Antimicrobial Susceptibility Testing

Antimicrobial Susceptibility Testing (AST) on Group B Streptococcus.

Pure culture isolated from a normally sterile site.

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

Isolate provided on culture medium.

Send as growth on culture medium (preferred) or on a swab in transport medium.  Chocolate or charcoal media are recommended.  Cultures can be also shipped frozen on dry ice. 

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.

Invasive disease due to Group B Streptococcus.

Completed Isolate Submission Requisition for Streptococcus form including sender lab name, address, telephone number and email address. Patient age or date of birth, sex, culture reference number, clinical source, date collected and test requested. Outbreak or specimens requiring expedited testing or phylogenetic analysis must be indicated as such on the requisition. The above information must be sent as a hardcopy with the shipment, and an excel file may be sent to nml.strepsti-lnm.strepits@phac-aspc.gc.ca.

**Duplicate samples should not be submitted without prior consent as they may not be processed. Isolates collected from the same patient within 3 weeks are considered duplicates.

*Prediction of antimicrobial susceptibility using whole genome sequencing (primary) (2)

*Antimicrobial susceptibility testing using Sensititre® plates (secondary) (1)

30 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. CLSI. Performance Standards for Antimicrobial Susceptibility Testing. 31th ed. CLSI supplement M100. Wayne, PA: Clinical and Laboratory Standards Institute; 2021.
2. Demczuk W, Martin I, Griffith A, Lefebvre B, McGeer A, Tyrrell GJ, Zhanel GG, Kus JV, Hoang L, Minion J, Van Caeseele P, Raafat Gad R, Haldane D, Zahariadis G, Mead K, Steven L, Strudwick L, Mulvey MR. Linear regression equations to predict β-lactam, macrolide, lincosamide and fluoroquinolone minimum inhibitory concentrations from molecular antimicrobial resistance determinants in Streptococcus pneumoniae. 2022;66(1):e0137021. doi: 10.1128/AAC.01370-21.