Evidence-Based Complementary and Alternative Medicine

Research Article

Influence of First-Line Antibiotics on the Antibacterial Activities of Acetone Stem Bark Extract of Acacia mearnsii De Wild. against Drug-Resistant Bacterial Isolates

Table 3

Fractional inhibitory concentrations of acetone stem bark extract of A. mearnsii in combination with the different antibiotics.


Tested bacterial isolates	Fractional inhibitory concentrations (FIC)
	AMA + Ery	FICI	AMA + Tet	FICI	AMA + Met	FICI	AMA + Amx	FICI
	mg/mL + µg/mL	FICI	mg/mL + µg/mL	FICI	mg/mL + µg/mL	FICI	mg/mL + µg/mL	FICI

Escherichia coli ATCC 25922	0.625/6.25	17.00Ant	0.0098/0.244	0.266 Syn	0.313/15.625	1.00 Add	0.156/7.813	1.25 Ind
Bacillus cereus ATCC 10702	0.0098/0.098	1.63 Ind	0.00122/0.061	0.258 Syn	0.156/7.813	1.25 Ind	0.078/3.906	1.000 Add
Pseudomonas aeruginosa ATCC 19582	0.0049/0.049	0.06 Syn	0.00122/0.061	0.133 Syn	0.625/31.250	6.00 Ant	0.039/1.953	0.750 Add
Serratia marcescens ATCC 9986	0.625/6.25	3.00 Ind	0.0781/3.906	0.37 Syn	0.625/31.250	2.00 Ind	0.156/7.813	0.500 Syn
Enterococcus faecalis KZN	0.156/1.563	0.38 Syn	0.313/15.625	1.5 Ind	0.625/31.250	1.50 Ind	0.0049/0.244	0.258 Syn
Staphylococcus aureus _OK1	0.0049/0.049	0.31 Syn	0.0098/0.244	0.375 Syn	0.625/31.250	10.00 Ant	0.0049/0.244	0.312 Syn
Salmonella typhi ATCC 13311	0.1563/1.953	0.81Add	0.00122/0.061	0.254 Syn	0.625/31.250	3.00 Ind	0.0049/0.244	0.265 Syn
Micrococcus luteus	0.0391/0.391	2.00 Ind	0.0781/3.906	2.128 Ind	0.313/15.625	10.00 Ant	0.0024/0.122	0.312 Syn
Proteus vulgaris CSIR 0030	≤0.0003/0.003	0.08 Syn	0.0049/0.122	0.281 syn	0.078/3.906	0.50 Syn	0.006/0.030	0.165 Syn
Shigella flexneri KZN	0.0098/0.098	0.38 Syn	0.156/7.813	18.01 Ant	0.313/15.625	4.25 Ant	0.0391/1.953	0.509 Add

Tested bacterial isolates	Fractional inhibitory concentrations (FIC)
	AMA + Cip	FICI	AMA + Nal	FICI	AMA + Chl	FICI	AMA + Kan	FICI
	mg/mL + µg/mL	FICI	mg/mL + µg/mL	FICI	mg/mL + µg/mL	FICI	mg/mL + µg/mL	FICI

Escherichia coli ATCC 25922	0.0098/0.0098	0.266 Syn	0.078/3.906	2.125 Ind	0.0391/1.953	0.563 Add	0.156/7.813	0.313 Syn
Bacillus cereus ATCC 10702	0.0781/0.0781	1.500 Ind	0.313/15.625	3.000 Ind	0.0195/0.977	0.375 Syn	0.078/3.906	0.531 Add
Pseudomonas aeruginosa ATCC 19582	0.0781/0.0781	1.000 Add	0.156/7.813	2.000 Ind	0.0195/0.977	0.375 Syn	0.0391/1.953	0.312 Syn
Serratia marcescens ATCC 9986	0.0098/0.0098	0.250 Syn	0.039/1.953	1.062 Ind	0.0098/0.488	0.512 Add	0.078/3.906	2.125 Ind
Enterococcus faecalis KZN	1.25/1.25	6.000 Ant	0.625/31.250	1.500 Ind	0.0781/3.906	0.250 Syn	1.250/62.500	2.125 Ind
Staphylococcus aureus _OK1	0.0098/0.0098	0.251 Syn	0.156/7.813	2.125 Ind	0.0391/1.953	0.750 Add	0.313/15.625	5.000 Ant
Salmonella typhi ATCC 13311	0.0049/0.0049	0.27 Syn	0.039/1.953	0.37 Syn	0.0195/0.977	0.44 Syn	0.0097/0.488	0.062 Syn
Micrococcus luteus	0.3125/0.3125	8.250 Ant	0.156/7.813	4.125 Ant	0.0391/1.953	2.000 Ind	0.625/31.500	16.13 Ant
Proteus vulgaris CSIR 0030	0.0049/0.0049	0.283 Syn	0.078/3.906	0.562 Add	0.0781/3.906	0.626 Add	0.0391/1.953	0.312 Syn
Shigella flexneri KZN	0.0098/0.0098	0.377 Syn	0.313/15.625	4.250 Ant	0.0391/1.953	0.750 Add	0.313/15.625	5.000 Ant

AMA: acetone extract of A. mearnsii; Ery: erythromycin; Tet: tetracycline; Met: metronidazole; Cip: ciprofloxacin; Nal: nalidixic acid; Chl: chloramphenicol; Kan: kanamycin; FICI: fractional inhibitory concentration indices.