Microbiology - Special Bacteriology
The Special Bacteriology unit serves primarily as a referral laboratory for bacteria that are unusual or difficult to identify. In this context, "Special Bacteriology" refers to the examination of a wide variety of microorganisms including the following: Bordetella pertussis, Brucella, Corynebacterium diphtheriae, Haemophilus, Legionella, Neisseria, Pasteurella, Pseudomonas and similar organisms and "unclassified" bacteria. Certain clinical specimens are accepted for primary isolation; otherwise, pure isolates are required for identification or serotyping. Specimens are accepted from public and private health care providers. Cultures from animal or environmental sources must be associated with human illness. Anaerobic cultures and antimicrobial susceptibility testing are not performed in this laboratory. Consultation and bench training are provided upon request.
Services available in the Special Bacteriology unit include:
- confirmation and serotyping of Neisseria meningitidis and Haemophilus influenzae
- confirmation of Neisseria gonorrhoeae
- culture and DFA staining for Bordetella pertussis and B. parapertussis
- culture and DFA staining for Legionella
- identification of nonfermentative gram-negative bacilli
- identification of gram-negative fermentative bacilli not included in the family Enterobacteriaceae
- identification of gram-positive Bacillus sp. and coryneform rods
- grouping of beta hemolytic streptococci and identification of clinically significant isolates of other gram-positive cocci and coccobacilli
- identification or referral of cultures which are unidentifiable at the local level due to special growth requirements, atypical test results or the hazardous nature of the suspected organism (ex.:Brucella)
- pulsed-field gel electrophoresis (PFGE) for epidemiological information on Salmonella, E. coli O157:H7, Shigella, Listeria monocytogenes, and Staph aureus
Please Note: The North Carolina Communicable Disease Control rules (10A NCAC 41A.0209) state that laboratories isolating Neisseria meningitidis and Haemophilus influenzae from a normally sterile site, shall test the organism for specific serogroup or send the isolate to the State Public Health Laboratory for serogrouping.
Services available through the CDC by referral from the SLPH include:
- Identification of Legionella isolates
- Identification of Francisella tularensis, Bacillus anthracis and Brucella sp. Some isolates may be referred to the CDC
- Specialized serotyping and strain characterization of meningococci from outbreaks
- Serotyping of Streptococcus pneumoniae (Pneumococcus) cultures from patients who have received pneumococcal vaccine or isolates from documented outbreaks
- Antimicrobial susceptibility testing of Pneumococci found to be penicillin-resistant by oxacillin disk screening
NOTE: All specimens forwarded to the CDC must be accompanied by a clinical history documenting the need for testing.
Specimen Collection
Specimens should be collected aseptically and cultured at the local laboratory. To assure purity, isolates should be subcultured onto appropriate media before referral to the SLPH. Each specimen should be clearly labeled with the patient´s name and accompanied by a completed Special Bacteriology requisition DHHS form #T806. Use separate forms for individual specimens. Unlabeled specimens will not be tested. Place forms in the outer container to avoid contamination in case of specimen leakage.
Specimens received without submitter return address are subject to rejection!
NOTE: CLIA regulations require the following information on all test requisitions:
- patient name or identifier
- name and address of submitting agency
- test requested
- date specimen collected
On the form indicate presumptive identification or preliminary test results and patient clinical information.
Telephone the Microbiology Branch at (919) 733-7367 to make special arrangements in urgent or unusual circumstances. Telephone before submitting large numbers of isolates or highly infectious organisms.
Specimen Shipping
Isolated organisms other than those requiring special handling preferably should be submitted on carbohydrate-free agar slants such as infusion, nutrient, trypticase soy, blood or chocolate. Broth or plate cultures should be taped, cushioned with absorbent material and securely packaged in leak-proof, crush-proof containers. Use the Microbiology Reference Mailer for agar slant cultures. Use double-walled or equivalent containers; ordinarily cultures do not require refrigeration in transit. When submitting large numbers of isolates, tubes may be wrapped individually in absorbent cushioning material and packaged together, securing against breakage.
Plainly label "Special Bacteriology" on the outside of all mailers. Ship specimens as soon as possible after collection. When shipping by U.S. Mail, use first-class postage. Be sure to place return address on outside of container, regardless of shipping method.
Reporting Procedure and Interpretation
Most culture identifications are reported within five to seven work days; mixed cultures or fastidious bacteria may require longer for identification. Final reports on isolates referred to the CDC may be delayed up to several months. Results of certain biochemical, microscopic and serological tests performed in this laboratory are returned with culture reports upon request.
Organisms are identified to a genus and species level only when cultural, morphological and biochemical test results indicate a good species correlation. Genus and species names are consistent with those designated in the Manual of Clinical Microbiology or the International Code of Nomenclature of Bacteria. Some organisms can be identified accurately only to the genus level. Organisms normally encountered as contaminants or those lacking clinical significance also may be reported only to the genus level. Test reactions of atypical organisms may fail to correlate with those of known cultures. Reports reflect any similarity to characterized bacterial strains.
Organisms reported as "unidentified" do not correspond to recognized genera and/or species. These cultures are not routinely forwarded to the CDC unless 1) the nature of the isolate, source and/or patient clinical history warrant further study, or 2) a special request is made for referral. The submitting laboratory may need to clear this request with CDC staff prior to forwarding the isolate to the SLPH for referral to the CDC.
Reports are returned only to the submitting agency; the submitter is responsible for sending copies to any other agency. Copies of reports are maintained in this Laboratory. The submitting agency is responsible for maintaining reports in the patient´s file. Reports of Haemophilus influenza and Neisseria meningitis from cases of invasive disease are forwarded to the Women’s and Children’s Health and Epidemiology and Communicable Disease Sections, respectively.
See also:
- About Microbiology
- Botulism
- Bordetella Pertussis
- Enteric Bacteriology
- Foodborne Illness
- Cholera
- Legionella
- Mycobacteriology
- Mycology
- Neisseria Gonorrhoeae
- Parasitology
- Special Bacteriology
