Microbiology of postoperative wound infection: a prospective study of 1770 wounds

A prospective study of postoperative wound infection was carried out over a 12-month period. Intra-operative swabs from the patients' anterior nares, the opened viscus and parietes were cultured using standard bacteriological techniques. Of the 1770 wounds studied, 167 (9·4%) became infected. Wound infection rates, according to clinical wound types, were clean 5·9%, clean-contaminated 10·7%, contaminated 24·3% and dirty 52·9%. The figures according to microbiological wound types were clean 4·7%, and potentially, lightly and heavily contaminated 15·3%, 22·1% and 30·2% respectively. The commonest causative organisms were Staphylococcus aureus 23·7%, Escherichia coli 16·9%, Staphylococcus epidermidis 13·5% and Pseudomonas aeruginosa 13·0%. When isolated intra-operatively, Enterobacter spp., Proteus spp., Klebsiella spp. and P. aeruginosa appeared to have a high probability of causing postoperative wound infection, but the intra-operative isolation of Bacteroides sp. was a poor predictor of subsequent wound infection. © 1992.