The detection of bacterial DNA in blood of rats with CCl4-induced cirrhosis with ascites represents episodes of bacterial translocation

Abstract

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-alpha), 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-alpha), 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.