Septic Arthritis due to Oral Streptococcal Species Following Intra-articular Injection: A Case Series and Retrospective Chart Review

BACKGROUND: Oral streptococcal species are a rare cause of septic arthritis. We hypothesized that one possible source of infection is oral bacteria from the mouth of a practitioner performing joint injection without a mask. While the use of a face mask is standard practice during lumbar puncture and other spinal procedures due to the risk of iatrogenic meningitis, mask usage during joint injection is not a standard recommendation. METHODS: The clinical microbiology laboratory database was reviewed to identify joint fluid cultures positive for oral streptococcal bacteria between January 2007 and December 2015. The corresponding patient charts were reviewed for evidence of joint injection within 90 days prior to the positive culture. RESULTS: We identified 18 cases of septic arthritis due to oral streptococcal species. Of those joint injection was performed prior to the development of acute septic arthritis in four (22%) cases. The implicated pathogen was Streptococcus mitis/oralis in two cases, Streptococcus sanguinis in one case, and Abiotrophia defectiva in one case. All four cases occurred in males over the age of 60 and affected native joints. Three of four patients had underlying osteoarthritis, and three of four had a history of diabetes. The patients all presented with acute worsening of joint pain and swelling 2–5 days after undergoing joint injection. Three cases followed corticosteroid injection and 1 followed an MRI arthrogram. All four patients underwent at least one surgical procedure (two required repeat irrigation and debridement) to treat the infection and received at least 4 weeks of antibiotic therapy. CONCLUSION: Oral streptococcal species should be considered in the differential of causative species of septic arthritis in patients presenting with worsening pain after a joint injection. The use of a face mask during joint injection should be explored as a simple and inexpensive precaution to prevent this rare but serious complication. DISCLOSURES: All authors: No reported disclosures.