In a laboratory review of 5,776 carbapenem-resistant Enterobacteriaceae (CRE) isolates collected over nine months, the CDC found 221 pathogens with “unusual” mechanisms for resistance. The CDC is using its nationwide Antibiotic Resistance Lab Network (ARLN) to detect these virtually untreatable bugs, which can be resistant to whole classes of drugs.
“The 221 [isolates] were in 27 different states,” Anne Schuchat, MD, CDC principal deputy director, said at a recent press conference. “So this wasn’t just a problem in one or two states where we have been following up outbreaks. The kinds of infections that they had included pneumonia, urinary tract infections, and bloodstream infections.”
According to the CDC, the laboratories conducted “carbapenemase-production testing and molecular detection of genes encoding for the five carbapenemases of primary public health concern.” The most prevalent by far is Klebsiella pneumoniae carbapenemase (KPC).
The 221 isolates with novel resistance mechanisms were “non-KPC” carbapenemase producers. “These included non-New Delhi metallo-beta-lactamase (NDM), Verona integron-encoded metallo-beta-lactamase (VIM), imipenemase (IMP), and oxacillinase-48-like carbapenemase (OXA-48),” the CDC reported.1
The CDC did not have data on the age range or underlying conditions of the patients. “These germs are out there and they’re a problem,” Schuchat said. “We have seen young people with cystic fibrosis succumb to these types of resistant germs. We have also seen them in the elderly.”
Overall, about 25% of all CRE tested had plasmids that can transfer antibiotic resistance to other bacteria — the “nightmare” aspect of CRE.
CDC’s containment strategy calls for quickly identifying unusual resistance in patients, and assessing infection control at the facility if there is concern about transmission. The ARLN labs use cutting-edge whole genome sequencing techniques to reveal antibiotic-resistant mechanisms at the genetic level in pathogens, including these 221 troubling outliers.
“Whenever you have something that’s unusual, it presents the greatest opportunity to control it and to prevent it from spreading to other people,” Arjun Srinivasan, MD, CDC associate director for healthcare-associated infections and prevention programs, said at the press conference.
“The genetic testing information goes back to the hospital through the state so that both the laboratory and the state are aware of what’s going on. And then the response team in the state can help the facility respond.”
The facility would then implement contact precautions and look at contacts to ensure transmission has not occurred.
“The provider is at the center of this,” he said. “They’re the primary focus of the information. They get these results back and then it really becomes a team effort. One of the messages that we want to send with this is that no provider has to go it alone.”
- CDC. Woodworth KR, Walters MS, Weiner LM, et al. Vital Signs: Containment of Novel Multidrug-Resistant Organisms and Resistance Mechanisms — United States, 2006–2017. MMWR 3 April 2018. DOI: http://dx.doi.org/10.15585/mmwr.mm6713e1.
