Vital Signs: Containment of Novel Multidrug-Resistant Organisms and Resistance Mechanisms — United States, 2006–2017

Abstract

BackgroundApproaches to controlling emerging antibiotic resistance in health care settings have evolved over time. When resistance to broad-spectrum antimicrobials mediated by extended-spectrum β-lactamases (ESBLs) arose in the 1980s, targeted interventions to slow spread were not widely promoted. However, when Enterobacteriaceae with carbapenemases that confer resistance to carbapenem antibiotics emerged, directed control efforts were recommended. These distinct approaches could have resulted in differences in spread of these two pathogens. CDC evaluated these possible changes along with initial findings of an enhanced antibiotic resistance detection and control strategy that builds on interventions developed to control carbapenem resistance.MethodsInfection data from the National Healthcare Safety Network from 2006–2015 were analyzed to calculate changes in the annual proportion of selected pathogens that were nonsusceptible to extended-spectrum cephalosporins (ESBL phenotype) or resistant to carbapenems (carbapenem-resistant Enterobacteriaceae [CRE]). Testing results for CRE and carbapenem-resistant Pseudomonas aeruginosa (CRPA) are also reported.ResultsThe percentage of ESBL phenotype Enterobacteriaceae decreased by 2% per year (risk ratio [RR] = 0.98, p<0.001); by comparison, the CRE percentage decreased by 15% per year (RR = 0.85, p<0.01). From January to September 2017, carbapenemase testing was performed for 4,442 CRE and 1,334 CRPA isolates; 32% and 1.9%, respectively, were carbapenemase producers. In response, 1,489 screening tests were performed to identify asymptomatic carriers; 171 (11%) were positive.ConclusionsThe proportion of Enterobacteriaceae infections that were CRE remained lower and decreased more over time than the proportion that were ESBL phenotype. This difference might be explained by the more directed control efforts implemented to slow transmission of CRE than those applied for ESBL-producing strains. Increased detection and aggressive early response to emerging antibiotic resistance threats have the potential to slow further spread.

How frequently are hospitalized patients colonized with carbapenem-resistant Enterobacteriaceae (CRE) already on contact precautions for other indications?

“…These findings are similar to the proportions of CRE (3.1%) and CP-CRE (32% of CRE) among clinical isolates reported to the National Healthcare Safety Network in 2015 and 2017, respectively. 6 …”

Evolution of New Delhi metallo-β-lactamase (NDM) in the clinic: Effects of NDM mutations on stability, zinc affinity, and mono-zinc activity

“…The five carbapenemases currently of primary public concern include Klebsiella pneumonia carbapanemase (KPC), New Delhi metallo-β-lactamase (NDM), Verona integrin encoded metallo-β-lactamase (VIM), imipenemase (IMP), and oxacillinase-48-like carbapenemase (OXA-48) (2). Three of these carbapenemases (NDM, VIM, and IMP) are metal-dependent β-lactamases that are not susceptible to any of the β-lactamase inhibitors incorporated into combination drugs used in the clinic.…”

Identification of a Carbapenemase-Producing Hypervirulent Klebsiella pneumoniae Isolate in the United States

“…Although infections due to hvKP have been reported in the United States (7), this report represents the first documented CP-hvKP isolate. Together, the global distribution of ST23 (18) and the fact that plasmids carrying bla KPC genes are ubiquitous in many U.S. health care settings (35) represent potential stages on which additional CP-hvKP strains may emerge in the United States. Such emergence of CP-hvKP strains underscores the importance of clinical awareness of this pathotype and the need for continued monitoring of CP-hvKP in the United States and abroad.…”