Diagnosis and Treatment of Infections dueto Mycobacterium avium Complex
Shannon H. Kasperbauer, M.D.1 and Charles L. Daley, M.D.1
Mycobacterium avium complex (MAC) consists of nontuberculous mycobacteria
that cause disease in immunocompromised and immunocompetent hosts. The organismsare ubiquitous in the environment, and acquisition occurs through ingestion or inhalationof aerosols from soil, water, or biofilms. Disease may manifest as disseminated infection,soft tissue infection, chronic pneumonia, or hypersensitivity pneumonitis. Nontuberculousmycobacteria are increasingly associated with pulmonary disease, with MAC being themost common nontuberculous mycobacteria to cause pulmonary disease in the UnitedStates. Pulmonary symptoms, nodular or cavitary opacities on a chest radiograph or high-resolution computed tomographic scan with multifocal bronchiectasis and multiple smallnodules, plus positive culture results from two sputum specimens or one bronchoscopicspecimen are consistent with MAC pulmonary disease. Treatment consists of a macrolide,rifamycin, and ethambutol given three times weekly for noncavitary disease and daily withor without an aminoglycoside for cavitary disease.
KEYWORDS: Mycobacterium avium complex, nontuberculous mycobacteria,diagnosis, treatment
Mycobacterium avium complex (MAC) includes
biofilms, and aerosols. MAC is resistant to disinfectants
at least two species, Mycobacterium avium and Mycobac-
used in water treatment centers and can thus be isolated
terium intracellulare. Recent molecular studies have
documented that M. avium is composed of severalsubspecies and that the one most likely to cause diseasein humans is subspecies hominissuis (Table 1).1 These
organisms belong to a much larger group of bacteria
Studying the incidence and prevalence of disease due to
referred to as nontuberculous mycobacteria (NTM),
NTM is challenging for many reasons. NTM infections
environmental mycobacteria, atypical mycobacteria, or
are not reportable, specimen contamination can con-
mycobacteria other than tuberculosis. Disease manifests
found results, and determining infection from disease
as chronic pneumonia; disseminated infection; skin, soft
relies on additional clinical insight. In a review of the
tissue, and bone infection; and acute hypersensitivity
epidemiology of nontuberculous pulmonary disease, the
infection rate in North America was estimated to be 1.0
Unlike tuberculosis, MAC is not transmitted
to 12.0 per 100,000 persons, whereas disease rates were
from person to person. It is ubiquitous in the environ-
0.1 to 2.0 per 100,000 persons.3 Ten different studies
ment; thus one likely acquires it from various exposures
from the 1960s through the 1990s were analyzed in the
to the environment. Organisms are present in soil, water,
review. The report defined infection as isolation of viable
1Division of Mycobacterial and Respiratory Infections, National Jewish
Tuberculosis; Guest Editor, Neil W. Schluger, M.D.
Semin Respir Crit Care Med 2008;29:569–576. Copyright #
Address for correspondence and reprint requests: Shannon H.
2008 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New
Kasperbauer, M.D., Division of Mycobacterial and Respiratory
York, NY 10001, USA. Tel: +1(212) 584-4662.
Infections, National Jewish Health, 1400 Jackson St., Denver, CO 80206
DOI 10.1055/s-0028-1085708. ISSN 1069-3424.
SEMINARS IN RESPIRATORY AND CRITICAL CARE MEDICINE/VOLUME 29, NUMBER 5
Table 1 Nomenclature for Mycobacterium aviumComplex (MAC) Organisms
Figure 1 Chest computed tomographic scan. Right upper
lobe cavitary opacities in 63-year-old man with Mycobacter-
ium avium complex infection and underlying emphysema.
