Bone and joint infections caused by gram-negative bacteria.

Infections of the bones and joints caused by gram-negative bacteria from the family Enterobacteriaceae account for 10%-15%. This family usually cause opportunistic infections, due to a low virulence factor, host and environmental factors. Gram-negative bacteria cause osteomyelitis, infectious arthritis and Reiter's syndrome. The family Enterobacteriaceae belong to the physiological flora of man and cause opportunistic and hospital infections. In order to reach an accurate etiologic diagnosis, it is therefore important for the samples for bacteriologic examination to be properly taken. The quality of samples depends on the type, time and method of sampling, duration of the disease prior to sampling, and antimicrobial therapy. Essential samples are bone biopsy, synovial fluid aspirate and blood culture. Improper interpretation of bacterial isolates and failure to exclude colonization are the most common errors encountered in daily routine.