Brucella species (B. abortus, B.melitensis, B. suis) – Confirmation

Consistent with O. Reg. 671/92 of the French Language Services Act, laboratory testing information on this page is only available in English because it is scientific or technical in nature and is for use only by qualified health care providers and not by members of the public.

Background
This page provides identification/confirmation testing information for Brucella species at Public Health Ontario (PHO). Bacteria of the genus Brucella are the causative agent of Brucellosis.

For information regarding other testing options, refer to the following PHO webpages:

Culture Identification of Aerobic Bacteria: Bacterial cultures – Aerobic – Reference ID/Confirmation
Antimicrobial Susceptibility Testing of Aerobic Bacteria: Antimicrobial Susceptibility Testing – Aerobic Bacteria

Updates

The turnaround time for Brucella confirmatory testing at National Microbiology Laboratory (NML) has been updated to align with their published turnaround time.
A table of possible results and corresponding interpretation has been added.

*Uncontrolled print copy. Valid only on day of print: 08 Oct 2025.

Testing Indications

Submitting laboratories must contact Public Health Ontario laboratory Customer Service Centre at 416-235-6556 or 1-877-604-4567 prior to submission of the isolate.

Indications for referral of Brucella isolates for confirmation include:

Inability to rule out Brucella species after performing Gram stain, oxidase, urease and observation of growth characteristics.^1,2
High index of clinical suspicion,^1,2, such as- history of exposure to livestock or unpasteurized dairy^1,2; symptoms consistent with brucellosis like undulating fever, night sweats, arthralgia, hepatosplenomegaly^1,2; travel to endemic area or occupational exposure like veterinarians or abattoir workers^1,2.

Acceptance/Rejection Criteria

Acceptable specimens include:

Pure cultures only: Mixed cultures or primary specimens are not accepted
Properly labeled cultures: The patient and specimen identification on the requisition form must match the label information on the culture container
Source of isolation indicated: The requisition must clearly state the specimen source from which the isolate was recovered e.g. blood, bone marrow, CSF, joint fluid, abscess material etc.

Rejected specimens include:

Swabs: Specimens received dry or gel-based swabs will be rejected.
Primary specimens: Direct human and animal samples will be rejected.
Missing source information: Cultures without a clearly indicated source of the isolate on the requisition will be rejected.
Mixed or non-viable cultures
Mis-labelled or un-labelled cultures

Specimen Collection and Handling

Specimen Requirements

Test Requested	Required Requisition(s)	Specimen Type	Minimum Volume	Collection Kit
Brucella species (Brucella abortus or Brucella melitensis or Brucella suis) - Confirmation	Reference Bacteriology Requisition	Pure viable subculture of organism on appropriate media that supports the growth	N/A	Agar plate or slant tube

Submission and Collection Notes

Complete all fields of the requisition form, including:

Test Requested : Select confirmation and identification
Culture information: Indicate the presumptive identification, Gram morphology, oxygen requirement for growth, oxidase test result, catalase test result, presence or absence of growth on MacConkey
Clinical diagnosis: Indicate if patient is immunocompromised
Epidemiology information
Contact information
Date of collection of the primary specimen from which the isolate was recovered
Source of isolate (Mandatory)
- The number of consecutive blood cultures positive for the submitted isolate when isolates are from blood cultures
- Type of urine specimen(s) (e.g. midstream, indwelling catheter, cystoscopy etc.)
- The site and type of wound swab; be as specific as possible (e.g. animal bite, surgical wound, decubitus ulcer, etc.
- If the source was collected for surveillance or screening, write the source or body part
- The type of specimen if other than blood culture, urine or wound swab, provide as much detail as possible

Label the culture container(s) with the patient’s first and last name, date of collection, and one other unique identifier such as the patient’s date of birth or Health Card Number. For additional information see: Criteria for Acceptance of Patient Specimens. Failure to provide this information may result in rejection or testing delay.

If the bacterial culture submitted for identification confirmation is provided on a broth media (instead of on a plate) the turnaround time will be delayed by at least 24 hours.

If susceptibility testing is required, the submitter must call within 5 days of receiving final results and provide necessary information and justification for susceptibility testing request.

Do not submit multiple isolates from the same specimen site of infection.

Primary specimens are unacceptable as they must be processed at the originating laboratory.

If full bacterial identification and susceptibility testing is clinically indicated-such as in cases involving immunocompromised patients, it must be clearly indicated on the requisition

Limitations

Culture must be viable. Use a fresh subculture and ship in conditions to ensure viability on receipt.

Storage and Transport

Place the sealed culture in a biohazard bag and properly seal. Store at 2-8°C while waiting for shipping. The requisition form must be placed in the outer pouch of the biohazard bag, separate from the culture container. Transport a fresh subculture to ensure viability on receipt. It should be shipped to PHO’s laboratory within 48 hours of isolation. All cultures must be shipped in accordance to the Transportation of Dangerous Good Act.

Special Instructions

Brucella species must be handled in accordance with the Canadian Biosafety Standards and shipped in accordance with the Transportation of Dangerous Goods Regulations. Refer to the Pathogen Safety Data Sheets (PSDS) for Brucella species (B. abortus, B.canis, B.melitensis, B.suis).³

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Testing is performed daily (Monday to Friday) as received at Public Health Ontario’s laboratory-Toronto site. Turnaround time for test results is up to 3 calendar days from receiving.

Isolates that are Brucella-positive at PHOare forwarded to the National Microbiology Laboratory (NML) for confirmatory testing. Turnaround time for test results from NML is from 4 to 14 calendar days.

STAT and Critical Samples Testing

Urgent testing is available upon request by calling the Customer Service Centre 416-235-6556 or 1-877-604-4567.

Test Methods

Brucella species identification is performed using the Canadian Laboratory Response Network (CLRN) real-time-PCR (Polymerase Chain Reaction) assay at Public Health Ontario.

Algorithm

Any isolate that is positive by the CLRN real-time PCR assay is considered as presumptive Brucella species and is forwarded to the National Microbiology Laboratory (NML) for confirmatory testing.

Interpretation

Result	Interpretation
Not Detected	Brucella spp. DNA NOT detected by real-time PCR
Presumptive Detected	Presumptive Brucella spp. DNA DETECTED by Real-time PCR.
Inconclusive	Brucella spp. real-time PCR result is inconclusive due to specimen quality. Please collect additional specimens for retesting.
Invalid	Brucella spp. real-time PCR result is invalid. Sample is unsuitable for PCR testing.

Reporting

Results are reported to the physician, authorized health care provider (General O. Reg 45/22, s.18) or submitter as indicated on the requisition.

Positive specimens are reported to the Medical Officer of Health as per the Ontario Health Protection and Promotion Act.

References

American Society of Microbiology. Guideline- Brucellosis-causing Brucella species (BBS). August 2025. Available from: https://asm.org/guideline/brucellosis-causing-brucella-species-bbs-sentinel [Accessed 15 September 2025]
Ministry of Health. Ontario Public Health Standards: Requirements for Programs, Services and Accountability. Infectious Disease Protocol- Appendix 1: Case Definitions and Disease Specific Information-Brucellosis. May 2023. Available from: https://www.ontario.ca/page/ontario-public-health-standards-requirements-programs-services-and-accountability [Accessed 15 September 2025]
Public Health Agency of Canada. Pathogen Safety Data Sheets-Brucella species. Available from: https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment.html [Accessed 15 September 2025]