Bacterial DNA (bactDNA) is present in blood and ascitic fluid (AF) in a third of patients with cirrhosis and ascites, but whether this phenomenon represents episodes of bacterial translocation (BT), strictly considered when culture of mesenteric lymph nodes (MLNs) are positive, remains unknown. This study assessed the relationship between bactDNA detection in biological fluids and MLNs and went on to investigate the local and systemic inflammatory status according to its presence. Cirrhosis was induced in rats by ingestion of CCL4. A subgroup of five animals with cirrhosis received norfloxacin (5 mg/kg/day) for 7 days. MLNs and ascitic and pleural fluids were collected at laparotomy and cultured; samples were collected for identification of bactDNA and measurement of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and nitric oxide (NO). BactDNA was detected in MLNs in 12 of 19 animals (63.1%), corresponding in seven cases to culture-positive MLNs, and in five to culture-negative MLNs. BactDNA was detected in biological fluids in 11 of 19 animals (57.9%), and in all cases the same bacteria spp. detected in samples was present in MLNs. BactDNA was not detected in any biological sample from animals receiving norfloxacin. Tumor necrosis factor alpha (TNF-α), IL-6, and NO were similar in culture-positive and culture-negative/bactDNA-positive samples, and significantly higher than those observed in animals with culture-negative/bactDNA-negative MLNs, animals with cirrhosis that were receiving norfloxacin, and controls. In conclusion , the presence of bactDNA in biological fluids in rats with cirrhosis constitutes a marker of BT, and it is associated with a marked inflammatory response, independent of the result of the culture.

An ascitic microenvironment can condition the immune response of cells from cirrhotic patients with spontaneous bacterial peritonitis. To characterize this response, we determined the cytokine concentrations in ascitic fluid and analyzed the phenotype and function of ascitic leukocytes at diagnosis and after antibiotic-induced resolution in sterile ascites and ascitic fluid of 2 spontaneous bacterial peritonitis variants: positive and negative bacteriological culture. At diagnosis, a high concentration was found of IL-6 and IL-10 in the ascitic fluid from negative and positive bacteriological culture. The IL-6 concentration correlated with the percentage of neutrophils (R = 0.686, P < 0.001). In this context, positive and negative culture neutrophils had an impaired oxidative burst, and, after the antibiotic, the negative culture spontaneous bacterial peritonitis burst was fully recovered. Higher concentrations of IL-6 and IL-10 correlated with the presence of low granular CD 14^low macrophages (R = −0.436, P = 0.005 and R = 0.414, P = 0.007, respectively). Positive culture spontaneous bacterial peritonitis macrophages expressed the lowest levels of CD16, CD86, CD11b and CD206, and HLA-DR, suggesting an impaired global function. Treatment increased all markers on the positive culture macrophages and CD11b and CD86 on negative culture macrophages. In negative culture spontaneous bacterial peritonitis, this increase was accompanied by phagocytic function recovery. The antibiotics then reverted the marker levels on positive and negative culture macrophages to the levels on sterile ascitis macrophages and restored ascitic negative culture cell function.