title: Geographic diversity and temporal trends of antimicrobial resistance in Streptococcus pneumoniae in the United States.
abstract: Resistance of Streptococcus pneumoniae to antibiotics is increasing throughout the United States, with substantial variation among geographic regions. We show that patterns of geographic variation are best explained by the intensity of selection for resistance, which is reflected by differences between the proportions of resistance within individual serotypes, rather than by differences between the frequencies of particular serotypes. Using a mathematical transmission model, we analyzed temporal trends in the proportions of singly and dually resistant organisms and found that pneumococcal strains resistant to both penicillin and erythromycin are increasing faster than strains singly resistant to either. Using the model, we predict that by 1 July 2004, in the absence of a vaccine, 41% of pneumococci at the Centers for Disease Control and Prevention (CDC)'s Active Bacterial Core surveillance (ABCs) sites, taken together, will be dually resistant, with 5% resistant to penicillin only and 5% to erythromycin only.
authors.affiliation: Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA.
authors.forename: Althea W
authors.initials: AW
authors.lastname: McCormick
authors.forename: Cynthia G
authors.initials: CG
authors.lastname: Whitney
authors.forename: Monica M
authors.initials: MM
authors.lastname: Farley
authors.forename: Ruth
authors.initials: R
authors.lastname: Lynfield
authors.forename: Lee H
authors.initials: LH
authors.lastname: Harrison
authors.forename: Nancy M
authors.initials: NM
authors.lastname: Bennett
authors.forename: William
authors.initials: W
authors.lastname: Schaffner
authors.forename: Arthur
authors.initials: A
authors.lastname: Reingold
authors.forename: James
authors.initials: J
authors.lastname: Hadler
authors.forename: Paul
authors.initials: P
authors.lastname: Cieslak
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Samore
authors.forename: Marc
authors.initials: M
authors.lastname: Lipsitch
mesh_terms: D004351:Drug Resistance; D004917:Erythromycin / Q000494:pharmacology; D005843:Geography; D008433:Mathematics; D008962:Models, Theoretical; D010403:Penicillin Resistance; D012641:Selection, Genetic; D013296:Streptococcus pneumoniae / Q000187:drug effects*; D013997:Time Factors; D014481:United States
chemical_list: D004917:Erythromycin