Background: Streptococci cause up to 20% of prosthetic joint infections but this has received little attention in the published literature.
Methods: We reviewed retrospectively our experience with treatment of streptococcal prosthetic joint infections. Patients were followed up for up to 15 years after discontinuation of antimicrobial therapy and up to 8.5 years while on continuous antimicrobial therapy.
Results: Eighteen cases were diagnosed between 1984 and 1995. These included one group A, seven group B, one group D, seven group G and one viridans-group streptococcal infection as well as one group B and D streptococcal co-infection. All were late-onset infections and most (11 of 18, 61%) were acute. Hip and knee joints were equally affected. Six of seven group G streptococcal infections were associated with skin or soft tissue infections. Sixteen patients were treated primarily with antimicrobial agents including 5 days to 6 weeks given intravenously and 2 weeks to 8.5 years given orally. At latest follow up, 10 patients had been off antimicrobial therapy for at least 18 months without relapse, one patient had been off antimicrobial therapy for 7 months without relapse and four infections were successfully controlled with long-term suppressive antimicrobial therapy. One infection was unable to be controlled with antimicrobial therapy.
Conclusions: Our results, and those of others, show that prosthetic joint infections caused by streptococci have a relatively good outcome with primary antimicrobial therapy and, when necessary, drainage, lavage or debridement. Provided the prosthesis is stable and the patient can tolerate long-term antimicrobial therapy, this may be an effective alternative to excision arthroplasty.