Cytotoxic enterotoxin produced by Aeromonas hydrophila: Relationship of toxigenic isolates to diarrheal disease

Nicholas Cumberbatch, Marc J. Gurwith, Claire Langston, R. Bradley Sack, James L. Brunton

Research output: Contribution to journalArticlepeer-review

116 Scopus citations


Ninety-six Aeromonas hydrophila isolates were tested for cytotoxin and hemolysin production. Sixty-six (69%) of the isolates were both cytotoxic and hemolytic, whereas the rest produced neither cytotoxin nor hemolysin. No evidence of a separate cytotonic activity could be found in any of the isolates. Cytotoxin activity correlated with enterotoxic activity. Of four cytotoxin-producing strains tested in the isolated rabbit ileal loop, three were definitely positive and one was borderline, whereas two nontoxigenic strains were negative. Cytotoxin activity appeared to be a stable property and could not be associated with any common identified plasmid; only 10 of 21 cytotoxin-producing strains could be shown to have any plasmid by agarose gel electrophoresis. Cytotoxin production correlated with a positive lysine decarboxylase phenotype (98%) or a positive Voges-Proskauer phenotype (94%), compared to 27% lysine decarboxylase-positive and 23% Voges-zProskauer-positive, cytotoxin-negative isolates (P<0.001 for both). In fecal samples, cytotoxin production correlated with diarrheal disease; of 40 diarrheal isolates, 32 (80%) were toxigenic compared to 9 (41%) of 22 nondiarrheal isolates (P=0.004). It appears that A. hydrophila can be a cause of diarrhea and that this enteropathogenic potential is mediated by a cytotoxic enterotoxin.

Original languageEnglish (US)
Pages (from-to)829-837
Number of pages9
JournalUnknown Journal
Issue number3
StatePublished - 1979
Externally publishedYes

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases


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