Mycobacteria Suspects


  • It is necessary to implement and enforce certain safety procedures specific to the clinical microbiology laboratory because of the nature of the organisms and the mode of transmission.
  • Common sense regarding minimization of the dispersal into the air and avoidance of the inhalation of airborne bacilli is of utmost importance.
  • Direct contact with mycobacteria is to be avoided if possible.
  • Persons working with mycobacteria should be in overall good health, and those who are immunocompromised should be discouraged from working in that area.
  • Persons working in the clinical microbiology laboratory should have a regularly scheduled skin test; if they have had a previously positive skin test, they should have a chest X-ray examination at yearly intervals.
  • Physical examinations should be obtained when circumstances indicate that it is necessary.
  • All specimens suspected of containing mycobacteria should be treated appropriately.
  • A class II biological safety cabinet should be used. The use of gloves and laboratory coats or gowns is essential.
  • All work involving specimens or cultures, such as making smears, inoculating media, and adding reagents to biochemical tests, must be performed within a biological safety cabinet.
  • The handling of all specimens suspected of containing mycobacteria (including specimens processed for other microorganisms), with the exception of centrifugation for concentration purposes, must be done within the laminar-flow hood.
  • Specimens that are to be taken from under the hood to a decontamination area must be covered before transport.
  • Towels soaked in a phenolic disinfectant can be used to cover the work surfaces, to line discard pans, and to wipe the edges of culture tubes to prevent dripping.
  • The cabinet area and work area should be cleaned with disinfectant before and after work. to prevent aerosols, sealed centrifuge cups, electric incinerators, and splash-proof discard containers must be used.

Specimen Collection

  • Laboratory personnel should provide guidance and consultation in the collection of specimens submitted for the recovery of mycobacteria.
  • Decisions on how fresh samples are handled, the type of holding medium, selection of transport containers, and the conditions under which specimens must be maintained should be made with appropriate input from clinical microbiologists.
  • This team approach is currently even more urgent, since mycobacterial infections are frequently presenting as clinical syndromes other than the classic chronic T.B.
  • Access should be limited to the wards holding suspect mycobacterium patients. Rooms/cages should be clearly labeled with a "Zoonotic Potential" sticker.
  • Access to the clinical microbiology lab will also be limited during periods of processing TB samples.
  • For the transport part of the specimen from the wards to the lab only closed containers (slide holders or petri dishes closed with scotch tape) will be used. Tissues should be submitted in capped containers.
  • Mycobacterial cultures will continue to be submitted to Ames, Iowa. Acid-Fast stains will be done by Clinical Microbiology using the kinyoun A-F Method. All requests for A-F stains suspect for mycobacteria should be submitted directly to the Microbiology Lab. Any mycobacterium suspect specimen submitted to Microbiology or to any other VTH diagnostic area should be immediately identified with a "Zoonotic Potential" sticker.
  • Decontamination and Disinfection: All persons handling specimens should wash and rinse their hands thoroughly. Laboratory bench surfaces should be cleaned with a phenolic disinfectant such as LPH. A twenty minute soak in Cidex is also effective.