Medically important bacteria (intracellular)

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Medically important bacteria (intracellular) by Mind Map: Medically important bacteria (intracellular)

1. Rickettsae

1.1. Proprieties

1.1.1. infection transmitted by insects infects the eggs (like dingy)

1.1.2. cannot generate their own energy

1.1.3. fragile plasma membrane

1.1.4. short bacilli

1.1.5. gram negative but poorly stained

1.1.6. Best seen using Giemsa stain

1.2. Diseases

1.2.1. Rocky mountain spotted fever R. Rickettsii infection through bites by dog or wood ticks infects local endothelial cells and multiply spreads to other parts through blood Clinical presentation incubation period 7 days High grade fever after incubation Macular rash appears first on the extremities The rash quickly becomes petechial or hemorrhagic may lead to death if untreated

1.2.2. Lousebourn typhus (epidemic typhus) caused by R. prowzekii - transmitted by human body louse symptoms develop after 8 days presents with high fever, chills, severe headache, and stupor rash may occur and may not May infect the CNS and may cause myocarditis activation of latent disease cause mild symptoms (Brill-Zinsser disease)

1.2.3. Maurine typhus (endemic typhus) Caused by R. typhi similar to epidemic typhus but symptoms are milder rodents are the reservoir infection transmitted to humans by rat fleas

1.2.4. other spotted fever R. conori R. seberica

1.3. Diagnosis

1.3.1. skin biopsy

1.3.2. direct immunoflurescence test in tissue Bx

1.3.3. Detection of specific IgG and IgM antibodies by ELISA or indirect immunoflurescence assay

1.4. Treatment

1.4.1. Doxycycline is the drug of choice including children

1.4.2. Azithromycin in pregnany women

2. bacteria are intracellular because

2.1. no cell wall

2.2. unable to generate their own energy

2.3. unable to multiply outside the cell

2.4. intracellular life cycle

2.4.1. infects endothelial cells

2.4.2. enter endothelial cells through endocytosis

2.4.3. elementary bodies are formed

2.4.4. multiply inside the endosome

2.4.5. migrate to cell wall and cause cell death releasing large number or organisms in the blood and lymphatic system

3. Myocaplasma

3.1. properties

3.1.1. some are normal flora of the mouth and the genitourinary tract

3.1.2. lack cell wall peptidoglycan but is enclosed in trilaminar plasma membrane

3.1.3. the smallest bacteria (can pass through bacterial filters and can contaminate cell cultures)

3.1.4. facultative anaerobes from small fried egg colonies after 10 days if incubation

3.1.5. intracellular but can grow in artificial media and take long time

3.1.6. highly polymorphic in shape

3.1.7. gram negative but difficult to stain

3.2. types

3.2.1. M. pneumoniae transmitted by droplets and cause reparatory tract infection present as atypical pneumonia, but sometimes can cause bronchitis, otitis media and pharyngitis cause more than 20% or pneumonia attach themselves though the P1 protein to the host cell sialic acid rich glycolipids up to 1 week incubation clinical presentation after incubation period the patient presents with atypical pneumonia with fever, productive cough, malaise, and chest auscultation self limiting and recovery usually in 10 days antibodies specific for membrane glycolipids and P1 protein cross react with I antigen on RBCs which known as cold agglutinin (because they react best with RBCs at low temperature, causing haemolytic anaemia) diagnosis most common: serology gram stain is not helpful PCR is good treatment Doxycycline is drug of choice Azithromycin is alternative

3.2.2. Genital mycoplasma Ureaplasma urealyticum urethritis in men endometritis and vaginal discharge in women M. hominis causes postpartum fever and pelvic inflammatory disease Treatment tetracycline (NOT azithromycin)

4. Chlamydia

4.1. Properties

4.1.1. Obligate intracellular bacteria

4.1.2. Obligate intracellular bacteria

4.1.3. infect epithelial cells only

4.1.4. grows in the cytoplasm forming inclusion bodies

4.1.5. Depends on target cells for ATP and NAD

4.1.6. Their cell wall is gram negative but lack peptidoglycan layer

4.2. Chlamydia trachomatis

4.2.1. 14 serotypes ABC cause eye infection (trachoma) conjunctivitis may lead to blindness D-K STDs urethra, cervix, proctitis, salpingitis, endometritis L1,L2,L3 Lymphogranuloma venereum (STD)

4.3. Chlamydia pneumoniae

4.3.1. community acquired interstitial pneumonia

4.3.2. infect upper resp. tract: laryngitis and bronchitis

4.3.3. linked to atherosclerosis

4.3.4. Diagnosed with PCR, or antibody detection and direct immunofluorescent test

4.4. Chlamydia psittaci

4.4.1. zoonotic disease caused by inhalation of organism from birds

4.4.2. starts by lower resp. infection and pneumonia

4.4.3. hepatospleenomegaly follows

4.4.4. diagnosis by culture, immunofluorescent test, and serology for specific antibodies

4.5. Treatment

4.5.1. doxycycline and erythromycin