Septic Arthritis due to E. coli: A Case Report

Septic arthritis (SA) is a medical emergency threatening both joint function and life prognosis, particularly when complicated by bacteremia and septic shock. While Gram-positive bacteria predominate, Gram-negative bacilli represent only 10% of bacterial arthritis in adults. We report a case of spontaneous septic arthritis in a 62-year-old female without trauma, invasive procedures, or immunosuppression, presenting with dysuria. Cytobacteriological examination confirmed Escherichia coli in both knee joint fluid and urine with identical antimicrobial resistance profiles, establishing a urinary tract infection complicated by septic arthritis. Early diagnosis and combined antibiotic therapy with arthroscopic lavage resulted in favorable outcome. This rare presentation emphasizes the importance of systematic urinary focus investigation in atypical septic arthritis and highlights the need for multidisciplinary management with rigorous microbiological identification before initiating antibiotic therapy.