Bacteriological study in perianal abscess is not useful and not cost-effective

The detection of gut organisms in perianal abscesses has been postulated to suggest an underlying communication with the anal canal. However, recent studies appear to contradict this observation. The aim of this study is to determine the value of bacteriological studies in perianal abscesses.

A retrospective study of all patients who have had a surgical drainage of their perianal abscesses with concomitant microbiological examination from January 2010 to December 2012 was performed. Patients with known underlying anal fistula, Crohn's disease or previous perianal operations were excluded.

A total of 164 patients, median age of 42.0 years (range 8-87) comprising of 78.7% males formed the study group. Gut organisms were cultured in 143 (87.2%) samples while 12 (7.3%) demonstrated skin organisms and nine did not yield any bacterial growth (5.5%). Twenty-nine (17.7%) patients developed anal fistula and 34 (20.7%) patients had a recurrence of the perianal abscess. The median follow-up period was 1450 (14-2391) days. There was no significant association between the presence of gut organism and development of fistulas (odds ratio = 0.48; 95% confidence interval = 0.17-1.37) or recurrence of perianal abscess (odds ratio = 1.66; 95% confidence interval = 0.46-6.01).

Bacteriological culture in perianal abscess is not useful for predicting the development of anal fistula or abscess recurrence. Hence, there is no need to perform this investigation on a routine basis.