1408. Next Generation Sequencing for Genomic Analysis of Cfr(B)-producing Enterococcus faecium Causing Infections in a New Orleans Medical Center
Session: Poster Abstract Session: HAI: Outbreaks
Friday, October 28, 2016
Room: Poster Hall
Posters
  • IDWeek16 cfr 1408-final.pdf (296.7 kB)
  • Background: CC17 is a major group of genetic lineage of E. faecium (EFM) that has spread worldwide and is associated with hospital outbreaks. We previously reported cfr(B) among two VRE linezolid-resistant (LZD-R) clinical EFM index isolates (18203 and 18961) belonging to CC17 from a medical center in New Orleans (AAC 2015, 59: 6256 - 6261). In the last year, four additional isolates (3 in 2015 and 1 in 2016) harboring cfr(B) were isolated in this hospital system. This study presents the characterization of these isolates in comparison to the index strains using next generation sequencing (NGS).

    Methods: EFM were susceptibility (S) tested by reference methods (M07-A10) and categorized according to CLSI (M100-S26) and US-FDA (tigecycline) guidelines. Screening for oxazolidinone mechanisms including cfr, optrA and mutations in 23S rRNA, L3 and L4 proteins was performed by PCR and sequencing techniques. Isolates were subjected to NGS and epidemiological and cfr(B) genetic context information extracted.

    Results: Four additional VRE LZD-R were isolated (3-blood and 1-bone culture; May 2015- Jan 2016) from immunocompromised/suppressed patients with severe underlying diseases. Index isolates and one of the four additional EFM were recovered from patients with previous LZD treatment. All isolates (these 4 plus 2 previously reported) were multidrug-resistant, and tedizolid MIC values (1 - 2 mg/ml) were eight-fold lower than LZD (8 - 16 mg/ml). G2576T in 23S rRNA was present, along with cfr(B) in all EFM. L3 and L4 proteins showed wildtype sequences, and optrA was not detected. The two index isolates belonged to ST794 (CC17), while the additional four EFM were categorized as ST794 or a close variant, ST78. cfr(B) was located on a Tn6218 structure and embedded in chromosomal DNA in all isolates.

    Conclusion: NGS and analysis demonstrate that E. faecium isolates originated from a common ancestor. However, alterations in conserved MLST housekeeping gene, suggest distant temporal relationships indicating prolonged persistency within Ochsner system. Both G2576T and cfr(B) were chromosomally-located; therefore, infection control measures should be effective in minimizing the spread of these MDR EFM isolates.


    Lalitagauri M. Deshpande, PhD1, Deborah Ashcraft, B.S.2, C. Naccari, BS3, Andrew P. Davis, BS1, George Pankey, MD, FIDSA2, Mariana Castanheira, PhD1 and Rodrigo E. Mendes, PhD1, (1)JMI Laboratories, Inc., North Liberty, IA, (2)Institute of Translational Research; Laboratory of Infectious Disease Research, Ochsner Clinic Foundation, New Orleans, LA, (3)University of Queensland-Ochsner Clinical School, New Orleans, LA

    Disclosures:

    L. M. Deshpande, None

    D. Ashcraft, None

    C. Naccari, None

    A. P. Davis, None

    G. Pankey, None

    M. Castanheira, None

    R. E. Mendes, None

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