title: Clinical and microbiologic characteristics of cephalosporin-resistant Escherichia coli at three centers in the United States.
abstract: We investigated the clinical and microbiologic features of 300 cases of cephalosporin-resistant Escherichia coli producing extended-spectrum β-lactamase (ESBL) or plasmid-mediated AmpC β-lactamase (pAmpC) at three medical centers in the United States. Solid-organ malignancy, connective tissue disease, and a recent history of surgery were more common among pAmpC-producing cases (n = 49), whereas urinary catheter at enrollment, diabetes, and hospitalization in the past year were more common among ESBL-producing cases (n = 233). The factors independently associated with clinical outcome were the following: the presence of cardiovascular disease (odds ratio [OR], 2.88; 95% confidence interval [CI], 1.29 to 6.43), intra-abdominal infection (OR, 6.35; 95% CI, 1.51 to 26.7), other or multiples sources of infection (OR, 8.12; 95% CI, 2.3 to 28.6), age of 65 years or greater (OR, 0.43; 95% CI, 0.2 to 0.95), favorable baseline health status (OR, 0.39; 95% CI, 0.16 to 0.95), and appropriate empirical antimicrobial therapy given in the first 72 h (OR, 0.42; 95% CI, 0.20 to 0.88). β-Lactamase genes responsible for cephalosporin resistance were identified in 291 cases. CTX-M-type ESBLs accounted for 72.0%. Of those, 88.0% were CTX-M-15. The next most common type was CMY-type pAmpC (16.7%), followed by SHV- and TEM-type ESBLs (6.3 and 1.3%, respectively). Seven cases (2.3%) had KPC-type β-lactamase. Ertapenem, imipenem, meropenem, doripenem, piperacillin-tazobactam, amikacin, nitrofurantoin, and tigecycline were highly active, with greater than 90% of the isolates being susceptible. Cefepime was less active, with only 74.2% being susceptible due to the predominance of CTX-M-15. These findings have implications in the selection of appropriate empirical therapy when infection due to cephalosporin-resistant E. coli is suspected.
authors.affiliation: Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors.forename: Yoon Soo
authors.initials: YS
authors.lastname: Park
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Adams-Haduch
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Shutt
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Yarabinec
authors.forename: Laura E
authors.initials: LE
authors.lastname: Johnson
authors.forename: Ameet
authors.initials: A
authors.lastname: Hingwe
authors.forename: James S
authors.initials: JS
authors.lastname: Lewis
authors.forename: James H
authors.initials: JH
authors.lastname: Jorgensen
authors.forename: Yohei
authors.initials: Y
authors.lastname: Doi
mesh_terms: D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D018550:Cephalosporin Resistance; D002510:Cephalosporinase / Q000378:metabolism; D003710:Demography; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology; D004927:Escherichia coli Infections / Q000150:complications / Q000453:epidemiology* / Q000382:microbiology*; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D002510:Cephalosporinase