Determination of resistance of slowly growing mycobacteria to antimicrobial agents
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
RSLG | Susceptibility Slow Grower | No, (BILL ONLY) | Yes |
When this test is ordered, susceptibility for slow growers will be performed at an additional charge. Antimicrobials are tested and reported using the Clinical and Laboratory Standards Institute (CLSI) guidelines.(1, 2)
Antimicrobials tested for Mycobacterium avium complex: amikacin, clarithromycin, clofazimine, linezolid, and moxifloxacin.
Antimicrobials tested for all other slowly growing Mycobacterium species: amikacin, clarithromycin, clofazimine, ciprofloxacin, doxycycline, linezolid, minocycline, moxifloxacin, rifabutin, rifampin, and trimethoprim /sulfamethoxazole.
Clofazimine interpretive criterion is not available.
Minimum Inhibitory Concentration (MIC) by Microtiter Broth Dilution Method
Acid-Fast Bacilli (AFB)
AFB (Acid-Fast Bacilli)
Antibiotic Susceptibility
Bacillus, Acid-Fast
MIC (Minimum Inhibitory Concentration)
Minimum Inhibitory Concentration (MIC)
Mycobacteria Antimicrobial Susceptibility (MIC) (Minimum Inhibitory Concentration)
Mycobacterium marinum Susceptibility Testing
Mycobacterium kansasii Susceptibility Testing
Mycobacterium avium complex Susceptibility Testing
Slow Growing Mycobacteria to Antimicrobial Agents
Susceptibility Testing
When this test is ordered, susceptibility for slow growers will be performed at an additional charge. Antimicrobials are tested and reported using the Clinical and Laboratory Standards Institute (CLSI) guidelines.(1, 2)
Antimicrobials tested for Mycobacterium avium complex: amikacin, clarithromycin, clofazimine, linezolid, and moxifloxacin.
Antimicrobials tested for all other slowly growing Mycobacterium species: amikacin, clarithromycin, clofazimine, ciprofloxacin, doxycycline, linezolid, minocycline, moxifloxacin, rifabutin, rifampin, and trimethoprim /sulfamethoxazole.
Clofazimine interpretive criterion is not available.
Varies
For Mycobacterium tuberculosis complex, see TB1LN / Antimicrobial Susceptibility, Mycobacterium tuberculosis Complex, First Line, Varies and TBPZA / Susceptibility, Mycobacterium tuberculosis Complex, Pyrazinamide, Varies.
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.
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.
Specimen source and organism identification are required.
Specimen Type: Organism
Supplies: Infectious Container, Large (T146)
Container/Tube: Middlebrook 7H10 agar slant or other appropriate media
Specimen Volume: Isolate
Collection Instructions: Organism must be in pure culture, actively growing.
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.
Agar plate | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Varies | Ambient (preferred) | ||
Refrigerated |
Determination of resistance of slowly growing mycobacteria to antimicrobial agents
When this test is ordered, susceptibility for slow growers will be performed at an additional charge. Antimicrobials are tested and reported using the Clinical and Laboratory Standards Institute (CLSI) guidelines.(1, 2)
Antimicrobials tested for Mycobacterium avium complex: amikacin, clarithromycin, clofazimine, linezolid, and moxifloxacin.
Antimicrobials tested for all other slowly growing Mycobacterium species: amikacin, clarithromycin, clofazimine, ciprofloxacin, doxycycline, linezolid, minocycline, moxifloxacin, rifabutin, rifampin, and trimethoprim /sulfamethoxazole.
Clofazimine interpretive criterion is not available.
The slowly growing nontuberculous mycobacteria are associated with a variety of infections including pulmonary, extra-pulmonary, and disseminated disease.
Slowly growing mycobacteria differ from the rapidly growing mycobacteria and Mycobacterium tuberculosis complex by their growth rates, metabolic properties, and antimicrobial susceptibility profiles. The antimicrobial susceptibility profile of an organism within this group varies depending on the species and is performed according to the Clinical and Laboratory Standards Institute (CLSI) guideline for slowly growing mycobacteria.(1, 2)
The antimicrobials listed below are included on the routine panel. Those marked with an "X" are routinely reported. | |||||||||||||
Organism | Antimicrobial agent | ||||||||||||
| Amikacin | Clarithromycin | Clofazimine | Ciprofloxacin | Doxycycline | Linezolid | Minocycline | Moxifloxacin | Rifabutin | Rifampin | Streptomycin | Trimethoprim-sulfamethoxazole | |
Mycobacterium avium complex | X | X | X | | | X | | X | | | | | |
Other slowly growing nontuberculous Mycobacterium species | X | X | X | X | X | X | X | X | X | X | | X |
The extremely fastidious slowly growing mycobacteria (Mycobacterium genavense and Mycobacterium haemophilum) will not be tested. Mycobacterium malmoense can be difficult to grow in the test medium so some isolates may not be amenable to testing.
