Geographic diversity and temporal trends of antimicrobial resistance in Streptococcus pneumoniae in the United States.
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.
McCormick
Althea W
AW
Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA.
Whitney
Cynthia G
CG
Farley
Monica M
MM
Lynfield
Ruth
R
Harrison
Lee H
LH
Bennett
Nancy M
NM
Schaffner
William
W
Reingold
Arthur
A
Hadler
James
J
Cieslak
Paul
P
Samore
Matthew H
MH
Lipsitch
Marc
M
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
D004917:Erythromycin