Antimicrobial Susceptibility Testing On Aerobic Actinomycetes

Antimicrobial Susceptibility Testing (AST) is done by the broth microdilution method as described by the Clinical and Laboratory Standards Institute (CLSI) guidelines. AST will be performed on the following organisms if clinically relevant:

Actinomadura spp.

Gordonia spp.

Nocardia spp.

Nocardiopsis spp.

Rhodococcus spp.

Streptomyces spp.

Tsukamurella spp.

• Various

Pure cultures of isolates recovered from normally sterile sites and serious wound infections.

N/A

Store samples at room temperature until shipped for testing.  Ship at room temperature. Ship before Wednesday to ensure receipt by Friday.

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.

Clinical illness with aerobic actinomycetes isolated from sterile sites such as blood, other sterile body fluids or tissue, skin and soft-tissue infections. For respiratory isolates (other than Nocardia spp.) CLSI recommends “at least two positive sputum samples or one transbronchial or lung biopsy, one bronchial wash, or lavage sample” before submitting for AST.

Notification of sample submission must be emailed or faxed prior to shipping isolates. Samples should be shipped attention: Melissa Rabb, Head, Reference and Diagnostic Services, NRCM/NML at 204-789-6081/204-789-6038.  A requisition must be completed and signed off by the supervisor/designate of the submitting laboratory.  The requisition must include the source of specimen, patient gender, date of birth, clinical history, submitting laboratory identifier and submitter information.  Please also include isolate characteristics:  microscopy, pigmentation, culture characteristics, growth rate/temperature, and identification. 

Cultures will be rejected if appropriate documentation and justification is incomplete or missing, or if an inappropriate culture is submitted (see “Specimen”). All patient and strain history must be included. Please note that multiple samples isolated from the same source and patient, and identified as the same organism by the sender, will need an explanation in order for testing to be done on all the samples. Acceptance and/or rejection of the additional samples is at the discretion of the NRCM. Contact the lab for further information.

Broth microdilution using commercially-available Sensititre® NOCARDIA panels.  Interpretations are based on the most recent CLSI guidelines. 

16 calendar days.  In cases where staff or resources are limited final report may be delayed. Poor- or slow-growing isolates may require longer turn around times.

1. Clinical and Laboratory Standards Institute. 2019. Performance Standards for Antimicrobial Susceptibility Testing; M100-Ed29. Clinical and Laboratory Standards Institute, Wayne, Pennsylvania.
2. Clinical and Laboratory Standards Institute. 2018. Susceptibility Testing of Mycobacteria, Nocardia spp., and Other Aerobic Actinomycetes; Approved Standard-Third Edition. M24-Ed3. Clinical and Laboratory Standards Institute, Wayne, Pennsylvania.
3. Clinical and Laboratory Standards Institute. 2018. Performance Standards for Susceptibility Testing of Mycobacteria, Nocardia spp., and Other Aerobic Actinomycetes; First Edition. M62-Ed1. Clinical and Laboratory Standrads Institute, Wayne, Pennsylvania.

Pathogen Safety Data Sheets: Infectious Substances – Nocardia spp.