Prophylactic Antibiotics Are Not Needed Following Rattlesnake Bites

Antibiotics are sometimes administered to victims of rattlesnake bites in the hope of preventing infections. Experts in the field recommend that prophylactic antibiotics not be used because secondary infections are rare. Current recommendations are based on a small number of studies conducted in the United States. We decided to reexamine the issue by taking advantage of a large database on snakebites in Arizona. This allowed us to determine how often prophylactic antibiotics were used and whether or not they were effective.

We obtained data from the Arizona Poison and Drug Information Center electronic medical record, Toxicall. Rattlesnake bites occurring over 18 years (1999-2016) were analyzed according to the descriptors: infection, pus, isolation of bacteria, and antibiotic use.

There were 2748 evaluable patients identified as having rattlesnake bites. The mean number of bite victims was 153 per year. Most (72%) were male. Their ages ranged from 8 months to 91 years. Prophylactic antibiotics were administered to 120 of 2748 (4.4%) victims. There were 27 postbite infections (0.98%) but no deaths. Victims sometimes manipulated the wound sites. Microorganisms were isolated from only 9 patients. Only a Salmonella sp. was of certain reptilian origin; the others were likely of human origin.

This large study supports recommendations that prophylactic antibiotics not be used following rattlesnake bites in the United States. The incidence of postbite infections was low, <1%. All but 1 of the bacteria isolated from the wounds were common inhabitants of human skin and not found in oral secretions of rattlesnakes.