oa Southern African Journal of Infectious Diseases - Vancomycin versus teicoplanin in the treatment of serious Gram-positive infections : what do the minimum inhibitory concentration data tell us? : original research
Glycopeptides are the mainstay of treatment against serious drug-resistant Gram-positive infections. The two principal agents are vancomycin and teicoplanin. Optimal dosing of both these antimicrobial agents, in terms of clinical outcomes and achievement of pharmacodynamic targets, has been shown to be dependent on the minimum inhibitory concentration (MIC). There are no MIC susceptibility data for vancomycin and teicoplanin in South Africa, and susceptibility from a clinical perspective is usually considered to be a class-specific phenomenon, and thus the two agents are often used interchangeably. The aim of this study was to assess and compare the MIC of teicoplanin with that of vancomycin, using broth microdilution, against a number of clinically significant Gram-positive isolates. Staphylococci and enterococci were collected from the Charlotte Maxeke Johannesburg Academic Hospital. Broth microdilution antimicrobial susceptibility testing was performed simultaneously for both vancomycin and teicoplanin. MIC data were analysed using descriptive statistics (mean, mode, MIC50 and MIC90) and comparative assessment using Student's t-test and Spearman's rank correlation coefficient. Vancomycin and teicoplanin MIC distribution differed for both staphylococci (n = 100) and enterococci (n = 27). There was a significant difference between the mean MIC of vancomycin and teicoplanin for all isolate groups (p-value < 0.0001-0.0168). A non-significant positive and negative correlation was noted between vancomycin and teicoplanin MIC for all of the isolates, indicating that susceptibility to one is generally independent of the other. Glycopeptide MIC data for Gram-positive bacteria indicate distinct differences between vancomycin and teicoplanin with regard to a variety of clinical isolates. This suggests that, from a clinical perspective, these agents should not be used interchangeably, and that more appropriate MIC-based utilisation would assist in dose optimisation.
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