Mycobacterium xenopi requires incubation at a higher temperature and may require extended incubation times.
Mycobacterium gordonae is frequently encountered in the environment and in clinical laboratories but is almost always considered nonpathogenic; therefore, antimicrobial susceptibility testing for M gordonae is performed by specific request only.
Interpretive criteria for Mycobacterium avium-intracellulare complex | |||
Antimicrobial agent | Minimum inhibitory concentration (MIC, mcg/mL) for each interpretation | ||
| S | I | R |
Clarithromycin | < or =8 | 16 | > or =32 |
Linezolid | < or =8 | 16 | > or =32 |
Moxifloxacin | < or =1 | 2 | > or =4 |
Amikacin (IV) | < or =16 | 32 | > or =64 |
Amikacin (liposomal, inhaled) | < or =64 | - | > or =128 |
Interpretative criteria for Mycobacterium kansasii and other slowly growing mycobacteria | |||
Antimicrobial agent | MIC (mcg/mL) for each interpretation | ||
| S | I | R |
Amikacin | < or =16 | 32 | > or =64 |
Ciprofloxacin | < or =1 | 2 | > or =4 |
Clarithromycin | < or =8 | 16 | > or =32 |
Doxycycline | < or =1 | 2-4 | > or =8 |
Linezolid | < or =8 | 16 | > or =32 |
Minocycline | < or =1 | 2-4 | > or =8 |
Moxifloxacin | < or =1 | 2 | > or =4 |
Rifabutin | < or =2 | - | > or =4 |
Rifampin | < or =1 | - | > or =2 |
Trimethoprim/ | < or =2/38 | - | > or =4/76 |
Results are reported as the minimum inhibitory concentration in micrograms/mL.
No significant cautionary statements
1. CLSI: Susceptibility Testing of Mycobacteria, Nocardia spp., and Other Aerobic Actinomycetes. 3rd ed. CLSI standard M24. Clinical and Laboratory Standards Institute; 2018
2. CLSI: Performance Standards for Susceptibility Testing of Mycobacteria, Nocardia spp., and Other Aerobic Actinomycetes. 1st ed. CLSI supplement M62. Clinical and Laboratory Standards Institute; 2018
3. Caulfield AJ, Richter E, Brown-Elliott BA, et al: Mycobacterium: laboratory characteristics of slowly growing mycobacteria other than Mycobacterium tuberculosis. In: Carroll KC, Pfaller MA, Landry ML, et al. eds. Manual of Clinical Microbiology. 12th ed. ASM Press; 2019:595-611
4. Philley JV, Griffith DE. Treatment of slowly growing mycobacteria. Clin Chest Med. 2015 Mar;36(1):79-90. doi: 10.1016/j.ccm.2014.10.005
5. Daley CL, Laccarino JM, Lange C, et al: Treatment of nontuberculous mycobacterial pulmonary disease: An official ATS/ERS/ESCMID/IDSA Clinical Practice Guideline. Clin Infect Dis. 2020 Aug 14;71(4):905-913. doi: 10.1093/cid/ciaa1125
The method employed in this assay is microtiter broth dilution using the commercially available SLOMYCO2 plate from Trek Diagnostics. Antimicrobials included in the assay are tested according to Clinical and Laboratory Standards Institute (CLSI) guidelines.(CLSI. Susceptibility Testing of Mycobacteria, Nocardia spp., and Other Aerobic Actinomycetes. 3rd ed. CLSI standard M24. Clinical and Laboratory Standards Institute; 2018; CLSI. Performance Standards for Susceptibility Testing of Mycobacteria, Nocardia spp., and Other Aerobic Actinomycetes. 1st ed. CLSI supplement M62. Clinical and Laboratory Standards Institute; 2018)
Varies
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.
87186
Test Id | Test Order Name |
Order LOINC Value
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
|
---|---|---|
MMLSG | Susc, AFB, Slowly Growing | 29579-0 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
MMLSG | Susc, AFB, Slowly Growing | 29579-0 |