Prosthetic hip-joint infection associated with a penicillin-tolerant group B streptococcus.

We report a case of prosthetic hip-joint infection with Streptococcus agalactiae (Lancefield group B streptococcus). The infection recurred after 3 months' treatment with amoxycillin. On further investigation, the isolate was found to be amoxycillin-tolerant. Addition of gentamicin abolished tolerance in vitro and the patient has remained asymptomatic since receiving a 10-day course of amoxycillin and gentamicin followed by amoxycillin alone.