||Neisseria gonorrhoeae (GC) Antibiotic Susceptibility Testing (AST) for Azithromycin, Ceftriaxone, and Cefixime
|bioMérieux Etest Gradient Strip (“GC Etest”)
|Pre-Approval for isolates meeting one of following is
N. gonorrhoeae isolates with decreased susceptibility to cefixime (MIC ≥0.25 µg/mL), ceftriaxone (MIC ≥0.125 µg/mL), or azithromycin (MIC >16.0 µg/mL).
- N. gonorrhoeae isolates from suspected treatment failures (Clinical Guidelines for Gonorrhea Treatment and Management of Suspected Treatment Failure PDF) and isolated from sites, including but not limited to urethra, endocervix/vagina, rectum, pharynx, blood, synovial fluid, and eye.
N. gonorrhoeae isolates from disseminated gonococcal infections (DGI).
N. gonorrhoeae isolates from ocular infections
Pre-approval for other
N. gonorrhoeae isolates is required.
Please contact STD program at firstname.lastname@example.org
|Supplemental Information and Required Form(s)
||Submitters can use one of the following methods to access the submittal form: MDL Lab Web Portal (LWP) (Preferred) or MDL barcode submittal form at
MDL Submission Instructions and Forms.
On the MDL General Submission form, select Form Antimicrobial Susceptibility Testing -AST: MDL General Electronic Submission Form (PDF)
The MDL General Electronic Submission Form should be downloaded and opened using a pdf viewer. To download, right-click the link and select "Save link as." If you are unable to open the Form using a pdf viewer, please contact MDL at 510-412-3700 or MDL.Submissions@CDPH.ca.gov.
Instructions on completing the form can be found at the following links:
MDL Form AST - Instructions
Gradient Strip (GC Etest) Neisseria gonorrhoeae Antimicrobial Susceptibility Testing Services Frequently Asked Questions (FAQ)
|Required Specimen/ Sample Type(s)
||Pure, fresh culture of N. gonorrhoeae submitted on chocolate or modified Thayer Martin media supporting growth of
|Minimum Volume Required
||Prepare culture for transportation: First, obtain fresh culture by growing a pure
N. gonorrhoeae isolate at 35°C in 5% CO2 on suitable media for gonorrhea (such as chocolate agar or modified Thayer-Martin) for 24-48 hours, until obtain visible growth. Then, prepare and submit the culture fresh (24-72 hr) at time of shipping. Three options are recommended.
Refer to ‘Specimen preparation for transport’ instructions in
Disseminated Gonococcal Infection (DGI) Guidance for Laboratories for details.
- To ship using an agar slant: Heavily inoculate a chocolate (or other suitable media for GC) slant with fresh growth. Incubate at 35°C with 5% CO2 until you see visible growth (18 – 24 hours is ideal). Then close cap tightly and ship at ambient temperature.
- To ship using an agar plate: Heavily inoculate a chocolate (or other suitable media for GC) plate with fresh growth. Incubate at 35°C with 5% CO2 until you see visible growth (18 – 24 hours is ideal). Then seal the plate lid tightly with parafilm and place the plate in zip lock biohazard bag and ship at ambient temperature.
- To ship using a frozen cryotube with TSB and 15% glycerol: Heavily inoculate a cryotube with fresh growth. Immediately place in a -60°C or lower freezer. Once the isolate is fully frozen, ship the isolate on dry ice.
- Isolate submissions with insufficient or conflicting labelling
- Broken or leaking samples
- Samples with insufficient quantities or growth
- Isolates that are too old or non-viable
- Specimen/sample types not meeting acceptance criteria (see FAQ), if no prior approval was received
- Mixed cultures
- Primary patient samples
||Culture isolates may be shipped at ambient temperature or frozen in TSB with 15% glycerol on dry ice.
||Two identifiers, including patient full name, and at least one other identifier (specimen accession number, date of birth, medical record number); date and time of collection as noted for specific tests, if applicable.
Shipping Instructions and Specimen Handling Requirements
||Ship isolates grown on media that supports
N. gonorrhoeae at ambient temperature or ship cultures frozen in TSB with 15% glycerol on dry ice.
Follow the appropriate DOT/IATA approved shipping procedures.
Ship to:California Department of Public Health
Microbial Diseases Laboratory
ATTN: Bacterial Diseases Section
850 Marina Bay Parkway, Specimen Receiving Room B106
Richmond, CA 94804
Specimen Collection Instructions, if applicable
||Only pure, live cultures of
N. gonorrhoeae are acceptable for testing at MDL. Primary clinical specimens for culture isolation are not accepted by MDL at this time. Primary clinical specimens from suspected treatment failures may be tested via the ARLN regional laboratory in Washington state. Contact
email@example.com or MDL.Submissions@CDPH.ca.gov for submission instructions.
||12 calendar days
Expedited testing may be available upon request.
Interferences & Limitations
||Pure culture isolates must be viable for testing.
||Gradient Strip (GC Etest) Neisseria gonorrhoeae Antimicrobial Susceptibility Testing Services Frequently Asked Questions (FAQ)
|MDL Point of Contact
||For more information on the GC Etest and submission criteria o instructions, please email MDL.Submissions@CDPH.ca.gov or call MDL Bacterial Diseases Section at (510) 412-3903