title: Dominance of multidrug resistant CC271 clones in macrolide-resistant streptococcus pneumoniae in Arizona.
abstract: BACKGROUND
  Rates of resistance to macrolide antibiotics in Streptococcus pneumoniae are rising around the world due to the spread of mobile genetic elements harboring mef(E) and erm(B) genes and post-vaccine clonal expansion of strains that carry them.
  
  
  RESULTS
  Characterization of 592 clinical isolates collected in Arizona over a 10 year period shows 23.6% are macrolide resistant. The largest portion of the macrolide-resistant population, 52%, is dual mef(E)/erm(B)-positive. All dual-positive isolates are multidrug-resistant clonal lineages of Taiwan19F-14, mostly multilocus sequence type 320, carrying the recently described transposon Tn2010. The remainder of the macrolide resistant S. pneumoniae collection includes 31% mef(E)-positive, and 9% erm(B)-positive strains.
  
  
  CONCLUSIONS
  The dual-positive, multidrug-resistant S. pneumoniae clones have likely expanded by switching to non-vaccine serotypes after the heptavalent pneumococcal conjugate vaccine release, and their success limits therapy options. This upsurge could have a considerable clinical impact in Arizona.
authors.affiliation: Translational Genomics Research Institute, Flagstaff, AZ, USA. jbowers@tgen.org
authors.forename: Jolene R
authors.initials: JR
authors.lastname: Bowers
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Driebe
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Nibecker
authors.forename: Bette R
authors.initials: BR
authors.lastname: Wojack
authors.forename: Derek S
authors.initials: DS
authors.lastname: Sarovich
authors.forename: Ada H
authors.initials: AH
authors.lastname: Wong
authors.forename: Pius M
authors.initials: PM
authors.lastname: Brzoska
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Hubert
authors.forename: Andrew
authors.initials: A
authors.lastname: Knadler
authors.forename: Lindsey M
authors.initials: LM
authors.lastname: Watson
authors.forename: David M
authors.initials: DM
authors.lastname: Wagner
authors.forename: Manohar R
authors.initials: MR
authors.lastname: Furtado
authors.forename: Michael
authors.initials: M
authors.lastname: Saubolle
authors.forename: David M
authors.initials: DM
authors.lastname: Engelthaler
authors.forename: Paul S
authors.initials: PS
authors.lastname: Keim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001130:Arizona / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D004251:DNA Transposable Elements; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D005798:Genes, Bacterial; D005838:Genotype; D006801:Humans; D007223:Infant; D018942:Macrolides / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D016133:Polymerase Chain Reaction; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D018942:Macrolides