Novel association of Streptococcus gallolyticus subspecies pasteurianus and hepatocelluar carcinoma: opening new frontiers

Background: Streptococcus gallolyticus subsp. gallolyticus bacteremia is associated with colorectal malignancies. There is limited data regarding the association of Streptococcus gallolyticus subsp. pasteurianus with malignancies. We aimed to study the pattern of isolation of Streptococcus gallolyticus and analysis of risk factors in patients with hepatobiliary diseases. We also planned to evaluate its association with hepatocellular malignancy.

Methods: We analyzed clinical and laboratory data of 68 cases of Streptococcus gallolyticus infections (77 isolates) from January 2013 to December 2017. These included blood (58), ascitic fluid (15), bile (2) and pleural fluid (2). We analyzed the risk factors in patients developing malignancy with Streptococcus gallolyticus infections.

Results: Amongst the 68 patients studied, eight (11.76%) had confirmed malignancies, hepatocellular carcinoma (HCC) (5), rectal adenocarcinoma (1), pancreatic carcinoma (1) and uterine tumors (1). Simultaneous isolation of S. gallolyticus subsp. pasteurianus from blood and ascitic fluid in eight patients (11.8%, p = .01) was significantly associated with the occurrence of HCC. Streptococcus gallolyticus infection with HCC was associated with younger age (median 55 years), lymphocytosis and elevated gamma-glutamyl transferase (GGT).

Conclusions: This study provides a novel insight into the association of Streptococcus gallolyticus subspecies pasteurianus with HCC. The isolation of the organism from blood and ascitic fluid should prompt the clinicians to search for evidence of HCC actively.