Gram negative opportunistic infections

Question 1

What are nosocomial infections?

Answer 1

Hospital acquired opportunistic infections

Question 2

Which pathogens are innately resistant to antimicrobials?

Answer 2

Pseudonomas and acinetobacter baumanii

Question 3

What can E coli cause?

Answer 3

1. GI infections (Only specialized pathogenic strains)
2. UTIs (commensal E coli)
3. Bacteremia (commensal E. Coli)
4. Meningitis (commensal E.Coli)

Question 4

What concentration is indicative of a bacteriurial infection?

Answer 4

10^5 bacteria/ml

Question 5

What is cystitis?

Answer 5

inflammation of the bladder causing dysuria

Question 6

What is acute pylenophritis?

Answer 6

urinary tract infection that has reached the kidney. Results in flank pain, fever, and dysuria

Question 7

What is the important adhesin in E Coli?

Answer 7

P Pili, which can cause pyelonephritis

Question 8

What is the most common cause of nonhospital acquired UTIs?

Answer 8

E coli

Question 9

What do P pili bind to?

Answer 9

Gal Gal moiety on human P blood group

Question 10

If individuals have P1 vs. P2 blood groups, what are they predisposed to developing?

Answer 10

P1 individuals are more likely to develop E Coli UTIs and pyelonephritis

Question 11

Significance of mannosides in uropathogenic E Coli?

Answer 11

UTI E Coli can bind mannosides on uroepithlial cells. This binding is blocked by mannose.

Question 12

What does mannose sensitive hemagglutination tell you?

Answer 12

Whether organism expresses mannose sensitive pili. If they do, they will be sensitive to inhibition by mannose and will NOT agglutinate

Question 13

What is the major cause of bacteremia?

Answer 13

E. Coli

Question 14

How does E Coli protect itself from serum when causing bacteremia?

Answer 14

Produces K1 capsule, with polysialic acid. This prevents complement binding.

Question 15

How can E Coli cause meningitis?

Answer 15

During delivery, can be transferred to neonates. Crosses blood brain barrier and survive in the CSF.

Question 16

What is the most important antigen in the pathogenesis of E Coli meningitis?

Answer 16

Siderophores

Question 17

What are the acute infections caused by pseudomonas?

Answer 17

burns, eye, wounds, catheters, implants, pneumonia, bacteremia in compromised patients

Question 18

What is associated with chronic infections of CF patients?

Answer 18

Pseudomonas

Question 19

What is produced in chronic Pseudomonas infections?

Answer 19

Alginate slime capsule

Question 20

What toxins Pseudomonas produce?

Answer 20

LPS
elastases, phospholipases
T3SS exotoxins

Question 21

Name the T3SS exotoxins secreted by pseudomonas and what each does.

Answer 21

ExoA: inhibits protein synthesis
ExoS and ExoT: Exoenzymes that modify host cell regulatory proteins
ExoU: Phospholipase activity within host cell

Question 22

What characteristic pigment-producing toxin does pseudomonas produce?

Answer 22

Pyocyanin: generates reactive oxygen species

Question 23

In what metabolic category is pseudomonas?

Answer 23

Obligate aerobe. Although it can also use other substances as electron acceptors to perform metabolic respiration.

Question 24

What can klebsiella pneumoniae cause?

Answer 24

Primary pneumonia
Red current jelly sputum
UTI
BACTEREMIA AND MENINGITIS

Question 25

What is the main virulence factor in Klebsiella?

Answer 25

Capsule

Question 26

Which opportunistic gram negative pathogens are part of the normal gut flora?

Answer 26

Enterobacter cloacae and E Coli and Klebsiella pneumoniae

Question 27

What can enterobacter cloacae infect?

Answer 27

Pneumonia, UTI

Question 28

What is characteristic of the serratia marcesens?

Answer 28

bright red/orange color. Often found on shower heads

Question 29

What are the virulence determinants of seratia marcesens?

Answer 29

proteases, siderophores, flagellar motility

Question 30

What do Proteus vulgaris and proteus mirabilis cause, pathologically?

Answer 30

UTIs

Question 31

What are the virulence determinants of proteus'?

Answer 31

flagella, urease production, which converts urea back to ammonia and an alkaline urine

Question 32

What is acinetobacterbaumanii cause, pathologically?

Answer 32

infection of medical devices, wounds, lungs

Question 33

Does acinetobacter baumanii ferment?

Answer 33

no

Question 34

Name the gram negative opportunistic pathogens

Answer 34

E Coli, P aeruginosa, Klebsiella pneumoniae, enterobacter cloacae, serratia marcesens, proteus vulgaris and mirabilis, acinetobacter spp

Question 35

Which of the gram negative opportunistics are facultative anaerobes?

Answer 35

E coli, Klebsiella pneumonia, serratia marcescens, enterobacter cloacae, proteus mirabilis

Question 36

Which of the gram negative opportunistics is a nonfermenter?

Answer 36

acinetobacter baumanii and pseudomonas

Question 37

Which of the gram negative opportunistics are lactose fermenting?

Answer 37

E coli, Klebsiella pneumonia, enterobacter cloacae

Question 38

Explain what it means if the butt of the kliegler slant turns yellow and what it means if the slant of the kliegler slant turns yellow

Answer 38

If the butt turns yellow, it means that the bug is a glucose fermenter. If the slant turns yellow, it means that the bug is a lactose fermenter

Question 39

You run a klieger slant and get the following results: 1. Butt is yellow 2. Slant is red 3. No gas 4. No H2S production What pathogen do you suspect?

Answer 39

Shigella or serratia. Because it is a glucose fermenter, does not produce gas OR H2S.

Question 40

The results of a kliegler slant shows the following: 1. butt yellow 2. slant is red 3. gas is produced 4. H2S is produced What pathogens would you suspect?

Answer 40

Salmonella or proteus

Question 41

You observe the following kliegler slant: 1. Yellow butt 2. yellow slant 3. Gas production 4. No H2S production Which pathogens would you suspect?

Answer 41

E. Coli, Enterobacter, Klebsiella

Question 42

You observe a kliegler slant with the following: 1. Red butt 2. Red slant 3. No gas 4. No H2S

Answer 42

pseudomonas