د.خديجة Flashcards
Mycobacteria are a large group of …… bacteria that are normal
inhabitants of soil, water, and house dust and it do not form …..
aerobic
spores
Mycobactria
Rod -shaped bacilli that sometimes resemble …..
fungal mycelium
Mycobactria Stained by …..methods like ….. because
they resist …..
Acid fast staining
Zeihl-Neelsen straining
decolorization with mineral acids or Alchol like sulphuricacid.
Mycobacterium tuberculosis
acid-fast
• non-sporing
• non-capsulated
• non-motile.
• Stained by:
Acid faststainslike Zeihl-Neelsen’s method
Mycobactrium tuberculoses
. …..(the preferred
Stains for clinical specimens)
Fluorchrome stainslike Auromine - rhodamine.
Mycobactria tuberculosis
.. … media is used most commonly used solid media.
Lowenstein-Jensen
Mycobactria tuberculosis
Liquid media which can be used like..
Middle brook 7H10
…Responsible for the
virulence of bacteria (Mycobactria tuberculosis)
Cord factor (trehalose dimycolate).
All this factors responsible for granuloma
formation (Mycobactria tuberculosis
Cell wall antigens:1Cord factor (trehalose dimycolate).
2Mycolic Acid
3Arabinogalactan
4Peptidoglycan
Cytoplasmic antigens:
Protein antigens 5, 6, 14.
These induce delayed type hypersensitivity and elicit tuberculin
reaction
Polysaccharides:
Their role in pathogenesis is not clear but they can induceimmediate type
of hypersensitivity
Tuberculosis(TB)caused mainly by…
M. tuberculosis complex (MTC)
. …tuberculosis infection can occur from
contaminated milk.
• M. bovis
T B
The cell mediated immunity results in a delayed hypersensitivity
reaction which results in formation of …..
agranuloma
Primary tuberculosis:
• In lungs, the tubercle bacilli within the macrophages form alesion
called ….
• It is found in the ….
• Some bacilli infect hilar lymph nodes.
• The enlarged hilar lymph nodes and Gohn focus together iscalled
…..
Gohn focus.
lower lobe or lower part of the upper lobe.
primary complex
- Secondary (post primary) Tuberculosis:
• The lesions occur in …….
apex of lungs resulting in tuberculomas
(granulomas caused by M. tuberculosis)
Rapid culture methods
- Radiometric method (BACTEC) – growth can be observedwithin 9-12
days. - Mycobacte tube (MGIT) – growth is ria growth indicator
observed in 7 -14 days
Biochemical reactions
T.B
- Niacin test: a canary yellow shows a positivetest.
- Catalase-peroxidase tests: M. tuberculosisisperoxidase positive and
weakly catalase positive. - Nitrate reduction test: pink color indicates apositive test.
Mantoux test (tuberculin test)
•
It is a skin test for delayed hypersensitivity reactionin tuberculosis.
• 0.1 ml of purified protein derivative (PPD) containing5 tuberculin units is
injected intradermally into skin on forearm.
• The injection site is observed after 48 hours forinduration
(swelling)
BCG (Bacillus Calmette Guerin) vaccine:
• Contains the live attenuated strain
M. bovis .
BCG vaccine does not …. but protects against…
prevent infection
miliary
tuberculosis.
The major disadvantage of BCG vaccine is …..
it gives false positive reaction
with Mantoux test & hence diagnosis of TB becomes difficult in vaccinated
persons.
• This organism infects cattle
Mycobacterium bovis
Mycobacterium bovis
• It is very similar to M. tuberculosis, but it can be distinguished by its…..
poor growth on L J medium andbeing highly pathogenic to rabbits.
Non-tuberculous Mycobacteria ( Environmental
mycobacteria )
• Called….. and are present in theenvironment.
Atypical Mycobacteria
T.B
They are not transmitted from one person to another.
Non-tuberculous Mycobacteria ( Environmental
mycobacteria )
• …..causes infectionsimilar to
pulmonary tuberculosis usually in HIV patients and immunocompromised
persons.
M. avium, M. intracellulare and M. kansasii
M. ulcerans causes skin ulcers commonly called as …
Buruliulcers
…. causes swimming pool granulomas
• M. marinum
NTM
They can be distinguished from
otherMycobacteria by:
• their rate of growth
• temperature required
• and pigment production.
• They are catalase strong positive and aryl-sulfatase positive, niacin
test negative.
Mycobacterium leprae
…. culture is available
Tissue
Mycobacterium leprae
• An …… Bacterium
obligate intracellular
Mycobacterium leprae• Causes a chronic granulomatous infection involving:
Skin
nasal septum
and peripheral nerves
Mycobacterium leprae
Morphology
• It is a slightly curved shortacid
fast bacillus found within:
the endothelial cells of
blood vessels
or in mononuclear cells.
….cannot be grown inculture media
in laboratory
M. leprae
M.leprea
The lesions develop in cooler areas of the body like ….
