Streptococcus anginosus group and osteomyelitis: a single centre clinical experience

Purpose The Streptococcus anginosus group comprises three species of bacteria classified within the viridans streptococci. This group is known for abscess formation and endocarditis. While a variety of sites in the body claim anginosus streptococci as an agent of infection, osteomyelitis is unusual. The objective of this study was to describe a series of patients with osteomyelitis due to S anginosus group pathogens in terms of demographics, comorbidities, presentation and outcomes. Study design We reviewed our database for cases of osteomyelitis caused by S anginosus organisms. Data described included demographics, comorbidities, site of infection, route of infection (haematogenous versus contiguous), laboratory data and course. Results 11 patients with S anginosus group osteomyelitis were identified. All cases arose from a contiguous anatomical site, with the exception of one haematogenous case. Five instances were related to foot osteomyelitis while three, two and one case, respectively, were related to mandibular, cranial and vertebral osteomyelitis. Seventy-five per cent of patients had associated abscesses. The mean length of antibiotic treatment was 10.9 weeks. One patient failed therapy while four others relapsed. Conclusions Osteomyelitis due to the S anginosus group is uncommonly reported. Our case series illustrates the virulence of these organisms in the context of osteomyelitis and the importance of aggressive management.