Authors: DMrs Onnicah Matuka, TS Singh, Z. Kirsten, B. Bello, P.Dayal

Source: Occupational Health Southern Africa: Vol 15 (5) Sept/Oct 2009


MTB infection remains a major concern for both the public and the workforce as it can lead to deterioration of health and loss of productivity. South Africa has the 7th highest TB incidence in the world. Droplet nuclei that transmit TB infection have long remained a research focus due to the difficulties in detecting infectious MTB. The organisms are present in low concentrations in indoor air and may be non-culturable due to stress of aerosolisation and sampling. Non-invasive, rapid and sensitive methods are needed to detect and quantify environmental MTB for controlling exposure. The main purpose of this pilot study was to detect and quantify MTB from various sampling media using different analytic instruments.
Using conventional PCR, PTFE yielded positive results (96.43%) when compared with gelatin filters, which were negative with 100% inhibition. All the samples were positive using RT-PCR except the sedimentation gel. RT-PCR coupled with magnetic bead separation yielded positive results (no inhibition) demonstrating 100% sensitivity, irrespective of sampling media used. The quantitative RT-PCR gave favourable results for the expected known MTB concentrations. This study demonstrated the usefulness of RT-PCR for detecting MTB in environmental samples with the aim of controlling exposure.