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Flashcards in Bacterial pneumonia Deck (72):
1

Pseudomonas aeruginosa

Gram(-) rods
Strict aerobes
Nonfermenters
Oxidase(+)
Produces pyocyanin (exotoxin) & pyoverdin (siderophore)
Glycocalyx (slime layer) (anti-phagocytic)
Usually free-living environmental
Can be normal flora
Minimal growth requirements
Resistant to detergents & disinfectants
Extremely Ab resistant

2

What are the 7 virulance factors for P. aeruginosa

Endotoxin: cell wall component; when bloodborne causes sepsis

Exotoxins: can be released into tissue (ExoA, similar to diphtheria tox) or injected into host cells (type III secretion sys, ExoS, damages cytoskeleton)

Enzymes: elastase, protease: histotoxic, facilitate invasion of bloodstream, collapse alveoli and rupture blood vessels

Pyocyanin interferes with the terminal electron transfer system

Glycocalyx of alginate is antiphagocytic, biofilm glue

Efflux pumps: toss antibiotics back out of cytoplasm


3

What is the exotoxin released into tissue by P. aeruginosa

ExoA

4

What allows release of exotoxin released into tissue by P. aeruginosa

type III secretion sys,
ExoS, damages cytoskeleton

5

What virulance factor of P. aeruginosa antiphagocytic and acts as a biofilm glue

Glycocalyx of alginate

6

Which virulance factor of P. aeruginosa interferes with the terminal electron transfer system?

Pyocyanin

7

T/F Outer membrane of P. aeruginosa is is 10-100X less permeable to antibiotics than E. coli’s

true

8

What factors enable pseudomona aeruginosa to cause nosocomial (hospital induced) infections?

grows in water
highly resistant to antibiotics
hospital is filled with vulnerable patients (e.g. burns/cuts etc)

9

Where is psuedomona aeruginosa typically found?

Environmentally ubiquitous (water and plants)

10

What conditions does psuedomona aeruginosa cause?

pneumonia

osteocondritis

nosocomial UTIs

surgical site infections

brain abscess in cancer patients

Otitis externa / folliculitis

Endocarditis

Corneal infection

11

psuedomona aeruginosa is the most common Gram(-) isolate from what conditions?

corneal ulcerations and endocarditis

12

What the most commoncomminuty aquired psuedomona aeruginosa infections

Otitis externa / folliculitis - from unchlorinated hot tubs

Endocarditis - IV drug users

Osteochondritis - puncture wounds through sneaker soles (most common in children)

Corneal infection in contact lens wearers

13

What is the mortality rate for immunocompromised infected with psuedomona aeruginosa?

>50%

14

What are the most common diseases caused by psuedomona aeruginosa in immunocompromised pts?

Pneumonia
Endocarditis
Meningitis
Ecthyma gangrenosum

15

What are most common causes of psuedomona aeruginosa infection in healthy hosts?

nosocomial UTI, Cystic fibrosis pneumonia, burns, local infections

16

What does a non-bacteremic pneumonia typically look like on chest x-ray?

diffuse bronchopneumonia (usually bilateral with distinctive nodular infiltrates with small areas of radiolucency) and pleural effusions

17

What does a bacteremic pneumonia typically look like on chest x-ray?

progresses rapidly,
(1) poorly-defined, hemorrhagic, often subpleural, nodular areas with a small central area of necrosis

(2) multiple, 2-mm to 15-mm, necrotic, umbilicated nodules with hemorrhagic parenchyma

18

Two cultures are ruitinely done for pneumonia (aerobic and non-aerobic) which will grow psuedomona aeruginosa?

aerobic

19

What are features that allow diagnosis of psuedomona aeruginosa?

Nonfermenting, oxidase(+)
Metallic sheen on triple-sugar-iron (TSI) agar
Green color on nutrient agar (pyocyanin)
Fruity aroma

20

For an uncomplicated psuedomona aeruginosa UTI what would you treat with?

ciprofloxacin

21

for all other psuedomona aeruginosa infections what treatment would you use?

