Open AccessDetection of Inducible Clindamycin Resistance in Staphylococci by Broth Microdilution Using Erythromycin-Clindamycin Combination Wells
Author(s) -
Jana M. Swenson,
William B. Brasso,
Mary Jane Ferraro,
Dwight J. Hardy,
C C Knapp,
Linda K. McDougal,
L. Barth Reller,
Hélio S. Sader,
Dee Shortridge,
Robert Skov,
Melvin P. Weinstein,
Barbara Zimmer,
Jean B. Patel
Publication year - 2007
Publication title -
journal of clinical microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.349
H-Index - 255
eISSN - 1070-633X
pISSN - 0095-1137
DOI - 10.1128/jcm.01501-07
Subject(s) - clindamycin , broth microdilution , microbiology and biotechnology , staphylococcus aureus , erythromycin , staphylococcus , biology , coagulase , antibacterial agent , incubation , antibiotics , bacteria , minimum inhibitory concentration , biochemistry , genetics
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 μg/ml) in a single well of a broth microdilution panel to predict the presence of inducible CC resistance. Each laboratory tested approximately 30Staphylococcus 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 μg/ml ERY and 0.5 μg/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 μg/ml correlated well with the D-zone test.