Table 4.

Fractional Inhibitory Concentration Index (FICI) of Gentamicin (GEN) and EOs against Klebsiella pneumoniae strains. The FICI indicated a synergistic effect if its value was ≤0.5, additive if it was from >0.5 to ≤1, indifferent if it was from >1.0 to ≤4, and antagonism if it was >4.

Kp Strain	889U	98LCR	197U	Mean FICI
GEN + thyme	0.333	0.333	0.563	0.410
GEN + turmeric	2.250	0.375	0.625	1.083
GEN + rosemary	0.250	0.500	0.625	0.458
GEN + peppermint	0.060	0.250	0.516	0.275