Identification of Bacterial Pathogens in Ascitic Fluids from Patients with Suspected Spontaneous Bacterial Peritonitis by Use of Broad- Range PCR (16S PCR) Coupled with High-Resolution Melt Analysis

Spontaneous bacterial peritonitis (SBP) can be a severe complication occurring in patients with cirrhosis and ascites, with asso-ciated mortality often as high as 40%. Traditional diagnostics for SBP rely on culture techniques for proper diagnosis, although recent reports suggest that the presence of bacterial DNA in peritoneal fluid in patients with cirrhosis and ascites is an indicator of SBP. A previously published broad-range PCR (16S PCR) coupled with high-resolutionmelt analysis (HRMA) was compared with standard culture techniques for diagnosis of SBP in 106 peritoneal fluid samples from patients with suspected SBP. The sensitivity and specificity for 16S PCR for detecting eubacterial DNA compared with those of standard culture techniques were 100 % (17/17) and 91.5 % (85/89), respectively. Overall, HRMA concordance with species identification was 70.6 % (12/17), al-though the 5 samples that were discordant at the species level were SBP resulting from a polymicrobial infection, and species-level identification for polymicrobial infections is outside the capability of HRMA. Both the broad-range 16S PCR and HRMA analysis provide useful diagnostic adjunctive assays for clinicians in detecting and identifying pathogens responsible for SBP. Spontaneous bacterial peritonitis (SBP) is a common and po-tentially fatal bacterial infection in patients with cirrhosis and ascites, occurring in 10 to 30 % of patients, with in-hospital mor-tality rates ranging from 20 to 30 % (1, 2, 6–8, 12). It is secondary to impaired humoral and cellular immune responses that result in indirect intestinal bacterial translocation into the ascitic fluid (1