Long-term antimicrobial suppression prevents treatment failure of streptococcal periprosthetic joint infection

To evaluate the effect of oral antimicrobial suppression on the outcome of streptococcal periprosthetic joint infection (PJI).

Consecutive patients with streptococcal PJI receiving antimicrobial suppression for >6 months were prospectively included and compared to a retrospective control group without suppression. Outcome was assessed with Kaplan-Meier analysis and compared by the log-rank Mantel-Cox test. Multivariate analysis was used to identify factors associated with treatment failure.

Of 69 streptococcal PJI episodes (37 knee, 31 hip and one shoulder PJI), 43 (62%) were caused by beta-hemolytic streptococci and 26 (38%) by viridans group streptococci. Debridement and prosthesis retention was performed in 27 (39%), one-stage exchange in 5 (7%), multi-stage exchange in 31 (44%) and prosthesis removal in 6 patients (9%). 24 patients (35%) were treated with antimicrobial suppression receiving oral amoxicillin (n = 22), doxycycline (n = 1) or clindamycin (n = 1). After a median follow-up of 13 months (range, 0.5-111 months), 38 of 65 patients (58%) were infection-free. Suppressive antimicrobial treatment was associated with higher success rate compared with no suppression (93% vs. 57%, p = 0.002), representing the only significant independent factor preventing treatment failure.

Long-term antimicrobial suppression was associated with significantly better treatment outcome and should be strongly considered in streptococcal PJI.