Antimicrobial suppression improves short-term outcome of streptococcal periprosthetic joint infection (PJI) compared to standard treatment. This study assesses the long-term effectiveness of suppression.

This prospective study included consecutive patients with streptococcal PJI. Infection-free survival was analyzed using the Kaplan-Meier method and compared between patients receiving standard therapy (12 weeks) and those with suppression therapy (>6 months) with the log-rank test.

A total of 63 PJI episodes were analyzed. Standard treatment was administered to 33 patients, while 30 patients received suppression therapy (10 had ongoing and 20 had discontinued suppression at time of follow-up). Predominant pathogens included Streptococcus agalactiae (n=20) and Streptococcus dysgalactiae (n=18). The main surgical procedures used were two-stage exchange (n=35) and prosthesis retention (n=21). At 7.5 years, infection-free survival was significantly higher in the suppression group (62%) compared to the standard therapy group (38%) (p=0.038). Streptococci accounted for 14 of 27 failures (52%). Suppression effectively prevented streptococcal infection during treatment; however, relapses or new streptococcal infections occurred in 5 of 20 patients (25%) after discontinuation. Failures during ongoing suppression were exclusively caused by gram-negative rods.

Suppression therapy significantly improves long-term outcome in streptococcal PJI. While suppression effectively prevents streptococcal reinfections during treatment, the risk of recurrence reemerges after discontinuation.