Maximizing bacterial isolation rates from CAPD fluid specimen.

Abstract

The major complication of Continuous Ambulatory Peritoneal Dialysis (CAPD) is Peritonitis which can be caused by various micro-organisms. The problem with CAPD fluid is that current culturing techniques lack sensitivity and result in a percentage of false negative cultures (10% to 50%). During this study, two culture techniques, which are the lysis-centrifugation by osmosis and Blood culture technique using BACTEC blood culture system, will be compared together and with the centrifugation technique, which is the current culturing technique for CAPD fluid at the Bacteriology laboratory at St. Luke's Hospital. A total of 53 samples were collected, 77% of which were positive cultures with all or any one method and 23% were negative cultures with all methods. From the total positive cultures (41}, 87.8% were recovered with the lysis-centrifugation technique, 90.2% with the centrifugation technique and 92.6% with the blood culture techniques. From the significance association test carried out, the Fisher's Exact Test, it was found that there was no significant difference between the positive culture outcome achieved with the three culturing methods (p = 0.756). The frequency of each organism isolated during the study was almost the same with every one method thus confirming that there was not significant difference between the methods. Therefore no method could be said to yield more positive results than another method used during this study.