Presence of multiple bacterial markers in clinical samples might be useful for presumptive diagnosis of infection in cirrhotic patients with culture-negative reports.

Bacterial infections in cirrhotic patients with ascites are associated with a severe prognosis and an increased risk of death. The microbiological standard tests for the diagnosis of suspected infection, based on culture test of blood and ascitic fluid, are, in many cases (30-40 %), negative, even when patients show symptoms of infection. A multiple culture-independent protocol was applied and evaluated as a diagnostic and prognostic tool for the detection of bacterial infection in cirrhotic patients. Sixty-four culture-negative samples obtained from 34 cirrhotic patients, with PMN < 250 cells/μl of ascitic fluid, were screened for the presence of bacterial DNA, endotoxin, peptidoglycan/β-glucan and microscopically visible bacterial cells. Correlations between the presence of multiple markers and various clinical and laboratory parameters were evaluated. Bacterial DNA was detected in 23 samples collected from 16 patients; a large part of these samples also showed the presence of other bacterial markers, which was associated with a worsening of liver functionality, a higher incidence of infections during the follow-up and a higher mortality rate in our cohort of cirrhotic patients. We believe that the detection of additional bacterial markers in bacterial DNA-positive clinical samples makes the bacterial presence and its clinical significance more realistic and might be useful as early markers of an ongoing bacterial infection and in establishing a clinical prognosis.