L2. Gram negative Infections

Question 1

name and define the two main groups of Gram-negative bacteria discussed in the workshop. Give examples

Answer 1

Enterobacteriaceae (fermenters) -
rod-shaped bacteria that can grow both in the presence of and without oxygen. commonly found in the GIT and environment - e.g E.coli

non-fermenters -
do NOT ferment carbohydrates to produce acid as part of their metabolic process
- can colonies the respiratory tract, especially in hospitals
- exist in soil and water
- E.g Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophilia, and Burkholderia species

Question 2

What is the significance of Gram-negative infections on a national and international scale?

Answer 2

Gram Negs have high resistance to antibiotics
and so can easily cause severe illness from infection

Question 3

Name three examples of Gram-negative bacteria belonging to the Enterobacteriaceae family and where they are commonly found

Answer 3

Escherichia coli -

Klebsiella - GIT, can colonize the mucous membranes of the mouth, nose, and intestines w/o causing damage
– Klebsiella pneumoniae - infects the respiratory tract - pneumonia

Yersinia - caused the plague
– Yersinia pestis found in the bloodstream of rodent reservoirs
– Yersinia enterocolitica and Yersinia pseudotuberculosis.
- found in foods, particularly raw or undercooked meats
- GIT infections

Question 4

What are some characteristics of non-fermenters among Gram-negative bacteria?

Answer 4

Non-fermenters among Gram-negative bacteria:
intrinsic antibiotic resistance resistance

include pathogens like Pseudomonas aeruginosa and Acinetobacter – opportunistic pathogens and prominent healthcare-associated infections
- pneumonia in cystic fibrosis and intensive care patients
- UTIs
- Bloodstream infections

Question 5

Describe the complex cell wall structure of Gram-negative bacteria.

Answer 5

• peptidoglycan - 5-10% of the cell wall
• inner and outer membranes
• porins - allow substances into the cell
• Lipopolysaccharide (LPS) - anchored to outer membrane - O-antigen, Core-polysaccharide​, Lipid A​

Question 6

What are superbugs, and why are Gram-negative bacteria considered significant in this context?

Answer 6

bacteria responsible for severe, life-threatening, and hard-to-treat infections.
Gram-negative bacteria are considered significant in this context due to their intrinsic resistance to antibiotics and their ability to acquire new resistance genes

Question 7

What are some common infections caused by Gram-negative bacteria in different body systems?

Answer 7

urinary tract infections:

food poisoning:

sexually transmitted infections:

respiratory tract infections:

Question 8

What socioeconomic factors influence the spread and impact of infectious diseases, including Gram-negative infections?

Answer 8

access to healthcare
sanitation and hygiene practices

Question 9

List three Gram-negative bacteria commonly associated with healthcare-associated infections (HCAIs).

Answer 9

Escherichia coli
Pseudomonas aeruginosa
Klebsiella pneumoniae.

Question 10

According to Public Health England, what are the leading causes of healthcare-associated bloodstream infections?

Answer 10

Gram-negative bacteria such as Escherichia coli, Klebsiella spp., and Pseudomonas aeruginosa

Question 11

What is the WHO Priority Pathogen List, and why are Gram-negative bacteria included on it?

Answer 11

a list of bacterial pathogens that require urgent research and development for new antibiotics.

Gram-negative bacteria included due to their high resistance to antibiotics

Question 12

Describe the pathogenesis and clinical significance of Escherichia coli as discussed in the workshop.

Answer 12

a diverse species
multiple pathogenic strains
that cause various infections, including UTIs, food poisoning, and bloodstream infections.

Question 13

What is Yersinia pestis, and what historical impact has it had on human populations?

Answer 13

the causative agent of plague
caused epidemics and pandemics that led to significant mortality

Question 14

How does Klebsiella pneumoniae contribute to the challenge of antibiotic resistance?

Answer 14

acquiring resistance genes, including carbapenemase genes
- making treatment difficult.

Question 15

Why is carbapenem resistance particularly concerning in Klebsiella pneumoniae infections?

