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Atypical
mycobacterial infection is caused by a type of mycobacterium other than
Tuberculosis
.
Mycobacteria other than M.
tuberculosis are widely distributed in nature and infrequently cause disease
though several species are potentially pathogenic.
The widely used
classification of Runyon based on pigment production and growth rate has
been superseded by classifications in which the organisms are grouped
according to biochemical and antigenic similarities.
The major pathogenic
groups include the following:
1. Slow-growing potential
pathogens:
i)Mycobacterium Avium Intracellulare
ii)Mycobacterium Kansasii
iii)Mycobacterium Marinum

iv)Mycobacterium Ulcerans
2. Rapidly growing potential
pathogens:
i)
M. fortuitum
ii) M. chelonei
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Non tuberculous mycobacterial infections.
Rev Med Interne. 2008 May;29(5):370-9. Epub 2007 Oct 22.
PURPOSE: Non
tuberculous mycobacterial (NTM) infections, also called atypical
mycobacterial infections, are caused by environmental mycobacteria
and usually occur in cases of general or local immunosupression.
These infections usually concern the lungs, the lymphatic system,
the skin or the bones tissues. They are sometimes disseminated. In
spite of new efficient antibiotics, including macrolides,
therapeutic failures are common and favoured by long treatments
with their potential adverse effects and drug interactions.
CURRENT KNOWLEDGE AND KEY POINTS: The prevalence of atypical
mycobacterial infections is increasing and is also observed in
internal medicine and geriatric wards. Their clinical expression
can be varied. Nowadays, these infections are more and more
frequent in non-infected HIV patients, whether immunosupressed or
not. Concerning other localisations of atypical mycobacterial
infections, iatrogenic causes seem to be increasing and cases of
nosocomial transmissions have also been described. When a NTM is
found in a sample, its role in the cause of an infection must be
assessed with criterias distinguishing infection from colonisation.
FUTURE PROSPECTS AND PROJECTS: For those who are not locally or
generally immunosupressed, it is important to search for an
immunological deficiency. Indeed, patients having congenital
deficiencies occurring in the interferon and interleukine pathways
can develop repeated NTM infections. Therefore, for pulmonary
infections in treatment failure and for disseminated infections,
an adjuvant treatment by interferon gamma could be proposed. New
molecules have recently been tested and can be used in some
atypical mycobacterial infections. |
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