Campylobacterales – Isolate Identification, Susceptibility, and Typing

Conformément au Règlement de l’Ontario 671/92 de la Loi sur les services en français, les renseignements d’analyses de laboratoire liés à la présente page ne sont offerts qu’en anglais parce qu’ils sont de nature scientifique ou technique et destinés uniquement à l’usage des fournisseurs de soins de santé qualifiés et non aux membres du public.

Background
This page provides identification, susceptibility, and typing information from Campylobacterales cultured isolates at Public Health Ontario (PHO) submitted by medical microbiology laboratories. The order Campylobacterales includes traditionally glucose non-fermenting, facultatively microaerobic helical Gram-negative bacilli (e.g. Campylobacteraceae, Arcobacteraceae, Helicobacteraceae, Sulfurospirillaceae, Sulfurimonadaceae, and Hydrogenimonadaceae)

For primary testing of Campylobacterales from fecal specimens, refer to the following PHO webpage: Enteric Bacteria (including Salmonella, Shigella, STEC, Plesiomonas, Yersinia, Aeromonas, Vibrio, or Campylobacter) – Culture and PCR

Updates

As of March 26, 2025, the previous page called “Enteric – Bacteria – Confirmatory Testing” has been separated into the orders Enterobacterales, Aeromonadales, Vibrionales, and Campylobacterales (this page). This page was also updated to include specific information on organisms tested, routine submission of isolates for surveillance, requisition requirements, requests for additional susceptibility testing, turnaround time for subtyping, methods used, and interpretations including inducible resistance.

* Copie d'impression non contrôlée. Valide uniquement le jour de l'impression : 24 mai 2025.

Testing Indications

Medical microbiology laboratories unable to confirm identification of Campylobacterales isolates locally may submit their isolate to PHO for further identification. Laboratories may also submit isolates for susceptibility testing if clinically needed, and may submit isolates for cluster subtyping if needed for outbreak investigations.

Acceptance/Rejection Criteria

Primary specimens, mixed cultures, non-viable cultures, cultures in inappropriate medium, mislabelled cultures, unlabelled cultures, and requisitions with missing information (e.g. primary source of isolation) will be rejected if received.

Specimen Collection and Handling

Specimen Requirements

Test Requested

Required Requisition(s)

Specimen Type

Minimum Volume

Collection Kit

Identification, confirmation, susceptibility, and/or typing
(specify organism)

Reference Bacteriology Requisition

Pure viable cultured isolate of organism

N/A

Solid agar medium (any non-selective solid agar that supports organism growth)

Semi-solid Amies charcoal transport medium swab

Submission and Collection Notes

Only medical microbiology laboratories can submit a cultured isolate for testing.

Complete all fields of the requisition form.

Clearly identify on the requisition the organism submitted, including the level of identification so far obtained and biochemical characteristics assessed.

Submit only one cultured isolate from the same primary specimen source of isolation per patient. If the organism was isolated from multiple specimen sources, the order of preference of specimen source is sterile site, otherwise non-sterile site.

Turnaround time will be delayed if an isolate swab is received due to the need for plating.

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. Failure to provide this information may result in rejection or testing delay.

If the patient is part of a cluster/outbreak investigation, contact PHO Laboratory Customer Service at 416-235-6556/1-877-604-4567 prior to sample submission.

Storage and Transport

Place the sealed culture in a biohazard bag and properly seal bag. Cultured isolates must be stored at 2-8°C if they cannot be shipped to PHO on the same day that the incubation is completed. Refrigerated (2-8°C) cultured isolates must be shipped to PHO on ice packs within 2 days. All cultured isolates must be shipped in accordance to the Transportation of Dangerous Good Act.

Special Instructions

If susceptibility testing is requested, clearly indicate which antibiotic(s) are of interest.

