<i>Mycobacterium avium</i> Complex Susceptibility - Broth
Dilution
Mycobacterium avium Complex Susceptibility - Broth
Dilution | | | |
| Number | | 182832 |
| CPT | | 87186 |
| Related Information | | Acid-Fast (Mycobacteria)
Broth-Based Culture and Smear and Susceptibility (182675)
Acid-Fast (Mycobacteria)
Antibiotic Susceptibilities (088161)
|
| Synonyms | | MAC Susceptibility Testing ; M. avium Complex
Susceptibility Testing ; Susceptibility Testing, MAC ;
Susceptibility Testing, M. avium Complex ; AFB
Susceptibility Testing |
| Test Includes | | Susceptibility testing for amikacin, ciprofloxacin,
clarithromycin, ethambutol, linezolid, moxifloxacin,
rifampin, and streptomycin. MIC values will be reported
with CLSI interpretive comments, if available. |
| Specimen | | Mycobacterium avium complex isolated from a primary
clinical specimen, on a submitted AFB conventional solid
medium, or an AFB broth medium. |
| Volume | | Pure culture isolate on an AFB conventional solid medium or
a minimum of 1 mL of AFB broth medium. |
| Minimum Volume | | Refer to specimen volume comment. |
| Container | | Conventional or broth medium, tightly sealed, in etiologic
agent packaging. |
| Storage Instructions | | Maintain media at room temperature. |
| Causes for Rejection | | Specimen received leaking or in broken transport tube or
vial; specimen received in expired transport medium; mixed
culture; unlabeled culture or name discrepancy between
specimen and request label. |
| Use | | Determine the susceptibility of Mycobacterium avium
complex isolates to a profile of antimycobacterial agents.
Routine susceptibility testing of MAC isolates is
recommended for clarithromycin only since no correlation
between "in vitro" susceptibility results for MAC and
clinical response for agents other than macrolides has been
established.3 Initial
isolates from patients with previously untreated MAC lung
disease should be tested against clarithromycin to
establish a baseline value. Other MAC isolates to be tested
should include:
-Isolates from patients with previous macrolide therapy
-Isolates from patients with MAC pulmonary disease
receiving macrolide-containing therapy regimens that
relapse or fail after six months of macrolide containing
therapy
-Isolates from patients with AIDS who develop bacteremia on
macrolide prophylaxis
-Blood culture isolates of MAC after three months of
therapy with macrolide-containing regimens from patients
with disseminated disease
|
| Limitations | | Susceptibilities cannot be reported if the organism fails
to grow in the test medium. Susceptibilities cannot be
performed on mixed cultures. This procedure may be
considered by Medicare and other carriers as
investigational and, therefore, may not be payable as a
covered benefit for patients. |
| Methodology | | Sensititre® broth microdilution (MIC) method. |
| Additional Information | | Failure to take all drugs in a multidrug regimen can lead
to a shift toward resistant organisms and treatment
failure. Nontuberculous mycobacteria, particularly strains
of the M. avium complex, are resistant to those drugs used
for therapy of
M. tuberculosis.1
Clarithromycin (and azithromycin) are the only agents for
which CLSI interpretive guidelines are established.
Treatment of MAC for most patients with
nodular/bronchiectatic disease includes a
three-times-weekly regiment of clarithromycin or
azithromycin, rifampin, and ethambutol. For patients with
MAC lung disease or sever nodular/bronchiectatic disease, a
daily regime of clarithromycin or azithromycin, rifampin or
rifabutin, and ethambutol with consideration of
three-times-weekly amikacin or streptomycin early in
therapy is recommended. Treatment should occur until the
patient is culture negative for one
year.2 Treatment of
disseminated MAC disease should include clarithromycin or
azithromycin and ethambutol with or without rifabutin until
the symptoms have resolved and cell-mediated immune
function has returned. |
| Footnotes | |
- Wolinsky E. Mycobacterial diseases other than
tuberculosis. Clin Infect Dis. 1992; 15(1):1-10.
- An Official ATS/IDSA Statement: Diagnosis,
treatment, and prevention of nontuberculous mycobacterial
diseases. Am J Respir Crit Care Med. 2007; 175:367-
416.
- Clinical and Laboratory Standards Institute
(CLSI), Susceptibility Testing of Mycobacteria,
Nocardia, and Other Aerobic Actinomycetes; Approved
Standard. Vol 23, No 18. Villanova, Pa: CLSI; 2003.
Document M24-A.
|
| References | |
An Official ATS/IDSA Statement: Diagnosis, treatment,
and prevention of nontuberculous mycobacterial diseases.
Am J Respir Crit Care Med. 2007; 175:367-416.
Brown BA, Wallace RJ Jr, Onyi G. Activities of
clarithromycin against eight slowly growing species of
nontuberculous mycobacteria, determined by using a broth
microdilution MIC system. Antimicrob Agents
Chemother. 1992; 36:1987-1990.
Brown-Elliott BA, Crist CJ, Mann, LB, Wilson RW,
Wallace RJ Jr. In vitro activity of linezolid against
slowly growing nontuberculous mycobacteria. Antimicrob
Agents Chemother. 2003; 47:1736-1738.
Clinical and Laboratory Standards Institute (CLSI).
Susceptibility Testing of Mycobacteria, Nocardia, and
Other Aerobic Actinomycetes; Approved Standard. Vol 23,
No 18. Villanova, Pa: CLSI; 2003. Document M24-A.
Heifets L. Drug Susceptibility in the Chemotherapy
of Mycobacterial Infections. Boca Raton, Fla: CRC
Press; 1991.
Heifets L. Qualitative and quantitative drug
susceptibility tests in mycobacteriology. Am Rev Respir
Dis. 1988; 137(5):1217-1222.
Horsburgh CR Jr, Mason UG, Heifets LB III, Southwick
K, Labrecque J, Iseman MD. Response to therapy of pulmonary
Mycobacterium avium-intracellulare infection
correlates with results of in vitro susceptibility testing.
Am Rev Respir Dis. 1987; 135:418-421.
Van Scoy RE, Wilkowske CJ. Antituberculous agents.
Mayo Clin Proc. 1992; 67(2):179-187. |
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