Abstract

Ethylenediamine Tetraacetic Acid (EDTA) is a compound predominantly known for its chelating ability. It has also been found that in combination with antibacterial agents like benzakolium and chlorocresol, they were able to kill resistant bacteria. EDTA was used in combination with ciprofloxacin, a fluoroquinolone, against Shigella sonnei. This was done by determining their respective and combined Minimum Inhibitory Concentration (MIC) and using their obtained MIC in combination to obtain their fractional inhibitory concentration (F.I.C) in order to determine if their interaction is synergistic, antagonistic or additive. Results obtained using the checkerboard technique showed that combinations of EDTA with ciprofloxacin showed synergy at ratios of 9:1, 8:2, 7:3 and 6:4, and additive effect at ratios of 5:5, 4:6, 3:7 and 2:8.

Key words: EDTA, ciprofloxacin, Shigella sonnei, synergy.