1814. Fecal Carriage of Genes Associated with Gram-Negative Multi-Drug Resistant Organisms
Session: Poster Abstract Session: Resistant Gram-Negative Infections: Epidemiology
Saturday, October 10, 2015
Room: Poster Hall
Background: Screening for colonization with Gram-negative multidrug-resistant organisms (MDRO) is usually limited to the investigation of outbreaks. We screened stool samples from hospitalized patients for carbapenemase and extended-spectrum β-lactamase (ESBL) genes to determine the prevalence of MDRO colonization and association with infection.   

Methods: Ninety-nine stool samples received for Clostridium difficile PCR testing at Cleveland Clinic were also analyzed at OpGen using the Acuitas® MDRO Gene Test, a microfluidic PCR array targeting seven antimicrobial resistance gene families (CTX-M, KPC, NDM, VIM, IMP, OXA, VanA). Stool was incubated overnight in tryptic soy broth containing 3 µg/mL ceftriaxone. The medical records of patients carrying genes associated with Gram-negative MDRO were reviewed. 

Results: The positivity rate for C. difficile PCR was 16%. VanA was detected in 51 patients. Samples from 12 patients were positive for Gram-negative resistance genes. CTX-M-1 genes were detected in the stool of six patients and infections due to ESBL-producing Klebsiella pneumoniae or Escherichia coli were documented in four of the patients. Gram-negative infections caused by carbapenem-resistant or AmpC phenotype organisms occurred in the remaining patients with CTX-M-1 carriage. KPC resistance genes were detected in five stool samples and three of those patients had Gram-negative MDRO infections (two with carbapenem-resistant K. pneumoniae.and one with an AmpC phenotype Enterobacter aerogenes). The one patient with VIM detected in the stool had abdominal drainage fluid cultures with meropenem-resistant Pseudomonas aeruginosa. OXA-23 was detected in the stool of one patient and the only documented Gram-negative infection was not caused by an MDRO. 

Conclusion: Colonization with OXA, VIM, KPC, and CTX-M genes was observed in 1%, 1%, 5% and 6% of inpatients.  The majority of patients (75%) with carriage of these genes had multidrug-resistant Gram-negative infections.

Sandra S. Richter, MD, FIDSA1, James Karichu, MT (ASCP)1, Susan M. Harrington, PhD1, Belinda Yen-Lieberman, Ph.D.1, Tony Rockweiler, BS2 and Trevor Wagner, PhD3, (1)Laboratory Medicine, Cleveland Clinic, Cleveland, OH, (2)OpGen, Gaithersburg, MD, (3)OpGen, Inc., Gaithersburg, MD


S. S. Richter, BD diagnostics: Investigator , Research support
OpGen: Investigator , Research support
bioMerieux: Investigator , Research support
Nanosphere: Investigator , Research support
Cerexa: Investigator , Research support
Pocared: Investigator , Research support
Biofire: Investigator , Research support
Achaogen: Investigator , Research support

J. Karichu, OpGen: Collaborator , Research support

S. M. Harrington, None

B. Yen-Lieberman, None

T. Rockweiler, OpGen: Employee , Salary

T. Wagner, OpGen: Employee , Salary

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