Influence of rectal washout on bacterial counts in the rectal stump

Abstract

Abstract Forty-three patients undergoing a restorative colorectal resection were randomized to have their rectal stump washed out with either 0·9 per cent saline, 2·5 per cent povidone—iodine or 0·3 per cent sodium hypochlorite. The bacterial counts before and after washout for Escherichia coli and Bacteroides fragilis were compared using the Mann—Whitney U test. There was no significant difference in the counts for E. coli before and after washout with saline (log 9·7–log 9·7 organisms/ml) and saline had no influence on the counts of B. fragilis (log 7·9–log 6·5 organisms/ml). Hypochlorite was associated with a significant reduction in E. coli counts (log 6·1–log 1·1 organisms/ml, P < 0·005) and the counts of B. fragilis (log 8·1–log 0·0 organisms/ml, P < 0·005). The counts of B. fragilis were significantly reduced by povidone—iodine (log 8·1–log 1·1 organisms/ml, P < 0·005) but there was no significant reduction in counts of E. coli (log 5·6–log 5·3 organisms/ml). The data suggest that sodium hypochlorite is better than povidone—iodine or saline as a rectal washout for colorectal anastomosis.