Sir—We read with interest the recent paper by Jacobs et al. (Acta Orthopaedica Sept 2015) concerning treatment of prosthetic joint infections caused by Propionibacterium acnes. The authors suggest from their findings that combination therapy with rifampicin is not more effective than therapy without rifampicin. They cite two of our papers, one of which they use to support their statement “the successful eradication of Propionibacterium biofilms with rifampicin in in-vitro studies” (Bayston et al. 2007). In fact, our paper compared activity against P. acnes biofilms of penicillin, linezolid or linezolid plus rifampicin. We did find that the addition of rifampicin to linezolid led to relapse-free eradication after 14 days compared to apparent eradication but relapse when linezolid alone was used. It must be borne in mind that this was an in vitro study, but it suggested that the addition of rifampicin, at least when linezolid was used, was beneficial, but equally importantly, it showed that the safe inexpensive drug, penicillin, was at least equally effective without rifampicin against P. acnes biofilms. Almost all non-dermatological P. acnes isolates are susceptible to penicillin, and Jacobs et al. confirmed that theirs were too, and it would have been interesting to have used this in their cases.
References
- Bayston R, Nuradeen B, Ashraf W, Freeman B J.. Antibiotics for the eradication of Propionibacterium acnes biofilms in surgical infection. J Antimicrob Chemother 2007; 60 (6): 1298–301. [DOI] [PubMed] [Google Scholar]
- Furustrand Tafin U, Corvec S, Betrisey B, Zimmerli W, Trampuz A.. Role of rifampin against Propionibacterium acnes biofilm in vitro and in an experimental foreign-body infection model. Antimicrob Agents Chemother 2012; 56 (4): 1885–91. [DOI] [PMC free article] [PubMed] [Google Scholar]