Researchers developed a new genetic fingerprinting test to track and identify outbreaks of a dangerous fungal infection called Trichosporon asahii in hospitals across South America. The test uses microsatellite markers to create a detailed genetic profile of different fungal isolates, making it much better at detecting when infections spread from patient to patient compared to older methods. This discovery revealed multiple hidden disease clusters in hospitals, including one that occurred over 13 years, highlighting the importance of this new surveillance tool for hospital infection control.