Antibacterial Activity of Salvadora persica L. (Miswak) Extracts against Multidrug Resistant Bacterial Clinical Isolates

Table 1

The antibacterial activities of aqueous and methanol extracts of miswak against 10 MDR pathogenic organisms.

MDR bacterial isolates	The diameter of inhibition zones (mm)
	⁢Aqueous extract (mg/mL)				⁢Methanol extract (mg/mL)				Positive control
	400	200	100	50	400	200	100	50	VAN (30 µg)	TOB (10 µg)
MRSA	6.2	5.1	3.8	3.0	8.3	5.1	3.4	2.0	18	NT
MRSE	6.0	4.8	3.2	2.7	7.6	5.8	3.1	1.8	19	NT
Streptococcus pyogenes	6.4	4.5	3.5	2.6	7.4	5.4	3.0	2.2	21	NT
E. faecalis	6.1	5.2	4.0	3.2	7.8	6.1	5.0	2.9	19	NT
E. coli	12.3	9.7	7.2	5.3	13.6	9.2	6.5	4.8	NT	21
K. pneumonia	11.8	8.5	7.0	4.3	12.7	8.7	5.8	4.6	NT	20
P. aeruginosa	10.5	8.0	5.9	4.0	10.2	8.8	6.2	4.2	NT	17
S. marcescens	12.0	9.2	5.6	4.8	12.5	8.1	5.0	4.5	NT	18
A. baumannii	8.5	7.3	4.6	3.2	9.8	8.0	5.2	3.5	NT	16
S. maltophilia	8.2	7.0	4.8	3.0	9.5	7.6	4.9	3.3	NT	16

MRSA: methicillin-resistant staphylococcus aureus, MRSE: methicillin-resistant staphylococcus epidermidis.
VAN: vancomycin, TOB: tobramycin, and NT: Not tested.
The CLSI zone diameter interpretive criteria for vancomycin (VAN): ≥15 mm: susceptible, 13-14 mm: intermediate, and ≤12 mm: resistant [21].
The CLSI zone diameter interpretive criteria for tobramycin (TOB): ≥17 mm: susceptible, 15-16 mm: intermediate, and ≤14 mm: resistant [21].