Serious infections in adults due to group B streptococci. Clinical and serotypic characterization.

Serious infections in adults due to group B streptococci have been infrequently reported. We describe 24 such patients. Bacteremic pyelonephritis, pneumonitis and endometritis were the most common clinical syndromes observed. Group B streptococci infections tended to occur in patients with underlying illnesses, particularly genitourinary disorders and diabetes mellitus. Mortality was surprisingly low (8 per cent). Type III was the serotype most commonly isolated, and there was no significant correlation of different serotypes with specific organ-system involvement. Group B streptococcal isolates from these patients were uniformly sensitive to penicillin, ampicillin, cephalothin, chloramphenicol, erythromycin and clindamycin; all were highly resistant to kanamycin. Eighty-seven per cent were resistant to tetracycline. Although consistently sensitive to penicillin, the minimal inhibitory concentrations were significantly higher for group B than group A streptococci (p less than 0.0005).