Although the New York/New Jersey (NY/NJ) area is an epicenter for carbapenem-resistant Enterobacteriaceae (CRE), there are few multicenter studies of CRE from this region. We characterized patients with CRE bacteremia in 2013 at eight NY/NJ medical centers and determined the prevalence of carbapenem resistance among Enterobacteriaceae bloodstream isolates and CRE resistance mechanisms, genetic backgrounds, capsular types (cps), and antimicrobial susceptibilities. Of 121 patients with CRE bacteremia, 50% had cancer or had undergone transplantation. The prevalences of carbapenem resistance among Klebsiella pneumoniae, Enterobacter spp., and Escherichia coli bacteremias were 9.7%, 2.2%, and 0.1%, respectively. Ninety percent of CRE were K. pneumoniae and 92% produced K. pneumoniae carbapenemase (KPC-3, 48%; KPC-2, 44%). Two CRE produced NDM-1 and OXA-48 carbapenemases. Sequence type 258 (ST258) predominated among KPC-producing K. pneumoniae (KPC-Kp). The wzi154 allele, corresponding to cps-2, was present in 93% of KPC-3-Kp, whereas KPC-2-Kp had greater cps diversity. Ninety-nine percent of CRE were ceftazidime-avibactam (CAZ-AVI)-susceptible, although 42% of KPC-3-Kp had an CAZ-AVI MIC of Ն4/4 g/ml. There was a median of 47 h from bacteremia onset until active antimicrobial therapy, 38% of patients had septic shock, and 49% died within 30 days. KPC-3-Kp bacteremia (adjusted odds ratio [aOR], 2.58; P ϭ 0.045), cancer (aOR, 3.61, P ϭ 0.01), and bacteremia onset in the intensive care unit (aOR, 3.79; P ϭ 0.03) were independently associated with mortality. Active empirical ther-

KPC variants. The assay consists of six molecular beacons and two oligonucleotide primer pairs, allowing for detection and classification of all currently described bla KPC variants (bla KPC-2 to bla KPC-11 ). The MB-PCR detection limit was 5 to 40 DNA copies per reaction and 4 CFU per reaction using laboratory-prepared samples. The MB-PCR probes were highly specific for each bla KPC variant, and cross-reactivity was not observed using DNA isolated from several bacterial species. A total of 457 clinical Gram-negative isolates were successfully characterized by our MB-PCR assay, with bla KPC-3 and bla KPC-2 identified as the most common types in the New York/New Jersey metropolitan region. The MB-PCR assay described herein is rapid, sensitive, and specific and should be useful for understanding the ongoing evolution of carbapenem resistance in Gram-negative bacteria. As novel bla KPC variants continue to emerge, the MB-PCR assay can be modified in response to epidemiologic developments.

The observed prevalence of S. aureus and MRSA colonization among HCPs exceeds previously reported prevalences in the general population. The proportion of community-associated MRSA among all MRSA in this colonized HCP cohort reflects the distribution of the USA300 community-associated strain observed increasingly among US hospitalized patients.