Author:
Johnson James R.,Urban Carl,Weissman Scott J.,Jorgensen James H.,Lewis James S.,Hansen Glen,Edelstein Paul H.,Robicsek Ari,Cleary Timothy,Adachi Javier,Paterson David,Quinn John,Hanson Nancy D.,Johnston Brian D.,Clabots Connie,Kuskowski Michael A.,
Abstract
ABSTRACTEscherichia colisequence type ST131 (from phylogenetic group B2), often carrying the extended-spectrum-β-lactamase (ESBL) geneblaCTX-M-15, is an emerging globally disseminated pathogen that has received comparatively little attention in the United States. Accordingly, a convenience sample of 351 ESBL-producingE. coliisolates from 15 U.S. centers (collected in 2000 to 2009) underwent PCR-based phylotyping and detection of ST131 andblaCTX-M-15. A total of 200 isolates, comprising 4 groups of 50 isolates each that were (i)blaCTX-M-15negative non-ST131, (ii)blaCTX-M-15positive non-ST131, (iii)blaCTX-M-15negative ST131, or (iv)blaCTX-M-15positive ST131, also underwent virulence genotyping, antimicrobial susceptibility testing, and pulsed-field gel electrophoresis (PFGE). Overall, 201 (57%) isolates exhibitedblaCTX-M-15, whereas 165 (47%) were ST131. ST131 accounted for 56% ofblaCTX-M-15-positive- versus 35% ofblaCTX-M-15-negative isolates (P< 0.001). Whereas ST131 accounted for 94% of the 175 total group B2 isolates, non-ST131 isolates were phylogenetically distributed byblaCTX-M-15status, with groups A (blaCTX-M-15-positive isolates) and D (blaCTX-M-15-negative isolates) predominating. BothblaCTX-M-15and ST131 occurred at all participating centers, were recovered from children and adults, increased significantly in prevalence post-2003, and were associated with molecularly inferred virulence. Compared with non-ST131 isolates, ST131 isolates had higher virulence scores, distinctive virulence profiles, and more-homogeneous PFGE profiles.blaCTX-M-15was associated with extensive antimicrobial resistance and ST131 with fluoroquinolone resistance. Thus,E. coliST131 andblaCTX-M-15are emergent, widely distributed, and predominant among ESBL-positiveE. colistrains in the United States, among children and adults alike. Enhanced virulence and antimicrobial resistance have likely promoted the epidemiological success of these emerging public health threats.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Pharmacology (medical),Pharmacology