Pyogenic arthritis caused by Streptococcus milleri in a nonimmunocompromised host.

We describe a case of pyogenic arthritis caused by S. milleri (S. anginosus) in a non-immunocompromised host. No other septic focus was found. S. milleri is now widely recognized as an important cause of pyogenic infection, though it eluded suspicion for many years. The rarity of reports of articular infections by S. milleri might be due to problems associated with its recognition.