Neisseria meningitidis – Identification, Confirmation and Serogrouping
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 testing information on the Identification, confirmation of identification and serogrouping of Neisseria meningitidis isolate from all body sites. N. meningitidis is the causative agent of invasive meningococcal disease (IMD).
For information on PCR testing of blood or CSF for Neisseria meningitidis refer to: Neisseria meningitidis – Real-time PCR
Updates
- Updated turnaround time for serogrouping
Testing Indications
Submit purified isolate of query Neisseria meningitidis for identification or confirmation of identification.Serogrouping is performed only on isolates confirmed to be Neisseria meningitidis from sterile body sites.
Acceptance/Rejection Criteria
- Primary specimens submitted will be rejected. Only purified cultures are acceptable for testing.
- Mixed or non-viable cultures will not be tested.
- Mislabelled or unlabelled cultures will not be tested.
- The submitting laboratory will be contacted regarding isolates from critical sites (e.g. CSF) that are submitted inappropriately (e.g. improper transport conditions or mis-labelled/un-labelled).
Specimen Requirements
| Test Requested | Required Requisition(s) | Specimen Type | Minimum Volume | Collection Kit |
| Neisseria meningitidis – identification, confirmation and serogrouping | Pure viable subculture of organism on fresh blood agar plate | N/A |
Appropriate media that supports the growth of Neisseria meningitidis | |
| Neisseria meningitidis – identification, confirmation and serogrouping | Swab of the pure subculture in Amies transport medium for identification/ serogrouping. | N/A |
Appropriate swab / transport medium for Neisseria meningitidis |
Submission and Collection Notes
Complete all fields of the requisition form, including:
- Test(s) requested (including confirmation and identification)
- Specimen source and date of collection of primary specimen
- Culture information (presumptive identification, gram morphology)
- Clinical diagnosis / epidemiologic information
- Person to contact at submitting laboratory
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 a swab is received, the turnaround time will be delayed by 24 hours to allow for sub-culture.
Storage and Transport
Place the sealed culture in a biohazard bag and seal. Cultures should be stored at room temperature following collection and shipped to PHO’s laboratory within 48 hours of collection. All clinical specimens must be shipped in accordance to the Transportation of Dangerous Good Act.
Test Frequency and Turnaround Time (TAT)
Neisseria meningitidis- identification, confirmation and serogrouping is performed daily (Monday – Saturday) at PHO’s laboratory in Toronto.
Turnaround time is up to 4 business days for identification/confirmation after receipt by PHO’s laboratory. Serogrouping could be available within 72 hours of receipt of the isolate in the laboratory.
Isolates from sterile sites are sent to the National Microbiology Laboratory (NML) for additional testing including serotyping, serosubtyping and Multi-Locus Sequence Typing (MLST); turnaround time is up to 28 days.
Identification of an isolate as Neisseria meningitidis is based on the following combination of methods:
- Gram stain morphologic examination and
- Matrix- Assisted Laser-Desorption Ionization –Time of Flight Mass Spectrometry (MALDI-TOF MS), and
- Biochemical testing
Serogrouping is performed with antisera specific to each of the known capsular polysaccharide of Neisseria meningitidis designated as A, B, C, W, X, and Y
For Neisseria meningitidis isolates where the serogroup cannot be identified due to “autoagglutination” (i.e. agglutination with all 6 antisera) and “poly-agglutination” (i.e. agglutination with more than 1 of the specific antisera),or if the identification with MALDI-ToF MS and Biochemicals is in question, the isolate will then be tested using real-time polymerase chain reaction (PCR) to detect the Neisseria meningitidis-specific gene ctrA as well as the capsular biosynthesis genes (genes for serogroups A, B, C, W , X and Y). Isolates from sterile sites that remain questionable are forwarded to the Public Health Agency of Canada (PHAC) National Microbiology Laboratory (NML) in Winnipeg for additional testing.
Isolates confirmed as Neisseria meningitidis from sterile sites are forwarded to the PHAC-NML in Winnipeg for additional typing which may include serotyping & serosubtyping and possible other methods for further characterization.
Interpretation
For the identification of the isolate:
If : |
Then: |
Results of gram stain, MALDI-TOF MS and biochemical testing are definitive for Neisseria meningitidis |
Final report is : “ Isolate identified as Neisseria meningitidis” |
Isolates confirmed as Neisseria meningitidis undergo serogrouping |
Final report is: “Serogroup A or B or C or W or X or Y” |
Results of gram stain, MALDI-TOF MS and biochemical testing are not consistent with Neisseria meningitidis |
Isolate identified as: Genus species |
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.
Specimens that are positive for Neisseria meningitidis from sterile sites (representing Invasive Meningococcal Disease – IMD)) are reported to the Medical Officer of Health as per Health Protection and Promotion Act.
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