Answer 15

carbapenems are considered drugs of last resort for treating severe infections, and resistance to them severely limits treatment options.

Question 16

Explain the term “superbug” in the context of antibiotic resistance.

Answer 16

bacteria that are highly resistant to multiple antibiotics, making them difficult or impossible to treat effectively

Question 17

What are some therapeutic challenges associated with treating Gram-negative infections?

Answer 17

• limited treatment options due to antibiotic resistance
• the need for effective antibiotic stewardship
• the risk of adverse outcomes in vulnerable patient populations.

Question 18

Describe the role of antimicrobial chemotherapy in combating Gram-negative infections.

Answer 18

target bacterial growth and proliferation
_
- consider resistance patterns and patient factors.
_

Question 19

What factors influence the selection of antibiotic treatment for Gram-negative infections?

Answer 19

type of infection
- antibiotic susceptibility testing results
- patient allergies
- the presence of comorbidities

Question 20

Summarize the key takeaways from the workshop regarding Gram-negative infections and their management.

Answer 20

the significance of Gram-negative infections, their impact on public health
the challenges posed by antibiotic resistance
he importance of effective surveillance, prevention, and antibiotic stewardship measures in managing these infections.

Question 21

What is the usual habitat of Escherichia coli in adults?

Answer 21

coliform microflora in the GIT

Question 22

What are the potential consequences of Escherichia coli infection in the urinary tract?

Answer 22

kidney failure, particularly if left untreated.

Question 23

Name the types of infections caused by Escherichia coli outside the gastrointestinal tract.

Answer 23

UTIs, pneumonia, meningitis, and bloodstream infections (bacteremia)

Question 24

What are the main toxins produced by certain strains of Escherichia coli?

Answer 24

Shiga toxins
- contribute to the pathogenesis of diseases like hemolytic uremic syndrome (HUS)

Question 25

What are the major enterovirulent classes of Escherichia coli?

Answer 25

Enterotoxigenic E. coli (ETEC),
Enteroinvasive E. coli (EIEC),
Enteropathogenic E. coli (EPEC),
and Enterohemorrhagic E. coli (EHEC or STEC)

Question 26

What is the major cause of severe diarrheal disease in young children in developing countries caused by Escherichia coli?

Answer 26

Enterotoxigenic E. coli (ETEC) infection

Question 27

What is the consequence of releasing large amounts of toxins due to inappropriate antibiotic therapy for ETEC?

Answer 27

exacerbate symptoms and prolong illness duration

Question 28

How are community-acquired urinary tract infections often caused by Escherichia coli?

Answer 28

due to its ability to translocate and establish infection in the urinary tract

Question 29

What are some of the virulence factors possessed by uropathogenic Escherichia coli (UPEC)?

Answer 29

(UPEC) possess virulence factors such as fimbriae, pili, curli, flagella, toxins, and iron-acquisition systems, which contribute to their ability to cause urinary tract infections.

Question 30

Why is E. coli bacteremia considered a significant healthcare-associated infection (HCAI)?

Answer 30

it can lead to severe bloodstream infections, especially in hospitalised patients

Question 31

Describe the appearance of Enterobacteriaceae and non-Enterobacteriaceae on MacConkey agar

Answer 31

Enterobacteriaceae (fermenters) typically pink/red on MacConkey agar​​

Non-Enterobacteriaceae (non-fermenters) typically colourless with agar colour changes on MacConkey (several versions of this product)​​

Question 32

What is the leading cause of UTIs?

Answer 32

E coli

Question 33

What is the leading cause of food poisoning?

Answer 33

Campylobacter sp.​

Question 34

what is the leading cause of STIs?

Answer 34

Chlamydia trachomatis​

Question 35

what bacteria can cause RTIs?

Answer 35

Wide range of viral, Gram positive and Gram negative agents​

Haemophilus influenzae​

Klebsiella pneumoniae​

Bordetella pertussis​

Legionella pneumophila ​