Article Sidebar
Published:
Jul 31, 2007Keywords:
Article Details
Submission of a manuscript to this journal is a representation that the manuscript has not been published previously and is not under consideration for publication elsewhere.
All authors named in each manuscript would be required to sign a form (to be supplied by the Editor) so that they may retain their copyright in the article but to assign to us (the Publishers) and its licensees in perpetuity, in all forms, formats and media (whether known or created in the future) to (i) publish, reproduce, distribute, display and store the contribution, (ii) translate the contribution into other languages, create adaptations, reprints, include within collections and create summaries, extracts and/or abstracts of the contribution, (iii) create any other derivative works(s) based on the contribution, (iv) to exploit all subsidiary rights in the contribution, (v) the inclusion of electronic links from the contribution to third party material where-ever it may be located, and (vi) license any thrid party to do any or all of the above.
Main Article Content
Comparative Evaluation of Three In Vitro Techniques in the Interaction of Ampicillin and Ciprofloxacin against Staphylococcus aureus and Escherichia coli
Abstract
Purpose: The study was designed to evaluate the consistency of interpretation of results of interaction between ampicillin and ciprofloxacin against S. aureus and E. coli using three in vitro techniques.
Methods: The interaction between ampicillin and ciprofloxacin was studied using three in vitro methods- Checkerboard technique, Overlay Inoculum Susceptibility Disc technique (OLISD) and the Decimal Assay for Additivity technique (DAA).
Results: In the Checkerboard technique, fractional inhibitory concentration (FIC) indices show that the ampicillin/ciprofloxacin combination is synergistic against the test organisms. In the DAA approach, a target IZD of 15 mm yielded Biological Equivalent Factors (BEF) of 1.35 μg (amp/Staph), 6.74 μg (cipro/Staph), 9.62 μg (ampicillin/E. coli), and 5.45 μg (cipro/E. coli). Statistical analyses show that all decimal combinations of ampicillin and ciprofloxacin were additive (p< 0.05). The overlay inoculum susceptibility disc method shows inhibition zone diameter increments ranging between 36 ± 8.00 % to 69.2 ± 23.08 % for S. aureus and 28.12 ± 3.13 % to 50 ± 12.50 % for E. coli. These increments are consistent with reported criteria for synergism in the OLISD method.
Conclusion: The study suggests a possible clinical use for the combination of ampicillin and ciprofloxacin against infections caused by these organisms. Equally, the apparent disagreement between DAA and the other two methods raises questions as to the consistency of inferences drawn on interaction studies when different techniques are used.
Keywords: Ampicillin, Ciprofloxacin, Interaction, Decimal Assay, Checkerboard, OLISD method.
> Tropical Journal of Pharmaceutical Research Vol. 5 (2) 2006: pp. 605-611
