Genes Similar to the Vibrio parahaemolyticus Virulence-Related Genestdh,tlh, andvscC2Occur in Other Vibrionaceae Species Isolated from a Pristine Estuary

Abstract

ABSTRACTDetection of the human pathogenVibrio parahaemolyticusoften relies on molecular biological analysis of species-specific virulence factor genes. These genes have been employed in determinations ofV. parahaemolyticuspopulation numbers and the prevalence of pathogenicV. parahaemolyticusstrains. Strains of theVibrionaceaespeciesPhotobacterium damselae,Vibrio diabolicus,Vibrio harveyi, andVibrio natriegens, as well as strains similar toVibrio tubiashii, were isolated from a pristine salt marsh estuary. These strains were examined for theV. parahaemolyticushemolysin genestdh,trh, andtlhand for theV. parahaemolyticustype III secretion system 2α genevscC2using established PCR primers and protocols. Virulence-related genes occurred at high frequencies in non-V. parahaemolyticus Vibrionaceaespecies.V. diabolicuswas of particular interest, as several strains were recovered, and the large majority (>83%) contained virulence-related genes. It is clear that detection of these genes does not ensure correct identification of virulentV. parahaemolyticus. Further, the occurrence ofV. parahaemolyticus-like virulence factors in other vibrios potentially complicates tracking of outbreaks ofV. parahaemolyticusinfections.