1. Cells in center of granuloma include... 2. What eventually forms upon tissue death?

1. _MQ_, _BC's_ + _DC's_ 2. _Caseum_ forms from necrotic tissue that is damaged by inflammatory response and lack of blood supply

Respiratory Pathogens Flashcards by Chris Rodarte

Three respiratory bugs (focused in this packet)

Mycobacteria

Mycoplasma

Corynebacteria

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Mycobacteria shape and growth

Acid Fast Rods

SLOW growth (from one pole only)

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Mycobacterium cell wall contains…

Mycolic acids

arabinogalactan

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3 characteristics of mycolic acids

acid fastness
protect from lysozyme + complement
anchored to PG directly or by arabinogalactan

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What is cord factor?

Trehalose Dymycolate + something else

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Mycobacterium product that stimulates cytokine production?

What cytokines?

Lipoarabinomannan (LAM)

TNF and IL-6 (which stimulate replication of HIV long terminal repeats)

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Mycobacterium Tuberculosis major symptoms

fatigue, unexplained weight loss, hemoptysis

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Clinical pathway for TB infection

primary infection = exudative lesion
either Heals, Necrotizes lung, or makes granuloma.
Granuloma is either encased or spreads via lymph and blood

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What is miliary TB?

a widely-disseminated TB infection

Also hits lungs

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Cells in center of granuloma include…
What eventually forms upon tissue death?

MQ, BC’s + DC’s
Caseum forms from necrotic tissue that is damaged by inflammatory response and lack of blood supply

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How many new TB cases per year?

10 million

(results in 1.5 million deaths)

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High TB risk populations? (5)

Minorities, Immigrants
HIV patients
Homeless
Young/old
Travelers

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TB is always spread….

person to person via respiratory droplets

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Tb attaches to _______ to invade.

What 3 cellular consequences does this have

Alveolar MQ

Prevents phagolysosome fusion
cytotoxicity from cord factor
Cytokine mediated inflammation

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Long term TB latency establishes in…

granulomas and bone marrow cells

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Detection of TB is dependent on…

presence of T memory cells

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Two ways to detect TB? Explain them?

Mantoux test

QuantiFERON-Gold assay (IGRA): tests for release of IFN-g when peripheral lymphocytes are stimulated by TB antigen

(more IGN-gamma is made when effector Tmem cells are present)

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TB control?

Culture takes too long (6-8 weeks) and acid fast sputum stain needs a massive infection to be able to detect.

PCR is best! Use Tb-specific primers

–98% detection

–takes 90 minutes

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Qualifications for latent TB? Treat or let it resolve?

IGRA+ or PPD+ without symptoms, and with normal Xray

ALWAYS treat (Isoniazid, Rifampin, or combination of both)

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Treatment regimens for TB

Chemotherapy = long term with 4 drugs (INH, P, R, E) = (4HREZ)

DOTS important!! (observe them taking medicine)

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BCG vaccine is used where? What is a pertinent fact regarding its use?

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Everywhere but here

It will cause PPD+

Treatment for XDR-TB

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NO = Beta lactams or carbapenems

YES =

Meropenem+clavulanate
Linezolid (but adverse reaction… neuropathy)

Other:

Delaminid (inhibits MA synthesis)
Bedaquiline (inhibits ATP synthase)

M. leprae initial presentation

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whitened, anaesthetized skin area

progresses to either Tuberculoid (paucibacillary) or Lepromatous (multibacillary)

tuberculoid leprosy Sx

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macular lesions

(usually) unilateral nerve involvement (sometimes bilateral)

Lepromatous leprosy Sx

Progressive nodular lesions bilateral nerve death \>\> bone resorption and loss of extremities

M. Leprae tranmission and reservoirs?

transmitted by long-term contact Humans and armidillos

M. leprae pathogenesis

inflammatory reaction damages nerve endings hyposensitivity = soft tissue damage

M. Leprae treatment

**Dapsone** (sulfone) and **Rifampin ...**(6-9 months) Double treatment reduces sulfone resistance

Other Mycobacteria?

