Comparative Evaluation of the Inhibitory Effect of Some Essential Oils with Antibiotics against Pseudomonas aeruginosa

Table 2

Inhibition zone diameter of the tested antibiotics alone and in combination with essential oils.

Antibiotic	Inhibition zone diameter (mm)	Combination of antibiotics and essential oils
		Antibiotic + thyme essential oil; (% enhancement)	Antibiotic + marjoram essential oil; (% enhancement)	Antibiotic + sage essential oil; (% enhancement)
Piperacillin	17^d	42^a (147%)	24^b (41.2%)	22^c (29.4%)
Cefepime	30^c	46^a (53.3%)	33^b (10%)	30^c (−0.03%)
Meropenem	34^c	52^a (52.9%)	41^b (20.5%)	42^b (23.5%)
Gentamicin	29^d	40^a (37.9%)	38^b (31.03%)	33^c (13.7%)
Norfloxacin	31^b	43^a (38.7%)	30^b (−0.03%)	26^c (−0.16%)

Mean values within a row not sharing common superscript letters are significantly different, .