The clinical epidemiology and malignancies associated with Streptococcus bovis biotypes in 506 cases of bloodstream infections.

Objectives: To determine the incidence of Streptococcus bovis (Sb) biotypes causing bacteraemia and associated malignancies.

Methods: This is a retrospective analysis of patients with Sb bacteraemia, pulled out from a prospective surveillance protocol of bacteraemia cases, in three areas of Spain (1990-2013): a cattle area (Lugo), a fishing area (Ferrol) and an urban area (Barcelona). Colonoscopy and Sb biotypes (Sb-I and Sb-II) were determined in most cases.

Results: 506 patients with Sb bacteraemia; mean age 68.1 (±14.1) years, and 66.2% were males. The cattle area, compared with the fishing and urban areas, had higher incidence of bacteraemia by SbI (40.29 vs 9.38 vs 6.15 cases/10(6) person-years, P < 0.001) and bacteraemia by Sb-II (29.07 vs 9.84 vs 13.37 cases/10(6) person-years, P < 0.001). The Sb-I cases (n = 224), compared with Sb-II cases (n = 270), had greater rates of endocarditis (77.6% vs 9.6%, P < 0.001) and colorectal neoplasm (CRN) (50.9% vs 16.6%, P < 0.001), and smaller rates of biliary tract infection (2.2% vs 29.6%, P < 0.001) and non-colorectal malignancy (8.9% vs 31.4%, P < 0.001).

Conclusion: There was a link between the cattle area and higher incidence of Sb bacteraemia. Sb-I differed from Sb-II cases in clinical findings and associated malignancies. Colonoscopy is mandatory in cases of endocarditis or bacteraemia caused by Sb-I.