Performance of the Q-checkerboard technique as a means to study the combination of four antibiotics against Staphylococcus aureus ATCC 29213

Abstract

The human body is an environment of colonization for many different bacterial species. They both aid one another concerning the nutrition, digestive processes and various protecting mechanisms. Different organisms inhabit different tissues. If a certain bacterium exits the normal habitat to different and new tissues, it can cause life threatening and harmful diseases. Antimicrobial agent discovery was an essential step to ending harmful conditions. Many classifications of various agents have been developed throughout the years. However, in some cases the infections caused did not resolve upon the use of these agents. By association, came the rise of resistance against these medications. To avoid the increase in further resistance, and to lower the harm on the patient with higher beneficial outcomes, there was the development of the antimicrobial combination therapy. Many studies proved that upon the combination of different agents, there was a higher success for clearing the infections. To study the state in which the agents are working, the most widely used techniques were the checkerboard and the time-kill curve assay. Many studies work on evaluating these two. In our study, we are trying to validate a checkerboard method (Q-checkerboard) that consists of the combination of four agents together (Cefotaxime, Amikacin, Levofloxacin and Trimethoprim-Sulfamethoxazole). The results obtained are further analyzed by the time-kill curve assay for more clarity. Bacterial resistance is rising more and more within each year, and antimicrobial agent synergy is an essential goal to be obtained. The study showed that there was a non-synergistic effect upon the combination of Cefotaxime with Amikacin alone. The same was proved for the combination of Cefotaxime with Amikacin and Levofloxacin, which was also seen while using those three with Trimethoprim-Sulfamethoxazole. The validity of the Q-checkerboard was confirmed upon the analogous result interpretations of the time-kill curve assay.