IV anti-pseudomona penicillins

piperacillin/tazobactam

or

ticarcillin/clavulanate plus gentamicin or amikacin

22

What would be an indicator of pseudomona aeruginosa infection at a lesion site?

green color caused by pyocyanin virulance factor -

23

what are similarities and differences between pseudomona aeruginosa and Burkholderia cepacia

Both grow easily in IV fluid, irrigation solutions

Unlike P. aeruginosa, Burkholderia cepacia doesnt usually infect healthy patients, “colonizing” rather than “infecting”

24

What diseases does colonization of Burkholderia cepacia lead to infection in?

Cystic fibrosis pneumonia,
pneumonia in other preexisting diseases with neutropenia,
catheter-assoc UTIs,
IV-assoc septicemia,
wound infections,
foot rot in swamp-deployed military

25

Burkholderia cepacia infection in CF, cancer, HIV should be treated with what?

trimethoprin-sulfamethoxazole

alternatives include third-generation cephalosporins, ciprofloxacin, ampicillin-sulbactam, chloramphenicol, or meropenem

26

T/F Experimental vaccines for Burkholderia cepacia are available to CF patients

true

27

Burkholderia pseudomallei causes what in primarily developing-nation veterinary cases?

melioidosis

28

What is transmission of Burkholderia pseudomallei?

Transmission by direct contact with contaminated water, soil

29

What is the structure gram stain of Burkholderia pseudomallei?

Motile Gram(-) rod

30

T/F Human-to-human transmission can rarely occur; standard precautions, mask on patient

true

31

T/F US has only few cases of Burkholderia pseudomallei per year and usually found in travelers, immigrants, IV drug users

true

32

What describes the appearance of B pseudomallei in culture?

Unusual “wrinkled” colony morphology

33

What are the initial symptoms of Burkholderia pseudomallei infection?

Initial Symptoms flulike (fever, sweats, rigors, headache) + muscle tightness, light sensitivity

pregression can range from acute local infection to septicemia with abscesses in all organs

34

Septicemia of B pseudomallei is associated with what course and symptoms?

Flushing
Cyanosis
Disseminated pustular eruption
High fevers
Rigor
Bloody, purulent sputum

If untreated fatal ==> 7-10d

35

What are the risk factors for B pseudomallei infection?

diabetes,
renal dysfunction,
chronic pulmonary disease

36

B pseudomallei infection may resolve and then reactivate years later resembling what disease?

TB

37

B pseudomallei infection should be treated with what?

Ceftazidime alone

or in combination with either trimethoprim-sulfamethoxazole or amoxicillin clavulanate

38

True or false B pseudomallei infection is reportable infection to authorities because it is weaponizable

true

inform CDC and FBI as well as local health authorities

39

True or false Burkholderia cepacia infection has extreme antibiotic resistance

true

40

Where is B. mallei found?

Primarily developing-nation veterinary: Glanders

41

T/F melioidosis (B pseudomallei) and glanders (B. mallei) have been used as biowarfare agents: during WWI, used to infect Russian horses&donkeys

true

42

Transmission of B. mallei is through what?

from animals (zoonosis)

43

What is resevior for B. mallei?

Maintained in animal reservoirs, not soil or water

44

What is “Farcy”?

Milder B. mallei infection that establishes a chronic form

45

T/F B. mallei Septicemia: flushing, cyanosis, and a disseminated pustular eruption untreated fatal 7-10 days

true

46

treat B. mallei with

amoxicillin and clavulanate

doxycycline,

or trimethoprim and sulfamethoxazole

47

Chlamydophilia pneumoniae can be transmitted from human-to human -- how?

Respiratory secretions

48

What transmits Chlamydophilia psittaci to humans ?

Infected birds - transmit via the respiratory route through direct contact or aerosolization. Quite rare, but serious.

49

What are the three clamydia pneumonia causing species?

C pneumoniae
C psittaci
C. trachomatis - infants from infected birth canal (CLAP)

50

What is the incubation period of C pneumoniae?

3-4 weeks

51

true/false C pneumoniae Infection is common, often asymptomatic, most symptoms relatively mild

true

52

When does fever present in course of disease with C pneumoniae?

first few days, often absent by the time of examination.

53

What clinical signs can be found in even mild course of infection with C pneumoniae?

What are other clinical signs?

Rhonchi and rales

Headache, sinus percussion tenderness

54

clamydia undergoes 2 form life cycle:

elementary bodies and reticulate bodies

55

What features describe C. trachomatis infection?

