Musculoskeletal infections caused by streptococcus infantarius - a case series and review of literature

The full spectrum of diseases caused by S. infantarius remains poorly understood, particularly its role in musculoskeletal infections.

A retrospective study was conducted from January 2008 to May 2024. Patients with bacterial infections and detection of S. infantarius in at least one tissue sample, fluid sample, or blood cultures were included. Follow-up controls in patients with musculoskeletal infection were performed.

S. infantarius could be identified in at least one sample (blood cultures, wound fluid, wound swab, bile, tissue or urine sample) of 72 patients. 33 were considered clinically relevant with symptomatic infections (63.4 ± 21.1 years; positive samples: 1.39 ± 0.86; total number of samples: 2.7 ± 1.76). Non-muskuloskeletal infections (n = 29; 61.1 ± 21.5 years; positive samples: 1.28 ± 0.59) included a variety of different infections (sepsis (n = 11), abdominal/gastrointestinal/urogenital infections (n = 16), soft tissue infections (n = 2)). Four patients with musculoskeletal S. infantarius infection (positive samples: 2.25 ± 1.89; diagnosis: acute PJI, spondylodiscitis, chronic PJI and postoperative spinal wound infection) required surgical and/or antimicrobial treatment. Follow-up after musculoskeletal infection varied between 10 and 60 months. Antibiotic susceptibility testing displayed a sensitivity to Penicillin in all isolates. No patient had a recurrent positive sample/infection with S. infantarius.

This study describes musculoskeletal infections caused by S. infantarius, highlighting its possible relevance as pathogen in orthopedic infections. The findings underscore the importance of recognizing and appropriately treating S. infantarius. In case of penicillin allergy, clindamycin shows to be an effective alternative treatment.