First report of acute septic arthritis caused by zoonotic staphylococcus hyicus in a 2-year-old boy. A case report and literature review

Ruben D. Arellano-Pérez-Vertti, Department of Orthopedics and Traumatology, Medicine School, Autonomous University of Coahuila; Department of Orthopedics And Traumatology, Hospital Regional de Alta Especialidad Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE). Torreon, Coahuila, México
Jesús S. Mascorro-Guillen, Department of Orthopedics And Traumatology, Hospital Regional de Alta Especialidad Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE). Torreon, Coahuila, México
Jesús A. Campuzano-Lozoya, Department of Orthopedics And Traumatology, Hospital Regional de Alta Especialidad Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE). Torreon, Coahuila, México
Brenda C. Franco-Villarreal, Department of Orthopedics And Traumatology, Hospital Regional de Alta Especialidad Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE). Torreon, Coahuila, México
Jorge J. Galindo-Cruz, Department of Orthopedics And Traumatology, Hospital Regional de Alta Especialidad Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE). Torreon, Coahuila, México
Arturo Vásquez-Salas, Department of Orthopedics And Traumatology, Hospital Regional de Alta Especialidad Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE). Torreon, Coahuila, México

The etiology of septic arthritis may vary according to age, geographical region, and preexisting comorbidities. Staphylococcus aureus is still the most frequent etiologic microorganism (50%-70%) for all age groups. S. hyicus is not a common microorganism in colonizing human skin or mucous membranes. Human infection is very uncommon, with just a few cases reported in the literature. We report the first case of septic arthritis in the knee joint of a child caused by S. hyicus in a 2-year-old boy which suffered trauma to his left knee. The infant was initially diagnosed with a simple knee contusion. We performed arthrocentesis obtaining 20 cc of cloudy yellow synovial fluid for Gram staining and culture analysis. Empirical antibiotic therapy started with clindamycin at 40 mg/kg/day. Gram staining revealed the presence of gram-positive cocci, and the synovial fluid culture grew S. Hyicus, non-resistant to antibiotic therapy. After 16 weeks of follow-up, the patient was asymptomatic and could walk independently. S. hyicus infection is sporadic in humans, so it may represent an emerging pathogen. We highlight the importance of considering clinical and epidemiological history, distant infections, trauma, and contact with domestic or farm animals, for an early diagnosis of bone or joint infections.

Keywords: Septic arthritis. S. hyicus. Child.