Antimicrobial Susceptibility Testing (AST)

Antimicrobial susceptibility testing of Neisseria gonorrhoeae, part of the Gonococcal Antimicrobial Surveillance Program (GASP) – Canada Antimicrobials on the testing panel include: azithromycin, cefixime, ceftriaxone, ciprofloxacin, penicillin,

Pure culture.

Specimens may be subject to rejection if they are not the appropriate sample type, have insufficient volume, are not accompanied by relevant patient information, or not on the correct requisition.

N/A

Pure Neisseria gonorrhoeae cultures can be transported in: i) Amies Clear Agar Gel Transport Swabs; ii) Chocolate Agar Slants that have been incubated at 35oC in a CO2 enriched atmosphere for 18-24 hours before transport; iii) BHI (Brain Heart Infusion) broth containing 20% glycerine, frozen at -80oC, shipped on dry ice.  Cultures MUST be shipped before the Wednesday of each week.

Shipping of specimens shall be done by a TDG certified individual in accordance with TDG regulations. For additional information regarding classification of specimens for the purposes of shipping, consult either Part 2 Appendix 3 of the TDG Regulations or section 3.6.2 of the IATA Dangerous Goods Regulations as applicable.

Infection with N. gonorrhoeae.

Completed Gonococcal Antimicrobial Surveillance Program (GASP) – Canada requisition form with sender lab name, address, telephone number and email address. All patient information must be filled out including specimen reference #, date of birth, sex, date collected, and isolation site. Test results to be included, if available, are antimicrobial susceptibility values and beta-lactamase results. Submit one GC culture per case unless related to a treatment failure investigation. Cultures are defined as being part of the same case if they are collected within four weeks of each other. If multiple isolates from the same case are available the hierarchy of isolation sites is used to determine which isolates are considered duplicates. The order of the hierarchy is 1) sterile site (DGI), 2) throat, 3) rectal and 4) urogenital. Urgent specimens or those requiring agar dilution testing must be noted as such on the requisition.

This test is done as part of the Gonococcal Antimicrobial Surveillance Program – Canada (GASP - Canada) testing algorithm. 

Prediction of antimicrobial susceptibilities using whole genome sequencing (primary) (1)

Antimicrobial susceptibility testing using agar dilution (secondary) (2). Controls used for agar dilution testing include ATCC49226, WHO F, WHO G, WHO K, and WHO U (3). For both test methods, CLSI breakpoints used for azithromycin, ciprofloxacin, penicillin, spectinomycin, and tetracycline (2). Breakpoints published by Tang et al. are used for cefixime, ceftriaxone (4)

180 calendar days

Outbreak associated or urgent isolates will be granted priority status and completed as soon as possible. Please contact Streptococcus and STI Section to notify of these requests.

**Turnaround times may not be guaranteed when isolates are submitted in large batches.

1. Demczuk W, Martin I, Sawatzky P, Allen V, Lefebvre B, Hoang L, Naidu P, Minion J, VanCaeseele P, Haldane D, Eyre DW, Mulvey MR. Equations to predict antmicrobial MICs in Neisseria gonorrhoeae using molecular antimicrobial resistance determinants. AAC 2020;64:e02005-19 https://doi.or/10.1128/AAC02005-19
2. CLSI. Performance Standards for Antimicrobial Susceptibility Testing. 29th ed. CLSI supplement M100. Wayne, PA: Clinical and Laboratory Standards Institute; 2019.
   
3. Unemo M, Golparian D, Sánchez-Busó L, Grad Y, Jacobsson S, Ohnishi M, Lahra MM, Limnios A, Sikora AE. Wi T, Harris SR. The novel 2016 WHO Neisseria gonorrhoeae reference strains for global quality assurance of laboratory investigations: phenoptyic, genetic and reference genome characterization. J Antimicrob Chemother 2016; 71(11):3096-3108.
   
4. Tang Y, Liu X, Chen W, Luo X, Zhuang P, Yang Y, Li R, Zheng H, Lin X, Antimicrobial Resistance Profiling and Genome Analysis of the penA-60.001 Neisseria gonorrhoeae Clinical Isoaltes in China in 2021. J Infect Dis. 2023 Sep 15;228(6):792-799