disease due to MAC manifests as a chronic lung
infection, with radiographic changes including bron-
chiectasis, nodules, and/or cavitary lesions. Patients
with isolated pulmonary disease due to MAC are
typically immunocompetent adults. Traditionally pa-
tients have been described with two types of clinicaldisease: (1) men with underlying lung disease who
organisms from an uncontaminated clinical specimen in
present with apical fibrocavitary disease (Fig. 1) and
the absence of obvious clinical manifestations, and dis-
(2) postmenopausal women who present with nodular
ease as the addition of signs or symptoms that suggest a
opacities and bronchiectasis typically in the right mid-
pathogenic process. Because the prevalence of pulmo-
dle lobe and lingula (Fig. 2).6 Investigation for under-
nary infection due to NTM in the United States
lying etiologies of bronchiectasis is warranted because
appeared to be rising, it was unclear whether this was
further progression of bronchiectasis will only make it
due to better detection of the disease or an actual
more difficult to treat the infection. Screening for
increase in the amount of infection. To answer this
genetic, immunologic, rheumatologic, and mechanical
question, Khan et al reviewed data on M. intracellularesensitization in 1971–72 and compared this to rates from1999–2000. The prevalence of M. intracellulare sensiti-zation increased from 11.2% (95% confidence interval,9.2 to 13.5%) to 16.6% (95% confidence interval, 13.2 to20.6%). Increasing sensitization to M. intracellulare anti-gens over time supports the theory that infection ratesare actually increasing.4 Marras et al studied the isolationprevalence of pulmonary NTM in Ontario from 1997–2003: 22,247 pulmonary isolates were obtained from10,231 patients. The isolation prevalence of all species(excluding Mycobacterium gordonae) was 9.1/100,000 in1997, increasing to 14.1/100,000 by 2003 (p < 0.0001). This was a mean annual increase of 8.4%.5 Of note, therate of tuberculosis was decreasing during the studyperiod.
Figure 2 Chest computed tomographic scan. Lingular and
right middle lobe bronchiectasis with scattered nodules in a
MAC is the most frequent cause of pulmonary infec-
50-year-old woman with Mycobacterium avium complex
tion due to an NTM in the United States. Pulmonary
DIAGNOSIS AND TREATMENT OF INFECTIONS DUE TO MYCOBACTERIUM AVIUM COMPLEX/KASPERBAUER, DALEY
Table 2 Clinical and Microbiological Criteria for
Treatment of Pulmonary Mycobacterium avium
Diagnosing Nontuberculous Mycobacterial Lung
A HISTORICAL PERSPECTIVETreatment for MAC can be thought of in three distinct
eras, that in which rifampin and ethambutol were not
used, that in the premacrolide era in which rifampin and/
or ethambutol were used, and that which occurs now in
the macrolide era. Field et al8 published a comprehensive
review of all of the treatment studies for MAC lung
disease. The reported ranges of success varied from 20 to
90% in the individual studies from the premacrolide era.
When an intention to treat strategy was applied the
estimated overall cure rate was 40%. Twelve studies were
included in the macrolide era. Including treatment
dropouts and relapses, the cure rate was 56%. Overall
treatment outcomes have improved with the addition of
macrolides to the standard regimen. Thus far, the
macrolide class is the only antibiotic for which in vitro
susceptibility has been shown to correlate with clinical
A prospective, multicentered trial took place in
France in the 1990s to assess treatment outcomes in
patients with pulmonary MAC with clarithromycin
alone or in combination with other antimycobacterial
HRCT, high-resolution computed tomography; NTM, nontuberculousmycobacteria.
agents. Of the 42 patients enrolled, seven either failedto convert their cultures at 12 months or experienced
causes has revealed that a significant degree of this
a relapse. Of these seven cases, susceptibilities of
patient population has an undiagnosed etiology asso-
MAC strains isolated from sputum before and after
3 months of treatment were compared, and a signifi-
The American Thoracic Society and the Infec-
cant increase of clarithromycin MIC was observed
tious Disease Society of America released the latest
(0.5 to 2 mg/L to 512 mg/L), indicating an acquired
guidelines for the diagnosis and treatment of NTM in
resistance of M. avium strains to clarithromycin in
2007.6 When compared with the previous statement
published in 1998 there were a few changes made to
In a later prospective, noncomparative trial pa-
the diagnostic criteria. The diagnosis of pulmonary
tients received initial clarithromycin monotherapy for
MAC is based on clinical, microbiological, and radio-
4 months or until their sputum cultures converted to
graphic criteria (Table 2). The minimum evaluation of
negative.10 Twenty patients completed 4 months of
a patient with suspected pulmonary disease due to
clarithromycin at 500 mg twice daily. Ninety-five per-
mycobacteria should include a chest radiograph or a
cent (19/20) were found to have pretreatment isolates
high-resolution computed tomographic scan (HRCT)
that were macrolide susceptible. Fifty-eight percent of
in the case of noncavitary disease, and three or more
these patients became sputum-culture negative, whereas
sputum specimens for acid-fast bacilli (AFB) analysis.
