Zone of inhibition (ZOI) diameter of ZnO samples against mcr-1 strains [(a) NCCP 16283, (b) NCCP 16284] of E. coli. Data shown here is one of the representative from n = 3. N.D. indicates that the zone of inhibition was not detected.

Bacterial cells	Zone of inhibition (mm)
	(i) ZO	(ii) 5NZO	(iii) Polymyxin B	(iv) Erythromycin	(v) DMSO
(a) NCCP 16283	N.D.	22	13	N.D.	N.D.
(b) NCCP 16284	N.D.	24	13	N.D.	N.D.