Tuberculosis Research Laboratories

Laboratory personnel working with M. tuberculosis are three times more likely to get infected with the agent as compared to those not working with it; it is the fourth most commonly reported laboratory infection. M. tuberculosis has a low infective dose: 10 bacilli by inhalation. Multidrug resistant (MDR) TB strains are one of the emerging pathogens and CDC has recently issued interim guidelines for handling these in clinical and research laboratories. Exposure to M. tuberculosis bacilli is likely when handling infected sputum, gastric lavage fluid, CSF, urine, and various tissues. Aerosols pose the most important hazard. Accidental needle-stick inoculation is also possible. Non-human primates (NHP) infected with M. tuberculosis are a potential source of human infections. A litter of infected guinea-pigs and mice are likely to produce aerosols. M. bovis may be acquired from infected cattle. Direct contact, ingestion, parenteral inoculation and aerosols when handling clinical material and cultures are a potential source of infection with NTM (non-tuberculous mycobacteria). The Public Health Agency of Canada site is an excellent resource for PSDS for these agents.

Biosafety Recommendations

  • Based on risk assessment, handling M. tuberculosis may be recommended at BSL- 2 or 3 and ABSL-2 or 3 containment and practices.
  • Researchers working at BSL-3 are required to enroll in the BioPath Program. Medical Alert Cards are provided for working with Respiratory/Contact agent (R/C).
  • NIOSH respiratory protection program is mandated for all individuals required to wear respiratory protection (N95/97 or PAPRs). Fit testing for respirators is absolutely necessary before commencing work requiring respirators, and annually thereafter. (See Occupational Medicine Program of this manual or the EH&S OCCMED website).
  • Tuberculin skin testing (TST) using protein purified derivative (PPD) is performed annually/semi-annually, based on risk assessment by the Biosafety Office, in previously skin-test negative personnel. If previously positive, annual follow-up medical evaluation is required.
  • For respiratory fit test and PPD testing, the researcher should enroll in the BioPath program.
  • Working with NTM requires BSL-2 containment and practices. ABSL-2 is recommended for animal work.