Bone and joint infections due to opportunistic mycobacteria, a review of French experience

Aims and objectives: Bone and joint infections due to environmental mycobacteria are rare and can develop very slowly. The source for these outbreaks is generally tap water supplies. In the present review, the focus is on a large outbreak of Mycobacterium xenopi spinal infections in patients who had undergone surgical microdiscectomy for disc hernia in a French hospital. Surprisingly, a patient was diagnosed with a M. xenopi discitis with secondary extension to the sacroiliac joint 15 years after spinal surgery. The findings of a national investigation launched by health authorities to determine the number of the bone and joint infections due to opportunistic mycobacteria are described in this study. Methods: National health authorities launched a retrospective investigation in patients who were exposed to M. xenopi contamination in that hospital. Moreover, a national survey was conducted across all French laboratories to collect information on bone and joint cases due to opportunistic mycobacteria. The National Reference Center for Mycobacteria investigated hospital tap water supplies and developed a species-specific probe for the rapid identification of M. xenopi. Results: Bone and joint infections, with the exception of the episode of the clinic where the large M. xenopi outbreak occurred, are rare in France. A very small number of cases, all sporadic, were detected and linked to an invasive procedure. In addition to M. xenopi, mycobacterial species involved are Mycobacterium marinum, Mycobacterium chelonae, Mycobacterium fortuitum, Mycobacterium avium and Mycobacterium kansasii. Despite awareness of laboratories to mycobacterial infections, no significant increase in iatrogenic infections has been demonstrated in care facilities. The source of infection of the large outbreak of spondylitis due to M. xenopi was traced to deficient hygiene practices and a high concentration of M. xenopi in the hospital tap water. Conclusions: Failures in hygiene practices could result in an uncontrolled outbreak of nosocomial infection. Patients who have been exposed to an iatrogenic infectious hazard should be screened promptly when symptoms develop.