Five and a half million people ride the New York City subway system every day and pass through train cars and the platforms of 466 stations. The number of microbes that live down there may be beyond imagining, but now microbiologists have created a microbial map of the system.
The good news is that the subway contains hundreds of different species of bacteria, viruses, fungi, and animal, and that the majority don't cause any diseases. Many of the species can already be found on the skin or in the gut of the average person. A lot of them are helpful because they crowd out the growth of disease-causing organisms. However, about 12% of the microbes found are associated with a disease; including very low levels of the bacteria that cause anthrax and the bacteria that causes bubonic plague. Twenty-seven percent of microbe samples showed some signs of antibiotic resistance
But nearly half of the DNA pieces the researchers found do not match any known organism. This means that a large urban system like a subway may have vast potential for scientific exploration.
Researchers led by Christopher E. Mason of Weil Cornell Medical School in Manhattan created a city-wide molecular profile of microbial DNA from the subway system by swabbing handrails, benches, and ticket booths. They also took samples from public parks in the city and the Gowanus Canal. They then sequenced the genetic material they found and used a supercomputer to analyze it all, and there was a lot of it-10 billion fragments of genetic code.
Creating a map of the microbes of the subway-called a PathoMap-does more than just satisfy scientific curiosity. It established a baseline that could be used to determine whether or how the microbial population changes over time. This in turn can help predict the spread of an epidemic or help manage a bioterrorism attack.
The study can be read at http://www.cell.com/pb/assets/raw/journals/research/cell-systems/do-not-delete/CELS1_FINAL.pdf.
