Infections resulting from wild land and aquatic species injuries: A case series from Mornington Peninsula, Australia

Abstract

Background

Urban expansion into natural habitats has increased human interactions with wild terrestrial and aquatic species, leading to a rise in animal-related injuries. These incidents often result in complex infections, posing major public health challenges. This study examines the epidemiology, therapeutic interventions, and clinical outcomes of infections from non-domesticated animal injuries in the Mornington Peninsula, Australia.

Methods

This retrospective study (February 2021–April 2024) evaluated medical records of patients presenting with injuries from wild species who subsequently developed infections. Selection criteria included only cases with confirmed infections determined by clinical assessment or positive microbial cultures. Injuries from domestic animals, insects, or humans were excluded. The analysis assessed timing of infection onset, microbial culture results, antibiotic sensitivity profiles, and postoperative trajectories.

Results

A total of 52 bites from non-domesticated animals were documented, with 23 % (12/52) being infected. Most were males with an average age of 43 years. Among the 12 infected cases, Staphylococcus aureus was isolated in 3/12 (25 %), β-haemolytic streptococci in 2/12 (17 %), Enterococcus faecalis in 1/12 (8 %), Pseudomonas aeruginosa in 1/12 (8 %), Prevotella bivia in 1/12 (8 %), and Vibrio vulnificus in 1/12 (8 %); mixed coliform growth was observed in 3/12 (25 %). Compared to typical dog and cat bites, usually caused by Pasteurella multocida, streptococci, staphylococci and anaerobes, our series revealed a higher presence of marine-associated pathogens such as Vibrio species and environmental Gram-negative bacilli. Management involved wound debridement with adjunctive medical therapy (7/12), delayed primary closure (3/12), and medical management alone (3/12). All patients received empirical broad-spectrum antibiotics, which were later adjusted based on culture results. Most isolates were pan-sensitive, except for Vibrio vulnificus (ciprofloxacin-sensitive, resistant to penicillins/cephalosporins) and penicillin-resistant Staphylococcus aureus. All patients recovered without complications following comprehensive wound care and targeted antibiotic therapy. Notably, some marine-derived infections exhibited unique resistance patterns that required specific antimicrobial regimens.

Conclusions

The necessity for immediate comprehensive wound management and empirically guided antibiotic therapy, adjusted based on culture results, was essential for managing these complex infections. The data derived from this study provides essential insights into the microbial dynamics and clinical management of wild animal bite infections, emphasizing the need for individualized medical strategies.