intestinal diseases to human. Amongst these last ones V. vulnificus, V. carchariae and V. alginolyticus are widely spread in the marine environment; both in closed seas, like the Mediterranean, and in oceans 5,10,11 .…”

“…Therefore, mussels consumed without cooking or after an insufficient process of cooking may be at risk for humans because these animals are capable to retain pollutants and pathogenic bacteria in their organisms 5,7 .…”