title: Protocol for the accelerated detection of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae strains from blood cultures.
abstract: The study presented here was performed to evaluate an accelerated protocol for the early detection of organisms producing extended-spectrum beta-lactamase (ESBL). The procedure involved testing isolates directly from positive blood-culture bottles, and a total of 40 clinical isolates (10 ESBL-producing and 10 non-ESBL-producing isolates of both Escherichia coli and Klebsiella pneumoniae) were used. The isolates were inoculated into blood cultures bottles and, upon growth signal, fluid from the bottle was cultured directly onto plates with combination discs containing cefotaxime or ceftazidime with and without clavulanate. Results were compared with those of standard methods for the detection of ESBL. High concordance between the two methods was found, and the direct test showed high sensitivity (95%) and specificity (100%). Use of this accelerated protocol may speed detection of the ESBL phenotype and thereby facilitate the early administration of appropriate antimicrobial therapy.
authors.affiliation: Laboratory for Molecular Epidemiology and Antimicrobial Resistance, Tel-Aviv Sourasky Medical Center, 6 Weizmann Street, Tel Aviv 64239, Israel. shiri_nv@tasmc.health.gov.il
authors.forename: S
authors.initials: S
authors.lastname: Navon-Venezia
authors.forename: R
authors.initials: R
authors.lastname: Ben-Ami
authors.forename: M J
authors.initials: MJ
authors.lastname: Schwaber
authors.forename: A
authors.initials: A
authors.lastname: Leavitt
authors.forename: D
authors.initials: D
authors.lastname: Schwartz
authors.forename: Y
authors.initials: Y
authors.lastname: Carmeli
mesh_terms: D001431:Bacteriological Techniques; D001769:Blood / Q000382:microbiology*; D015169:Colony Count, Microbial; D017077:Culture Media, Conditioned; D004926:Escherichia coli / Q000201:enzymology* / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000175:diagnosis; D006801:Humans; D007710:Klebsiella Infections / Q000175:diagnosis; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000302:isolation & purification*; D010865:Pilot Projects; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D013997:Time Factors; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D017077:Culture Media, Conditioned; D001618:beta-Lactamases