Neisseria gonorrhoeae is fastidious and fragile, so careful consideration must be given to proper methods for collection and transport of specimens for testing. An atmosphere of 3-10% CO2 is required for incubation and transport. An enriched, selective media is essential for reliable isolation of gonococci which generally needs to be isolated from a variety of microbial flora including saprophytic Neisseria species. Gonorrhea culture is usually only requested for cases of treatment failure or antimicrobial resistance testing.
SAMPLE COLLECTION, HANDLING AND SHIPMENT
- All specimens should be obtained using the Modified Thayer Martin (MTM) plates and candle cans supplied by the laboratory. (If the sample will be transported to the laboratory within 24 hours it can be collected using a culturette and sent directly to the lab for culturing)
Supplies can be obtained by contacting the laboratory , faxing orders or emailing Labsupplies@delaware.gov.
- Collect specimen and prepare Smear and Culture plate according to directions listed below.
- Arrange transport of candle jar to Laboratory using the Lab Courier, preferably the same day of collection.
- For sites without incubators, after culture plates are inoculated the closed candle cans may sit at room temperature until courier pickup the SAME DAY.
- For sites with properly maintained incubators, the candle cans may incubate up to 4 days prior to courier pickup.
- Complete the Test Requisition Form including patient information or order request on-line
through our Laboratory information management system (LIMS). Specimen and forms should be placed in a designated location at each site for the lab courier to pickup.
- ENDOCERVICAL: preferred site for specimens from females.
- Specimen collection should be done with a sterile swab or culturette. Cytobrush is not recommended as it may cause trauma and bleeding that can render the specimen unsatisfactory.
- Rotate swab against the wall of the endocervical canal several times for 20-30 seconds and withdraw without touching the vaginal surface. Inoculate MTM plate as described below.
- The order of testing for specimen collection should be GC culture/gram stain, Pap smear, then Chlamydia/GC NAAT test. Since the visible presence of blood may interfere with test results, it is advisable to collect the Pap smear last when using the cytobrush because of induced bleeding that might occur.
- Speculum should be lubricated with water only.
- URETHRAL: preferred site in men, or in women with no cervix (e.g. post-hysterectomy).
- Delay obtaining specimens until 2 hours after patient has last voided.
- Obtain specimens for gram stain and gonorrhea culture first, BEFORE specimens for Chlamydia or Pap smear.
- Gently insert the urogenital swab into the urethra (women 1-2 cm, men 2-4 cm). Rotate the swab in one direction for at least one revolution for a minimum of 10 seconds. Withdraw the swab and inoculate MTM plate as described below.
- OROPHARYNX (THROAT):
- Swab the back of throat and tonsillar area with a sterile swab.
- Insert sterile swab approximately 1-1.5 inches in the anal canal. Move swab from side to side in the anal canal to sample crypts.
- Allow swab to remain 10-30 seconds for absorption of organisms onto the swab.
INOCULATION OF CULTURE PLATE (MTM)
- Roll swab directly on MTM medium in a large "Z" pattern to provide adequate transfer of organisms.
- Label culture plate with patient name/barcode and collection date on media side of plate, not the lid which may be separated from the specimen itself.
- Place culture in a candle can as soon as possible (within 15 minutes). Be sure to relight the candle each time the can is opened. Place can in 35-37℃ incubator if available. If incubator is not available, plates may stay at room temperature only if transport is to occur the same day.
Gonorrhea cultures are incubated for a minimum of 48-72 hours. Growth on MTM is screened for presumptive positives by oxidase test and gram stain. Positive cultures are confirmed by biochemical identification.
The turnaround time for negative culture results is 72 hours.
Positive results are available on day of detection, generally 24-48 hours from the receipt of culture.
Samples will be rejected if they are:
- Unlabeled - All specimens must have a unique patient identifier.
- Insufficient in Quantity - No specimen received, no specimen on plate or insufficient specimen to perform testing.
- Improperly Preserved - Specimens must be received on MTM culture plates.
- Damaged - Specimen broken or damaged in transit.
- Too Old - Plates not incubated 35-37℃ and received <24 hours after collection will be rejected. Incubated plates <4 days old may be unable to confirm.
- Overgrown with contaminating organism - Plates so overgrown yeast, Proteus or other contaminating organism will be unable to determine presence or absence of N. gonorrhoeae.
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