Intra-operative culture in appendicitis: traditional practice challenged

Traditionally, microbiological swabs are taken for culture during appendicectomy. However, the pathogens encountered are largely predictable, and sensitive to broad-spectrum antibiotics. Thus, we aimed to examine the clinical value of this practice, by determining the influence of microbiological results on postoperative outcome in patients undergoing appendicectomy.

The study population comprised 721 consecutive patients undergoing appendicectomy for suspected acute appendicitis in a single district general hospital. Microbiological culture results and sensitivities of isolates were recorded in relation to histopathological findings and infective morbidity, to establish whether they influenced postoperative outcome.

Swabs were taken during 463 (64%) appendicectomies. Only 113 (24%) yielded positive cultures ('coliforms', anaerobes and Streptococcus milleri were most frequently isolated). Organisms resistant to broad-spectrum antibiotics were encountered in only 11 of 463 patients (2%) where swabs were taken. Overall, 39 patients (5%) developed significant infective complications postoperatively. Neither the presence of a positive intra-operative culture, nor the isolation of resistant organisms were significant in predicting infective complications (P = 0.11 and 0.17, respectively).

In the population studied, the results of intra-operative culture did not influence clinical outcome in patients undergoing appendicectomy. The practice of taking routine microbiological swabs for culture must be seriously questioned.