As public health authorities across the globe grapple with the growing problem of antibiotic resistance, Tufts University School of Medicine microbiologists and colleagues have identified the unique resistance mechanisms of a clinical isolate of E. coli resistant to carbapenems. Carbapenems are a class of antibiotics used as a last resort for the treatment of disease-causing bacteria, including E. coli and Klebsiella pneumonia, which can cause serious illness and even death. Infections involving resistant strains fail to respond to antibiotic treatments, which can lead to prolonged illness and greater risk of death, as well as significant public health challenges due to increased transmission of infection. The study, published in the April issue of Antimicrobial Agents and Chemotherapy, demonstrates the lengths to which bacteria will go to become resistant to antibiotics.
Resistance to carbapenems usually emerges through the acquisition of an enzyme, carbapenemase, which destroys the antibiotic intended to treat infection. Resistance may also block entry of the drug into the E-coli bacteria. The current research, led by corresponding author Stuart Levy, M.D., Professor of Molecular Biology & Microbiology and of Medicine and Director of the Center for Adaptation Genetics & Drug Resistance at Tufts University School of Medicine, sought to determine what made this particular clinical isolate of E. coli resistant to carbapenem in the absence of carbapenemase.
"The Centers for Disease Control and Prevention has documented a significant increase in Carbapenem-resistant Enterobacteriaceae (CRE) - so-called 'super bugs' that have been found to fight off even the most potent treatments," Levy said. "We knew that bacteria could resist carbapenems, but we had never before seen E. coli adapt so extensively to defeat an antibiotic. Our research shows just how far bacteria will go with mutations in order to survive."