Novel plate culture method to improve the microbiological diagnosis of peritonitis in patients on continuous ambulatory peritoneal dialysis.

A novel economical plate culture technique incorporating Tween 80 was used for the isolation of organisms from dialysis effluent in cases of continuous ambulatory peritoneal dialysis peritonitis. It was found to be convenient for routine laboratory use and increased the yield of positive plate cultures in specimens without antibiotics from 53 to 75% (P less than 0.01) and in specimens containing antibiotics from 24 to 38% (P less than 0.05). It allowed for the identification and susceptibility testing of isolates 24 h earlier than did broth culturing and a more ready appreciation of mixed cultures and contaminants.