an additional 21% of patients had a significant reduction
Isolation of the bacteria on a single sputum culture
in their sputum positivity. Unfortunately, three of the
is not sufficient for a diagnosis of pulmonary
19 patients developed macrolide resistance from expo-
MAC because the organisms exists naturally in the
sure to monotherapy, which was associated with clinical
Table 3 Outcomes of Clinical Trials for the Treatment of Pulmonary MAC
SEMINARS IN RESPIRATORY AND CRITICAL CARE MEDICINE/VOLUME 29, NUMBER 5
At the same center, the authors initiated a non-
disease is another risk factor for the development of
comparative trial of initial azithromycin use in patients
macrolide resistance in the face of monotherapy.
with pulmonary MAC. Of 29 patients enrolled, 23
Griffith et al went on to further characterize
completed therapy. Thirty-eight percent met the pri-
patients with macrolide resistance.15 Of 51 patients
mary end point of culture negativity, whereas two
included in the study, 27 were of the upper lobe cavitary
patients (9%) were later found to have developed macro-
phenotype and 24 were the nodular/bronchiectatic phe-
notype. Initial macrolide monotherapy, a macrolide plus
The relationship between clinical efficacy of treat-
a quinolone, or either of these occurring as a result of
ment regimens and drug susceptibility was also examined
discontinuation of ethambutol were the major reasons
in Japan by Kobashi et al.12 Fifty-two patients with
for development of macrolide resistance.
pulmonary MAC were enrolled in a prospective study.
One explanation for the combination of a macro-
MICs of rifampin, ethambutol, streptomycin, and clar-
lide and flouroquinolone leading to macrolide resistance
ithromycin were obtained on each isolate. The only
is examined in a study by Kohno et al.16 They evaluated
consistent relationship between clinical efficacy and
the in vitro and in vivo activities of three fluoroquino-
susceptibility was with clarithromycin. However, the
lones and clarithromycin against clinically isolated MAC
doses of the other drugs used in the study were too
strains using a mouse model. Clarithromycin showed the
low to allow definitive conclusions regarding clinical
best anti-MAC activity in vivo. When the combinations
efficacy and in vitro susceptibility results.
of fluoroquinolones and clarithromycin were studied
A multicentered observational study from Japan
in vitro 53 to 57% of the isolates exhibited antagonism
enrolled 65 patients able to complete 24 months of
measured in a fractional inhibitory concentration index
antibiotics and had at least 12 months of follow-up.13
(FIC). In vivo studies noted that most of the fluoroqui-
The treatment consisted of rifampin 450 mg/day,
nolone–clarithromycin combinations did not show a
significant difference in antibacterial effects in organs
400 mg/day for weight < 50 kg, or 600 mg/day for a
compared with treatment with clarithromycin alone.
weight > 50 kg), and streptomycin 1 g/ thrice weekly for
However, several combinations (e.g., moxifloxacin–
the first 2 to 3 months. They noted the sputum con-
clarithromycin and gatifloxacin–clarithromycin against
version rate was significantly lower in patients infected
MAC strain N084) showed significantly greater num-
with clarithromycin-resistant strains (0%) and inter-
bers of viable bacteria in organs than treatment with
mediate strains (29%) than in those infected with sus-
clarithromycin alone. This suggests that the antagonism
ceptible strains (66%, p < 0.05). Clinical improvement
seen with the fluoroquinolone–clarithromycin combina-
was also significantly lower in patients with clarithro-
mycin-resistant strains (0%) and intermediate strains
Recently developed fluoroquinolones, including
(14%) than in those infected with susceptible strains
the C-8 methoxy group, have antimycobacterial activity.
(37%; p < 0.05). The degree of lung involvement also
For patients who have failed prior treatment or have
correlated with outcomes. Patients with more advanced
developed resistance the class holds promise as an alter-
disease beyond the unilateral lung field had significantly
native agent. Although we do not clearly understand the
higher sputum relapse rates and significantly lower
relationship of flouroquinolone in vitro susceptibility
clinical improvement. Finally, a significant difference
testing to in vivo response, we reported recently the
in sputum conversion was demonstrated in 600 mg/day
overall susceptibility to fluoroquinolones in MAC to be
of clarithromycin versus 400 mg/day of clarithromycin
low. Four hundred and eighteen MAC isolates were
examined for their in vitro susceptibility to ciprofloxacin
As clearly demonstrated macrolide resistance con-
versus moxifloxacin; the percent susceptible were 9 and
fers worse outcomes. Apart from macrolide monother-
apy the risk factors for the development of resistance are
Treatment of pulmonary MAC is expensive and
has been associated with significant drug intolerance. In
The minimum inhibitory concentrations (MICs)
an attempt to reduce drug intolerance investigators
to 283 strains of M. avium were determined by Kuwa-
reported the use of three times weekly (tiw) for the
bara and Tsuchiya.14 They found 1/243 isolates from
treatment of pulmonary MAC disease. In three studies
untreated individuals to be macrolide susceptible versus
evaluating the use of azithromcyin-based regimens, the
17/40 (43%) patients who had received prior macrolide
authors reported that 55 to 65% of patients converted
chemotherapy. All 17 had been treated with clarithro-
their culture to negative with 12 months of negative
mycin monotherapy. Interestingly 8/23 patients who
cultures.17 Failure to convert cultures to negative after
were susceptible to clarithromycin had also been treated
6 months of therapy occurred in 35 to 45% of patients.
