Antimicrobial test (Inhibition zone/disk) method is based on the principle that antibiotic-impregnated disk, placed on agar previously inoculated with the test bacterium, and the antibiotic diffuses radially outward through the agar medium producing an antibiotic concentration gradient. A clear zone or ring is formed around an antibiotic disk after incubation if the agent inhibits bacterial growth.

The disk diffusion method is performed using Mueller-Hinton Agar (MHA), the best medium for routine susceptibility tests. It has good reproducibility, low sulfonamide, trimethoprim, and tetracycline inhibitors, and gives satisfactory growth of most bacterial pathogens.

How SIG can Help

SIG Laboratory can perform analysis on antimicrobial tests according to the disk diffusion method using Mueller-Hinton Agar (MHA).

Method of Analysis

Antimicrobial test in SIG Laboratorium using Disk-diffusion Method.

Several microorganisms can be tested:

• Bacillus cereus
• Bacillus subtilis
• Enterobacter aerogenes
• Enterococcus faecalis
• Enterococcus hirae
• Escherichia coli
• Lactobacillus sp
• Listeria monocytogenes
• Pseudomonas aeruginosa
• Salmonella sp
• Salmonella typhimurium
• Shigella sp
• Staphylococcus aureus
• Vibrio cholerae
• Klebsiella pneumonia
• Streptococcus pneumonia
• Aspergillus niger (Mold)
• Aspergillus brasiliensis (Mold)
• Candida albicans (Yeast)