Moroccan Propolis: A Natural Antioxidant, Antibacterial, and Antibiofilm against Staphylococcus aureus with No Induction of Resistance after Continuous Exposure

Table 5

Impact of continued exposure of Staphylococcus aureus strains on increasing concentrations of propolis.

Passages	Concentration of propolis sample (mg/mL)
	0.12	0.24	0.36	0.49	0.73
Staphylococcus aureus ATCC 6538
1°	72.44±21.8	42.81±1.4	40.24±9.8	14.22±0.43	NA
2°	36±10.7	50.88±7.2	61.33±10.0	NG
3°	87.17±61.1	100.52±47.2	57.33±15.1
4°	24.71±6.	103.68±16.	74.35±18.2
Staphylococcus aureus methicillin-resistant 2 (MRSA 2)
1°	114.09±35.2	131.95±24.2	5.33±0.9	26.35±3.3	35.92±18.6
2°	139.7±45.7	99.90±4.8	48.49±15.9	39.26±3.6	8.98±3.0
3°	75.38±13.0	86.15±16.1	55.75±24.9	46.59±4.5	31.46±26.6
4°	105.17±21.6	119.59±28.2	33.20±3.8	83.55±20.6	0.73±0.4
Staphylococcus aureus methicillin-resistant 15 (MRSA 15)
1°	123.65±40.9	125.40±15.7	30.74±0.4	32.74±27.9	NA
2°	100.45±58.7	124.64±9.2	39.02±84.6	27.13±7.2
3°	110.22±48.2	123.99±36.0	33.38±9.1	18.38±15.4
4°	62.66±2.0	65.66±11.6	42.03±12.9	0.59±0.4
Staphylococcus aureus methicillin-resistant 16 (MRSA 16)
1°	129.79±14.6	43.57±6.8	46.80±21.5	43.22±8.1	NA
2°	113.68±13.4	96.39±13.4	45.30±17.6	22.09±10.6
3°	57.71±7.8	66.98±6.86	38.99±4.9	21.60±9.0
4°	92.88±28.6	57.50±15.6	83.80±29.5	0.28±0.2

Fold change in growth at each passage is indicated as the ratio between the OD at T24 and the OD at T0 (ODT24/ODT0). NG: no growth; NA: not applied. Data are representative of three independent replicates. For each strain, data in the column with different letters are significantly different (p < 0.05).