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Test ID: MMLRG Antimicrobial Susceptibility, Acid-Fast Bacilli, Rapidly Growing, Varies

Infectious

Reporting Name

Susc, AFB, Rapidly Growing

Useful For

Determination of susceptibility of rapidly growing mycobacteria to the antimicrobial agents on the test panel

Specimen Type

Varies


Additional Testing Requirements


CTB / Mycobacteria and Nocardia Culture, Varies or CTBID / Culture Referred for Identification, Mycobacterium and Nocardia, Varies must also be ordered and will be charged separately unless identification of organism is provided by the client.



Shipping Instructions


1. See Infectious Specimen Shipping Guidelines in Special Instructions.

2. Place specimen in a large infectious container (T146) and label as an etiologic agent/infectious substance.



Necessary Information


Specimen source and organism identification are required unless either CTB / Mycobacteria and Nocardia Culture, Varies or CTBID / Culture Referred for Identification, Mycobacterium and Nocardia, Varies is also ordered.

 

Identification to the species level is required for Mycobacterium species in order for the correct antimicrobial susceptibility drug panel to be selected. Identification to the genus level is sufficient for Nocardia species and other aerobic actinomycetes (eg, Gordonia species, Rhodococcus species).



Specimen Required


Specimen Type: Organism

Supplies: Infectious Container, Large (T146)

Container/Tube: Middlebrook 7H10 agar slant or other appropriate media

Specimen Volume: Pure isolate

Collection Instructions: Organism must be in pure culture, actively growing.


Specimen Minimum Volume

See Specimen Required

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Ambient (preferred)
  Refrigerated 

Reference Values

 
Antimicrobial

Susceptible (mcg/mL)

Intermediate (mcg/mL)

Resistant (mcg/mL)

Amikacin

≤16

32

≥64

Cefoxitin

≤16

32-64

≥128

Ciprofloxacin

≤1

2

≥4

Clarithromycin

≤2

4

≥8

Clofazimine

No interpretations available

Doxycycline

≤1

2-4

≥8

Imipenem

≤4

8-16

≥32

Linezolid

≤8

16

≥32

Moxifloxacin

≤1

2

≥4

Tigecycline

No interpretations available

Tobramycin

≤2

4

≥8

Trimethoprim/Sulfamethoxazole

≤2/38

-

≥4/76

Day(s) Performed

Monday through Sunday

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

87186

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MMLRG Susc, AFB, Rapidly Growing 29579-0

 

Result ID Test Result Name Result LOINC Value
MMLRG Susc, AFB, Rapidly Growing 29579-0

Additional Tests

Test ID Reporting Name Available Separately Always Performed
SRG Susceptibility Rapid Grower No, (Bill Only) Yes

Testing Algorithm

When this test is ordered, rapid grower susceptibility will be performed at an additional charge.

Clinical Information

There are more than 100 species of rapidly growing mycobacteria and many are significant human pathogens (eg, Mycobacterium abscessus, Mycobacterium chelonae, Mycobacterium fortuitum). Rapidly growing mycobacteria cause a variety of infections including pulmonary infections, skin and soft tissue infections, and disseminated disease. Antimicrobial susceptibility testing of clinically significant rapidly growing mycobacteria is important to help guide patient care.

 

Antimicrobials tested in this assay are amikacin, cefoxitin, ciprofloxacin, clarithromycin, clofazimine, doxycycline, imipenem, linezolid, moxifloxacin, tigecycline, tobramycin, and trimethoprim/sulfamethoxazole.

Interpretation

Results are reported as the minimum inhibitory concentration in micrograms/mL. Interpretive criteria (susceptible, intermediate, or resistant) are reported according the Clinical and Laboratory Standards Institute (CLSI) guidelines.

Clinical Reference

1. Brown-Elliott BA and Pilley JV. Rapidly growing mycobacteria. Microbiol Spectr. 2017;5:1-19

2. Apiwattankul N, Flynn PM, Hayden RT, Adderson EE. Infections caused by rapidly growing mycobacteria spp in children and adolescents with cancer. J Pediatric Infect Dis Soc. 2015 Jun;4(2):104-113

3. Kasperbauer SH, De Groote MA. The treatment of rapidly growing mycobacterial infections. Clin Chest Med. 2015 Mar;36(1):67-78

Report Available

12 to 28 days

Method Name

Minimum Inhibitory Concentration (MIC) by Microtiter Broth Dilution Method

Forms

If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.

Mayo Clinic Laboratories | Microbiology and Infectious Disease Catalog Additional Information:

mml-mycobacteria