Bacterial Culture and Antimicrobial Sensitivity Testing

    -------------------------------------------------------



Because infectious diseases are the most common causes of illness

in caged and aviary birds, the microbiology laboratory plays a

vital diagnostic role for the avian veterinarian.  Samples

collected from the patient may yield pathogenic (disease-causing)

bacteria or fungi.  The major function of the microbiology

laboratory is to identify these microorganisms so that the

appropriate treatment can be initiated.



After one or more bacterial isolates from a specimen have been

identified, the next step is to conduct antimicrobial

sensitivity testing.  Drug-impregnated discs are placed in

contact with colonies of each previously identified microbial

isolate.  The effectiveness of each antimicrobial is determined

by measuring the zone around each disc in which the growth of the

organisms have been completely inhibited.  Generally speaking,

the larger the zone, the more effective the antimicrobial.  It

is from these effective anti-microbials, then, that the

veterinarian selects a drug with which to treat the patient.

This type of antimicrobial testing is not used with fungal

isolates.