title: Multicenter clinical laboratory evaluation of a beta-lactamase disk assay employing a novel chromogenic cephalosporin, S1.
abstract: S1, a new chromogenic cephalosporin (International BioClinical, Inc., Portland, Oreg.), was used to detect beta-lactamase production among a variety of commonly encountered bacteria in a four-center collaborative study. Results of an S1 disk assay were compared with those obtained by a nitrocefin-based disk procedure (Cefinase; Becton-Dickinson Microbiology Systems, Cockeysville, Md.), with repetitive testing of five quality control organisms and with individual tests of recent clinical isolates of Neisseria gonorrhoeae (162 strains), Haemophilus influenzae (162 strains), Moraxella catarrhalis (155 strains), Staphylococcus aureus (161 strains), and Bacteroides fragilis (164 strains). The performances of the two beta-lactamase disk assays were comparable for the first three species cited above. However, the S1 assay appeared to be a more sensitive procedure than the Cefinase assay when applied to S. aureus and B. fragilis, with respect to both total numbers of positive results and length of time to a definitive positive endpoint.
authors.affiliation: University of Massachusetts Medical Center, Worcester 01655, USA.
authors.forename: G V
authors.initials: GV
authors.lastname: Doern
authors.forename: R N
authors.initials: RN
authors.lastname: Jones
authors.forename: E H
authors.initials: EH
authors.lastname: Gerlach
authors.forename: J A
authors.initials: JA
authors.lastname: Washington
authors.forename: D J
authors.initials: DJ
authors.lastname: Biedenbach
authors.forename: A
authors.initials: A
authors.lastname: Brueggemann
authors.forename: M E
authors.initials: ME
authors.lastname: Erwin
authors.forename: C
authors.initials: C
authors.lastname: Knapp
authors.forename: J
authors.initials: J
authors.lastname: Raymond
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000201:enzymology* / Q000302:isolation & purification; D001431:Bacteriological Techniques / Q000706:statistics & numerical data; D001441:Bacteroides fragilis / Q000201:enzymology; D002511:Cephalosporins; D002863:Chromogenic Compounds; D004352:Drug Resistance, Microbial; D005069:Evaluation Studies as Topic; D006193:Haemophilus influenzae / Q000201:enzymology; D006801:Humans; D007202:Indicators and Reagents; D001936:Moraxella catarrhalis / Q000201:enzymology; D009344:Neisseria gonorrhoeae / Q000201:enzymology; D012680:Sensitivity and Specificity; D013211:Staphylococcus aureus / Q000201:enzymology; D001618:beta-Lactamases / Q000032:analysis*
chemical_list: D002511:Cephalosporins; D002863:Chromogenic Compounds; D007202:Indicators and Reagents; D001618:beta-Lactamases