Increased microbial yield from continuous ambulatory peritoneal dialysis peritonitis effluent after chemical or physical disruption of phagocytes.

The laboratory diagnosis of continuous ambulatory peritoneal dialysis-associated peritonitis is often hindered by either the absence of or the recovery of low numbers of viable microorganisms. This may be the result of sequestration of bacteria within phagocytes. Sonication of clinical specimens prior to culturing or culturing on saponin-containing media resulted in the growth of significantly greater numbers of colonies than standard culturing on conventional media. In addition, the demonstration that microorganisms are sequestered in phagocytes helped to establish the pathogenic nature of such isolates and distinguish them from contaminants even when present in low numbers. A variety of physical and chemical techniques can disrupt phagocytes and improve the sensitivity of laboratory methods used to confirm the diagnosis of peritonitis in continuous ambulatory peritoneal dialysis patients.