Oral challenge with Aeromonas in protein-malnourished mice.

The lack of an animal model for Aeromonas-associated diarrhoea has hindered progress toward understanding the pathogenesis of this potentially important enteric infection. Protein-malnourished mice were challenged orally with Aeromonas strains to determine if diminished levels of resistance would allow the induction of a diarrhoeal response. The 15 Aeromonas spp. faecal isolates used for challenge included 7 A. caviae, 4 A. hydrophila, 1 A. sobria bv. sobria, and 1 A. sobria bv. veronii from patients with diarrhoea, and 2 A. caviae from healthy volunteers. All had at least 1 known virulence marker, with the exception of 1 strain. Mice on the protein deficient diet had lost an average of 23% of their initial body weight at the time of challenge. Although mice consumed 10(8) cfu per day for a minimum of 4 days, none became ill due to Aeromonas spp. ingestion. Aeromonas spp. were isolated from 75% of faecal cultures obtained 7 days after initial challenge, indicating bowel colonization had occurred.