with clarithromycin monotherapy. Many of the resistant
In a short term study of intermittent clarithromycin,
isolates exposed to monotherapy were classified as the
78% of patients had converted their cultures to negative
nonnodular bronchiectasis type, suggesting that cavitary
by 6 months of therapy, a proportion that was not
DIAGNOSIS AND TREATMENT OF INFECTIONS DUE TO MYCOBACTERIUM AVIUM COMPLEX/KASPERBAUER, DALEY
significantly different from previous studies that used
ered in patients who have focal cavitary disease, under-
daily clarithromycin or intermittent azithromycin-based
lying macrolide resistance or who are failing treatment.
The procedure should be performed by surgeons with
Treatment outcomes of tiw therapy were de-
experience in this type of lung resection and in collab-
scribed in a study that was designed to evaluate the
oration with a physician or team with experience in
impact of inhaled interferon-gamma in the treatment of
managing these difficult-to-treat patients.
moderate to severe pulmonary MAC disease.19 Thestudy was halted because of no documented activity of
PUBLICATIONS SINCE RELEASE OF THE AMERICAN
interferon. However, the outcomes of the patients, all
of whom received tiw therapy, were reported. Only 44%
Aminoglycosides are currently recommended in pa-
of the patients converted their sputum cultures to
tients with cavitary disease, treatment failures, and
negative; however, this ranged from 71% in persons
those who have been treated previously. These drugs
with noncavitary disease to 20% in those with cavities
have potent antimycobacterial activity but little is
present on a chest radiograph. Factors associated with
known about long-term outcomes with their use in
culture conversion included having noncavitary disease,
MAC. Kobashi et al conducted a prospective, random-
being AFB smear negative, no history of previous
ized, controlled study of the clinical efficacy of strep-
treatment, older age, and longer duration of ethambutol
tomycin in the treatment of pulmonary MAC. Patients
were randomized to received streptomycin versus pla-cebo, administered intramuscularly at 15 mg/kg three
times per week for the initial 3 months of therapy in
Based on the studies just described, the American
combination with oral clarithromycin, rifampin, and
Thoracic Society (ATS) and Infectious Disease Society
ethambutol. The sputum conversion rate at completion
of America (IDSA) published guidelines for the treat-
of therapy was significantly better in the streptomycin
ment of MAC and other NTM.6 In treatment-naive
group; however, there were no significant differences in
patients, therapy for pulmonary disease due to MAC
the sputum relapse rate and clinical improvement,
includes three oral antimicrobials: a macrolide (clari-
including both clinical symptoms and radiological
thromycin or azithromycin), ethambutol, and a rifamy-
cin (rifampin or rifabutin). For initial therapy of
The British Thoracic Society21 recently reported
nodular/bronchiectatic disease, tiw therapy is recom-
the results of a large randomized, controlled trial for the
mended (Table 4). Daily therapy is recommended for
treatment of MAC pulmonary disease. They compared
initial treatment for cavitary disease. Some experts would
clarithromycin versus ciprofloxacin as the third drug
also recommend intravenous or intramuscular amikacin
added to ethambutol and rifampin for treatment of
or streptomycin for the initial first 2 to 3 months in
pulmonary MAC, M. malmoense, and M. xenopi. Doses
patients with cavitary disease.6 Duration of treatment is
used in the trial were those recommended by the ATS
for 12 months beyond the time that the patient’s cultures
for daily treatment of cavitary disease. Ciprofloxacin was
convert to negative, which usually equates to 18 to
dosed as 750 mg by mouth twice daily. Patients’ clinical
24 months of therapy. Referral should be considered in
and bacteriologic progress was documented annually
patients who have failed therapy or are intolerant of a
during the 2 years of treatment and for 3 years thereafter.
standard treatment regimen. Surgery should be consid-
If at 1 year a patient was not improving, the regimen was
Table 4 Treatment Regimens for Mycobacterium avium Complex Lung Disease
yFor older patients with nodular/bronchiectatic disease or for patients who require a prolonged course (i.e., > 6 months), some expertsrecommend 8 to 10 mg/kg/day two to three times per week. Adapted from Griffith et al.6
SEMINARS IN RESPIRATORY AND CRITICAL CARE MEDICINE/VOLUME 29, NUMBER 5
supplemented by the addition of the one drug that had
Antimicrobial treatment of disseminated MAC in-
After the completion of therapy clinical and bac-
cludes at least two agents, the first of which is a
teriology status of patients were assessed annually. The
macrolide, either clarithromycin or azithromycin.
primary end points were failure of treatment or relapse.
