2. MYCOBACTERIA:
CHARACTERISTICS
thin,nonmotile and
nonspore forming rods
obligate aerobes
slow growing
cell wall has high lipid
content and mycolic acid
generally catalase positive
acid-fast
3. MYCOBACTERIA:
CHARACTERISTICS
thin,nonmotile and
nonspore forming rods
obligate aerobes
slow growing
cell wall has high lipid
content and mycolic acid
generally catalase positive
acid-fast
5. CLASSIFICATION
Mycobacterium
M. tuberculosis MOTT
M. leprae
complex (Nontuberculous)
M. tuberculosis
M. bovis Runyon 1 to IV
M. microti
M. africanum
6. M. TUBERCULOSIS
optimal growth: 37 C/ 5-10% CO2/ pH 6.0-7.6.
in vivo, it can use a variety of enzymes for anaerobic
metabolism
requires complex media such as Löwenstein Jensen
doubling time of ~18 hours. Colonies visible in 3-6
weeks
multiplies intracellularly in phagosome and prevents
phagolysosome fusion
9. VIRULENCE FACTORS
Mycolic acid glycolipids Catalase, peroxidase
and trehalose 6,6 and lipoarabinomannan
dimycolate (cord - help resist the host
factor)- cause cell oxidative response
granuloma formation
Sulfatides and trehalose
dimycolate- toxic to
animal models
10. MAGNITUDE OF TB PROBLEM
>1/3 of world’s population infected
8-9 million new cases annually
3 million deaths annually
~1.3 million of these new cases are in children with
~500 thousand deaths annually
Philippines ranks no.1 in Western-Pacific
16. CLINICAL MANIFESTATIONS
asymptomatic other symtoms and
signs depending on the
fever organ involved e.g.
CNS, bone, renal
cough >3 weeks
chest pain
hemoptysis
lymphadenpathy
17. CHILDHOOD TB
asymtomatic ~50% failure to make a quick
return to health after an
cough/wheezing > 2 infection e.g.
weeks measles,tonsillitis or
pertussis
fever > 2 weeks
failure to respond to
painless cervical and/or
appropriate antibiotics
other lymphadenopathy
as in AOM or
poor weight gain pneumonia
22. TUBERCULIN TEST
Mantoux test
0.1 ml of solution
containing or equivalent
to1g ( 5 TU PPD-S)
read at 48-72 hours using
ballpoint pen method
results recorded in mm
delayed-type
hypersensitivity
23. TUBERCULIN TEST
Mantoux test
0.1 ml of solution
containing or equivalent
to1g ( 5 TU PPD-S)
read at 48-72 hours using
ballpoint pen method
results recorded in mm
delayed-type
hypersensitivity
24. CULTURE
incubated at 35° to 37° C in an atmosphere of 5 to
10% CO2
cultures should be examined weekly for 8 weeks.
solid media e.g. Lowenstein-Jensen allows visualization
of colony morphology but requires 3-4 weeks
broth systems detecting 14C labelled CO2
(BACTEC) require only 5-12 days
25. ANTI-TB DRUGS
isoniazid (H) - 5 to 10 mg/kg ( max 300 mg)
rifampicin (R) - 10 to 15 mg/kg (max 600 mg)
pyrazinamide (Z) - 15 to 30 mg/kg (max 2 gm)
ethambutol (E) - 15 to 25 mg/kg (max 2.5 gm)
streptomycin (S) - 20 to 30 mg/kg (max 1 gm)
second-line drugs
PROBLEM OF DRUG RESISTANCE
26. MOTT
Nontuberculous mycobacteria (NTM) are soil and
water organisms
noncommunicable
Disease develops in setting of trauma/surgery or
immunosuppression.
INH resistant
Diagnosis is by acid fast staining of the specimen;
followed by culture and/or 16s rRNA probes culture
27. RUNYON CLASSIFICATION
Group Growth Pigment Examples Disease
1. similar to TB
yellow-orange on light 1. M. kansasii
I slow (photochromogen) 2. M. marinum
2. swimming pool
granuloma
yellow-orange in light
II slow or dark M. scrofulaceum cervical adenitis
(scotochromogen)
M. avium intracellulare similar to TB,
III slow no pigment complex (MAC) esp. in AIDS
M. fortuitum soft tissue, lung, bone,
IV rapid (5 days) no pigment M. cheilonae CNS, eye infections
28. MYCOBACTERIUM LEPRAE
cannot be cultured
can be grown in armadillos or in
mouse footpads
optimal T for M. leprae is lower than
core body temp, so it grows on skin
and superficial nerves
found in macrophages and Schwann
cells.
complex cell wall has
lipoarabinomannan (LAM) & a
unique M. leprae-specific phenolic
glycolipid (PGL-1).
29. MYCOBACTERIUM LEPRAE
cannot be cultured
can be grown in armadillos or in
mouse footpads
optimal T for M. leprae is lower than
core body temp, so it grows on skin
and superficial nerves
found in macrophages and Schwann
cells.
complex cell wall has
lipoarabinomannan (LAM) & a
unique M. leprae-specific phenolic
glycolipid (PGL-1).
30. LEPROSY
anesthetic plaques, symmetric skin
and asymmetric nodules, plaques,
peripheral nerve leonine (i.e., lion-like)
trunk involvement, facies, loss of
paucibacillary eyelashes and body
hair, multibacillary
31. LEPROSY
tuberculoid lepromatous
anesthetic plaques, symmetric skin
and asymmetric nodules, plaques,
peripheral nerve leonine (i.e., lion-like)
trunk involvement, facies, loss of
paucibacillary eyelashes and body
hair, multibacillary
32. LEPROSY (HANSEN’S DISEASE)
M. leprae causes leprosy, which is also known as Hansen’s Disease.
The incubation period for leprosy is 5-7 years. Prolonged exposure
required to become infected
8 million infected with 600,000 new cases annually
33. LEPROSY (HANSEN’S DISEASE)
M. leprae causes leprosy, which is also known as Hansen’s Disease.
The incubation period for leprosy is 5-7 years. Prolonged exposure
required to become infected
8 million infected with 600,000 new cases annually
36. TREATMENT
dapsone, rifampin, clofazimine, and either ethionamide
or prothionamide
Paucibacillary cases (tuberculoid and borderline
tuberculoid) x 6 months, dapsone alone is usually given
for up to 3 years after disease inactivity
lepromatous or borderline lepromatous leprosy may
require primary treatment for 3 years, with dapsone
alone continued for the rest of the patient's life
antiinflammatory drugs; wound care
