Aeromonas hydrophila soft-tissue infection as a complication of snake bite: report of three cases.

Aeromonas hydrophila soft-tissue infection has been associated with fish and reptile bites. There have bee three recent cases from Brazil of abscesses complicating snake bites in which A. hydrophila was isolated from the purulent exudates. One of the snakes responsible for the bites was a specimen of Bothrops moojeni, and the others were most probably also lance-headed vipers. These snakes have a local necrotizing, myotoxic, oedema-inducing venom that must have favoured the multiplication in the injured tissue of A. hydrophila strains, which were probably present in the mouth, fangs or venom of the snakes. The use of a tourniquet by two of the patients probably worsened the local envenoming, and contributed to the occurrence of soft-tissue infection. The patients had a good outcome after the abscesses were incised and drained, and after being treated with chloramphenicol. Chloramphenicol appears to be a good alternative for the empirical treatment of soft-tissue infection complicating snake bite in Brazil, because: it is active against the majority of the anaerobic and aerobic bacteria found in these abscesses, including A. hydrophila; it can be administered by the oral route; and its is inexpensive. Suitable alternatives are cotrimoxazole or fluoroquinolones, to which aeromonads are usually susceptible in vitro, associated with antibiotics, such as clindamycin and metronidazole, with an anti-anaerobic spectrum.