Screening strategies among pregnant women have decreased the incidence of group B Streptococcus, which causes severe neonatal infections. The incidence of these infections has increased among diabetic patients, however.To specify the characteristics of diabetic foot infections in which surgical samples have isolated one or several germs including group B Streptococcus, study its risk factors and determine its course.We retrospectively evaluated the records of all patients admitted to the University Hospital of Geneva from January 1999 through October 2004, with diagnoses of severe foot infection (+/- osteomyelitis) documented during surgery.Twenty-five severe diabetic foot infections were identified, 21 with osteomyelitis. The most common risk factors were age older than 60 years (n=10), chronic renal failure (n=7), severe arteriopathy (n=6), and immune depression (n=2). Most lesions were classified as grade 3 or 4 of Wagner's classification. 80% of the surgical samples were polymicrobial. Blood cultures were positive in 4 patients, one in septic shock. Half the patients (n=13) underwent amputation, despite initially appropriate antibiotic treatment. No patients died but 3 relapsed.Group B streptococcal foot infections often occur in fragile patients with immune depression or severe arterial disease. Despite intensive antibiotic therapy and adequate debridement, amputation is often required in diabetic patients because of severe damage to the tissue and poor vascularization.