title: Identification of a novel clone, ST736, among Enterococcus faecium clinical isolates and its association with daptomycin nonsusceptibility.
abstract: Resistance to daptomycin in enterococcal clinical isolates remains rare but is being increasingly reported in the United States and worldwide. There are limited data on the genetic relatedness and microbiological and clinical characteristics of daptomycin-nonsusceptible enterococcal clinical isolates. In this study, we assessed the population genetics of daptomycin-nonsusceptible Enterococcus faecium (DNSE) clinical isolates by multilocus sequence typing (MLST) and whole-genome sequencing analysis. Forty-two nonduplicate DNSE isolates and 43 randomly selected daptomycin-susceptible E. faecium isolates were included in the analysis. All E. faecium isolates were recovered from patients at a tertiary care medical center in suburban New York City from May 2009 through December 2013. The daptomycin MICs of the DNSE isolates ranged from 6 to >256 μg/ml. Three major clones of E. faecium (ST18, ST412, and ST736) were identified among these clinical isolates by MLST and whole-genome sequence-based analysis. A newly recognized clone, ST736, was seen in 32 of 42 (76.2%) DNSE isolates and in only 14 of 43 (32.6%) daptomycin-susceptible E. faecium isolates (P < 0.0001). This report provides evidence of the association between E. faecium clone ST736 and daptomycin nonsusceptibility. The identification and potential spread of this novel E. faecium clone and its association with daptomycin nonsusceptibility constitute a challenge for patient management and infection control at our medical center.
authors.affiliation: Department of Pathology, New York Medical College, Valhalla, New York, USA Department of Pathology and Clinical Laboratories, Westchester Medical Center, Valhalla, New York, USA guiqing_wang@nymc.edu.
authors.forename: Guiqing
authors.initials: G
authors.lastname: Wang
authors.affiliation: Philips Research North America, Briarcliff Manor, New York, USA.
authors.forename: Sitharthan
authors.initials: S
authors.lastname: Kamalakaran
authors.affiliation: Department of Medicine, New York Medical College, Valhalla, New York, USA.
authors.forename: Abhay
authors.initials: A
authors.lastname: Dhand
authors.affiliation: Department of Pathology, New York Medical College, Valhalla, New York, USA.
authors.forename: Weihua
authors.initials: W
authors.lastname: Huang
authors.affiliation: Department of Pathology, New York Medical College, Valhalla, New York, USA.
authors.forename: Caroline
authors.initials: C
authors.lastname: Ojaimi
authors.affiliation: Department of Pathology and Clinical Laboratories, Westchester Medical Center, Valhalla, New York, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhuge
authors.affiliation: Department of Pharmacy, Westchester Medical Center, Valhalla, New York, USA.
authors.forename: Leslie Lee
authors.initials: LL
authors.lastname: Yee
authors.affiliation: Philips Research North America, Briarcliff Manor, New York, USA.
authors.forename: Pramod
authors.initials: P
authors.lastname: Mayigowda
authors.affiliation: Department of Pathology, New York Medical College, Valhalla, New York, USA.
authors.forename: Pavan Kumar Makam
authors.initials: PK
authors.lastname: Surendraiah
authors.affiliation: Philips Research North America, Briarcliff Manor, New York, USA.
authors.forename: Nevenka
authors.initials: N
authors.lastname: Dimitrova
authors.affiliation: Department of Pathology, New York Medical College, Valhalla, New York, USA Department of Medicine, New York Medical College, Valhalla, New York, USA Department of Pathology and Clinical Laboratories, Westchester Medical Center, Valhalla, New York, USA.
authors.forename: John T
authors.initials: JT
authors.lastname: Fallon
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002648:Child; D002999:Clone Cells; D017576:Daptomycin / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D016984:Enterococcus faecium / Q000145:classification / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D005260:Female; D016680:Genome, Bacterial; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy* / Q000382:microbiology; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D009519:New York City; D017422:Sequence Analysis, DNA; D062606:Tertiary Care Centers
chemical_list: D000900:Anti-Bacterial Agents; D017576:Daptomycin