Ethambutol is the recommended second agent. Mono-
One hundred and seventy patients with pulmonary MAC
therapy is never advised in the treatment of MAC
were included in the study. There was no significant
because of the concern for developing resistance. Add-
difference in the number of patients who completed
ing a third agent such as rifabutin is controversial.
therapy and were ‘‘alive and well’’ at 5 years (24% in the
Before effective antiretroviral therapy was available,
clarithromycin group vs 23% in the ciprofloxacin group).
one randomized, controlled trial noted improved sur-
Failure and relapse rates for the clarithromycin versus
vival with the addition of rifabutin to a treatment
ciprofloxacin groups were 4.8% versus 14.9% and 8.4%
regimen, and two randomized, controlled trials noted
versus 8%, respectively. These outcomes appear dismal
a reduced emergence of macrolide resistance.28,29
compared with the studies reviewed by Field et al.8 Two
Successful treatment of disseminated MAC re-
explanations include the high percentage of cavitary
lies on recovery of the immune system. Highly active
disease among this population (69% in the clarithro-
antiretroviral therapy is imperative in the setting of
mycin group versus 63% in the ciprofloxacin group)
disseminated MAC and AIDS. Antiretrovial therapy
and the high all-cause mortality. Forty-six percent of
should be initiated simultaneously or 1 to 2 weeks after
patients in the clarithromycin arm and 23% in the
beginning antibiotics.27 It is important to follow pa-
ciprofloxacin arm died of causes other than that due
tients closely for evidence of an immune reconstitution
syndrome that can develop after the initiation of anti-
HRCT findings may be able to predict response
retroviral therapy.30–32 Antimycobacterial therapy
to therapy. Kuroishi et al found that atelectasis, cavities,
can be discontinued once a patient has met all of the
and pleural thickening in HRCT findings were signifi-
following criteria: completed 12 months of therapy,
cantly more frequent among patients unable to convert
remains asymptomatic, and sustains (> 6 months) a
their sputum cultures to negative versus those in the
converted group. In addition, the extent of pulmonaryinvolvement of bronchiectasis, atelectasis, cavities, andpleural thickening was significantly greater in the non-
INFECTIONMAC infection can present as cutaneous lesions,abscesses, lymphadenitis, arthritis, tenosynovitis, or
osteomyelitis. Risk factors include traumatic injury to
Disseminated disease occurs almost exclusively in im-
the skin, recent surgery, corticosteroid injection, or
munocompromised hosts. With the advent of the
immune reconsitution as in the setting of AIDS. Soft
AIDS epidemic, disseminated MAC was one of the
tissue abscesses and lymphadenitis due to MAC after the
most common opportunistic infections recognized. M.
initiation of highly active antiretroviral therapy are well
avium is the etiologic agent responsible for greater than
described in the literature.30–32 Reports from soft tissue
95% of cases of disseminated disease in HIV-infected
infections in immunocompromised populations such as
persons. Most cases occur in patients with a CD4
patients receiving antirheumatoid agents are emerging as
lymphocyte count less than 50 cell/mL.23 A study by
well.33 Septic arthritis is an unusual clinical manifesta-
Chin et al found that isolation of MAC from the
tion that is frequently overlooked initially.34 MAC
respiratory or gastrointestinal tract had an association
can also cause a granulomatous tenosynovitis, which
with development of bacteremia (relative hazards for
may be preceded by a surgical procedure, trauma, or
respiratory and gastrointestinal tract, 2.3 and 6.0; 95%
confidence intervals, 1.1 to 4.6 and 2.5 to 14.6, respec-
In children, cervical lymphadenitis represents the
tively).24 Epidemiological associations have been made
predominant manifestation of NTM infection.36 Diag-
such as outbreaks linked to water sources via genotyp-
nosis is made by aspiration of a lymph node or tissue
ing.25 Clinical symptoms include fever, night sweats,
culture, with the latter having a greater sensitivity.
