Antibiotic-resistant bacteria found in the states, presenting a triple threat

Researchers from the Emory Antibiotic Resistance Center describe the first strain of carbapenem-resistant, hypermucoviscous Klebsiella pneumoniae exhibiting colistin heteroresistance and enhanced virulence isolated from a patient in the United States. The research is presented at ASM Microbe, the annual meeting of the American Society for Microbiology, held from June 7th to 11th, in Atlanta, Georgia. “The problem of antibiotic resistance is becoming increasingly alarming. The combination of increased virulence and multidrug resistance makes the situation worse,” said Dr. David Weiss, director of the Emory Antibiotic Resistance Center. The researchers showed that the K. pneumoniae isolate was heteroresistant to the last resort antibiotic colistin. This means that a small subpopulation of cells showed resistance. Heteroresistance is more difficult to detect with standard antibiotic susceptibility tests in clinical microbiology labs, and this isolate was classified as susceptible to colistin by standard methods. This discrepancy is particularly important, as Weiss’ lab has shown that such undetected colistin heteroresistance can cause antibiotic treatment failure in mice. In a hospital in Hangzhou, China, a 2016 deadly outbreak of carbapenem-resistant, hypervirulent K. pneumoniae was recently reported in Lancet Infectious Diseases. (Read more)