Microbiology of human and animal bite wounds in children

Aspirates from bite wounds in 39 children (21 with animal bites and 18 with human bites) were cultured for aerobic and anaerobic bacteria. Aerobic bacteria only were recovered in 7 (18%) wounds, anaerobic bacteria only in 3 (8%) and mixed aerobic and anaerobic bacteria in 29 (74%). A total of 59 isolates was recovered from animal bites (2.8/specimen): 37 aerobes (1.8/specimen); and 22 anaerobes (1.0/specimen). A total of 97 isolates were recovered from human bites (5.4/specimen): 44 aerobes (2.4/specimen); and 53 anaerobes (3.0/specimen). The most frequent isolates in both types of wounds were Staphylococcus aureus, anaerobic cocci and Bacteroides spp. Present only in animal bites were Pasteurella multocida, Pseudomonas fluorescens and M-5. Present only in human bites were Group A streptococci. Eighteen beta-lactamase-producing organisms were isolated in 16 wounds. This study demonstrates the polymicrobial aerobic-anaerobic nature of human and animal bite wounds.