The incidence of virulence factors in mesophilicAeromonasspecies isolated from farm animals and their environment

Abstract

SUMMARYSixty-one isolates ofAeromonasspp. from the faeces of pigs, cows and a variety of associated environmental sources were examined for the characteristics that are reputed to have roles in pathogenicity. Most isolates ofAeromonas hydrophilawere cytotoxic (96·4%) and were capable of producing cell elongation factor (75%) and haemagglutinins (67·9%). In contrast few of theAeromonas caviaeisolates produced these three markers (13·6 %, 27·3% and 36·4% respectively). In general,Aeromonas sobriaoccupied an intermediate position (36·4%, 27·3% and 54·5%), but they did produce the highest mean invasion index for HEp-2 cells. Statistical analysis revealed significant associations between the carriage of these factors and it was clear that many isolates of aeromonads from water and animals possessed the full battery of putative virulence factors.