_M. avium_ * Most common nosocomial infctn in AIDS * disseminated bacteremia * Treat with **clarithromycin** and **ethambutol** for life _M. Kansasii_ * TB like symptoms, *noncommunicable*

Mycoplasma types?

Mycoplasma pneumoniae Mycoplasma genitalium Ureaplasma urealyticum

Mycoplasma organism

really, really smalll. 380 genes. like really small.

Mycoplasma cell wall

No cell wall! Only a membrane, which has **_sterols_** that it **steals from host**

Mycoplasma appearance on agar?

fried-egg appearance

Mycoplasma presentation

(Walking) Atypical PNA (20%) Tracheobronchitis (70%) insidious onset, mild fever, lasts about 4 weeks

Mycoplasma can trigger...

Autoimmune encephalomyelitis | (due to immune mimicry)

Difference in breath sounds between typical and atypical PNA

Typical = bronchial breathing Atypical = Wheeze (musical, high pitched, *fine crackle*)

Mycoplasma is transmitted via

respiratory droplets

Mycoplasma is common among...

school kids highest in winter

Mycoplasma major pathogenic factors?

**Proline-rich adhesion protein** = forms elongated tip to adhere to epithelial cells **Protein M** covers Fab region of antibody to block it Cytotoxic effects = H₂O₂, O₂ radical, competition for nutrients

Mycoplasma treatment

Can treat with **Tetracycline** or **Erythromycin** (macrolides) (**Azith** is more common for treating lung infections right now, but resistance may become a problem) \*\*often do NOT treat if mild

Other Mycoplasmas typically present as \_\_\_\_. What are the three we covered?

**STD's** 1. _M. genitalium_ (normal flora, NGU) 2. _M. hominis_ (salpingitis and post-partum) 3. _Ureaplasma urealyticum_: Produces _urease_ because it requires 10% urea for growth. Cause of **nongonococcal urethritis** in males (bladder stone)

Corynebacterium diptheriae shape / structure (hint: what is weird about this organism's structure?)

* Club shaped, pleomorphic * Gram + * Aerobic * \*contains outer membrane with mycolic acid

Corynebacterium culturing medium? (related to cell metabolism)

It will show up as black colonies on **tellurite blood agar** b/c it reduces **potassium tellurite** to tellurium metal

Corynebacterium clinical presentation

* Throat infection * Fever * Swollen lymph nodes --\> **Bull neck** * **PSEUDOMEMBRANE**

How are toxigenic strains of Corynebacterium ID'd?

**Elek immunodiffusion test** * filter paper with antitoxin placed at right angles to streaks of bacteria * toxin and antitoxin form a _precipitate_

Corynebacterium spread via...

aerosolized droplets

Corynebacterium pathogenicity

**AB toxin** from beta phage conversion * B binds to EGF-like receptor * Partially denatures toxin in vesicle, hydrolysis occurs * A binds to NAD--\> **ADP Ribosylates EF-2 transcription factor (_STOPS_ protein synthesis)**

How are Corynebacterium pathogenic factors controlled by the cell?

"tox" genes are controlled by the DtxR repressor * Iron is a co-repressor * The ToxAB operon gets shut off at iron concentrations above 10uM * (Iron is normally kept low in the body by lactoferrin/transferrin

Clinically, why is the Corynebacterium toxin bad?

It causes cardiac damage, often resulting in heart failure and death

Do infants have passive immunity to Corynebacterium?

Yes! Lasts for about two months

Corynebacterium vaccine type/dosing

Formalin-treated toxoid vaccine (DTaP) Booster given every 10 years \*\*\*important for travelers to areas of high prevalence

Post infection control of Corynebacterium?

Quarantine equine **anti-toxin** **PEN** / **ERYTH ** (despite intoxication, not infection... it's to keep the number of bacteria low)

Respiratory Pathogens Flashcards

(52 cards)