Mycobacteria/ Mollicutes Flashcards
mycobacteria- o2, motile?, spore?, intra/extracellular, shape
o2- obligate aerobes motile- non motile spore- no Faculative intracellular (in and out) Rod shaped
Gram of mycobacteria and what stain is it best seen in
Neither G+ or - it is acid fast (thick layer of mycolic acids)
-Ziehl-Meelsen stain (will be bright red)
steps of ziehl meelsan stain
- application of primary stain
- application of heat
- application of acid (releases stain from non acid ones
- counter stain applied
3 myobacterium spp
- Mycobacterium tuberculosis
- Mycobacterium lapraee
- Mac complex (m avium/m intracellulare)
Where is the transmission of tuberculosis
Inhalation of aerosolized infectious particles or respiratory droplets generated by coughing/sneezing
What are the risk factors of Tb infection
HIV Close contact immune supression overcrowding malnutrition
What is the general pathology of TB and how does it evade immune
tb multiply in alvelolar spaces/withing macrophages
- survive in macrophage by producing urease
- after multiplying they egress from cell killing it in process (inflammation/necrosis)
How does the immune system contain TB
triggering Th1 cells and forming granulomas around infected tissues (infected macrophage surrounded by t cells)
What is active vs latent tb
active TB occurs when protectibe mechanisms disapear allowing contained bacteria to spread/overgrow
Latent TB not known to cause symtoms
Pulmonary tb symptoms
lung tissue progressivly famaged causing systemic symptoms like fever, productive cough, chest pain, weight loss, night sweats
Extrapulmonary tb symptoms + % of time
20% of time
- CNS- menengitis
- lymph nodes- scrofula
- miliary tb
- bones, liverm kidney, gi
What is potts disease of the spine
Tuberculous spondylitis
-rare complication of tb that spreads to spine (infect intervetebral disk/vert)
How to diagnose TB
s/s present for 2 w
-positive culture, acid fast bacilli noted
chest xrays (opacities in upper lobes)
Does TB have a vaccine
preventable (does not prevent infection but usually prevents serious)
-live attenuated
What are the antibitics required for tb tx (4)
- Isoniazid (inhitis mycoloc acid synthesis)
- Rifampin (inhibits bac RNA polymerase)
- Pyrazinamide
- Ethambutol
myobacterium laprae- what does it cause, intra/extra cellular, o2, shape
Leprosy
- Obligate intracellular
- Aerobic
- bacilli
How is leprosy transmitted + mc age
Spread thru cough or contact with respiratory secretions
-soom zoonic transmission as well
mc- 10-19 years of age, 30+)
pathogenisis of leprosy (2 things it infects +symptoms)
Bacilli infect and replicate in skin cells leading to characteristic lesions of hyperpigmentation souroneded by red border
-infect schwann cells leading to demyleination in peripheral nerves (Sensory deficits)
What are the 2 forms of leprosy and which is more severe
- Tuberculoid- milder, small # of skin lesions, well formed granulomas (th1)
- Lepromatous- severe, more skin lesions, poorly formed granulomas (th2)
what is the tx of leprosy
multidrug therapy- 6-24 m regimen of 2-3 antibiotics
How is the MAC complex transmited
due to inhalation or ingestion
What are the 2 major diseases in humans caused by MAC
- Pulmonary disease- presents like pulmonary tb
2. Disseminated disease- Common in GI, liver, lymphoid tissues
What are the 2 spp related to mollicutes
- Mycoplasma pneumoniae
2. Gentital mollicute
What are mollicutes resistent to
b lactams (as they have no cell wall)
what are the virulence factors of mycoplasma pneumoniae
Makes cytotoxin that damages respiratory epithelium and cillary activity
Who does myocplama pneumoniae usually affect and symptoms
children/adolescents (upper respiratory tract infection)
Atypical pneumonia- gradual onset of low fever, malaise, headache, cough
-skin infections (small, target shaped)
is myocplasma pneumoniae vaccine preventable
not vaccine preventable
How is genital mollicute infections transmitted and what does it cause
Exposure is comon, possibly thru sex
Urethritis- discharge, painful burning urination
