Bacteriological sampling of peritoneal dialysis fluids. How to limit negative-culture peritonitis rate?

Abstract

Peritonitis is a major and serious complication in terms of morbi-mortality for patients treated with peritoneal dialysis. Their microbiological diagnosis is challenging for both the detection of the etiological agents and in interpreting positive cultures. Many microorganisms can cause this infection; usual micro-organisms such as coagulase-negative staphylococci or Enterobacteriaceae, but also ‘atypical’ bacteria, which culture or detection, is more tedious can be found. To identify the responsible bacteria, molecular biology and culture techniques can be set up. Molecular biology (particularly the sequencing of the universal 16s rDNA gene) makes it possible to identify atypical agents, but antimicrobial susceptibility testing cannot be performed following these technics. The culture of peritoneal dialysis fluids remains the ‘gold-standard’ for the diagnosis of these infections. Nevertheless this must be optimized to enhance its sensitivity. The etiological diagnosis of peritonitis in patients treated with peritoneal dialysis may be difficult, but modern microbiology combined with a bacterioclinical discussion allow the identification of the microorganism responsible for the infection in the great majority of the cases.