Non Mycobacterium Tuberculosis

1. MYCOBACTERIUM II
Non-Tuberculous Mycobacteria
[NTM]
PRESENTED BY EKTA

2.  Mycobacteria other than mammalian
tubercle bacilli, which may occasionally
cause human disease are called ‘non-
tuberculous mycobacteria (NTM)’
 Other names include atypical mycobacteria,
anonymous, unclassified Mycobacteria and
Mycobacteria other than M. tuberculosis
(MOTT).
 They cause opportunistic infections inhuman
beings.
 Over 80 species of NTM are found worldwide
in soil and animals
INTRODUCTION

3. Runyoun classification
NTM have been categorized into four groups by Runyoun
(1959) based on pigment production and the growth rate:
1. Photochromogenes
2. Scotochromogens
3. Non-photochromogens
4. Rapid growers

4. Runyon
Group
Numbe
r
Group Name Description
I Photochromogens Colonies of NTM that develop pigment following
exposure to light after being grown in the dark
and take more than 7 days to appear on solid
media
II Scotochromogens Colonies of NTM that develop pigment in the
dark or light and take more than 7 days to
appear
on solid media
III Nonphotochromogens Colonies of NTM that are nonpigmented
regardless
of whether they are grown in the dark or
light and take more than 7 days to appear
on solid media
IV Rapid-growers Colonies of NTM that appear on solid media in
less
than 7 days

5. They are not usually transmitted from person to
person
Source of infection is water, soil, food and animals
Human infection with NTM is common in some
areas, disease is rare
Exhibits dysgonic growth on LJ medium
Niacin and nitrate reduction tests are negative
Not able to cause progressive disease in guniea
pigs

6. Photochromogens
 The important species in this group are M. kansasii,
M. marinum and M. simiae
M. kansasii
 M. kansasii causes chronic pulmonary disease resembling
tuberculosis
 It may also occasionally cause infections of the cervical
lymphnodes, penetrating wound infections and
granulomatous synovitis
 It can produce generalized infection in HIV patients

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8. Mycobacterium marinum
 Causes a warty skin lesion known as swimming pool or
fish tank granuloma
 Closely resembles M. kansasii but can be differentiated by its
poor growth at 370C, negative nitratase, and positive
pyrazinamide hydrolase

10. Scotochromogens
 These strains form pigmented colonies (yellow-orange-red)
even in the dark
 They are widely distributed in the environment and
sometimes contaminate cultures of tubercle bacilli

11. Important species in this group:
M. scrofulaceum may cause scrofula (cervical
adenitis) in children
M. gordonae often found in tap water is a
common contaminant in clinical specimens and
a rare cause of pulmonary disease
M. szulgai, an uncommon cause of pulmonary
disease and bursitis
It is a scotochromogen when incubated at 370C
but a photochromogen at 250C

12. Scrofula (cervical adenitis)

13. Non-photochromogens
 Medically important species in this group are M. avium,
M. intracellulare, M. xenopi and M. ulcerans
M. avium
 Which causes natural tuberculosis in birds and
lymphadenopathy in pigs, is one of the most common
opportunistic human pathogens
M. intracellulare
 Is commonly known as Battey bacillus

14.  M. avium and M. intracellulare are so similar that that they
have been considered as one group, the M. avium complex
(MAC)
 MAC complex cause lymphadenopathy, pulmonary
lesions or disseminated disease, particulary in AIDS
patients
 M. xenopi, originally isolated from toads, may
occasionally cause chronic lung disease in human
beings
 M. ulcerans cause buruli ulcer

15. Rapid growers
 This is a heterogeneous group of mycobacteria capable of
rapid growth, colonies appearing within 7 days of incubation
at 370C or 250C
 Within the group, photochromogenic, scotochromogenic,
and non-chromogenic species occur
 Most of these are purely are environmental saprophytes

16.  The medically important species are M. fortuitum and
M. chelonae
 M. fortuitum and M. chelonae occasionally cause
pulmonary or disseminated disease but are principally
responsible for postinjection abscesses and wound
infections
 Outbreaks of abscesses following injections of
vaccines contaminated by these mycobacteria have
been reported

17. Lesions produced by NTM
1. Localized lymphadenitis
2. Skin lesions (Postinjection abscesses, swimming pool
granuloma and buruli ulcer)
3. Tuberculosis-like pulmonary lesions
4. Disseminated disease

18. Swimming pool granuloma
 It is caused by M. marinum and is also known as fish tank
granuloma
 M. marinum occurs as a saprophyte in fresh or salt water
 Human infection originates from contaminated swimming
pools or fish tanks
 The bacilli enter scratches and abrasions and cause warty
lesions similar to those seen in skin tuberculosis

19.  The lesion, beginning as a papule and break down to
form an indolent ulcer
 The disease is usually self-limiting although
chemotherapy with minocycline, cotrimoxazole or
rifampicin with ethambutol hastens its resolution

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21. Buruli ulcer
This disease is caused by M. ulcerans
The name is derived from the Buruli district of Uganda where
a large outbreak was extensively investigated
Ulcers are usually seen on the legs or arms and are
believed to follow infection through minor injuries
After an incubation period of a few weeks, indurated nodules
appear, which break down forming indolent ulcers which
slowly extend under the skin
When the immunoreactive phase sets in ulcers heal
with disfiguring scars

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