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. 2007 Dec;45(12):4018-20.
doi: 10.1128/JCM.01158-07. Epub 2007 Oct 17.

Agar dilution method for detection of inducible clindamycin resistance in Staphylococcus spp

Clarence J Fernandes  1 , Matthew V N O'Sullivan, Yongwei Cai, Fanrong Kong, Xianyu Zeng, Gwendolyn L Gilbert, George Kotsiou
Affiliations

Agar dilution method for detection of inducible clindamycin resistance in Staphylococcus spp

Clarence J Fernandes et al. J Clin Microbiol. 2007 Dec.

Abstract

We describe the development and validation of an agar dilution method for the detection of inducible clindamycin resistance by using 227 previously characterized erythromycin-resistant, clindamycin-susceptible Staphylococcus sp. isolates. Mueller-Hinton agar with defibrinated horse blood containing a range of erythromycin concentrations (1 to 8 mg/liter) combined with clindamycin at 0.5 mg/liter was used to determine the optimal concentration that produced growth of inducible isolates while inhibiting that of isolates without the inducible phenotype. A concentration of clindamycin of 0.5 mg/liter with erythromycin at 1 mg/liter was the optimal combination for detection of inducible resistance and resulted in a sensitivity of 100% (95% confidence interval [CI], 97.9 to 100) and a specificity of 100% (95% CI, 93.0 to 100). Attention must be paid to ensuring that a sufficient inoculum has been used, since an inoculum below the standard 10(7) bacteria/ml may result in false-negative results. This method has been incorporated into routine use in our laboratory.

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Figures

FIG. 1.
FIG. 1.
Agar dilution method for detection of inducible clindamycin resistance. Columns: A, MS strain (ATCC BAA-976); B, iMLSB strain (ATCC BAA-976); C, macrolide-sensitive strain; D, cMLSB strain. Rows: GC, growth control (no antibiotics); E 1, erythromycin at 1 mg/liter; C 0.5, clindamycin at 0.5 mg/liter; E1, C 0.5, erythromycin at 1 mg/liter and clindamycin at 0.5 mg/liter.
See this image and copyright information in PMC

References

    1. Bell, S. M., B. J. Gatus, J. N. Pham, and D. L. Rafferty. 2006. Antibiotic susceptibility testing by the CDS method. [Online.] http://web.med.unsw.edu.au/cdstest. South Eastern Area Laboratory Services, Sydney, New South Wales, Australia.
    1. British Society For Antimicrobial Chemotherapy. April 2004. Testing for dissociated resistance in staphylococci. [Online.] http://www.bsac.org.uk/_db/_documents/Testing_for_dissocit.pdf. Accessed 24 October 2006.
    1. Clinical and Laboratory Standards Institute. 2006. Performance standards for antimicrobial disk susceptibility tests; approved standard—ninth edition. CLSI document M2-A9. Clinical and Laboratory Standards Institute, Wayne, PA.
    1. Drinkovic, D., E. R. Fuller, K. P. Shore, D. J. Holland, and R. Ellis-Pegler. 2001. Clindamycin treatment of Staphylococcus aureus expressing inducible clindamycin resistance. J. Antimicrob. Chemother. 48:315-316. - PubMed
    1. Fiebelkorn, K. R., S. A. Crawford, M. L. McElmeel, and J. H. Jorgensen. 2003. Practical disk diffusion method for detection of inducible clindamycin resistance in Staphylococcus aureus and coagulase-negative staphylococci. J. Clin. Microbiol. 41:4740-4744. - PMC - PubMed

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