Table 3.

Antibacterial activity of l-tyrosine against six MDR bacterial strains

Strains	Zone of inhibition (mm) ± standard deviation					MIC (µg/ml)
	Different concentrations of l-tyrosine (µg/ml)
	10	20	30	40	50
Gram-negative bacteria
PA-02	9.0 ± 0.5	11 ± 0.7	19 ± 0.3	28 ± 1.1	31 ± 1.0	6
PA-09	8.0 ± 0.7	10 ± 1.0	17 ± 0.9	25 ± 0.9	28 ± 1.5	8
KP-01	0.0 ± 0.0	8 ± 0.9	10 ± 0.4	16 ± 0.8	19 ± 0.5	15
EC-03	8.0 ± 1.0	11 ± 0.9	15 ± 1.0	20 ± 0.8	24 ± 1.1	10
Gram-positive bacteria
SA-03	0.0 ± 0.0	9.0 ± 1.0	10 ± 0.5	13 ± 1.0	18 ± 1.0	20
SA-04	0.0 ± 0.0	8.0 ± 0.8	11 ± 0.6	19 ± 1.1	21 ± 0.9	15

MIC: Minimum inhibitory concentration. DMSO (1%) was used as a negative control and had no effect against the tested bacteria