Incidence of Aeromonas species isolated from fresh fish , canned fish and shrimp in Sohag Governorate, Egypt

Abstract

A total of 180 samples of fish meat and canned fish were randomly collected from different markets and retail shops in Sohag city as the following; fresh water fish (Nile tilapia and catfish), marine water fish (mullet), shrimps, and canned fish (tuna and salmon) with 30 samples of each, to study the incidence of Aeromonas species (Aeromonas spp.) with special reference to Aeromonas hydrophila (A.hydrophila) and its virulence genes. The results of this study showed that the mean of Aeromonas counts were 0.122×102 , 0.504×102 , 0.124×102 , 0.037×102 cfu/g for Nile tilapia, catfish, mullet and shrimps, respectively. While in canned fish it was uncountable. Aeromonas spp. were isolated from 60 of 180 examined samples with a percentage of 33.3%, 7 species were identified: A. caviae, A. hydrophila, A. media, A. shubertii, A. sobria, A. veronii biovar sobria and A. veronii biovar veronii were detected at a percentage of 5%, 7.8%, 2.8%, 7.2%, 5%, 2.8% and 2.8%, respectively. The results of PCR showed that, 12 isolates out of 14 were positive for 16S rRNA gene of A. hydrophila with a percentage of 85.7 %. Virulence gene like, Aerolysin AHA was found in 41.6 % of the examined samples while, the heat stable enterotoxin AST gene was not detected. This study spots the lights on Aeromonas spp. especially A. hydrophila as potential biological hazard in fish meat and canned fish, as a foodborne pathogen.

Keywords

• aeromonas spp.
• a. hydrophila
• canned fish
• fish meat
• virulence genes