Animal bite wounds and their management in tropical Australia

To define the microbiologic characteristics of animal bites in tropical Australia and the appropriateness of current Australian antimicrobial guidelines for their management.

This retrospective audit examined hospitalizations in tropical Australia after an animal bite or animal-associated penetrating injury between 2013 and 2020. The primary outcome was a composite of death, intensive care unit admission, amputation, quaternary center transfer, or unplanned rehospitalization.

A wide variety of animals were implicated, but snakes (734/1745, 42%), dogs (508/1745, 29%), and cats (153/1745, 9%) were the most common. Hospital presentation after 24 hours (odds ratio (OR) (95% confidence interval (CI)): 68.67 (42.10-112.01)) and a cat-related injury (OR (95% CI): 22.20 (11.18-44.08)) were independently associated with an increased risk of infection. A pathogen not covered by the relevant antimicrobial regimen recommended in Australian guidelines was identified in only 12/1745 (0.7%) cases. The primary outcome occurred in 107/1745 (6%) and was independently associated with tissue trauma (OR (95% CI): 9.29 (6.05-14.25), p<0.001), established deep infection at presentation (OR (95% CI): 2.95 (1.31-6.61), p=0.009) and hospital presentation after 24 hours (OR (95% CI): 1.77 (1.12-2.79), p=0.01).

A wide variety of animals bite humans in tropical Australia, but empiric antimicrobial regimens recommended in current national guidelines cover almost all the microbiologic isolates from the resulting wounds.