Spatiotemporal distribution of Vibrio parahaemolyticus in relation to environmental parameters in a coastal lagoon on the Pacific coast of northwestern Mexico

Vibrio parahaemolyticus has been responsible for the increasing number of diarrhea cases in Sinaloa, Mexico, since 2003. We investigated the presence, distribution, and content of V. parahaemolyticus toxigenic genes detected in water, zooplankton, and sediment samples in relation to environmental variables in Caimanero Lagoon (Mazatlán, Sinaloa). Samples were analyzed by PCR to detect the presence of V. parahaemolyticus and its toxigenic factors. Of all the samples analyzed, 57.5% tested positive for thermolabile hemolysin (tlh), a gene indicative of the species. The thermostable direct hemolysin (tdh) and tdh-related hemolysin (trh) genes, which are both pathogenicity markers of this species, were detected in 9% and 6% of the samples, respectively. The orf8 fragment, which has been recently detected in pandemic strains (O3:K6), was detected in 11% of the samples. Vibrio parahaemolyticus was detected more frequently in zooplankton, with the highest incidence observed in February. Salinity was positively correlated with V. parahaemolyticus; however, no correlation was found between V. parahaemolyticus and temperature. The presence of toxigenic V. parahaemolyticus during the different seasons indicates the need to maintain continuous sanitary inspection of fish products from Caimanero Lagoon

Pathogenic <i>Vibrio parahaemolyticus</i> isolated from biofouling on commercial vessels and harbor structures

<div><p>Ballast water is a significant vector of microbial dissemination; however, biofouling on commercial vessel hulls has been poorly studied with regard to pathogenic bacteria transport. Biofouling on three commercial vessels and seven port structures in Ensenada, Baja California, Mexico, was examined by qPCR to identify and quantify <i>Vibrio parahaemolyticus</i>, a worldwide recognized food-borne human pathogen. Pathogenic variants (<i>trh</i>+, <i>tdh</i>+) of <i>V. parahaemolyticus</i> were detected in biofouling homogenates samples from several docks in Ensenada and on the hulls of ships with Japanese and South Korean homeports, but not in reference sampling stations. A total of 26 <i>tdh</i>+ <i>V. parahaemolyticus</i> colonies and 1 ORF8+/O3:K6 strain were also isolated from enriched biofouling homogenate samples confirming the qPCR analysis. Our results suggest that biofouling is an important reservoir of pathogenic vibrios. Thus, ship biofouling might be an overlooked vector with regard to the dissemination of pathogens, primarily pathogenic <i>V. parahaemolyticus</i>.</p></div