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Mycobacterium
kansasii is a
slow-growing photochromogenic mycobacterium
causing infection in patients with AIDS, but has also been identified
in HIV negative patients.
Visit:
Atypical Mycobacterial Infection
; Mycobacterium Marinum
Infection.
After
Mycobacterium Avium Intracellulare, Mycobacterium
kansasii is the second most common non-tuberculous infection in
patients with AIDS. This important mycobacterial pathogen usually infects patients late in
the course of AIDS.
Visit:
Cutaneous
lesion associated with AIDS
;
AIDS related malignant tumours ;
Mycobacterium Leprae Inf.
;
Mycobacterium ulcerans Inf.
It can
cause
pulmonary infection
in patients with predisposing lung diseases, such as chronic
obstructive pulmonary disease, bronchiectasis, pneumonoconiosis,
previous
tuberculosis
or bronchogenic carcinoma.
South African gold miners with a
background of silicosis or old tuberculous scarring have increased
susceptibility to this infection, which is most often found in the
lungs.
Disseminated
infections, mainly in immunosuppressed patients, also occur.
Various other
clinical settings have been described including involvement of skin
and skeletal system. It can
cause various focal infections,
such as osteomyelitis, gastrointestinal infection, gingivomandibular
disease, appendicitis, and brain abscess.
The disease is usually acquired after
contact with infected water and there is often a history of
concomitant trauma.
Typically M. kansasii infections show
granulomatous inflammation associated in some instances with acute
inflammatory changes and necrosis.
According one study
five types of reactions
were seen - (i) abscesses; (ii) granulomas without giant cells but
with large areas of central eosinophilic necrosis with numerous
neutrophils and nuclear debris ; (iii) well-organized granulomas
without giant cells or necrosis, but with a mononuclear cell
infiltrate ; (iv) areas of eosinophilic granular necrosis with
scattered clusters of epithelioid histiocytes ; (v) and spindle-cell
proliferations with scattered clusters of neutrophils. According
to another study a sixth pattern has been recorded - (vi) that of
sheets of foamy histiocytes containing AFB.
The bacilli have a distinctive
appearance when compared to other mycobacteria, being larger, broader
and more coarsely beaded.
Special stains:
Both
Mycobacterium Avium Intracellulare
and
Mycobacterium kansasii
stain with periodic acid–Schiff,
although staining appears more intense with MAC.
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