Antimicrobial susceptibility testing – Aerobic bacteria

Specimen Collection and Handling

Specimen Requirements

Test Requested Required Requisition(s) Specimen Type Minimum Volume Collection Kit

Antimicrobial susceptibility testing – Aerobes

Pure viable subculture of 24 – 48 hours growth of organism on an appropriate medium (e.g. Columbia sheep blood agar) or a swab of a pure culture in Amies charcoal media for susceptibility testing2,3


Submission and Collection Notes


Complete all fields of the Reference Bacteriology Requisition, including:

  • Test requested
  • Date of primary specimen collection
  • Primary source of isolation (mandatory)
  • Culture information
  • Clinical/epidemiology
  • Contact information

If a swab or broth is received, the turnaround time will be delayed by at least 24 hours.


Primary cultures are unacceptable; they should be processed in the originating lab and will be rejected.


Mixed or nonviable cultures will not be tested. The submitter will be contacted by telephone. A written report will be issued to indicate the test has been rejected.

Preparation Prior to Transport

Label the specimen with the patient’s full name, date of primary specimen collection and one other unique identifier such as the patient’s date of birth or Health Card Number. Failure to provide this information may result in rejection or testing delay.

Complete all fields of the Reference Bacteriology Requisition. Include the patient’s full name, date of birth, Health Card Number (must match the specimen label). Enter the test requested, culture information, clinical/epidemiology information, date of primary specimen collection, primary source of isolation (mandatory), submitting laboratory name and address, and clinical diagnosis.

Place in biohazard bag and seal.

Special Instructions

Transport a fresh subculture to ensure viability on receipt. 

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Antimicrobial Susceptibility testing is performed from Monday to Saturday.

Turnaround time for test results is up to 8 days from date of receipt at the PHO laboratory.


Results are reported to the ordering physician or health care provider as indicated on the requisition.

Test Methods

Antimicrobial Susceptibility testing on a bacterial isolate is performed as per current CLSI guidelines.

Testing methods in use are:

  • Agar dilution
  • Micro-broth dilution (Sensititre)
  • E-test
Mis à jour le 25 sept. 2019