Is detection of bacterial DNA in ascitic fluid of clinical relevance?

Abstract

In patients with cirrhosis, bacterial DNA has been found in ascites reflecting bacterial translocation. However, the clinical relevance of this finding is ill-defined especially compared with the standard diagnostics for detection of spontaneous bacterial peritonitis (SBP). Furthermore, other DNA tests have not been sufficiently evaluated. We prospectively included 151 patients with cirrhosis and ascites admitted to our department. The patients were evaluated for diagnosis of SBP (polymorphonuclear count > 250 cells/mm) or finding of bacterascites, defined by positive bacterial culture from ascites. To detect bacterial species of bacterial DNA fragments in ascites, broad-range polymerase chain reaction and nucleotide sequencing analysis with the LightCycler SeptiFast Kit Mgrade were performed. Routine parameters were correlated with these findings. Eighteen of 151 patients (12%) had SBP according to the classic definition. Bacterial DNA was detected in five of these 18 patients (3%), whereas in 13 patients (9%), bacterial DNA was detected without standard SBP. Seven patients (5%) had culture-positive SBP, only in two of them bacterial DNA was detected. In multivariate analysis, C-reactive protein (P = 0.000), white blood cell count (P = 0.019), and lactic acid dehydrogenase in ascites (P = 0.000) were independently associated with SBP. In the DNA-positive ascites group, none of the assessed parameters was significantly associated with the bacterial DNA positivity. We found no correlation between detection of bacterial DNA in ascites and SBP (polymorphonuclear count > 250/mm). In contrast to the patients with bacterial DNA in ascites, patients with SBP showed clinical signs of infection. This study provides no evidence that detection of bacterial DNA in ascites of patients with liver cirrhosis is of clinical or diagnostic relevance when using the panel of LightCycler SeptiFast Kit Mgrade.