Abstract
Abstract The genus Citrobacter commonly found in water and soil as well as the intestinal and urinary tracts of animals and humans. Although Citrobacter infections are infrequently diagnosed in environmental contexts, the rising incidence of nosocomial manifestations underscores the importance of considering this organism in the differential diagnosis of hospital-acquired infections. We present a case of patient with septic arthritis of the shoulder who had been originally admitted for the management of acute-on-chronic congestive heart failure exacerbation and severe sepsis. On hospital day 1, joint aspiration cultures and Gram stain confirmed the presence of Citrobacter koseri , a pathogen not commonly associated with septic arthritis, and ceftriaxone was administered to target it. On hospital day 7, antibiotic was transitioned to levofloxacin, every other day for 4 weeks. The patient was discharged to an acute rehabilitation facility after a 14-day hospital stay. This case stresses the importance of maintaining a broad differential diagnosis for any patients who present with fever and joint inflammation or swelling, especially in a postoperative setting.