Microbiome, Biofilm, AMR Flashcards
(33 cards)
Define microbiome
Microbiome
* Collection off genomes from all microorganisms in any given environment
Define microbiota
- Microbiota: collection of microorganisms in an environment
What factors impact the microbiota
o Many factors: Species/age/organ/diet/medication
o Most are impacted by maternal microbiome (except chickens – no contact with mother
Why is microbiota important
- Many roles: immune/heart/other aspects off health
o Product antimicrobial peptides = prevent pathogen overgrowth
Microbiome influences vaccine response/wound healing/AMR
List the main bacteria in the GI/skin/resp/urogenital
- Gut: Bacteroides/Firmicutes/Lactobacillus
o Clostridium (opportunistic) - Skin: Corynebacterium/Pseudomonas
o Staphylococcus (opportunistic) - Resp: Pasteurella/Mycoplasma/Bordetella
- Urogenital: Lactobacillus/Streptococcus
o Escherichia (opportunistic)
Define dysbiosis
Dysbiosis: imbalance in microbiota = disrupt microbiome
How is necrotic enteritis related to microbiome in poultry
Poultry: Necrotic Enteritis
1. Exposure to Eimeria or feeding indigestible non-starch polysaccharides or high protein or immunosuppression
2. Reduce abundance of lactic acid producing bacteria
3. Promote Clostridium perfringens growth + promote Enterobacteriaceae in chicken intestine
How is post-weaning diarrhea associated with microbiome in swine
Swine: Postweaning diarrhea
1. Stress at weaning (waned early 3 weeks = before a stable microbial population is formed)
2. Disrupt microbiota by reducing lactobacillus spp.
3. Promote enterotoxigenic EE. Coli
How is colitis associated with microbiome in horses
Horse: colitis
1. Sudden det change (grain overload) or antimicrobials (macrolide/lincosamides)
2. Disrupt intestinal microbiota (reduce firmicutes)
3. Promote proliferation of colitis-associated bacteria
a. Clostridium perfringes and difficile/Salmonella/Lawsonia intracellularis/E. coli)
How is BRD associated with microbiome in cattle
Cattle: BRD
* Complex
o Virus/bacteria
o Stress: transport/new environment/diet
* Bacterial invasion with Mycoplasma bovis/Histophilus somni/Mannheimia haemolytica/Paasturella multocida
How is IBD associated with microbiome in dogs/cats
Dog/Cat: IBD
* Chronic irritation of GI
1. Stress/allergies/genetics
2. Disrupt bacteria: reduce firmicutes
3. Reduce diversity of pathogenic bacteria (Campylobacter jejuni/C. difficile/ C. perfringens/Salmonella)
Define biofilm
Biofilm: assembly of surface associated microbial cells that are enclosed in an extracellular polymeric substance matrix
* Population that is attached to a surface and all the substances that envelops it
What is the function of biofilms
- Protects bacteria:
o Dehydration
o UV light
o Immune system
o Aantimicrobials
What are the 5 steps of biofilm formation
Biofilm Formation: some bacteria will have (some not)
1. Reversible adhesion: planktonic cells attached to surface – if environment is right it will proliferate
a. Critical because it is the stage in which we can intervene + remove
b. Length of time in this stage depends on bacterial and surface type
2. Irreversible adhesion; extracellular matrix produced
3. Biofilm proliferation: extracellular matrix envelop cells
4. Biofilm maturation
5. Deadhesion
What are nosocomial infections? Provide 3 examples
Nosocomial infections: all associated with biofilm formation
* Ventilator associated pneumonia
* SSI due to contaminated instruments
* Catheter associated infections
* Common bacteria: Staphylococcus aureus and epidermidis
How is biofilms important in dairy industry
Dairy: biofilm formation in milking equipment/water sprinklers/bulk tank
* Can cause contagious mastitis and corrosion of expensive equipment
How is biofilms important in dental health
Dental: plaque = type of biofilm
* Plaque will calcify to tarter/calculus = gingivitis = periodontal disease = systemic infection
Why do some bacteria form biofilms and others don’t
some bacteria will have (some not) = virulence factor (some have genes for it and others don’t)
Define AMR
Antimicrobial Resistance: ability of microorganisms to overcome antibiotics that used to be effective in the past
Define antimicrobials
can be synthetic or natural, affecting all microbes
Define antibiotics
Antibiotic: naturally produced only affecting bacteria
What are 4 mechanisms that antimicrobials use to work
Inhibit cell wall synthesis
Damage cell membrane
Inhibit protein synthesis
Inhibit nucleic acid synthesis or function
How do beta lactams work? What are the features of beta lactams? Provide examples of beta lactams?
- Beta-lactams: beta lactam is a ring in the bacterial cell wall – targets bacterial penicillin binding protein
o Cell wall: peptidoglycan (N-acetylglucosamine and N-acetylmuramic acid layers – bound by penicillin binding proteins/transpeptidases)
o Broad spectrum
o Low toxicity
penicillin/amoxicillin/cephalosporin/carbapenams/monoobactams
What are 2 mechanisms bacteria use to develop AMR
- Acquire resistance mechanisms
o Acquire exogenous AMR genes: transduction/conjugation/transformation
Mobile elements/plasmids
Most common method
o Mutate and form AMR genes: mutation
More mutations when bacteria under stress conditions
