Molecular detection and genetic diversity of virulent Aeromonas hydrophila (Chester, 1901) Stanier, 1943 isolates from raw and processed fish

Aeromonas hydrophila is a mesophilic motile aeromonad present ubiquitously and causes a high number of fish mortalities particularly in India along with various intestinal and extraintestinal diseases in humans. In this study, a total of 88 samples of fish and their processed products were screened by PCR targeting species-specific 16S rRNA gene, and the virulent genes such as aerA, hly and ahh1. The findings of the study showed that a total of 36.36 % of samples harboured A. hydrophila of which 51.61 %, 71.87 % and 78.12 % of isolates possessed virulent genes such as aerA, hly, and ahh1, respectively. The phylogenetic analysis of the isolates using AP-PCR assay suggested that five different clusters of organisms were prevalent among A. hydrophila with a high degree (> 95.00 %) of lineage. In conclusion, it may be presumed that raw and processed fish harboured the pathogenic A. hydrophila which may serve as a reservoir/ source of infection to human beings.