Bacterial Pneumonia 1 Flashcards by Justin Faulkner

What are the 4 Pseudomonad pathogens

Pseudomonas aeruginosa
Burkholderia cepacia
Burkholderia pseudomallei
Burkholderia mallei

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Who are the pts most vulnerable to P. aeruginosa infection

Extensive burns--no flowers in burn unit
Chronic respiratory dz--CF
Immunosuppression
Long-term catheterization
IVs
Neonates

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What is the #1 cause of ICU pneumonia?

P. aeruginosa

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What are 4 common community acquired pathogenesis of P. aeruginosa?

Endocarditis in IV drug users
Otitis externa/folliculitis in under chlorinated hot tubs
Osteochondritis in puncture wounds through sneaker soles
Corneal infection in contact lens wearers

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What is the virulence factor of P. aeruginosa that can cause sepsis?

Endotoxin

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What virulence factors facilitate invasion of bloodstream, collapse alveoli and rupture blood vessels by P. aeruginosa?

Enzymes–elastase, protease, histotoxic

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What virulence factor of P. aeruginosa interferes with the terminal electron transfer system?

Pyocyanin

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What virulence factor of P. aeruginosa is antiphagocytic, biofilm glue?

Glycocalyx or alginate

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Why is the treatment of P. aeruginosa so difficult to treat?

Many virulence especially efflux pumps that toss the antibiotics back out of the cytoplasm–less permeable

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If immunocompromised or neonate become infected with P. aeruginosa, what is most likely to occur

> 50% mortality

Pneumonia
Endocarditis
Meningitis
Ecthyma gangrenosum

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A pt is infected with P. aeruginosa through bacteremia. What will be seen on CXR?

Poorly-defined, hemorrhagic, often sub pleural, nodular areas with a small central area of necrosis and multiple, 2-15 mm, necrotic, umbilicate nodules with hemorrhagic parenchyma

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What is the appearance of P. aeruginosa on triple-sugar-iron agar?

Metallic sheen

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What is the appearance of P. aeruginosa on nutrient agar?

Green color

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What is the tx for P. aeruginosa?

Remove and replace catheters and IVs

Begin Abx without delay

Uncomplicated UTIs–> ciprofloxacin

Anything else (IV):
Antipseudomonal penicillin--> piperacillin/tazobactam or ticarcillin/clavulanate 
PLUS gentamicin or amikacin

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How are B. cepacia and P. aeruginosa similar?

They grow easily in IV fluid/irrigation solutions

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How are B. cepacia and P. aeruginosa different?

B. cepacia has very limited ability to infect, otherwise healthy pts

Who are at the greatest risk of being infected by B. cepacia?

CF pts

Neutropenia pts

What are infections caused by B. cepacia?

CF pneumonia
Pneumonia in other preexisting dzs with neutropenia
Catheter-associated UTIs
IV associated septicemia
Wound infections
Foot rot in swamp-deployed military

What is Cepacia syndrome?

seen in CF patients–accelerated pulmonary course with rapidly-fatal bacteremia

What is the tx for B. cepacia?

No tx for healthy ind.

If CF, Cx, HIV

Trimethoprin-sulfamethoxazole
OR
-third-gem cephalosporins
-Ciprofloxacin
-Ampicillin-subactam
-chloramphenicol
-meropenem

How is B. pseudomallei transmitted?

by direct contact with contaminated water or soil

What is the range of severity of B. pseudomallei?

Acute local to septicemia with abscesses in all organs

Untreated fatal in 7-10 days

What are the risk factors for the a severe infection caused by B. pseudomallei?

DM
Renal dysfunction
Chronic pulmonary dz

What bacterial pneumonia bacteria can cause a mild infection that resolves and then reactivates years later from lung abscess–resembling TB?

B. pseudomallei

What is unique about a B. pseudomallei infection that allows for dx?

It affects the lungs as well as the liver and spleen at the same time CXR will be abnormal and there will be small abscesses in liver and spleen on sonogram

What is the tx for B. pseudomallei infection?

Several weeks of Ceftazidime alone or in combination with either trimethoprim-sulfamethoxazole or amoxicillin/clavulanante

How is B. mallei contracted by humans?

Zoonosis Comes directly from the animal--seen in vets or farmers

What occurs if septicemia occurs with B. mallei?

Flushing cyanosis Disseminated pustular eruption If untreated--fatal in 7-10 days

What is the tx for B. mallei infection?

Long-term Abx Amoxicillin and clavulanant Doxycycline Trimethoprim and sulfamethoxazole

What are the 3 stains of Chlamydophilia that can cause Pneumonia and which one can cause serious problems?

Pneumoniae Psittaci--serious but rare Trachomatis

Pt presents with nonproductive cough, chest pain and splenomegaly. Fever of 104. Has Horder spots--erythematous, blanching, maculopapular rash. Has a history of handling sick birds.

C. Psittaci

What is for C. trachomatis?

``` Nasal obstruction and discharge Cough Tachypnea Inclusion conjunctivitis Middle ear abnormality Scattered crackles with good breath sounds ```

What is the Tx for C. pneumoniae?

Doxycycline Most cases are mild and usually respond to tx in an outpatient setting Has to be intracellular penetrator

What is the tx for C. Psittaci?

Tetracycline or doxycycline Infection is usually curable in 7-14 days with early dx and tx Has to be intracellular penetrator

What is the tx for C. trachomatis?

Treat infant with erythromycin Prophylactic--use oral erythromycin --NOT just eye ointment Has to be intracellular penetrator