Polymicrobial polyarticular septic arthritis.

A bacteriology technologist was found to have acute polyarticular arthritis after a brief prodromal illness. Gram's stain of fluid from the right knee showed pleomorphic gram-negative organisms, while that of fluid from the right elbow and left wrist showed gram-negative cocci and diplococci. Culture of fluid from the right knee yielded Salmonella enteritidis. Cultures of fluid from all other joints, collected after starting therapy, were negative. An enzyme-linked immunosorbent assay of fluid from the right elbow confirmed Neisseria meningitidis, group C. This organism was also isolated from the patient's throat. This case represents concurrent infection of separate joints by two bacterial pathogens, one confirmed by culture and one by current immunodiagnostic techniques.