weight loss, fatigue, diarrhea, and abdominal pain. The
Excisional surgery without chemotherapy is the recom-
most commonly identified laboratory abnormalities
mended treatment for children with MAC lympha-
include anemia and elevated alkaline phosphatase.26
denitis.6 In cases of localized infection with immune
Diagnosis of disseminated MAC is made with a com-
reconstitution, surgery is not routinely recommended. In
bination of clinical signs and symptoms coupled with
all other presentations a combination of surgery and
the isolation of MAC from blood, bone marrow, or
antimicrobials is curative in most patients.37 The recom-
other normally sterile tissue or body fluids.27
mended drug regimen is the same as for MAC pulmonary
DIAGNOSIS AND TREATMENT OF INFECTIONS DUE TO MYCOBACTERIUM AVIUM COMPLEX/KASPERBAUER, DALEY
with tuberculosis, isolation of a single positive sputumculture does not necessarily represent disease so diag-nostic criteria have been developed to aid the clinician indeciding whether treatment is indicated. Unfortunately,well-designed and appropriately powered studies for thetreatment of immunocompetent hosts are still lacking. Until the results of such studies are available, therecommended treatment regimen for pulmonary diseaseis a three-drug macrolide-based regimen. Extrapulmo-nary disease is increasing in frequency and is more likelyto require surgical intervention than pulmonary disease. Sadly, prevention of MAC infections remains elusivegiven our poor understanding of host factors, organismcharacteristics, and environmental exposure.
1. Turenne CY, Wallace RJr, Behr MA. Mycobacterium avium
in the postgenomic era. Clin Microbiol Rev 2007;20:205–229
Figure 3 Left hand tenosynovitis due to Mycobacterium
2. Falkinham JO III. Nontuberculous mycobacteria in the
avium complex infection in a 70-year-old woman.
environment. Clin Chest Med 2002;23:529–551
disease, and the optimal duration is unknown, but 6 to
3. Marras TK, Daley CL. Epidemiology of human pulmonary
12 months of treatment is usually recommended.6
infection with nontuberculous mycobacteria. Clin Chest Med2002;23:553–567
4. Khan K, Wang J, Marras TK. Nontuberculous mycobacterial
sensitization in the United States: national trends over three
decades. Am J Respir Crit Care Med 2007;176:306–313
Hypersensitivity pneumonitis (HP) occurs with exposure
5. Marras TK, Chedore P, Ying AM, Jamieson F. Isolation
to aerosols containing mycobacteria, most notably in hot
prevalence of pulmonary non-tuberculous mycobacteria in
tub users (‘ hot tub lung’’). A recent report from Ro-
Ontario, 1997 2003. Thorax 2007;62:661–666
chester, Minnesota, studied consecutive patients with HP
6. Griffith DE, Aksamit T, Brown-Elliott BA, et al. An official
presenting to their institution between 1997 and 2002.38
ATS/IDSA statement: diagnosis, treatment, and preventionof nontuberculous mycobacterial diseases. Am J Respir Crit
The etiology was identified in 75% of cases (64/85).
Twenty-one percent were due to MAC in the water of
7. Pasteur MC, Helliwell SM, Houghton SJ, et al. An
hot tubs. The symptoms of HP secondary to MAC are
investigation into causative factors in patients with bron-
dyspnea, cough, and fever.39 The computed tomographic
chiectasis. Am J Respir Crit Care Med 2000;162(4 Pt 1):
findings are most commonly diffuse centrilobular nod-
ularity, ground-glass attenuation, and evidence of air
8. Field SK, Fisher D, Cowie RL. Mycobacterium avium
trapping on expiratory images.40 In one review of 21
complex pulmonary disease in patients without HIVinfection. Chest 2004;126:566–581
cases of hot tub lung, all patients had MAC isolated from
9. Dautzenberg B, Piperno D, Diot P, Truffot-Pernot C,
their hot tub, respiratory secretions, and/or lung tissue.41
Chauvin JP. Clarithromycin in the treatment of Mycobacterium
Eighteen patients had a lung biopsy performed that
avium lung infections in patients without AIDS. Clarithro-
demonstrated bronchiolocentric granulomatous in-
mycin Study Group of France. Chest 1995;107:1035–1040
flammation. In this study, antimycobacterial therapy
10. Wallace RJ Jr, Brown BA, Griffith DE, et al. Initial
was infrequently required in the management. Only
clarithromycin monotherapy for Mycobacterium avium–intra-
15% of patients received antibiotics and all patients
cellulare complex lung disease. Am J Respir Crit Care Med1994;149:1335–1341
recovered with avoidance of the exposure or a combi-
11. Griffith DE, Brown BA, Girard WM, Murphy DT, Wallace RJ
nation of avoidance and corticosteroids (62%). Finally,
Jr. Azithromycin activity against Mycobacterium avium complex
it should be emphasized that this HP picture secondary
lung disease in patients who were not infected with human
to MAC can be acquired from other aerosols as well.
