title: Molecular correlation for the treatment outcomes in bloodstream infections caused by Escherichia coli and Klebsiella pneumoniae with reduced susceptibility to ceftazidime.
abstract: Data are limited on outcomes of treatment with extended-spectrum cephalosporins (ESCs) for infections caused by Enterobacteriaceae that produce extended-spectrum beta-lactamases (ESBLs). This study describes the largest treatment experience of a nonoutbreak series of bloodstream infections caused by strains of Escherichia coli (23 episodes) and Klebsiella pneumoniae (13 episodes) with a ceftazidime minimal inhibitory concentration of > or =2 microg/mL. E. coli isolates produced a greater variety of beta-lactamase types than did K. pneumoniae isolates, among which ESBL production was predominant. Five ESBL types were identified: TEM-12, TEM-71, TEM-6, SHV-12, and SHV-5. Most patients were treated empirically with an ESC-based regimen. A favorable response to treatment with a nonceftazidime ESC was observed when the causative pathogen produced either TEM-6 or TEM-12; ceftazidime treatment was associated with failure of therapy in all patients. Despite the limited clinical success, ESCs are currently not recommended for the treatment of serious infections caused by ESBL-producing strains.
authors.affiliation: Western University of Health Sciences, College of Pharmacy, Pomona, CA 91766, USA. anniewb@westernu.edu
authors.forename: Annie
authors.initials: A
authors.lastname: Wong-Beringer
authors.forename: Janet
authors.initials: J
authors.lastname: Hindler
authors.forename: Michael
authors.initials: M
authors.lastname: Loeloff
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Queenan
authors.forename: Nancy
authors.initials: N
authors.lastname: Lee
authors.forename: David A
authors.initials: DA
authors.lastname: Pegues
authors.forename: John P
authors.initials: JP
authors.lastname: Quinn
authors.forename: Karen
authors.initials: K
authors.lastname: Bush
mesh_terms: D016470:Bacteremia / Q000188:drug therapy*; D001426:Bacterial Proteins; D002442:Ceftazidime / Q000378:metabolism / Q000627:therapeutic use*; D018550:Cephalosporin Resistance / Q000235:genetics; D002511:Cephalosporins / Q000378:metabolism / Q000627:therapeutic use; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D004927:Escherichia coli Infections / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007526:Isoelectric Point; D007710:Klebsiella Infections / Q000188:drug therapy*; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000235:genetics; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010641:Phenotype; D016896:Treatment Outcome; D001618:beta-Lactamases / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D002511:Cephalosporins; D002442:Ceftazidime; C048795:AmpC beta-lactamases; D001618:beta-Lactamases