Transcript Mycobacteria-Chlamydia-Mycoplasa-

• GUIDLINE:
2- Clarification for mycobacteria in general
3-general characteristics for myco –acid fast4-pathogenicity characteristics
5-TB types
6- TB primary type
7-TB secondary type
8- TB diagnosis and treatment
Mycobacteria (Acid-Fast)
• Mycobacteria is divided into 3 types:
1. M.tuberculosis
2. M.Leprae –we didn’t take3. Nontuberculosis Mycobacteria –we didn’t takeThey are rods with lipid-laden cell walls, and that’s what makes
them acid fast, how?
When we have a smear of sputum for example, and we cover it
with red stain carbofusion -stain with high affinity for
mycobacterial cell walls component, it’s found in Ziehl-Neelsen
stain -and heated for better penetration, then poured with
acid alcohol -95% ethanol and 3% HCL- and then
counterstained with methylene blue, the cell wall lipids will not
dissolve when alcohol is applied and thus red stain won’t be
washed off. So acid-fast organisms resist decolorization and
hold fast to their red stain.
Mycobacteria Group
Acid-Fast Bacilli:
1. are obligate aerobic which makes snese because they mostly infect the lungs
where O2 is abundant
2. Their cell call contains protein-polysaccharides with high Phospholipids (mycolic
acid –large fatty acid-, waxes) and they act like virulence factors (it is loaded with
lipids and that’s what makes them acid-fast ).
3. When they attack tissues they cause Necrosis, in case of tuberculosis as we took in
pathology they cause caseous necrosis and forms granuloma where they can
remain viable.
4. Resistant to Dryness, low Acidity, Alcohol and detergents (like carbafusion
mentioned before)
5. Susceptible to UV-light and heat.
6. They’re Common in Human and infected ones are Asymptomatic persons -like in
case of primary asymptomatic tuberculosis which is the common type but the
primary symptomatic is less common and happen mostly in children and elderly
or immunocompromised patients because they have a weak immune system or
when reactivation happens- , domestic Animal and Birds, Environment
7. They kill 3-5 Million yearly.
• Human/animals Pathogens:
1. Slow growth in vitro, the culture needs (2-6 weeks)
1. Nonpathogenic species: lives in genital tract or skin ( like M.
smegmatis which has rapid growth 3-7 days and lives in normal
genital secretions).
1. Pathogenic species : Mostly M. tuberculosis and few percentage
M. bovis which causes tuberculosis in Animals –cattle- , and if
transmitted through Dairy products to humans can cause
Intestinal tuberculosis. Atypical Mycobacteria (nontuberculosis
mycobacteria) they are divided into pigmented and nonpigmented, common in environment and Rarely cause lung
Tuberculosis.
• Pulmonary Tuberculosis:
1. Exudative, primary type
2. Active productive, reactivation,
secondary type
• Pulmonary Tuberculosis/ Exudative type –primary-:
1. Slow intracellular growth in lung tissue
2. Incubation time 1-12 months transmitted via droplet infection (cough,laugh,..)
3. Primarily causes mild Lung lesion infects Mostly Children (90%)
4. Causes Asymptomatic infection discussed earlier and Rarely causes active lesions
which are called (cavitary lesions with air-fluid levels) caused by progressive
tuberculosis leading to severe cases where lung necrosis is developed and cavities
and holes are formed and they’ll be filled with fluid which is seen in CT scan and
chest radiography.
5. Recovery: even with no treatment most cases will control infection and have
healing by encapsulation and forming granuloma which decrease the number but
they’re still viable.
6. Positive skin tuberculin test: it’s anintradermal injecetion of antigenic protein
particles from killed M.tuberculosis, will reveal if the person is infected or not,
because many of infected individuals will not manifest a clinical infection for
years. When a positive PPD test occurs, you can treat and eradicate the disease
before it significantly damages the lungs or other organs. And we use it when we
have suspects in person with a low-grade fever and cough or a person who has
been in contact with infected ones.
We inject it intradermally and within 1-2 days, skin will be red, raised and hard
(positive)
7. Hypersensivity Immunity
“ Asymptomatic infection is not necessary result in Disease.”
• Active-Productive type: Adult infection: Most adult cases of
tuberculosis occur after the bacteria have been dormant for some
time.
1. Happens by Reactivation of old tuberculosis lesions
2. may present in any Body site, The infection can occur in any of
the organ systems seeded during the primary infection. It is
presumed that a temporary weakening of the immune system
may precipitate reactivation. Like in Intestinal tract, Kidney and
bones.
