title: vanG element insertions within a conserved chromosomal site conferring vancomycin resistance to Streptococcus agalactiae and Streptococcus anginosus.
abstract: Three vancomycin-resistant streptococcal strains carrying vanG elements (two invasive Streptococcus agalactiae isolates [GBS-NY and GBS-NM, both serotype II and multilocus sequence type 22] and one Streptococcus anginosus [Sa]) were examined. The 45,585-bp elements found within Sa and GBS-NY were nearly identical (together designated vanG-1) and shared near-identity over an ~15-kb overlap with a previously described vanG element from Enterococcus faecalis. Unexpectedly, vanG-1 shared much less homology with the 49,321-bp vanG-2 element from GBS-NM, with widely different levels (50% to 99%) of sequence identity shared among 44 related open reading frames. Immediately adjacent to both vanG-1 and vanG-2 were 44,670-bp and 44,680-bp integrative conjugative element (ICE)-like sequences, designated ICE-r, that were nearly identical in the two group B streptococcal (GBS) strains. The dual vanG and ICE-r elements from both GBS strains were inserted at the same position, between bases 1328 and 1329, within the identical RNA methyltransferase (rumA) genes. A GenBank search revealed that although most GBS strains contained insertions within this specific site, only sequence type 22 (ST22) GBS strains contained highly related ICE-r derivatives. The vanG-1 element in Sa was also inserted within this position corresponding to its rumA homolog adjacent to an ICE-r derivative. vanG-1 insertions were previously reported within the same relative position in the E. faecalis rumA homolog. An ICE-r sequence perfectly conserved with respect to its counterpart in GBS-NY was apparent within the same site of the rumA homolog of a Streptococcus dysgalactiae subsp. equisimilis strain. Additionally, homologous vanG-like elements within the conserved rumA target site were evident in Roseburia intestinalis. Importance: These three streptococcal strains represent the first known vancomycin-resistant strains of their species. The collective observations made from these strains reveal a specific hot spot for insertional elements that is conserved between streptococci and different Gram-positive species. The two GBS strains potentially represent a GBS lineage that is predisposed to insertion of vanG elements.
authors: Centers for Disease Control and Prevention, Division of Bacterial Diseases, Respiratory Diseases Branch, Atlanta, Georgia, USA.
authors: Velusamy
authors: V
authors: Srinivasan
authors: Centers for Disease Control and Prevention, Division of Bacterial Diseases, Respiratory Diseases Branch, Atlanta, Georgia, USA.
authors: Benjamin J
authors: BJ
authors: Metcalf
authors: Division of Scientific Resources, Biotechnology Core Facility Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
authors: Kristen M
authors: KM
authors: Knipe
authors: Centers for Disease Control and Prevention, Division of Bacterial Diseases, Respiratory Diseases Branch, Atlanta, Georgia, USA.
authors: Mahamoudou
authors: M
authors: Ouattara
authors: Centers for Disease Control and Prevention, Division of Bacterial Diseases, Respiratory Diseases Branch, Atlanta, Georgia, USA.
authors: Lesley
authors: L
authors: McGee
authors: Centers for Disease Control and Prevention, Division of Bacterial Diseases, Respiratory Diseases Branch, Atlanta, Georgia, USA.
authors: Patricia L
authors: PL
authors: Shewmaker
authors: Minnesota Department of Public Health, Stillwater, Minnesota, USA.
authors: Anita
authors: A
authors: Glennen
authors: New Mexico Department of Health, Santa Fe, New Mexico, USA.
authors: Megin
authors: M
authors: Nichols
authors: Jacobi Medical Center, Bronx, New York, USA.
authors: Carol
authors: C
authors: Harris
authors: Jacobi Medical Center, Bronx, New York, USA.
authors: Mary
authors: M
authors: Brimmage
authors: Montefiore Medical Center and Albert Einstein College of Medicine, New York, New York, USA.
authors: Belinda
authors: B
authors: Ostrowsky
authors: Montefiore Medical Center and Albert Einstein College of Medicine, New York, New York, USA.
authors: Connie J
authors: CJ
authors: Park
authors: Centers for Disease Control and Prevention, Division of Bacterial Diseases, Respiratory Diseases Branch, Atlanta, Georgia, USA.
authors: Stephanie J
authors: SJ
authors: Schrag
authors: Division of Scientific Resources, Biotechnology Core Facility Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
authors: Michael A
authors: MA
authors: Frace
authors: Division of Scientific Resources, Biotechnology Core Facility Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
authors: Scott A
authors: SA
authors: Sammons
authors: Centers for Disease Control and Prevention, Division of Bacterial Diseases, Respiratory Diseases Branch, Atlanta, Georgia, USA bbeall@cdc.gov.
authors: Bernard
authors: B
authors: Beall
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002876:Chromosomes, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D013292:Streptococcus agalactiae / Q000187:drug effects* / Q000235:genetics*; D034366:Streptococcus anginosus / Q000187:drug effects* / Q000235:genetics*; D020713:Vancomycin Resistance / Q000235:genetics / Q000502:physiology
chemical_list: D001426:Bacterial Proteins