Ac. Freitas et al., VIRULENCE FACTORS PRODUCED BY AEROMONAS-HYDROPHILA STRAINS ISOLATED FROM DIFFERENT SOURCES, Revista de Microbiologia, 24(3), 1993, pp. 168-174
Virulence factors produced by Aeromonas hydrophila derived from water,
pasteurized milk, urine and a standard strain were compared. All four
strains were hemo lytic, and had protease and staphylolytic activity.
Production of enterotoxin like activity in suckling mice and cytotoxi
n (Vero cell) were observed in A. hydrophila isolated from food, water
and standard strains. Autoagglutination in broth culture was found on
ly for two strains (standard and food strain). The biological properti
es of lipopolisaccharide from A. hydrophila were analysed by the mouse
LD 50 determination and dermonecrotic factor. Tests of purified LPS d
emonstrated toxicity assayed by LD50 in mice. The characteristic lesio
ns of local Schwartzman reaction in albino rabbits with all strains te
sted demonstrated the endotoxic potential of the LPS assayed. Mice cha
llenged by the intraperitoneal route showed mortality rates of 50, 55,
75 and 92%, respectively, for A. hydrophila isolated from food, water,
standard and urine strains. Production of virulence factors by A. hyd
rophila strains isolated from food and water had a significative corre
lation with virulence markers found in the strains isolated from urine
and standard. This finding indicates that strains of A. hydrophila is
olated from food or environment sources may play a significant role as
potential pathogens associated with human infections.