Researchers use genomic sequencing technique to detect presence of various microbes About 12,000 bacteria and viruses collected in a sampling from public transit systems and hospitals around the world from 2015 to 2017 had never before been identified, according to a study by the International MetaSUB Consortium, a global effort at tracking microbes that is led by Weill Cornell Medicine investigators. For the study, published May 26 in Cell, international investigators collected nearly 5,000 samples over a three-year period across 60 cities in 32 countries and six continents. The investigators analyzed the samples using a genomic sequencing technique called shotgun sequencing to detect the presence of various microbes, including bacteria, archaea (single-celled organisms that are distinct from bacteria), and viruses that use DNA as their genetic material. (Other types of viruses that use RNA as their genetic material, such as SARS-CoV-2, the virus that causes COVID-19, would not have been detected with the DNA analysis methods used in this pre-pandemic study.)