Different cities have their own microbial fingerprint, a global study reports "If you gave me your shoe, I could tell you with about 90% accuracy the city you came from," the authors boast. Reset An international team of researchers says that every city has its own fingerprint — in the shape of pathogens. Image credits Denis Poltoradnev. The largest ever genetic study of urban microbiomes (including both surfaces and the air in 60 cities worldwide) reports that each city has its own microbial fingerprint. The project sequenced and analyzed samples from public transit systems and hospitals in cities around the world, identifying thousands of viruses, bacteria, and two archaea not found in reference databases.