Diffusion of teicoplanin and vancomycin in agar

Luigi A. Cavenaghi, Elia Biganzoli, Antonio Danese, Francesco Parenti

Research output: Contribution to journalArticle

Abstract

Teicoplanin, although more active than vancomycin [by minimum inhibitory concentration (MIC)], produces smaller inhibition zones in sensitivity testing with 30-μg disks. Our data support the hypothesis that this is due to lower diffusion of teicoplanin in agar media. After 6 hr of incubation, ≈70% of vancomycin, but only 20% of teicoplanin entered the agar from a paper disk charged with 30 μg of antibiotic. This is due to a difference between the diffusion coefficients: 0.47 mm2/hr for teicoplanin and 0.72 mm2/hr for vancomycin. With the methodology used in this work, it is possible to calculate the range of concentrations of the antibiotic occurring at times likely to include the critical time-the time when the inhibition zone is formed-of most strains at any given distance from the reservoir. One can thus estimate the breakpoint diameter for a given MIC breakpoint; for example, an MIC breakpoint of ≤4 μg/ml would correspond to a ≥15-mm breakpoint diameter for vancomycin (30-μg disk) and a ≥13-mm breakpoint diameter for teicoplanin (30-μg disk).

Original languageEnglish
Pages (from-to)253-258
Number of pages6
JournalDiagnostic Microbiology and Infectious Disease
Volume15
Issue number3
DOIs
Publication statusPublished - 1992

Fingerprint

Teicoplanin
Vancomycin
Agar
Microbial Sensitivity Tests
Anti-Bacterial Agents

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Immunology
  • Microbiology
  • Parasitology
  • Virology
  • Immunology and Allergy
  • Infectious Diseases

Cite this

Diffusion of teicoplanin and vancomycin in agar. / Cavenaghi, Luigi A.; Biganzoli, Elia; Danese, Antonio; Parenti, Francesco.

In: Diagnostic Microbiology and Infectious Disease, Vol. 15, No. 3, 1992, p. 253-258.

Research output: Contribution to journalArticle

Cavenaghi, Luigi A. ; Biganzoli, Elia ; Danese, Antonio ; Parenti, Francesco. / Diffusion of teicoplanin and vancomycin in agar. In: Diagnostic Microbiology and Infectious Disease. 1992 ; Vol. 15, No. 3. pp. 253-258.
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