Borrelia, Leptospira, Treponema
- long, slender, spiral-shaped
- require sliver stains like Warthin Starry/ Fontana's stain
Poorly Gram-staining organisms- Spirochetes
RIckettssia, Chlamydia
- Form intracellular inclusions
-Immunohistochemical Staining of tissues
Poorly Gram-staining organisms- Obligate Intracellular Organisms
Mycobacteria
- high lipid content in well wall
- thin rods
- require acid fast stain (ZN stain)
Acid- Fast Organisms
mycoplasma, Ureaplasma
-pleomorphic
-must provide sterols for membrane support
- Diene's stain for culture media or DNA stains (DAPI/ Hoechst stain) for cell lines growing mycoplasma
--> Borrelia burgdorferi
- most common vector-borne disease in the US
Reservoir: White- footed mouse and white-tailed deer
Vector: Deer tick (blacklegged ticks) -Ixodes species
Transmission: Tick bite
Human illness mainly in late spring and summer when tiny nymphs are the most active
Fever, headaches, myalgias (body aches) and new rash.
Northeastern coast of the U.S
Annular (bullseye) rash → 20 cm in diameter
ELISA ( screens IgM antibodies and IgG antibodies) and Western blot (confirmatory test) positive
1.OSP: major outer surface proteins
→ Leads to autoimmune response
→ Antigenic variation (immune invasions) -- borrelia recurrentis (also undergoes antigenic variation)
2.LPS(lipopolysaccharides) → inflammation
Borrelia Burgdorferi can infect several parts of the body
→ different symptoms at different times
→ skins, heart, joints, CNS
2 -4 weeks
Western blot to confirm the diagnosis
Complications of Rocky Mountain spotted fever:
Disseminated Intravascular Coagulation
Shock
Fever, arthralgias, myalgias and malaise
-Living in North carolina
-Physical Examination: Maculopapular rashes on hands and soles, vasculitis. Low blood pressure → shock
Rickettsia rickettsii
Reservoir: Small wild rodents, larger wild and domestic animals ( dogs) hard shell ticks
Vector: Dog tick (hard shell ticks or wood tick) → Dermacentor species
Transmission: Tick bite
Preferentially infect endothelial cells lining the small blood vessels.
Vasculitis → increases vascular permeability
Bacteria escape from the phagosome.
S/Sx: rash small and becomes big blotches later. Edema, hemorrhage → decreased organ perfusion (due to leaky blood vessels) → shock
Indirect immunofluorescence assay (IFA)
- four-fold rise in antibody titer is diagnostics
- usually negative 1st week of infection.
Weil-Felix Test (historical)
- Cross- reaction of RMSF antibodies with Proteus (gram negative bacteria) antigens OX2 and OX19. → similar to RMSF.
Pt’s Serum + proteus antigen = agglutination.
Skin biopsy from rash site
- not well stained by gram stained
- immunohistochemical stains
- obligate intracellular organism
No, not stained well by gram stains.
Need to use Acid fast stain.
Stain - principle **
→ stains bacteria with high lipid content
Primary stain: Carbolfuchsin (lipid soluble)
Dye penetration: via steam heating (Ziehl-Neelsen) or detergen (kinyoun)
Decolorization: acid alcohol (or sulfuric acid)
Counterstain: Methylene blue
Name the steps of the Acid fast (Ziehl Neelsen)
Primary illness of the respiratory system can attack any part of the body.
Reservoir- infected humans
Transmission: inhalation of infectious aerosols.
-bacteria travels via airways to pulmonary alveoli → ingestion by alveolar macrophage. (multiply in the phagocyte)
Hallmark of the disease = GRANULOMA FORMATION → leads to domino effect of immune damage
Cell wall componesnts -- Mycolic acid, lipoarabinomannan & lipids) help w/ surivival and growth in macrophages
Cord factor
Clinical symptoms
→ persistent cough, weight loss, night sweats, malaise, hemoptysis
→ Delayed hypersensitivity skin test Positive (PPD test or tuberculin test) purified protein derivative
→ Abnormal Chest Xray
Lab Tests → sputum
Ziehl-Neelsan stain = acid fast stain
→ rapid presumptive test
Culture =confirm diagnosis
→ lowenstein- Jensen medium shows rough, tough and buff colonies
PCR = rapid diagnosis
-Antibiotic susceptibility test
-smallest free-living bacteria and smallest genome size
- No cell wall → pleomorphic and not seen on gram stain.
→ sterol in membrane but cannot synthesize them → require sterol for in vitro culture
→ reservoir: human respiratory tract
-causes tracheobronchitis (chest cold) and primary atypical pneumonia, AKA walking pneumonia
- most common in school age children and young adults
entry : spread via aerosol droplets
Characteristic of Mycoplasma Pneumoniae
Attachment to respiratory epithelial cells via P1 adhesin causes inhibition of ciliary action (ciliostasis) and leads to inflammation.
Microscopy - not seen on gram stain
-culture from throat washing or sputum on Eaton’s media (fried egg colonies)
→ provide the sterol required for growth
→ slow growth - generation time
Serological test- most common
-Complement fixation test for antibodies to M. pneumonaie
-ELISA or immunofluorescence
- Cold agglutinins → agglutinate human erythrocytes at 4 degree celsius but not 37 degree celsius.
Lab diagnosis
bronchopneumonia with dry, hacking cough
Symptoms
penicillin and don't have cell walls
--> Tx: erythromycin
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