Notes from the Field: New Delhi Metallo-β-Lactamase-Producing Carbapenem-Resistant Enterobacteriaceae Identified in Patients Without Known Health Care Risk Factors - Colorado, 2014-2016.

Carbapenem-resistant Enterobacteriaceae (CRE) are considered an urgent threat in the United States because they are associated with high morbidity and mortality, limited treatment options, and potential for rapid spread among patients (1). Carbapenemases, enzymes that confer resistance to the carbapenem class of antibiotics, are believed to contribute to increasing transmission and regional spread of CRE because the genes encoding these enzymes can reside on mobile plasmids and can be transferred among bacterial species. Klebsiella pneumoniae carbapenemase (KPC) is the most common carbapenemase seen in the United States, but isolates with the New Delhi metallo-ß-lactamase (NDM) are emerging. Known risk factors for carbapenemase-producing CRE, including NDM, include health care exposures such as hospitalization outside the United States, recent overnight admissions to short-stay and long-term acute care hospitals, residence in long-term care facilities, surgical procedures, and having indwelling devices. Community-associated CRE lack these health care exposures and are rare in the United States (2). During 2014–2016, NDM-producing CRE were isolated from patients in Colorado without known health care risk factors. The Colorado Department of Public Health and Environment (CDPHE) has conducted statewide laboratory-based surveillance of CRE since November 2012. CRE isolates that are resistant to two or more carbapenems are tested for the KPC and NDM genes by polymerase-chain reaction at the CDPHE laboratory. As of April 2016, Colorado had reported the second highest number of NDM-producing CRE in the United States (3). NDM was first detected in Colorado in 2012 in eight patients during a hospital outbreak (4). Ten additional patients with NDM-producing CRE were identified in Colorado during 2014–2016. Among these 10 patients, the mean age was 64 years (range = 20–85 years); isolates from nine patients were from urine, and in one patient, from bile. Five patients had traveled internationally in the 2 months before specimen collection (two of whom had known hospitalizations during international travel) (Figure). In six patients, the isolate was detected from cultures collected in outpatient settings and lacked the known CRE risk factors of overnight stays in health care settings, dialysis, or surgery in the preceding 12 months, and had no invasive devices in the preceding 2 days (i.e., the isolates were community-associated). Among the six patients identified with community-associated, NDM-producing CRE, two patients traveled internationally: one to an unknown country in Africa and one to the Bahamas. Mean age was 61 years (range = 20–85 years). All patients received diagnoses of urinary tract infections. Medical record review indicated that three of these six patients had antibiotic exposure, two within 1 month and the other within 10 months prior to the positive culture. Three of the six patients with community-associated, NDM-producing CRE had no underlying comorbidities; one patient was pregnant at the time of her positive culture, and two patients had underlying medical conditions. One patient with underlying medical conditions reported caring for a family member in multiple health care facilities before the positive NDM culture, including an acute care hospital, a long-term acute care hospital, and an assisted living facility. 0 1 2 3 4 5 6 7 8 9