The invention relates to direct-fed microbials for use in E. coli inhibition in animals in combination with antibiotics selected from the group consisting of ceftiofur, oxytetracycline, tulathromycin, and lincomycin. More particularly, the invention relates to isolated Bacillus strains 2, 3, 4, 5, 9, 57, 71, and 126, and strains having all of the identifying characteristics of these strains, for a use comprising the above-mentioned use.