A simple inexpensive technique for collection of airborne biomarkers of nosocomial infections is described. Biomarkers were collected on water-soluble electrospun nanofilters attached to a household vacuum cleaner from 6-10m(3) of air in 10-15 min within several wards of a tuberculosis clinic. Filters were then dissolved in water and tested for the presence of the IS6110 and regX3 genes of Mycobacterium tuberculosis (MTB) using real-time polymerase chain reaction. It was demonstrated that trace amounts of airborne MTB DNA (> 3 gene copies/m(3)) were always present in the air and on the surfaces in the wards occupied with tuberculosis patients having positive smear tests. (C) 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.