Shewanella infection of snake bites: a twelve-year retrospective study

OBJECTIVE: Infections of snake bite wounds by Shewanella are rarely discussed in the medical literature. This study aims to characterize the presentation and management of Shewanella infections in snake bite wounds. METHOD: We retrospectively investigated the microbiology, clinical features, and outcomes of patients with Shewanella infected snake bite wounds admitted to a tertiary medical center from January 1998 to December 2009. RESULTS: Ten patients with Shewanella-infected snake bite wounds were identified. All of the snake bites were caused by cobras. The majority of patients had moderate to severe local envenomation and polymicrobial infections. Shewanella isolates are susceptible to ampicillin-sulbactam, piperacillin-tazobactam, third-and fourthgeneration cephalosporins, carbapenems, aminoglycosides, and quinolones but are resistant to penicillin and cefazolin. All of the patients examined had favorable outcomes. CONCLUSION: It is recommended that Shewanella infection be considered in snake bite patients, especially when patients present with moderate to severe local envenomation.

Infections in the bite site after envenoming by snakes of the Bothrops genus

Envenomation caused by snakes of the Bothrops genus produces a lesion in the bite site and can result in extensive necrosis. The dead tissue can be secondarily infected by bacteria that come from the snake, and the bacteria can be inoculated at the moment of the bite. The bacteria that most commonly cause infection are the enterobacteria, mainly Morganella morganii, Proteus rettgeri, Enterobacter sp., and Escherichia coli. Group D streptococci including here Enterococcus sp. and the Bacteroides sp. are also involved. Based on a study of the sensibility of these bacteria, it has been suggested that this infection must be treated with chloramphenicol, as a sole antimicrobial agent, or with the combinations of benzylpenicillin or ampicillin with aminoglycoside or trimethoprim/sulfamethoxazole. Although Governmental Health Services do not recommend the prophylactic use of antimicrobial drugs, it is not yet clear that such a procedure would not be useful in cases with a high probability of infection.