To request additional antimicrobial agents for susceptibility testing after susceptibility testing was already finalized by PHO:

Determine if and when the susceptibility testing report was finalized at PHO (“Final” written on the report). Additional susceptibility requests on previously tested isolates are only accepted if the request is received within 5 days of the final report.
Fill out a new requisition form and indicate in the “Submitter lab no.” field the lab number provided by PHO instead. Under Test(s) Requested section, select “antimicrobial susceptibility” and in “other – (specify)”, write “Additional AST for [name of drug(s)]”.
Call PHO Laboratory Customer Service at 416-235-6556/1-877-604-4567 and ask for the appropriate number to fax the completed requisition with the indicated additional susceptibility agents requested.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Campylobacterales cultured isolates are processed for identification and/or susceptibility testing daily on weekdays (Monday to Friday) at PHO’s laboratory, Toronto location. If requested, turnaround time for genus or species identification results is up to 4 days from receipt date, and turnaround time for susceptibility results is up to 8 days from receipt date.

Cluster subtyping for Campylobacter outbreak detection is performed as needed at the National Microbiology Laboratory (NML) in Winnipeg. Turnaround time for cluster subtyping is up to 15 days for outbreak isolates and 21 days for routine isolates from receipt date at PHO. Note: unless requested, cluster subtyping results are not provided to submitters and only used for internal surveillance purposes.

STAT and Critical Specimens Testing

Priority testing for cluster/outbreak investigations is available upon request. If needed, contact PHO Laboratory Customer Service as 416-235-6556/1-877-604-4567 prior to sample submission.

Test Methods

Campylobacterales identification of cultured isolates is based on colony morphology, Gram stain morphology, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS, Bruker RUO systems), catalase test, oxidase test, hippurate test, indoxyl acetate test, nalidixic acid test, and cephalotin test. Results may be further investigated with a range of biochemical reactions and/or 16S targeted Sanger sequencing where applicable.

Susceptibility testing for Campylobacter jejuni/C. coli is performed by minimal inhibitory concentration (MIC) measurement following the Clinical and Laboratory Standards Institute (CLSI) M45.¹

Campylobacter cluster subtyping for outbreak detection is performed by whole genome sequencing (WGS) following PulseNet Canada protocols, comparing national databases to identify closest isolate matches by whole genome multilocus sequence typing (wgMLST) and/or single nucleotide variant (SNV) typing.²

Algorithm

If identification or confirmation is requested: Cultured isolates are identified at PHO using the identification methods described above.

If susceptibility testing is requested: When the identification provided on the requisition is sufficient to conduct testing, cultured isolates are tested for susceptibility without confirmation of identification. If the identification provided is insufficient, the submitted isolate is first identified at PHO using the identification methods described above. Unless specific agents are requested, antimicrobial agents routinely tested for Campylobacter jejuni/coli include ciprofloxacin and erythromycin by broth microdilution. Additional testing may be offered for select agents if requested. For other Campylobacterales organism, an MIC value may be provided upon request however no CLSI clinical breakpoints are currently established.

Interpretation

If identification, confirmation, or typing is requested: Identification will be confirmed to the species level if feasible, otherwise the taxonomic classification most closely aligned to the organism will be reported.

If susceptibility testing is performed: Results will be provided for each antimicrobial agent tested as either “susceptible”, “susceptible dose-dependent”, “intermediate”, or “resistant” according to the applicable CLSI clinical breakpoint for systemic therapy use. MIC values may be provided upon request or if there are no applicable CLSI clinical breakpoints. If the identification provided on the requisition was sufficient, the following will be stated: “Antimicrobial susceptibility testing results and interpretations are based on the submitter’s identification. Identification was not requested and was not performed at PHO.”

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.

Isolates confirmed as Campylobacter are reported to the local Medical Officer of Health as per the Ontario Health Protection and Promotion Act.

At this time, routine results of Campylobacter cluster subtyping are not reported to the submitter and are only used internally by PHO and Public Health Agency of Canada (PHAC) epidemiologists through PulseNet Canada for surveillance purposes. When isolates are identified as potentially related by subtyping, PHO collaborates with local health units and, where applicable, the Outbreak Investigation Coordination Committee (OICC) partners to corroborate epidemiological evidence to the subtyping results.

References

Clinical and Laboratory Standards Institute. M45 Methods for Antimicrobial Dilution and Disk Susceptibility Testing of Infrequently Isolated or Fastidious Bacteria. Wayne, PA.
Public Health Agency of Canada. PulseNet Canada. 2022 Jun. Available online at: https://www.canada.ca/en/public-health/programs/pulsenet-canada.html