Skip to main content

Table 4 Fractional inhibitory concentration (FIC) and FIC indices (FICI) of antibiotics-hydrolate of C. capitatus pairs against MRSA strains

From: Evaluation of antimicrobial activity of the hydrolate of Coridothymus capitatus (L.) Reichenb. fil. (Lamiaceae) alone and in combination with antimicrobial agents

Bacteria Combination MICa MICc FIC FICI Type of interaction
S. aureus ATCC 43300 Tetracycline 0.125 0.125 1 1.48 Indifference
Hydrolate 25 (0.035)a 12.5 (0.017)a 0.48   
S. aureus 815 (MRSA) Tetracycline 0.25 0.125 0.5 0.98 Additive
Hydrolate 25 (0.035) 12.5 (0.017) 0.48   
S. aureus 74CCH (MRSA) Tetracycline 0.25 0.125 0.5 0.98 Additive
Hydrolate 25 (0.035) 12.5 (0.017) 0.48   
  1. (As essential oil % (v/v) content in hydrolate product)a
  2. MICa, MIC of one sample alone; MICc, MIC of one sample of the most effective combination
  3. FIC of antibiotic = MIC of antibiotic in combination with hydrolate/MIC of antibiotic alone
  4. FIC of hydrolate = MIC of hydrolate in combination with antibiotic/MIC of hydrolate alone
  5. FICI = FIC of antibiotic+FIC of hydrolate
  6. FICI ≤0.5, synergy; FICI > 0.5 and ≤ 1, additive; FICI > 1 and ≤ 4, indifference; FICI > 4 antagonism