Bacterial Pneumonia 1 Flashcards
What are the 4 Pseudomonad pathogens
Pseudomonas aeruginosa
Burkholderia cepacia
Burkholderia pseudomallei
Burkholderia mallei
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
What is the #1 cause of ICU pneumonia?
P. aeruginosa
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
What is the virulence factor of P. aeruginosa that can cause sepsis?
Endotoxin
What virulence factors facilitate invasion of bloodstream, collapse alveoli and rupture blood vessels by P. aeruginosa?
Enzymes–elastase, protease, histotoxic
What virulence factor of P. aeruginosa interferes with the terminal electron transfer system?
Pyocyanin
What virulence factor of P. aeruginosa is antiphagocytic, biofilm glue?
Glycocalyx or alginate
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
If immunocompromised or neonate become infected with P. aeruginosa, what is most likely to occur
> 50% mortality
Pneumonia
Endocarditis
Meningitis
Ecthyma gangrenosum
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
What is the appearance of P. aeruginosa on triple-sugar-iron agar?
Metallic sheen
What is the appearance of P. aeruginosa on nutrient agar?
Green color
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
How are B. cepacia and P. aeruginosa similar?
They grow easily in IV fluid/irrigation solutions
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
