4.1 Factors that increase the risk of infection

In addition to the general risks that are addressed by the biosafety measures described in Chapter 2 (such as unauthorized persons in the laboratory, mouth pipetting, cluttered work stations, improper waste disposal), the TB laboratory classified as moderate risk also faces the following challenges, all of which increase risks:

  • staff may work in areas with poor ventilation;
  • they may work with poor illumination;
  • BSCs may be poorly maintained and not certified;
  • BSCs may not be properly ducted;
  • the work environment may be dusty, and high-efficiency particulate air (HEPA) filters in BSCs may become blocked;
  • careless manipulation of specimens may lead to aerosolization;
  • precautions for using the vortex may not be followed properly (for example, it may be used outside the BSC);
  • specimen containers may break or leak during centrifuging;
  • problems may be associated with opening centrifuge buckets outside the BSC;
  • adequate warnings of biohazards may be lacking, and information on who should be contacted during an emergency may be inadequate;
  • cooling or heating systems may not work properly.

Good microbiological techniques are essential to minimize the risk of aerosolization.

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