Bacterial cultures – Anaerobic – Reference Identification/Confirmation

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Specimen Collection and Handling

Specimen Requirements

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

Bacterial Cultures – Anaerobic – Reference ID

Pure viable subculture of 24 – 48 hours growth of organism on  appropriate pre-reduced medium submitted in an anaerobic transport kit or anaerobic swab2,3


Submission and Collection Notes


Complete all fields of the Reference Bacteriology Requisition, including: 

  • Test(s) requested
  • Date of primary specimen collection
  • Primary source of isolation (mandatory)
  • Antibiotic treatment
  • Gram stain description, aerotolerance test results and catalase reaction
  • Presumptive identification
  • If isolate is part of a polymicrobic infection
  • The number of consecutive blood cultures positive for the submitted isolate when isolates are from blood cultures

 If a swab or broth is received, the TAT 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 non-viable cultures will not be tested. The submitter will be contacted by telephone. A written report will be issued to indicate that the test has been rejected.
  • Mis-labelled or un-labelled specimens will not be tested. A report will be sent stating "Specimen received un-labelled" or "Requisition identification does not match the specimen identification information. Please resubmit".
  • The submitting laboratory will be contacted regarding isolates or specimens from critical sites (e.g. brain abscess) that are submitted inappropriately (e.g. improper transport conditions or mis-labelled/un-labelled).
  • Do not submit multiple isolates from the same specimen/site of infection - for polymicrobic infections, only submit the two most predominant isolates. Laboratories should perform preliminary identification tests including catalase (15% hydrogen peroxide) and Gram stain.  Note growth characteristics on all isolates on the Reference Bacteriology Requisition.

Storage and Transport

Label the specimen with the patient’s full name, date of 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, primary source of isolation (mandatory), date of primary specimen collection, submitting laboratory name and address and clinical diagnosis.

Place specimen in biohazard bag and seal. Specimen should be transferred at room temperature to the laboratory within 48 hours of collection in anaerobic conditions


Special Instructions

Transport a fresh subculture in anaerobic conditions to ensure viability on receipt.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Anaerobic bacteria cultures are tested Monday to Friday.

Turnaround time for test results is 6 to 8 days from date of receipt at the PHO laboratory.

Test Methods

All anaerobe isolates are identified/confirmed by MALDI –TOF and/or 16S rRNA Gene Sequencing.

Lactobacillus spp.: 

  • Species level identification and / or susceptibility Lactobacillus spp. from urine cultures will not be processed.
  • Speciation and/or susceptibility testing will be attempted for Lactobacillus spp. isolated from systemic infections only (e.g. blood, pleural fluid etc).

Cutibacterium acnes (formerly Propionibacterium acnes)

  • Pleomorphic Gram positive bacilli that are catalase-positive and spot indole-positive are reported as P. acnes. These do not require further testing at PHO laboratory.
  • Indole or catalase negative strains may be forwarded to the PHO laboratory for confirmation. 

Susceptibility Testing:

  • Susceptibility testing will only be performed on isolates from sterile sites (excluding urines).
  • For treatment failure cases, please include the clinical information and antimicrobial therapy. 
  • Requests for susceptibility testing may require consultation with the Medical Microbiologist.


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

Mis à jour le 25 sept. 2019