A rare first case of prosthetic knee joint infection by Citrobacter koseri

Citrobacter generally colonizes the gastrointestinal and urogenital tracts of humans, but musculoskeletal infection by Citrobacter in the elderly is extremely rare. To our knowledge, less than 15 cases of causing musculoskeletal infection have been reported in the literature. In the last few years, there has been a considerable increase in the incidence of prosthetic knee joint infection in the United States, with a higher risk of infection in the first two years following surgery. Although gram-positive bacteria like Staphylococcus and Streptococci are more common cause of PJI, gram-negative bacteria can also be found in infected joints. We report the first case of PJI in the left knee due to in an 82-year-old adult two years after bilateral knee arthroplasty. This case report intends to educate and raise awareness for causing PJI as a long term post-op complication even in healthy individuals. We searched articles on Pubmed and Medline for PJI and citrobacter infection. We report clinically and microbiologically confirmed in a synovial fluid sample of the left knee joint. should be considered as a possible pathogen for PJI in long term setting even in an otherwise healthy individual.