3. Meningitis common in children: TB causes subacute meningitis
and forms granulomas in the brain.
4. Lung lesion: patient will usually persent with a chronic lowgrade
fever Cough, Bloody sputum, night sweats and weight loss.
5. Detection by X-ray and shows positive tuberculin test, Larger
reaction.
• Lab Diagnosis:
1. Direct AFS(acid fast stain) : Ziehl-Neelsen stain
2. Culture in Lowenstein -Jensen Medium from Sputum, urine,
Pleural fluid, CSF, Biopsy. we have to incubate for at least 6
weeks. However we may recognize the first colonies after 2
weeks. From these colonies we have to prepare an Acid Fast
Stain and then do biochemical tests to confirm a case of TB.
3. PPD
4. X-rays
• Treatment: Combination of anti-tuberculosis drugs for 6-24
months. (Rifampin, streptomyocin,Isoniazid,..)
• Prevention by BCG vaccine ( Bacilli Calemtte- Guerin) for
Children.
Chlamydia group
• Chlamydia Cell is Small and it has a Gram-ve wall but unlike other Gves it has few amount of liposaccharides and no murmaric acid.
• It’s obligate intracellular means it lives inside the cells and take ATP
from host cells.
• Dimorphic growth: has two forms 1)Infectious stage(Elementary
bodies/ Infectious) which are responsible for attaching to the host
mucosa cell and promoting its entry and then inhibit phagosomelysosome fusion and develop into 2) (Inclusion bodies/Reticulate
bodies) and replication occurs by binary fission.
• There are 3 species only two are required:
1. Chlamidya Trachomatis
2. Chlamidya Pneumoniae
Firstly, Chlamydia trachomatis: infects eyes and genital organs
Genital tract:
A common cause of STD worldwide causes Nonspecific urethritis –urethritis isi caused
by nisseria also and called gonococcal urethritis but the one caused by chalmydia is
nongonococcal urethritis that’s why it’s called NGU or nonspecific only for
differentiation- and it’s associated with pus. It can also cause Prostatitis, Vagnitis
and Cervicitis which are associated with discharges and the inflamed areas are
swollen and red, it might lead to infertility
Eyes:
Newborns with chlamydial conjunctivitis:
Pregnant mothers during pregnancy especially in the delivery can transmit the disease
to her fetus, infecting its Eyes causing an inflammatory reaction in the conjunctiva
and later in the cornea, producing trachoma; trachoma means developing damage
in the conjuctiva causing blindness; and this is associated with blindness so it can
be so severe. All newborns in the US are given erythromyocin eye droplet
prophylatically.
infected patients shows mild to severe eyes redness, swollen eyelids and discharge
from the eyes which can be thin and watery or thick and yellow..
Trachoma leads to Blindness if not treated.
Secondly, Chlamydia pneumoniae:
Attached to Tracheal Epithelial cells and cause acute bronchitis and
Atypical pneumonia which is Mild-severe pulmonary infection
associated with mild-sever dry cough, abdominal paing and
some GI symptoms and it may recover without the need of
antibiotic –not dangerous or fatal- and it’s Common in children
in All ages
• Diagnosis & treatment : it’s diagnosed by Clinical features &
serological test.
• After 4-8 weeks of chlamidya incubation is develops antibodies
against it and then could be discovered
• It’s cultured only in McCoy tissue culture –livinng culturebecause it can’t live in nonliving cultures because of the need of
ATP from the host cells.
• PCR test are also used and immunoflourescence techniques.
• Treated by Antibiotics and there’s No Vaccine
Chlamydia inclusion bodies/Acid-Fast
Mycobacteria
Mycoplasma group
• The smallest Bacteria and what is unique about it that it Lacks Cell
Wall but has a Lipid bi-layer Membrane paded with cholestrol coating
it –so penicillin cannot attack it because its target is peptidoglycans in
cell wall which not found-.
• Aerobic and lives in Respiratory/Urinary Mucosa.
• Found in Human, Animals and Birds.
• It has 2 species :
1. M. pneumoniae: Human pathogens. causes mild Pharyngitis,
Bronchitis, Pneumonia, and associated with Dry cough and Fever –
similar to atypical pneumonia-. Most Common in old children &
Young adults and it’s Less Elderly, Common infection in Fall-Winter.
2. M.hominis/M.genitalium : Part of oral- genital flora cause
Nonspecific Urethritis, Vaginitis, Cervicitis.