immunodeficiency virus. Clin Infect Dis 1996;23:983–989
Exposure to metal-working fluids and showering are
12. Kobashi Y, Yoshida K, Miyashita N, Niki Y, Oka M.
other potential activities that can lead to HP.39,42,43
Relationship between clinical efficacy of treatment ofpulmonary Mycobacterium avium complex disease and drug-sensitivity testing of Mycobacterium avium complex isolates. J Infect Chemother 2006;12:195–202
13. Kobashi Y, Matsushima T. The microbiological and clinical
MAC disease syndromes are well described and recog-
effects of combined therapy according to guidelines on the
nized in normal and immunocompromised hosts. Unlike
treatment of pulmonary Mycobacterium avium complex disease
SEMINARS IN RESPIRATORY AND CRITICAL CARE MEDICINE/VOLUME 29, NUMBER 5
in Japan—including a follow-up study. Respiration 2007;74:
Institutes of Health, and the HIV Medicine Association/
Infectious Diseases Society of America. MMWR Recomm
14. Kuwabara K, Tsuchiya T. Clinical features and treatment
history of clarithromycin resistance in M. avium–intracellulare
28. Benson CA, Williams PL, Currier JS, et al. A prospective,
complex pulmonary disease patients [in Japanese]. Nihon
randomized trial examining the efficacy and safety of
Kokyuki Gakkai Zasshi 2007;45(8):587–592
clarithromycin in combination with ethambutol, rifabutin,
15. Griffith DE, Brown-Elliott BA, Langsjoen B, et al. Clinical
or both for the treatment of disseminated Mycobacterium
and molecular analysis of macrolide resistance in Mycobacte-
avium complex disease in persons with acquired immunode-
rium avium complex lung disease. Am J Respir Crit Care
ficiency syndrome. Clin Infect Dis 2003;37:1234–1243
29. Gordin FM, Sullam PM, Shafran SD, et al. A randomized,
16. Kohno Y, Ohno H, Miyazaki Y, et al. In vitro and in vivo
placebo-controlled study of rifabutin added to a regimen of
activities of novel fluoroquinolones alone and in combination
clarithromycin and ethambutol for treatment of disseminated
with clarithromycin against clinically isolated Mycobacterium
infection with Mycobacterium avium complex. Clin Infect Dis
avium complex strains in Japan. Antimicrob Agents Chemo-
30. Corti M, Villafane MF, Ambroggi M, Sawicki M, Gancedo E.
16a. Kasperbauer S, Wilson SE, Graham JJ, Heifets L, Daley C.
Soft tissue abscess and lymphadenitis due to Mycobacterium
Fluoroquinolone susceptibility in non-tuberculous mycobac-
avium complex as an expression of immune reconstitution
teria. Presented at: The American Thoracic Society Inter-
inflammatory syndrome after a second scheme of highly active
national Conference; May 23, 2007; San Francisco, CA:
antiretroviral therapy. Rev Inst Med Trop Sao Paulo 2007;49:
17. Griffith DE, Brown BA, Girard WM, Griffith BE, Couch
31. Phillips P, Bonner S, Gataric N, et al. Nontuberculous
LA, Wallace RJ Jr. Azithromycin-containing regimens for
mycobacterial immune reconstitution syndrome in HIV-
infected patients: spectrum of disease and long-term follow-
Mycobacterium avium complex lung disease. Clin
32. Shelburne SA III, Hamill RJ. The immune reconstitution
18. Griffith DE, Brown BA, Cegielski P, Murphy DT, Wallace
inflammatory syndrome. AIDS Rev 2003;5:67–79
RJ Jr. Early results (at 6 months) with intermittent
33. Salvana EM, Cooper GS, Salata RA. Mycobacterium other
clarithromycin-including regimens for lung disease due to
than tuberculosis (MOTT) infection: an emerging disease in
Mycobacterium avium complex. Clin Infect Dis 2000;30:288–
infliximab-treated patients. J Infect 2007;55:484–487
34. Olsen RJ, Cernoch PL, Land GA. Mycobacterial synovitis
19. Lam PK, Griffith DE, Aksamit TR, et al. Factors related to
caused by slow-growing nonchromogenic species: eighteen
response to intermittent treatment of Mycobacterium avium
cases and a review of the literature. Arch Pathol Lab Med
complex lung disease. Am J Respir Crit Care Med 2006;173:
35. Hellinger WC, Smilack JD, Greider JL Jr, et al. Localized
20. Kobashi Y, Matsushima T, Oka M. A double-blind
soft-tissue infections with Mycobacterium avium/Mycobacte-
randomized study of aminoglycoside infusion with combined
rium intracellulare complex in immunocompetent patients:
therapy for pulmonary Mycobacterium avium complex disease.
