Common ‘Superbug’ Found to Disguise Resistance to Potent Antibiotic

Betsy McKay – March 6, 2018

Researchers from Emory University have detected “heteroresistance” to colistin in Klebsiella pneumoniae, a common “superbug” that is already highly resistant. Colistin is an antibiotic often administered to patients as a last resort against highly drug-resistant bacteria. The heteroresistance is not easily detectable in standard laboratory tests because most of the cells are susceptible to the drug. “These are really bad infections that are occurring in really sick patients,” said David Weiss, director of Emory’s Antibiotic Resistance Center, who led the research. “It’s all the more critical that you figure out what’s wrong and how to treat it.” In the study, reported Tuesday in mBio, mice infected with the bacteria were treated with colistin, but the mice died. The bacteria given to the mice originally came from two older human patients at hospitals in the Atlanta area. The Klebsiella bacteria were found in one patient’s blood. That individual, a transplant recipient, died.