Culture of dialysate in suspected CAPD associated peritonitis using the BacT/Alert system

The BacT/Alert blood culture system was evaluated as a method of culturing dialysates by comparing inoculation of culture bottles directly (DBTA) or after centrifugation of 50 mL of dialysate (CBTA) with conventional culture. Of the 122 dialysates cultured, 84 were positive by one of the 3 methods. After eliminating contaminants, DBTA and CBTA detected 84% (59 of 70) and 93% (65 of 70) of the positive cultures, respectively, compared to 77% (54 of 70) for conventional culture. CBTA and DBTA detected 87% (82 of 94) and 73% (68 of 94) of the significant organisms isolated, respectively, compared to 61% (57 of 94) by conventional culture. However, 60% of the contaminants occurred with the CBTA method. When a dialysate was positive by all 3 methods, both BacT/ Alert methods detected growth earlier by a mean of almost 19 hours. The BacT/Alert system is a useful alternative method for culturing dialysates with the advantages of an earlier detection of positive cultures and minimal handling for the processing of negative cultures.