granulomatous tenosynovitis of the hand or wrist. Clin Infect
21. Jenkins PA, Campbell IA, Banks J, Gelder CM, Prescott
36. Maltezou HC, Spyridis P, Kafetzis DA. Nontuberculous
RJ, Smith AP. Clarithromycin vs ciprofloxacin as adjuncts
mycobacterial lymphadenitis in children. Pediatr Infect Dis J
to rifampicin and ethambutol in treating opportunist myco-
bacterial lung diseases and an assessment of Mycobacterium
37. Liao CH, Lai CC, Ding LW, et al. Skin and soft tissue
vaccae immunotherapy. Thorax 2008;63:627–634
infection caused by non-tuberculous mycobacteria. Int J
22. Kuroishi S, Nakamura Y, Hayakawa H, et al. Mycobacterium
avium complex disease: prognostic implication of high-
38. Hanak V, Golbin JM, Ryu JH. Causes and presenting
resolution computed tomography findings. Eur Respir J
features in 85 consecutive patients with hypersensitivity
pneumonitis. Mayo Clin Proc 2007;82:812–816
23. Horsburgh CR Jr. Mycobacterium avium complex infection in
39. Marras TK, Wallace RJ Jr, Koth LL, Stulbarg MS, Cowl CT,
the acquired immunodeficiency syndrome. N Engl J Med
Daley CL. Hypersensitivity pneumonitis reaction to Mycobac-
terium avium in household water. Chest 2005; 127:664–671
24. Chin DP, Hopewell PC, Yajko DM, et al. Mycobacterium
40. Hartman TE, Jensen E, Tazelaar HD, Hanak V, Ryu JH.
avium complex in the respiratory or gastrointestinal tract and
CT findings of granulomatous pneumonitis secondary to
the risk of M. avium complex bacteremia in patients with
Mycobacterium avium–intracellulare inhalation: ‘‘hot tub lung’’.
human immunodeficiency virus infection. J Infect Dis 1994;
41. Hanak V, Kalra S, Aksamit TR, Hartman TE, Tazelaar HD,
25. von Reyn CF, Maslow JN, Barber TW, Falkinham JO III,
Ryu JH. Hot tub lung: presenting features and clinical course
Arbeit RD. Persistent colonisation of potable water as a
of 21 patients. Respir Med 2006;100:610–615
source of Mycobacterium avium infection in AIDS. Lancet
42. Centers for Diseases Control and Prevention. Respiratory
illness in workers exposed to metalworking fluid contaminated
26. Benson CA. Disease due to the Mycobacterium avium
with nontuberculous mycobacteria—Ohio, 2001. JAMA 2002;
complex in patients with AIDS: epidemiology and clinical
syndrome. Clin Infect Dis 1994;18(Suppl 3):S218–S222
43. Centers for Disease Control and Prevention (CDC).
27. Benson CA, Kaplan JE, Masur H, Pau A, Holmes KK.
Respiratory illness in workers exposed to metalworking fluid
Treating opportunistic infections among HIV-infected adults
contaminated with nontuberculous mycobacteria—Ohio,
and adolescents: recommendations from CDC, the National
2001. MMWR Morb Mortal Wkly Rep 2002;51:349–352
Midterm #2 General Instructions. This is a closed book exam. Please turn off and put away all cell phones, iPods, and other electronic devices. Answer all of questions 1-4, then pick either essay 5 or 6 to answer. Don’t miss the extra credit on the last page. Part 1. Short answer. Answer questions 1-4. Pay attention to all components of the questions to get full credit. 1.a.
Finnish philosopher Georg Henrik von Wright (1916-2003) is one of the foremost logicians of the 20th century, whose status was truly set in stone when he succeeded Ludwig Wittgenstein (1889-1951) at Cambridge. Outside the action typologies, von Wright’s logic is too technical and too deep into the realm of analytic philosophy for me to fully understand. But then it is not as an analytical philos