Abstract
BACKGROUND Haemophilus influenzae is a gram-negative bacterium that normally inhabits the mucosal surfaces of the upper-respiratory tract system of many healthy individuals. The capsular types of H. influenzae are found to be responsible of invasive infections such as meningitis, epiglottitis, orbital cellulitis, and bacteremia. H. influenzae is rarely described as a causative agent of periprosthetic joint infection (PJI). Here, we report a case of H. influenzae causing prosthetic knee joint infection 1 year after total knee arthroplasty. CASE REPORT A 59-year-old woman was admitted with a 1-day history of a painful right knee and inability to bear weight. She had undergone a unilateral total knee arthroplasty 1 year ago. She reported a history of recurrent upper-respiratory tract infections, with the most recent episode occurring 3 months prior to the current presentation. H. influenzae grew on 2 knee aspirate specimens and a peripheral blood culture. The isolated H. influenzae strain was beta-lactamase-negative and identified as a non-type B by the public health laboratory. The patient was successfully treated with intravenous ceftriaxone for a total of 30 days followed by oral cefuroxime for 14 days. She underwent a first-stage revision of the right total knee arthroplasty, debridement, irrigation, and spacer placement; subsequently, second-stage revision was performed. CONCLUSIONS The findings of this case report, coupled with a thorough review of the literature, demonstrate the pathogenic potential of H. influenzae in periprosthetic joint infection (PJI). The diagnosis of PJI can be difficult and the management needs a multidisciplinary team.