Group B Streptococcal Prosthetic Knee Joint Infection Linked to the Consumption of Raw Fish

INTRODUCTION: Group B Streptococcal (GBS) prosthetic joint infections (PJI) are rare, accounting for only 4.6-6% of primary and revision total knee replacements (TKRs). In 2015, there was an outbreak of GBS infections in Singapore with an association confirmed between consumption of Chinese-style raw fish dishes (snakehead fish, Asian bighead carp) and GBS infection, Type III GBS ST283 strain, affecting more than 200 patients in Singapore. This outbreak is the largest of its kind in the world and also the first time that foodborne transmission of GBS has been proven. We present the first reported case in the literature of a confirmed PJI in a TKR related to foodborne transmission of GBS through consumption of raw fish (Snakehead fish). CASE REPORT: Our patient is a 66-year-old Chinese female admitted with a 24-h history of acute right knee pain and swelling with associated fever in the context of consuming raw fish porridge 3 days before the onset of her symptoms. She had a TKR performed in the same knee 7 years before this presentation. Her GBS PJI was confirmed on both blood and intraoperative tissue/fluid cultures during the outbreak of GBS infections in Singapore. This was managed with debridement, polyethylene liner change, retention of metal prosthesis, and culture-directed antibiotics with good outcomes. CONCLUSION: Snakehead fish is a popular dish in the Asian community as a traditional remedy to promote wound healing after surgery. Our paper highlights the link between raw fish consumption and invasive GBS causing PJIs. This can occur in healthy adults, even in the absence of gastrointestinal symptoms, despite being a foodborne transmission. Our paper also highlights that GBS PJIs can be managed with debridement, antibiotic therapy, and implant retention with good outcomes in the setting of acute hematogenous infection. We recommend the inclusion of raw fish consumption on history taking in the workup of suspected PJIs and counseling patients preoperatively on the risk of GBS PJIs with the consumption of raw fish dishes (snakehead fish and Asian bighead carp) to mitigate unnecessary PJI risk.