L8: GNB 1 - Coliforms, Proteus, Pseudomonas

Question 1

What are enterobacterales?

Answer 1

gram negative bacilli
mostly live in intestine
most motile - have flagella
facultative anaerobes

Question 2

What are the 3 antigens present in enterobacterales and where are they located?

Answer 2

O antigen = cell wall
H antigen = flagella
K antigen = capsule

Question 3

List some of the virulence factors of enterobacterales

Answer 3

adhesins
LPS
capsules
toxins
antimicrobial resistance

Question 4

What are some community-acquired infections that may occur as a result of non-toxin producing E. coli strains?

Answer 4

UTI
BSI
Intra-Abdominal Infection (cholecystitis, appendicitis)
Neonatal Meningitis

Question 5

Pathogenic strains of E.coli may cause a UTI. Which virulence factor aids the pathogen in infecting the host?

Answer 5

Type 1 Fimbriae

Question 6

Certain serotypes of E.coli are more commonly associated with UTIs. Which serotypes are these?

Answer 6

01, 02, 04

Question 7

Many E.coli are resistant to which antibiotic?

Answer 7

amoxicilin

Question 8

Which enterobacterales are lactose fermenters?

Answer 8

E. coli, Klebsiella spp.

Question 9

Which enterobacterales are not lactose fermenters?

Answer 9

Proteus mirabilis

Question 10

What type of pneumonia does Klebsiella pneumonia cause?

Answer 10

• necrotizing pneumonia (“red currant jelly” sputum)
• ventilator associated pneumonia

esp. affects alcoholics and the upper lobes of lungs

Question 11

What are some characteritics of Proteus mirabilis?

Answer 11

• non lactose fermenter
• “swarming” on agar
• fishy smell
• often health-care associated infections

Question 12

Proteus mirabilis may cause UTIs in which patients?

Answer 12

infection common in pts with urinary catheters

Question 13

There is a high prevalence of ESBL produceres in which environment/location in Ireland?

Answer 13

nursing homes

Question 14

In bacteria that has ESBL enzymes what would be the last resort antibiotic?

Answer 14

A Carbapenem - specifically, Meropenem

Question 15

There are CPE organisms which are resistant to meropenem. They produce enzymes called carbapenamases which may be coded for by which genes?

Answer 15

IMP, KPC, OXA-48, NDM

Question 16

Which CPE carbapenamase genes are the most common in Ireland?

Answer 16

KPC, OXA-48

Question 17

VTEC is associated with which serotypes/strains of E.coli typically?

Answer 17

E.coli O157 or O26

Question 18

In what vessel/organism is VTEC part of the normal flora?

Answer 18

Cows

Question 19

How can VTEC be diagnosed?

Answer 19

PCR of stool - looking for verotoxin 1 or verotoxin 2

Question 20

What is the treatment for VTEC? Why is the treatment preffered - what complications necessitate this treatment?

Answer 20

Treatment = supportive/rehydration

do not give antibiotics as this can precipitate Haemolytic Uraemic Syndrome (HUS)

Question 21

List the virulence factors for pseudomonas spp.

Answer 21

pili
flagellae
polysaccharide capsule
pyocyanin
endotoxin - LPS

Question 22

What is the function of pyocyanin?

Answer 22

impairs cilia

Question 23

List some characteristics of pseudomonas aeruginosa

Answer 23

• non lactose fermenter
• strict aerobe
• oxidase positive
• forms biofilms
• in moist areas (sinks, drains…)

Question 24

What type of infections can pseudomonas aeruginosa cause?

Answer 24

BSI (in burns patients)
Neutropenic Sepsis (haemotology/oncology pts)
Pneumonia (VAP)
UTI
Eye Infection
Ear Infection (otitis externa in swimmers + diabetics)

Question 25

What is Burkholderia cepacia associated with?

Answer 25

opportunistic infection in lungs of CF patients

causes Cepacia Syndrome (acute fatal necrotizing pneumonia ± BSI)

Question 26

What is Cepacia Syndrome?

Answer 26

caused by Burkholderia cepacia

acute fatal necrotizing pneumonia ± BSI

Question 27

What pathogen causes melioidosis?

Answer 27

Burkholderia pseudomallei

Question 28

What is the reservoir of burkholderia pseudomallei?

Answer 28

water (e.g. paddy fields)

Question 29

Stenotyophomonas maltophilia may cause a BSI or pneumonia following what??

Answer 29

following prolonged broad-spectrum antibiotics

Question 30

Which opportunistic pathogen can survive on wet/dry surfaces in hospitals? This pathogen is a/w injured soldiers returning from Iraq/Afghanistan.

Answer 30

Acinetobacter Baumanni

Question 31

List 3 things/conditions that are a/w Haemolytic Uraemic Syndrome (HUS)

Answer 31

1. Haemolytic Anaemia
2. Acute Renal Failure
3. Thrombocytopenia