title: Haemagglutinating activity, serum sensitivity and enterotoxigenicity of Aeromonas spp.
abstract: Of 97 isolates of Aeromonas spp. that were examined for haemagglutination (HA) and enterotoxigenicity, 35 were from clinical and 62 from environmental sources; 66 of them were also screened for sensitivity to normal human serum (NHS). HA was caused by 44 isolates (45%); it was unrelated to the source of the strain, but it was caused by a higher proportion of the isolates of A. hydrophila than of A. sobria or A. caviae. Of the haemagglutinating strains, 82% were enterotoxigenic, whereas most of the non-haemagglutinating strains were non-toxigenic when tested initially. All the latter became enterotoxin producers after serial passage through rabbit ileal loops, but without change in HA. Most (64%) of the isolates, including 68% of A. caviae (72% of clinical and 65% of environmental), were resistant to the bactericidal action of NHS. Most (92%) of the serum-sensitive strains were killed by activation of both the classical and alternate pathways of complement, the others only by the alternate pathway. Most (74%) of the serum-resistant strains caused fluid accumulation in the initial tests in ileal loops, regardless of species or source. Haemagglutinating and serum-resistant strains caused significantly more accumulation of fluid (p < 0.05) than non-haemagglutinating and serum-sensitive strains. This study shows partial correlation between HA or serum sensitivity and enterotoxigenicity, but the properties are probably not genetically linked.
authors.affiliation: Department of Microbiology, Banaras Hindu University, Varanasi, India.
authors.forename: D V
authors.initials: DV
authors.lastname: Singh
authors.forename: S C
authors.initials: SC
authors.lastname: Sanyal
mesh_terms: D000328:Adult; D000333:Aeromonas / Q000276:immunology / Q000378:metabolism* / Q000472:pathogenicity; D016980:Aeromonas hydrophila / Q000276:immunology / Q000378:metabolism / Q000472:pathogenicity; D001770:Blood Bactericidal Activity; D002648:Child; D003967:Diarrhea / Q000382:microbiology*; D004768:Enterotoxins / Q000096:biosynthesis*; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology*; D006384:Hemagglutination; D006801:Humans
chemical_list: D004768:Enterotoxins