Diversity of Vibrio spp. isolated at ambient environmental temperature in the Eastern English Channel as determined by pyrH sequencing.

AIMS To describe the diversity of the culturable mesophilic and potentially pathogenic vibrios isolated at 22 and 37°C on TCBS medium, in September 2009 from seawater and surface sediments. METHODS AND RESULTS q-PCR assays previously selected for the identification of bacterial strains isolated at 37°C were used in combination with the partial sequencing of two housekeeping genes, pyrH and toxR, to identify 315 strains isolated at 22°C. The great majority of the 37°C strains was identified by q-PCR assays, (five of the six species) with the predominance of Vibrio alginolyticus (85·9%) and V. harveyi (10·7%). The human pathogens V. parahaemolyticus and V. cholerae were rarely detected (two strains each). The 22°C strains were successfully identified by the phylogeny analysis of pyrH and toxR genes, revealing 20 Vibrio species, with the predominance of the clam pathogen V. celticus (36·8%). The Splendidus and the Harveyi groups represented the main Vibrio group at 22°C (80%) and 37°C (99·5%), respectively. CONCLUSIONS The combination of q-PCR assays and the sequencing of pyrH and toxR genes highlighted two different Vibrio communities at 22 and 37°C both dominated by pathogenic species for marine organisms. SIGNIFICANCE AND IMPACT OF THE STUDY The sequencing of the pyrH gene revealed to be a valuable tool to identify environmental Vibrio spp. strains isolated at 22°C, as 92·3% of them were identified in this study.