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

Table 3

In vitro time-kill assessment of the crude ethanolic stem bark extract of E. caffra.

	Log10 Kill			Log10 Kill			Log10 Kill
Tested bacterial isolates	(1/2) × MIC			1 × MIC			2 × MIC
	0 h	4 h	8 h	0 h	4 h	8 h	0 h	4 h	8 h
Micrococcus luteus	2.187	2.895	3.233	2.207	1.135	0.183	2.244	−0.264	−2.213
Shigella flexneri KZN	2. 229	3.177	3.983	2.246	1.399	0.872	2.410	0.298	−1.526
Proteus vulgaris KZN	2.286	3.243	4.427	2.308	1.147	0.265	2.275	0.459	−1.503
Proteus vulgaris CSIR 0030	2.270	3.392	4.268	2.254	1.109	0.045	2.297	−0.161	−3.968
Enterococcus faecalis KZN	2.227	2.821	3.289	2.334	1.058	0.404	2.366	0.129	−1.741
Staphylococcus aureus OK3	3.177	4.384	5.986	2.889	0.916	0.381	3.238	−0.475	−2.686
Shigella sonnei (ATCC 29930)	2.453	3.243	4.276	2.553	1.172	0.878	2.683	0.961	−1.819
Bacillus pumilus (ATCC 14884)	2.442	3.772	4.478	2.398	1.413	0.697	2.778	0.448	−1.216
Escherichia coli (ATCC 25922)	2.135	3.327	5.482	2.247	1.548	0.899	2.541	0.678	−1.697
Enterococcus faecalis (ATCC 29212)	2.399	3.648	4.887	2.368	0.976	0.637	2.465	0.394	−0.425
Staphylococcus aureus (ATCC 6538)	2.387	3.512	4.674	2.351	1.391	0.902	2.391	0.681	−1.839
Pseudomonas aeruginosa (ATCC 19582)	2.724	3.805	4.921	2.923	1.851	1.105	2.612	0.831	−1.287

Key: −ve sign = extent of bacterial reductions as indicated by the Log (cfu/mL) at the respective sampling times.