Nasal obstruction and discharge,
cough,
tachypnea,
“inclusion conjunctivitis”,
middle ear abnormality,
Scattered crackles with good breath sounds

56

What is most common cause of pneuromnia from C. trachomatis

12,000 cases/yr in infants from infected mothers

57

Treat C. pneumonea with?

Doxycycline

Alternatives include erythromycin, azithromycin, and clarithromycin, Telithromycin

58

Treat C psittaci

Tetracycline or doxycycline

curable within 7-14 days

59

Treat C. trachomatis

infants with erythromycin

60

If prophylactic treatment of C. trachomatis treat with

oral erythromycin, not just eye ointment

prevents progression to pneumonia

61

Four Pseudomonas and Burkholderia pneumonia causing bacterial pathogens

P. aeruginosa
B. cepacia
B. pseudomallei
B. mallei rare in US but can be lethal

Have what common attributes?

Gram(-), strict aerobes, nonfermenters, Oxidase(+), grow easily in culture.

62

common&serious nosocomial pathogen

P. aeruginosa

63

common, serious in context of CF

B. cepacia (P. aeruginosa is also dangerous for CF)

64

Which species are rare in US?


B. cepacia
B. pseudomallei
B. mallei

B. pseudomallei and B. mallei rare in US but can be lethal

65

P. aeruginosa and B. cepacia have minimal growth requirements which allows what?

contaminate hospital solutions

66

what is biggest cause of anitbiotic resistance in bacterial pulminary infections caused by gram (-) bacteria?

All, but particularly P. aeruginosa, have extreme antibiotic resistance from combination of low-permeability outer membrane and efflux pumps

67

endocarditis in IV drug addicts, Otitis externa in underchlorinated hot tubs, Osteochondritis in sneaker punctures, corneal infections under contact lenses

Caused by what bacterial pneuomea causing species?

P. aeruginosa

68

Most common presentations for serious disease:

P. aeruginosa
B. cepacia
B. pseudomallei
B. mallei

P. aeruginosa in hospitals,
B. cepacia in CF centers,
B. pseudomallei in previously-ill travelers/immigrants or Vietnam veterans,
B. mallei in previously-ill travelers/immigrants with animal handling history.

All can present as septicemia/pneumonia with poor prognosis.

69

How would you diagnose?

P. aeruginosa
B. cepacia
B. pseudomallei
B. mallei

culture and Gram stain

Treat with latest combinations of antibiotics, test Ab sensitivity both before and during treatment

70

Clyamydia summary slide

Chlamydia is a small, obligate intracellular bacterium (so must use drugs that penetrate the human cell membrane).

Chlamydia replicate in a unique manner beginning with tiny, infectious, rugged, elementary bodies which “unpack” into reticulate bodies after infection.

Reticulate bodies form intracellular inclusions that are visible on microscopy; within the inclusions they multiply by binary fission, forming new reticulate bodies and later new elementary bodies.

Unusual life cycle complicates research; one known virulence factor is T3SS used for entry & establishing inclusion body.

C. trachomatis is the cause of several human diseases, particularly the common urogenital infection (safe sex practices!).

C. pneumoniae, C. psittaci, and C. trachomatis can all cause pneumonia.

Treatment can often be initiated based on physical findings, additional diagnostics are available and may be desired in various situations (tissue culture for C. trachomatis in rape victims; serology or MIF to differentiate pneumonias).

Treat with tetracyclines (doxycycline) EXCEPT for pregnant/pediatric/allergic patients, who get erythromycin or other alternatives. Patients who get alternatives may need follow-up testing and retreatment.

71

. What is problematic about P. aeruginosa as a nosocomial infection?
A Extreme antibiotic resistance
B Propensity to grow in low-nutrient aqueous solutions
C Ability to cause bacteremia
D All of the above

D: P aeruginosa is a formidable opponent for your hospital infection control

72

To which patient(s) is a B. cepacia infection dangerous despite treatment?
A A pediatric CF patient
B A geriatric cancer patient
C A previously-healthy woman undergoing urinary catheterization
D A and B not C
E All of the Above

A

Cystic Fibrosis is the most important predisposition for poor outcomes of cepacia infection.