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Gram-Positive bacteria
Grows as filaments and forms spores when nutrients run out


Produce Antibiotics:
Tetracyclines
Macrolides (erythromycin)
Aminoglycosides (Streptomycin, Gentamycin)

Opportunistic Pathogen
Transmitted via inhalation (lungs) or trauma (cutaneous infection)

Can cause
Pulmonary disease (bronchitis, pneumoniae, lung abscesses)

Cutaneous Infections ( Lymphocutaneous infection, cellulitis, subcutanous abscesses)

Secondary CNS infections (Meningitis, Brain Abcesses)

Strict aerobe

Partial acid-fast stain
Catalase positive

Some cording

Caused by Actinomycetes

Causes lesions on the small intestine. Damages the villi => Poor nutrition

Associated Symptoms:
Look like fasting, weight loss


Men (80%) during middle age
higher in Caucasians (possibly genetic)

Actinomycetes

Forms hyphae-> Spores as nutrients depleted, otherwise filamentous network in soil


Produces streptomycin

Leprosy and Tuberculosis

IIntracellular organism

Weakly Gram positive, acid fast

Lipid-rich cell wall.



Transmitted via food / water.
prevalent in Immunocompromised patients (mostly in this group)


Generates chronic pulmonary disease (middle lobe infiltrates / solitary nodules). Can also progress to disseminated disease

Intracellular growth - hard to culture on artificial media

Tuberculoid Leprosy
Borderline tuberculoid leprosy
Borderline Lepromatous leprosy
Lepromatous leprosy

All caused by M. leprae

transmitted by contact, aerosols, inhalation

Grows intracellularly

Causes skin lesions (can fuse fingers together). Damage to nerves

Diagnosed with skin test (lepromin). Or can use Light Microscopy with AFB stain

Non motile
Aerobic rods
Cording

M. tuberculosis
M. Bovis - a modified form of this is used to make BCG
M. Africanum

M. Bovis is no longer found in the US, but can still find it if a person immigrates

Diagnose using 3 early morning sputum samples

BCG only protects against TB early in life, not later in life

9M new cases
2M deaths


China has a lot of new cases
Africa has a very high incidence rate

2 ways:
1) Early transmission as kid. Latency. Reactivated disease when older / immunocompromised (1/3 of cases like this)
2) Recent transmission

immune system responds:
TGF-, IFN-, IL-12

Granuloma formed around the disease to wall it off. These can be seen on XR


If the granuloma breaks, then you can get persistence of the disease

Inhibits drug entry

has Glycolipid surface molecules associated with MYCOLIC ACIDS

Slow growing:
M. tuberculosis, M. Avium complex, M. Kansasii

The ones we care about are slow growing



Fast Growing:
M. Chelonae, M. Fortuitm, M. Abscess

1) Chronic cough (>= 15 days)
2) Night Sweats
3) Fever
4) Weight Loss
5) Hemoptysis
6) Fatigue, Shortness of breath

Stethescope
CXR


AFB (Acid Fast Bacilli) stain and LM can be used to diagnose. But this requires training, and even in the best cases can be non-specific.
- This also requires cultures, which in the US require stringent safety methods

Tuberculin Skin Testing - test for LATENT infection. threshold depends on the pt. If HIV / immunesupressed, threshold is lower.

Quantiferon-Gold. Use IELISA to see how much IFN-##\gamma#

ELISPOT-TB. newset one

CA has a lot of migrants, which means that it has a much higher incidence rate.

Estimate about 3M latent infections in the country (10%)

If PPD positive, treat with 9mo course of Isoniazide


If active TB, then you use multiple drugs for 6 months.