Comparison of bedside- and laboratory-inoculated Bactec high- and low-volume resin bottles for the recovery of microorganisms causing peritonitis in CAPD patients.

There is not yet a universally accepted protocol for the recovery of microorganisms causing peritonitis in patients on continuous ambulatory peritoneal dialysis (CAPD). We prospectively analyzed 343 peritoneal effluent specimens by three protocols: 1) 10 ml of effluent centrifuged and the pellet plated onto blood, MacConkey agars, and into thioglycolate broth (routine method); 2) 5 ml and 10 ml inoculated at the bedside into Bactec 16A and 26A aerobic resin-containing blood culture bottles, respectively; and 3) 5 ml and 10 ml inoculated in the laboratory into Bactec 16A and 26A media, respectively. One hundred and forty (41%) peritoneal effluent specimens had microorganisms recovered, and, of these, 101 were recovered by routine culture compared to 117 (p < .021), 125 (p < .0001), 115 (p < .047), and 116 (p < .032) for bedside-inoculated 16A and 26A and for laboratory-inoculated 16A and 26A, respectively. Bedside-inoculated bottles were not significantly better than laboratory-inoculated bottles, and high-volume bottles were not significantly better than low-volume bottles for detection of patients positive for microorganisms; however, the number of total microorganisms recovered were significantly better from all inoculated blood culture bottles compared to routine culture. Bedside- and laboratory-inoculated resin-containing blood culture bottles are superior to the routine method for recovery of microorganisms causing peritonitis in CAPD patients.