In Vitro Antibacterial and Time-Kill Evaluation of the Erythrina caffra Thunb. Extract against Bacteria Associated with Diarrhoea

Table 1

Results of agar diffusion assays to determine the antibacterial activity of the crude ethanolic extract of E. caffra.

Tested bacterial isolates	Average zones of inhibition (±1.0 mm)
	Agar diffusion assay							Agar dilution
	Ciprofloxacin	Ethanolic extract
	2.5	650	1250	2500	5000	10000	20000	MIC
	𝜇g/mL
Micrococcus luteus	17	0	0	0	14	17	19	≤100
Shigella flexneri KZN	26	0	0	13	15	15	17	≤500
Proteus vulgaris KZN	35	0	0	0	14	15	15	≤500
Proteus vulgaris CSIR 0030	31	14	17	18	20	21	23	≤100
Enterococcus faecalis KZN	19	0	0	13	15	16	19	≤100
Staphylococcus aureus OK3	38	0	0	12	14	17	19	≤100
Shigella sonnei (ATCC 29930)	22	13	14	15	17	18	20	≤500
Bacillus pumilus (ATCC 14884)	25	0	0	16	18	19	21	≤500
Escherichia coli (ATCC 25922)	26	11	12	13	15	17	19	≤1000
Enterococcus faecalis (ATCC 29212)	25	15	15	17	19	21	22	≤500
Staphylococcus aureus (ATCC 6538)	34	0	0	11	13	13	15	≤500
Pseudomonas aeruginosa (ATCC 19582)	26	13	13	15	17	18	21	≤500