Periprosthetic Joint Infection Caused by Streptococcus equi Subspecies zooepidemicus: The First Reported Case Confirmed by Synovial Fluid Culture.
5 affiliations
- 1Åland Health Services Mariehamn Åland Islands Finland.
- 2Infectious Diseases Inflammation Center Helsinki University Hospital and University of Helsinki Helsinki Finland helsinki.fi.
- 3Department of Clinical Microbiology Turku University Hospital University of Turku Turku Finland utu.fi.
- 4Veterinary Clinic ElisaVet Jomala Åland Islands Finland.
- 5Orthopaedics Department of Surgical Sciences Uppsala University Hospital Uppsala University Uppsala Sweden uu.se.
Abstract
Streptococcus equi subspecies zooepidemicus (SEZ) is a pathogen associated with infections in horses. It can occasionally transmit and cause clinical infections in humans. Even though the bacterium is an opportunistic pathogen, human infections are often severe such as meningitis, septicemia, endocarditis, and septic arthritis. We report a unique case of synovial fluid culture-confirmed periprosthetic joint infection (PJI) caused by SEZ. The patient had undergone a total knee arthroplasty due to osteoarthritis. Five months postoperatively, she was admitted to the hospital with fever and clinical signs of PJI of the knee. The bacterial culture of the synovial fluid and blood cultures revealed SEZ. The 16S rRNA polymerase chain reaction (16S rRNA PCR) and culture of perioperative synovial tissue samples confirmed the same bacterium. Within 48 h of the onset of PJI symptoms, an operation with DAIR (debridement, antibiotics, and implant retention) was performed and followed by 12 weeks of antibiotic therapy. The prosthetic joint was preserved, and the patient had fully recovered with no signs of infection relapse at the 2-year follow-up. Two weeks prior to the PJI symptoms, the patient had visited a horse stable, where one of the horses had symptoms of an upper respiratory infection. We present the first case of synovial fluid culture-confirmed PJI caused by SEZ described in the literature. SEZ can be transmitted from horses to humans and cause serious infections, including PJI. The bacterium should be kept in mind when investigating acute infections, including PJI, in people who encounter horses due to their profession or hobbies.
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BibTeX
@article{pitkapaasi2026periprosthetic,
title = {{Periprosthetic Joint Infection Caused by Streptococcus equi Subspecies zooepidemicus: The First Reported Case Confirmed by Synovial Fluid Culture.}},
author = {Marjaana Pitkäpaasi and Goran Varda and Juha O Grönroos and Elisabet Fellman and Kaisa Huotari and Stergios Lazarinis and Marika Nordberg},
journal = {Case reports in infectious diseases},
year = {2026},
month = oct,
doi = {10.1155/crdi/3356794},
url = {https://europepmc.org/article/MED/42953724},
note = {CC BY},
}
RIS
TY - JOUR
TI - Periprosthetic Joint Infection Caused by Streptococcus equi Subspecies zooepidemicus: The First Reported Case Confirmed by Synovial Fluid Culture.
AU - Marjaana Pitkäpaasi
AU - Goran Varda
AU - Juha O Grönroos
AU - Elisabet Fellman
AU - Kaisa Huotari
AU - Stergios Lazarinis
AU - Marika Nordberg
PY - 2026
DA - 2026/10/28
JO - Case reports in infectious diseases
DO - 10.1155/crdi/3356794
UR - https://europepmc.org/article/MED/42953724
AB - Streptococcus equi subspecies zooepidemicus (SEZ) is a pathogen associated with infections in horses. It can occasionally transmit and cause clinical infections in humans. Even though the bacterium is an opportunistic pathogen, human infections are often severe such as meningitis, septicemia, endocarditis, and septic arthritis. We report a unique case of synovial fluid culture-confirmed periprosthetic joint infection (PJI) caused by SEZ. The patient had undergone a total knee arthroplasty due to osteoarthritis. Five months postoperatively, she was admitted to the hospital with fever and clinical signs of PJI of the knee. The bacterial culture of the synovial fluid and blood cultures revealed SEZ. The 16S rRNA polymerase chain reaction (16S rRNA PCR) and culture of perioperative synovial tissue samples confirmed the same bacterium. Within 48 h of the onset of PJI symptoms, an operation with DAIR (debridement, antibiotics, and implant retention) was performed and followed by 12 weeks of antibiotic therapy. The prosthetic joint was preserved, and the patient had fully recovered with no signs of infection relapse at the 2-year follow-up. Two weeks prior to the PJI symptoms, the patient had visited a horse stable, where one of the horses had symptoms of an upper respiratory infection. We present the first case of synovial fluid culture-confirmed PJI caused by SEZ described in the literature. SEZ can be transmitted from horses to humans and cause serious infections, including PJI. The bacterium should be kept in mind when investigating acute infections, including PJI, in people who encounter horses due to their profession or hobbies.
SN - 2090-6625
SN - 2090-6633
ER -