L2. Gram negative Infections Flashcards
name and define the two main groups of Gram-negative bacteria discussed in the workshop. Give examples
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
What is the significance of Gram-negative infections on a national and international scale?
Gram Negs have high resistance to antibiotics
and so can easily cause severe illness from infection
Name three examples of Gram-negative bacteria belonging to the Enterobacteriaceae family and where they are commonly found
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
What are some characteristics of non-fermenters among Gram-negative bacteria?
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
Describe the complex cell wall structure of Gram-negative bacteria.
- 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
What are superbugs, and why are Gram-negative bacteria considered significant in this context?
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
What are some common infections caused by Gram-negative bacteria in different body systems?
urinary tract infections:
food poisoning:
sexually transmitted infections:
respiratory tract infections:
What socioeconomic factors influence the spread and impact of infectious diseases, including Gram-negative infections?
access to healthcare
sanitation and hygiene practices
List three Gram-negative bacteria commonly associated with healthcare-associated infections (HCAIs).
Escherichia coli
Pseudomonas aeruginosa
Klebsiella pneumoniae.
According to Public Health England, what are the leading causes of healthcare-associated bloodstream infections?
Gram-negative bacteria such as Escherichia coli, Klebsiella spp., and Pseudomonas aeruginosa
What is the WHO Priority Pathogen List, and why are Gram-negative bacteria included on it?
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
Describe the pathogenesis and clinical significance of Escherichia coli as discussed in the workshop.
a diverse species
multiple pathogenic strains
that cause various infections, including UTIs, food poisoning, and bloodstream infections.
What is Yersinia pestis, and what historical impact has it had on human populations?
the causative agent of plague
caused epidemics and pandemics that led to significant mortality
How does Klebsiella pneumoniae contribute to the challenge of antibiotic resistance?
acquiring resistance genes, including carbapenemase genes
- making treatment difficult.
Why is carbapenem resistance particularly concerning in Klebsiella pneumoniae infections?
carbapenems are considered drugs of last resort for treating severe infections, and resistance to them severely limits treatment options.
Explain the term “superbug” in the context of antibiotic resistance.
bacteria that are highly resistant to multiple antibiotics, making them difficult or impossible to treat effectively
What are some therapeutic challenges associated with treating Gram-negative infections?
- limited treatment options due to antibiotic resistance
- the need for effective antibiotic stewardship
- the risk of adverse outcomes in vulnerable patient populations.
Describe the role of antimicrobial chemotherapy in combating Gram-negative infections.
target bacterial growth and proliferation
_
- consider resistance patterns and patient factors.
_
What factors influence the selection of antibiotic treatment for Gram-negative infections?
type of infection
- antibiotic susceptibility testing results
- patient allergies
- the presence of comorbidities
Summarize the key takeaways from the workshop regarding Gram-negative infections and their management.
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.
What is the usual habitat of Escherichia coli in adults?
coliform microflora in the GIT
What are the potential consequences of Escherichia coli infection in the urinary tract?
kidney failure, particularly if left untreated.
Name the types of infections caused by Escherichia coli outside the gastrointestinal tract.
UTIs, pneumonia, meningitis, and bloodstream infections (bacteremia)
What are the main toxins produced by certain strains of Escherichia coli?
Shiga toxins
- contribute to the pathogenesis of diseases like hemolytic uremic syndrome (HUS)
What are the major enterovirulent classes of Escherichia coli?
Enterotoxigenic E. coli (ETEC),
Enteroinvasive E. coli (EIEC),
Enteropathogenic E. coli (EPEC),
and Enterohemorrhagic E. coli (EHEC or STEC)
What is the major cause of severe diarrheal disease in young children in developing countries caused by Escherichia coli?
Enterotoxigenic E. coli (ETEC) infection
What is the consequence of releasing large amounts of toxins due to inappropriate antibiotic therapy for ETEC?
exacerbate symptoms and prolong illness duration
How are community-acquired urinary tract infections often caused by Escherichia coli?
due to its ability to translocate and establish infection in the urinary tract
What are some of the virulence factors possessed by uropathogenic Escherichia coli (UPEC)?
(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.
Why is E. coli bacteremia considered a significant healthcare-associated infection (HCAI)?
it can lead to severe bloodstream infections, especially in hospitalised patients
Describe the appearance of Enterobacteriaceae and non-Enterobacteriaceae on MacConkey agar
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)
What is the leading cause of UTIs?
E coli
What is the leading cause of food poisoning?
Campylobacter sp.
what is the leading cause of STIs?
Chlamydia trachomatis
what bacteria can cause RTIs?
Wide range of viral, Gram positive and Gram negative agents
Haemophilus influenzae
Klebsiella pneumoniae
Bordetella pertussis
Legionella pneumophila
