Synergistic Effect between Usnic Acid and Polymyxin B against Resistant Clinical Isolates of Pseudomonas aeruginosa

Table 1

Susceptibility profile to polymyxin B of Pseudomonas aeruginosa and Acinetobacter spp. clinical isolates.

Clinical isolates	Identification of the bacteria	Polymyxin B agar-spot test	MIC (μg/mL)
A15	Acinetobacter spp.	+	>32 [R]
A25	Acinetobacter spp.	+	>32 [R]
A71	Acinetobacter spp.	+	>32 [R]
A72	Acinetobacter spp.	+	>32 [R]
A76	Acinetobacter spp.	+	>32 [R]
PA05	Pseudomonas aeruginosa	+	4 [I]
PA07	Pseudomonas aeruginosa	+	4 [I]
PA18	Pseudomonas aeruginosa	+	8 [R]
PA19	Pseudomonas aeruginosa	+	4 [I]
PA46	Pseudomonas aeruginosa	+	32 [R]
PA56	Pseudomonas aeruginosa	+	8 [R]
PA57	Pseudomonas aeruginosa	+	32 [R]
PA78	Pseudomonas aeruginosa	+	32 [R]
PA82	Pseudomonas aeruginosa	+	4 [I]

MIC: minimum inhibitory concentration; R: resistance; I: intermediate resistance.