IT IS CONSIDERED ACTIVE AGAINST THE FOLLOWING MICROORGANISMS :- STAPHYLOCOCCUS AUREUS, STREPTOCOCCI INCLUDING STREPTOCOCCUS PNEUMONIAE, ESCHERICHIA COLI, HAEMOPHILUS INFLUENZAE, KLEBSIELLA SPECIES AND PSEUMOMONAS AERUGINOSA. BACITRACIN IS BACTERICIDAL FOR A VARIETY OF GRAM- POSITIVE AND GRAM-NEGATIVE ORGANISMS. IT INTERFERES WITH BACTERIAL CELL WALL SYNTHESIS BY INHIBITION OF THE REGENERATION OF PHOSPHOLIPID RECEPTORS INVOLVED IN PEPTIDOGLYCAN SYNTHESIS.