• Diagnosis & treatment: Sputum, Urine Culture, Cold-Agglutination
Test, ELSA Specific antibodies, PCR. TREATMENT : Antibiotics and No
Vaccine.
Legionella pneumonphila
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It causes Legionnaires’ disease –severe pneumonia- which was
found in 1976 USA
It’s Thin G-ve Coccobacilli-Filments.
Facultative Anaerobes and Survive at 0-80 C.
Lives in Cold/Hot Water, Air Condition, Wet Soil, Aerosols ‫بخاخات‬Fine
sprays.
Droplet infection.
Infect Respiratory Mucosa.
It’s a facultative Intracellular parasite that settle in the lower RT
and is globbed up by Monocyte-Macrophage This means that once
it’s phagocytosed it inhibits the phagosom-lysosome fusion,
surviving and replicating intracellularly
Extracellular growth,Not contagious disease.
Legionella Pneumophila
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Clinical Features: High Fever, dry Cough, vomiting, stomach
discomfort and Diarrhea. Other common symptoms include
headaches, muscle aches, chest pain, and shortness of
breath, Pneumonia, Renal Failure, and if it was severe it
might lead to Death.
Mostly common in elderly, Immumodeficient patients like
AIDS pateints and heavy Smoking Persons.
Diagnosis & treatment: Special Culture Media, Blood-sputum
culture. Detection by Specific antibodies, PCR. Treatment:
Antibiotics.. No Vaccine.
Legionella pneumophila is the most common cause of
community acquired pneumonia.
Spirochetes Group-1
• They’re Gram-ve and have Spiral forms and Long –very selinder and
tightly coiled- and Have long helically coiled cells (5-20um).
• Common Human, Animals, Arthropodes.
• Nonpathogenic /Pathogenic.
• 2 species:
1. Treponema species: Nonpathogenic, and lives in Oral cavity.
2. Treponema palldium: causes Syphilis which is a Veneral
Disease(STD) transmitted through Sexual Contact.
entering the host via breaches in squamous or columnar epithelium.
• It gains access to host's blood and lymph systems through tissue and
mucus membranes.
• Incub. 2-week-Few Months: it changes from Acute to Chronic
Infection with time (because it has stages)
• Associated with Mucosa/Skin Lesions-Chancre on Genitalia, Anal
area and Mouth. It’s a Systemic Disease and can Affect Any Body
Organ because of its ability to reach blood and lymhp and causes
Meningitis, Hepatitis, Nephritis, Granulomatous lesions.
• Congenital Syphilis: happens with infected pregnant women, the
Treponema pallidum crosses placenta and infect the fetus.
• Diagnosis: spirochetes cannot be cultured in ordinary media and
even it’s G-ve but it’s too small to be seen with light microscope
so we use special ways like Direct Dark-field Microscopy,
immunoflurecense and silver stain.
• Serological Test like
1. VDRL (Venereal Disease Research Lab).
2. Fluorescent Trep. Antibody-Test (FTA).
3. No Culture and treated with Antibiotics
Legionella- Spirochete Cells
Spirochetes Group-2/ Borrelia
1- Borrelia Burgdorferi: causes Lyme Disease and Common in USA.
• Carried by Biting Insects (Ticks), Wild Animals, Rodents and Birds.
• Incubation : Few Weeks- Months.
• The primary stage is featured by Single/Multiple Skin Erythematic Lesions and
then in the upcoming stages after years it turns into a Systemic Disease by invading
body systems and organs, and in stage 2 and 3 causing Arthritis, CNS diseases –
encephalopathy and meningitis and nevre palsies- and Cardiac Abnormalities.
2- Borrelia Recurrentis is found Worldwide. They cause an Epidemic/Endemic
Relapsing Fever by Biting Insects (Human Lice/ Animal Ticks) which may lead after
reachin blood to Septicemia and associated with Low-High Fever, Chills, Severe
Headache and symptoms are resolved in 3-6 days then developing similar features
for another 3-6 dadys and relapses will continue to occur with shorter and milder
inervals, Common Relapses.
3- Leptospira which causes Liptospiral diseases: Zoonosis –infect humans and
animals- ,and cause mild-severe fatal systemic disease which is Weils’s
disease(infection with jaundice), it involves renal failure, hepatits , mental status
change and hemorrhage in many organs associated with high Fever, vasculitis ,
Bleeding.
• Diagnosis: Serological Tests and Special fluid culture methods. Especially for CSF
Lyme Disease/ Tick
Erythematic lesions