• The bacilli develop within the ….
earlobes and
superficial nerves.
skin, histiocytes, endothelialcells of blood
vessels and Schwann cells of peripheral nerves.
There are two major forms of leprosy:
Lepromatous leprosy (LL)
Tuberculoid leprosy (TL)
Rickettsia
They are obligate intracellular parasites
stained best by Giemsa stain
grown in tissue cultur
• They are maintained in nature in certain arthropods such as
ticks, lice, fleas and mites.
• They are transmitted to humans by the bite or faeces of the
arthropod
Ricktissia 2 group
Typhus group
Spotted fever group
Rickettsial diseases
EPIDEMIC TYPHUS
ENDEMIC TYPHUS
ROCKY MOUNTAIN SPOTTED FIVER
-EPIDEMIC TYPHUS or ….
Causative organism:…
• Vector ….:
brill zinsser disease
Rickettsia prowazeki
esuol ydob, lice, louse
The Rickettsia prowazeki
circulate in the blood
strea during the ….
• They invade the capillary
endothelium causing
. …….
• Disseminated
intravascular coagulatio
and vascular occlusion
may occur
first
week.
vasculitis in the brain,
heart and other organs
Rickettsia remains latent in lymph nodes for several years.
• when exposed later to factors which lower their immunity,
• Rickettsia may be activated to produce disease again
• This condition is known as .. …in which the infection
is
….
Brill’s disease
endogenous
ENDEMIC TYPHUS
• Causative organism:
…….
• Vector :…..
• Mode of transimission:
Infection occurs by
Rickettsia typhi
rat fleas
bite of
rat flea
ROCKY MOUNTAIN SPOTTED FIVER
Causative organism:
……
• Vector ….
• Mode of transimission:
1.The organism is transmitted
trans ovarian among ….
2……..are also
reservoirs of infection.
3.Humans are ……..
no ……. transmissionمهم
Rickettsia Richtessi
tick
ticks
Dogs and rodents
accidental hosts;
person to person
ROCKY MOUNTAIN SPOTTED FIVER
Most cases occur in….
.
children
Rash of ROCKY MOUNTAIN SPOTTED FIVER
• The typical
rash, which
appears 6-2
days later,
begins With
……. that
progress to
…… that
appear first on
hands and feet
then move to
the trunk.
macules
petechiae
Early diagnosis and prompt treatment are lifesaving of Rickettsial diseases;
specimen blood and skin biopsy specimens
methods are very useful for establishing a diagnosis in
the acute stage.
immuno-histochemical methods and PCR.
Isolation procedures
are only done in few
laboratories, as they
are ……..
hazardous
Weil–Felix test( imprtant relation between protus and
rickettsia!!!!)
•
The basis of the test is the presence of antigenic cross-reactivity
between Rickettsia spp. and certain serotypes of nonmotile Proteus spp., a phenomenon first published by Edmund
Weil and Arthur Felix in 1916. Weil-Felix is a nonspecific agglutination
test which detects anti-rickettsial antibodies in patient’s serum. WeilFelix test is based on cross-reactions which occur between antibodies
produced in acute rickettsial infections with antigens of OX (OX 19,
OX 2, and OXK) strains of Proteus species. Dilution of patient’s serum
are tested against suspensions of the different Proteus strains
The treatment of
choice for all
rickettsial diseases
is ….. .. the second
choice
tetracyclines ,
htiw
chloramphenicol
as
……. is the only
species and causes Q fever.
Coxiella burnetii
COXIELLA differs from rickettsia in
.
1being more resistant to drying,
disinfectants and UV.
.2It can survive for months in dried
animal discharges (placental tissues
or aminiotic fluid) faeces, urine or
milk; due to endospore formation
during an intracellular
developmental cycle.
Mode of transmission of COXIELLA
• It is not transmitted to humans by …….
• However, the organism is found in ticks which transmit it to
…….
• These animals are the …. , passing the
organism in their milk, discharges and excreta.
the bite of an arthropod.
goats, sheep and cattle.
reservoir for human infection
Coxeilla
Inhalation of aerosols containing the organism, which enter the
lungs, results in infection of alveolar macrophages and a ….
brief
rickettsaemia.
Coxiella
• Acute disease begins with …. and ….
….occurs in about half of cases.
• …. is frequent enough that the combination of ……..should suggest Q fever.
fever
influenza-like symptoms.
Pneumonia
Hepatitis
pneumonia and
hepatitis
Chronic Q fever characterized by life threatening …….. may
occur in patients with abnormal valves.
• It is associated with a rise in antibody titre to phase I C. burnetii
and
• negative blood cultur
endocarditis
Coxiella diagnosis
……
is considered the best method
Indirect immunofluorescence
All ricketssial diseases transmetted by
arthropodes except ..
All ricketssial diseases manifested by skin
rash except …
All ricketssial diseases are zoonetic disease except ……….
wich are transmetted
from human to human by lice.
Qfever (coxiella burnitti).
Q fever
epidemic typhus
