VLD 421: Veterinary Clinical Biochemistry and Laboratory Diagnosis-II (0+1)

CONSTRAINT OF ABST

Limitations of the agar diffusion method (Bauer-Kirby Method)

• Not applicable to slow growing organisms.
• Not applicable to antibiotics that diffuse slowly in agar such as Polymyxin B.
• Not applicable to anaerobic organisms.

Errors in the result

• The possible errors in the result may be due to the following
  • Making mistakes while measuring the zone of inhibition
  • Improper sampling could lead to the growth contaminants in the culture than the actual pathogen.
  • Incorrect dose of inoculum.
  • Always check new batches of medium and antibiotics discs for their purity and potency.