title: Detection of inducible clindamycin resistance in staphylococci by broth microdilution using erythromycin-clindamycin combination wells.
abstract: A study conducted by 11 laboratories investigated the ability of four combinations of erythromycin (ERY) and clindamycin (CC) (ERY and CC at 4 and 0.5, 6 and 1, 8 and 1.5, and 0.5 and 2 microg/ml) in a single well of a broth microdilution panel to predict the presence of inducible CC resistance. Each laboratory tested approximately 30 Staphylococcus aureus isolates and 20 coagulase-negative staphylococcus (CoNS) isolates in a panel using cation-adjusted Mueller-Hinton broth from three different manufacturers. Only the strains resistant to ERY and those susceptible or intermediate to CC were included in the analysis (S. aureus, n = 333; CoNS, n = 97). Results of the D-zone test were used as the gold standard. After an 18-h incubation, the combination of 4 microg/ml ERY and 0.5 microg/ml CC performed the best, with 98 to 100% sensitivity and 100% specificity for both organism groups. After a 24-h incubation, the ERY-CC combinations of 4 and 0.5, 6 and 1, and 8 and 1.5 microg/ml correlated well with the D-zone test.
authors.affiliation: Antimicrobial Resistance Team, Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. jms1@cdc.gov
authors.forename: Jana M
authors.initials: JM
authors.lastname: Swenson
authors.forename: William B
authors.initials: WB
authors.lastname: Brasso
authors.forename: Mary Jane
authors.initials: MJ
authors.lastname: Ferraro
authors.forename: Dwight J
authors.initials: DJ
authors.lastname: Hardy
authors.forename: Cynthia C
authors.initials: CC
authors.lastname: Knapp
authors.forename: Linda K
authors.initials: LK
authors.lastname: McDougal
authors.forename: L Barth
authors.initials: LB
authors.lastname: Reller
authors.forename: Helio S
authors.initials: HS
authors.lastname: Sader
authors.forename: Dee
authors.initials: D
authors.lastname: Shortridge
authors.forename: Robert
authors.initials: R
authors.lastname: Skov
authors.forename: Melvin P
authors.initials: MP
authors.lastname: Weinstein
authors.forename: Barbara L
authors.initials: BL
authors.lastname: Zimmer
authors.forename: Jean B
authors.initials: JB
authors.lastname: Patel
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002981:Clindamycin / Q000494:pharmacology*; D003470:Culture Media / Q000737:chemistry; D024881:Drug Resistance, Bacterial; D004917:Erythromycin / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D008826:Microbial Sensitivity Tests / Q000379:methods*; D012680:Sensitivity and Specificity; D013210:Staphylococcus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D002981:Clindamycin; D004917:Erythromycin