Avaliação quantitativa de vírus entéricos em mexilhão (Mytella guyanensis e Mytella charruana) e ostra (Crassostrea rhizophorae) em área de manguezal da Baía de Vitória (ES) com a utilização da PCR em tempo real

Abstract

Ilha das Caieiras is a region located at the estuary of Vitoria Bay (Vitoria ES, Brazil) surrounded by a large area of urban mangrove. Great part of the population is involved on shellfish harvesting as economic as well as a subsistence activity in this region. Previous studies have already demonstrated water as well as shellfish contamination by pathogenic microorganisms from fecal contamination. The objective of this work was to improve the knowledge of microbiological quality of mussels (Mytella guyanensis and Mytella charruana) and oysters (Crassostrea rhizophore) colleted from two points of the estuary mangrove area over 13 months of monitoring (January/2011 - January/2012). A total of 31 samples were evaluated for the presence of E. coli and enteric viruses (adenovirus - AdV; rotavirus - RV, and norovirus - NoV GII), using the nested-PCR and real-time quantitative PCR (qPCR). Physico-chemical parameters of the water near the point of collection of shellfish were also evaluated. The results of microbiological analyses of mussels: Mytella guyanensis (n=5), Mytella charruana (n=13) and oysters (n=13) showed a high prevalence of E. coli, with geometric mean of 1.47x105 , 1.47 x105 and 4.24 x x104 FCU /100g of tissue, respectively. In water samples the concentration of E coli was in accordance with the Brazilian Standard for Recreational Waters. Enteric viruses were detected by nested and qPCR at frequencies ranging from 31-54% for AdV, 54-70% for RV and 54-85% for NoV GII. Adenoviruses and rotaviruses were positively correlated with turbidity and total dissolved solids (TDS). In water samples the maximum values obtained were 3.0 x102 , 3.2 x104 and 1.6 X101 CG/100ml for AdV, NoV and RV, respectively. In conclusion, the high bacteriological and viral contamination of bivalves indicates that the region remains under anthropogenic impact, resulted of the discharge of sewage in the region, and that the consumption of different types of shellfish from Ilha das Caieiras presents a potential risk of gastrointestinal diseases to consumers, especially if ingested raw.