Z Gastroenterol 2015; 53 - KG165
DOI: 10.1055/s-0035-1559191

Bacterial DNA quantification in ascites: a novel tool to define high risk patients?

C Engelmann 1, S Krohn 1, D Prywerek 1, A Böhlig 1, A Herber 1, K Zeller 1, S Böhm 1, T Berg 1
  • 1Universitätsklinik Leipzig, Gastroenterologie/Hepatologie, Leipzig, Deutschland

Background:

Spontaneous bacterial peritonitis (SBP) represents a serious complication in patients with liver cirrhosis. Culture-based methods to detect bacteria in the ascites fluid showed limited sensitivity, and the diagnosis of SBP is therefore usually made by the surrogate of an increased total ascites leukocyte or neutrophil count. Culture-independent 16S rRNA-gene based amplification methods allowed for the detection of bacterial DNA (bactDNA) in both neutrocytic and non-neutrocytic AF but the significance of this novel tool is still debated. In the current study the impact of bactDNA quantification in ascites on the clinical outcome of patients with cirrhosis was evaluated.

Material and Methods:

AF-samples of 173 cirrhotic patients were collected between February 2011 and December 2012. BactDNA was quantified by using real-time PCR with broad range primers targeting the V3 and V4 variable region of 16S rRNA-Gene. Positive AF-samples were sequenced and chromatograms were identified using RipSeq. The detection of bactDNA in AF was correlated with routinely recorded clinical parameters and survival.

Results:

BactDNA was detected in 57/144 (39.6%) non-leukocytic AF and 10/23 (43.5%) of leukocytic AF (p = 0.724). The median level of bactDNA was significantly lower in non-leukocytic than in leukocytic AF (5.7 × 102 copies/mL vs. 1.2 × 104 copies/mL, p = 0.008). The detection of a bactDNA level above the quantification limit of the assay but not the presence of leukocytic AF was significantly associated with a reduced 180-day survival (180-day survival rate 42.6% vs. 60.9% (p = 0.030)). The bacterial spectrum detected by molecular methods was dominated by gram-positive strains such as Staphylococcus, Streptococcus, and Enterococcus species.

Conclusion:

The presence of quantifiable concentrations of bacterial DNA in patients with non-leucocytic ascites fluid samples using culture-independent 16S rRNA-gene based methods may help to define a new risk group with reduced survival. Sequence analyses confirmed a shift to gram positive and multibacterial strains. Pre-emptive antibiotic therapy in bactDNA positive patients should be investigated in further prospective interventional trials.