1797. An Overview of the Molecular Epidemiology of Carbapenemase-producing Bacteria in the U. S. Military Health System
Session: Poster Abstract Session: Resistant Gram-Negative Infections: CRE Epidemiology
Saturday, October 10, 2015
Room: Poster Hall
Background: Carbapenemase-producing (CP) bacteria (CPB) are an urgent public health threat. Enhanced surveillance is a main component of the 2015 National Action Plan to combat antimicrobial resistance. Describe the molecular epidemiology of genotypically confirmed CP Gram-negative clinical isolates submitted to the multidrug-resistant organism referral laboratory (MRSN) of the Military Health System (MHS).  

Methods: Hospital laboratories in the MHS submit suspected CPB, as determined by susceptibility testing, to the MRSN, where they undergo Carba NP testing and real-time PCR for all alleles of the most common carbapenemase-encoding genes (CEGs): blaKPC, blaIMP, blaNDM, blaOXA48-like, and blaVIM. A. baumannii are also tested for blaOXA23, -24, and -58-like.  Health Level 7 formatted laboratory data feeds are used to supplement surveillance by notifying hospital laboratories and the central laboratory. All CEG-containing (CEG-c) isolates undergo whole genome sequencing.

Results: From 2009 through 2014, 1073 suspected CP isolates were submitted.  207(19%) were confirmed to contain one or more CEGs. 83% (171) of isolates were associated with infection.  The remainder were surveillance/colonizing isolates.  CEG-c isolates were found in 14 different species and in 141 patients from 21 facilities. The most common genes were blaKPC (66%) and blaNDM (23%) in Enterobacteriaceae, and blaOXA23-like variants in Acinetobacter spp. CEGs were very rarely found in P. aeruginosa. blaKPC (and blaOXA23 in Acinetobacter spp) was the most prevalent CEG in the contiguous U.S. The other CEGs were more commonly found overseas The incidence of CEGs peaked in 2013, and then decreased throughout 2014 and the first quarter of 2015.  Some CEG-c isolates were clonal and found in more than one hospital, suggesting nosocomial transmission.

Conclusion: CEG-c isolates were frequently resistant to most other antibiotics as well. The molecular epidemiology of CP pathogens in the MHS is complex and dependent upon mechanism (gene) and locality. Some identified cases of CPB were part of a single larger outbreak. Others were not clonal or were part of independent smaller outbreaks. Continued surveillance is imperative.

Emil Lesho, D.O., FIDSA1, Mary Hinkle, M.D.1, Yoon Kwak, MS1, Ana Ong, BS1, Rosslyn Maybank, BA1, Uzo Chukwuma, MPH2, Charlotte Neumann, MSc2, Katherine Mcauliffe, MPH2, Robert Clifford, Ph.D.1, Eric Steele, MS3, Lakshmi Appalla, MS1, Fatma Onmus-Leone, MS1, Erik Snesrud, BS1, Michael Julius, PMP1, Paige Waterman, M.D.4 and Patrick Mc Gann, PhD1, (1)Walter Reed Army Institute of Research, Silver Spring, MD, (2)Navy and Marine Corps Public Health Center, Portsmouth, VA, (3)San Antonio Military Medical Center, San Antonio, TX, (4)GEIS, Armed Forces Health Surveillance Center, Silver Spring, MD


E. Lesho, None

M. Hinkle, None

Y. Kwak, None

A. Ong, None

R. Maybank, None

U. Chukwuma, None

C. Neumann, None

K. Mcauliffe, None

R. Clifford, None

E. Steele, None

L. Appalla, None

F. Onmus-Leone, None

E. Snesrud, None

M. Julius, None

P. Waterman, None

P. Mc Gann, None

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