Group B streptococcal infection in older patients. Spectrum of disease and management strategies.

Group B streptococcal infection has recently been recognised as an important and apparently increasingly common cause of invasive disease in nonpregnant adults. The annual incidence of invasive disease has been estimated at 4.4 per 100,000 nonpregnant adults and is highest among adults over 60 years of age. The most common clinical diagnoses include skin and soft-tissue infections, bacteraemia with no identified source, osteomyelitis, urosepsis and pneumonia. Other important but less common infections include peritonitis, infectious arthritis, meningitis and endocarditis. The majority of adults with group B streptococcal infections have underlying diseases including diabetes mellitus, malignant neoplasms and liver disease. Nosocomial infection and polymicrobial bacteraemia occur in a significant proportion of patients with invasive group B streptococcal disease. Mortality from invasive disease is particularly high in the elderly. For treatment of serious group B streptococcal infections, high doses of benzylpenicillin (penicillin G) are recommended because of the somewhat higher minimal inhibitory concentrations. In addition to parenteral antibiotic therapy surgical management may be required for successful treatment, particularly in the case of soft-tissue or bone infection. Invasive group B streptococcal infection is a major problem in elderly adults and those with chronic diseases, and efforts should be made to identify and treat such infections early. Future approaches may include vaccine prevention of serious group B streptococcal infection in adults at highest risk.