Septic arthritis due to streptococci and enterococci in native joints: a 13 year retrospective study.

ABSTRACT

OBJECTIVES: Streptococcal species are the second most common cause of native joint septic arthritis (SA). However, there are few systematic data about streptococcal SA. METHODS: The medical records of adults with SA caused by streptococci, pneumococci, and enterococci at our tertiary care centre between 2003 and 2015 were reviewed. RESULTS: 71 patients (34% female) with 83 affected joints were included. Median age was 62 years. A single joint was involved in 62 patients (87%). One or more comorbidities were present in 58 patients (82%). 16 patients (23%) had a concomitant soft-tissue infection overlying the affected joint. The hematogenous route was the dominating pathogenesis (42/71, 59%). 9 (13%) patients were diagnosed with endocarditis. The knee was the most commonly affected joint (27/83, 33%) followed by shoulder (13/83, 16%). ß-haemolytic streptococci were most commonly identified (37/71, 52%) followed by polymicrobial infections (12/71, 17%). Surgical interventions included arthroscopic irrigation and debridement in 31 (44%), arthrotomy in 23 (32%), and amputation in five patients (7%). Median duration of antimicrobial therapy was 42 days. Antibiotic treatment without any surgical intervention was performed in 5 (7%) patients. Outcome was good in 55 (89%) patients; mortality was 13% with four of nine deaths attributed to joint infection. Age and pathogen group independently predicted poor outcome in recursive partitioning analysis. CONCLUSIONS: Streptococcal SA was mostly due to ß-haemolytic streptococci in older and polymorbid patients. Old age, anginosus group streptococci, enterococci, and polymicrobial infections predicted poor outcome, while antibiotic treatment duration can likely be shortened.