In vitro activity of antimicrobial combinations against clinical isolates of susceptible and resistant Mycobacterium tuberculosis
Abstract:Setting: University of Texas Medical Branch, Clinical Microbiology Laboratory.
Objective: To evaluate in vitro the activity of rifabutin plus each of four other antimicrobial agents: isoniazid, amoxicillin/clavulanate, sparfloxacin and clarithromycin, against five susceptible (S-MTB) and five multidrug-resistant (MDR-TB) clinical isolates of Mycobacterium tuberculosis.
Design: The antimicrobial activity of each two-drug combination was assessed by macrodilution checkerboard technique using Bactec 460 and classified as synergistic, additive, or antagonistic, using the fractional inhibitory concentration index.
Results: For S-MTB, rifabutin + amoxicillin/clavulanate, rifabutin + isoniazid, rifabutin + sparfloxacin and rifabutin + clarithromycin acted synergistically against four, three, one and one isolate, respectively; clarithromycin + rifabutin was additive for one isolate. None of the combinations were antagonistic against S-MTB. For MDR-TB, rifabutin + amoxicillin/clavulanate, rifabutin + isoniazid, rifabutin + sparfloxacin and rifabutin + clarithromycin acted synergistically against one, one, one and two isolates, respectively, and additively against two, one, one and two isolates, respectively. Rifabutin + amoxicillin/clavulanate, rifabutin + isoniazid, and rifabutin + clarithromycin were antagonistic against one, two and two MDR-TB isolates, respectively.
Conclusion: Certain drug combinations acted synergistically against MDR-TB; however, the clinical predictive value of these in vitro experiments is unknown.
Document Type: Regular Paper
Affiliations: Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA
Publication date: August 1, 1998
The International Journal of Tuberculosis and Lung Disease publishes articles on all aspects of lung health, including public health-related issues such as training programmes, cost-benefit analysis, legislation, epidemiology, intervention studies and health systems research. The IJTLD is dedicated to the continuing education of physicians and health personnel and the dissemination of information on tuberculosis and lung health world-wide.
Certain IJTLD articles are selected for translation into French, Spanish, Chinese or Russian. They are available on the Union website
- Editorial Board
- Information for Authors
- Subscribe to this Title
- International Journal of Tuberculosis and Lung Disease
- Public Health Action
- Ingenta Connect is not responsible for the content or availability of external websites