How should human samples be handled in accordance with the BioStoffV? – Part 2

In the 1st part of the series in AGCT Genetic Engineering. Report 02/2024 We discussed laboratory activities involving human samples from risk groups 1-4 under the corresponding protection levels (TRBA 100). Here, we discuss how to handle human samples in the laboratory for tuberculosis and anthrax diagnostics.

Tuberculosis diagnostics starting from Primary material (test material), e.g. sample preparation and processing/pretreatment, direct microscopic examination, culture cultivation and inactivation for molecular biological techniques (PCR), can be carried out under conditions of Protection level 2 be carried out. Are Cultural media (after cultivation) positive and further work steps are non-targeted activities , it can be checked activity-related according to No. 4.3.2 TRBA 100 whether protective measures of the Protection level 2 , possibly with additional protective measures, is sufficient. For example, if an immediate Inactivation or no further proliferation of the sample material occurs. Employees must be protected from aerosol exposure. Further diagnostics of mycobacteria grown in culture media ( risk group 3 ), i.e. Differentiation and identification using physiological tests or phenotypic susceptibility testing to antituberculotic drugs, targeted activities that fall under the Protection level 3 must be carried out in accordance with No. 5.4.2 TRBA 100.

The Anthrax diagnostics is the Protection level 2 (No. 5.3 TRBA 100) if it is diagnostic orientation examinations samples of human or animal origin such as swabs, blood, etc., or environmental samples, e.g., soil samples, which may contain anthrax pathogens. Diagnostic orientation tests include the preparation and evaluation of microscopic specimens, the preparation and evaluation of cultures, and, if necessary, serological and molecular biological tests. In addition to recording morphological characteristics, the evaluation of cultures may also include PCR and other methods (e.g., MALDI-ToF) using inactivated bacterial material.

If diagnostic tests (primary samples or cultures) provide clear evidence of the presence of Bacillus anthracis (e.g. positive PCR signal for the detection of virulence plasmid DNA, MALDI-ToF with corresponding reference database), it may be suspected anthrax pathogens Further diagnostics, ie the final differentiation (exclusion or confirmation of anthrax pathogens) of the enriched bacteria using microbiological, biochemical and molecular biological techniques (unless inactivated material is involved) as well as diagnostic animal testing are Protection level 3 according to No. 5.4.2 TRBA 100.