Bacterial Pneumonia 1

Question 1

What are the 4 Pseudomonad pathogens

Answer 1

Pseudomonas aeruginosa
Burkholderia cepacia
Burkholderia pseudomallei
Burkholderia mallei

Question 2

Who are the pts most vulnerable to P. aeruginosa infection

Answer 2

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

Question 3

What is the #1 cause of ICU pneumonia?

Answer 3

P. aeruginosa

Question 4

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

Answer 4

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

Question 5

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

Answer 5

Endotoxin

Question 6

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

Answer 6

Enzymes–elastase, protease, histotoxic

Question 7

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

Answer 7

Pyocyanin

Question 8

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

Answer 8

Glycocalyx or alginate

Question 9

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

Answer 9

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

Question 10

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

Answer 10

> 50% mortality

Pneumonia
Endocarditis
Meningitis
Ecthyma gangrenosum

Question 11

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

Answer 11

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

Question 12

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

Answer 12

Metallic sheen

Question 13

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

Answer 13

Green color

Question 14

What is the tx for P. aeruginosa?

Answer 14

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

Question 15

How are B. cepacia and P. aeruginosa similar?

Answer 15

They grow easily in IV fluid/irrigation solutions

Question 16

How are B. cepacia and P. aeruginosa different?

Answer 16

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

Question 17

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

Answer 17

CF pts

Neutropenia pts

Question 18

What are infections caused by B. cepacia?

Answer 18

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

Question 19

What is Cepacia syndrome?

Answer 19

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

Question 20

What is the tx for B. cepacia?

Answer 20

No tx for healthy ind.

If CF, Cx, HIV

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

Question 21

How is B. pseudomallei transmitted?

Answer 21

by direct contact with contaminated water or soil

Question 22

What is the range of severity of B. pseudomallei?

Answer 22

Acute local to septicemia with abscesses in all organs

Untreated fatal in 7-10 days

Question 23

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

Answer 23

DM
Renal dysfunction
Chronic pulmonary dz

Question 24

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

Answer 24

B. pseudomallei

Question 25

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

Answer 25

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

Question 26

What is the tx for B. pseudomallei infection?

Answer 26

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

Question 27

How is B. mallei contracted by humans?

Answer 27

Zoonosis

Comes directly from the animal–seen in vets or farmers

Question 28

What occurs if septicemia occurs with B. mallei?

Answer 28

Flushing
cyanosis
Disseminated pustular eruption

If untreated–fatal in 7-10 days

Question 29

What is the tx for B. mallei infection?

Answer 29

Long-term Abx
Amoxicillin and clavulanant
Doxycycline
Trimethoprim and sulfamethoxazole

Question 30

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

Answer 30

Pneumoniae
Psittaci–serious but rare
Trachomatis

Question 31

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.

Answer 31

C. Psittaci

Question 32

What is for C. trachomatis?

Answer 32

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

Question 33

What is the Tx for C. pneumoniae?

Answer 33

Doxycycline

Most cases are mild and usually respond to tx in an outpatient setting

Has to be intracellular penetrator

Question 34

What is the tx for C. Psittaci?

Answer 34

Tetracycline or doxycycline

Infection is usually curable in 7-14 days with early dx and tx

Has to be intracellular penetrator

Question 35

What is the tx for C. trachomatis?

Answer 35

Treat infant with erythromycin

Prophylactic–use oral erythromycin –NOT just eye ointment

Has to be intracellular penetrator