University at Buffalo (UB) researchers are expressing concern about a new, under-recognized, more potent variant of a common bacterium. "Historically, in Western countries, classical strains of Klebsiella pneumoniae have caused infections mostly in sick, hospitalized patients whose host defense systems are compromised," says Thomas Russo, of the UB School of Medicine and Biomedical Sciences. "But in the last 10 to 15 years, a new variant of it has begun causing community-acquired infection in young, healthy individuals. This variant causes serious, life-threatening, invasive infections." Perhaps most important, these hypervirulent strains have the potential to become highly resistant to antibiotics. Russo and his UB colleagues are studying the microbiology of the new variant of Klebsiella pneumoniae in an effort to identify the genes that make it hypervirulent so they can figure out how to stop it in its tracks.