Microbiology of wound infection after head and neck cancer surgery

Specimens of pus were obtained from 24 patients who developed postoperative wound infection after head and neck cancer surgery. Aerobic bacteria only were isolated in two instances (8%), anaerobic bacteria only in one (4%), and mixed aerobic and anaerobic bacteria in 21 (88%). A total of 146 isolates were recovered (66 aerobic and 80 anaerobic), an average of six isolates per specimen (2.7 aerobic and 3.3 anaerobic). The most frequently recovered isolates were Peptostreptococcus sp, Staphylococcus aureus, Bacteroides sp, Fusobacterium, and enteric gram-negative rods. Twenty-two isolates recovered from 17 wounds (71%) produced beta-lactamase. These included all five isolates of S aureus and nine of 17 (53%) of the Bacteroides melaninogenicus group. The polymicrobial aerobic/anaerobic nature of postoperative wound infections after head and neck cancer surgery and the presence of beta-lactamase-producing bacteria may have important implications for the management of these infections.