Lecture 5: Biofilms and AMR

Question 1

what is a microbiome?

Answer 1

the collection of genomes from all microorganisms in any given environment

Question 2

what is a microbiota?

Answer 2

collection of all microorganisms within a specified environment

Question 3

what is dysbiosis?

Answer 3

a disruption to the microbiome resulting in an imbalance in the microbiota, either from a gain or loss of community members, or changes in relative abundance of microbes. dysbiosis is associated with disease

Question 4

an example of a dysbiosis event in poultry is:

Answer 4

necrotic enteritis, caused by clostridium perfringens. this happens when predisposing factors such as simeria infection, immunosuppression, and certain diets can cause a dysbiosis that allows clostridium to proliferate

Question 5

an example of a dysbiosis event in swine is:

Answer 5

post weaning diarrhea, caused by stress at weaning which reduces the amount of lactobacillus and promotes prolfieration of enterotoxigenic E coli

Question 6

an example of a dysbiosis event in horses is:

Answer 6

colitis, either a sudden change in diet or antimicrobial treatment disrupts the microbiota, promoting proliferation of colitis associated bacteria such as salmonella and clostridium difficle

Question 7

an example of dysbiosis in cattle is:

Answer 7

bovine respiratory disease complex, where stressors lead to a dysbiosis event which allows certain microbes to invade the respiratory tract (like histophilus somni, pasturella multocida, etc)

Question 8

an example of dysbiosis in dogs and cats is:

Answer 8

inflammatory bowel disease, where predisposing factors such as stress or allergies disrupts the microbiiota, reducing diversity of pathogenic bacteria and allowing one to proliferate (campylobacter jejuni, C. difficile, etc)

Question 9

what 3 things is a microbiome affected by?

Answer 9

• age
• lifestyle/diet
• medication use

Question 10

why is a microbiome important?

Answer 10

because it is associated with proper functioning of the immune system, heart, and many other aspects of health

Question 11

what is a biofilm?

Answer 11

assemblage of surface-associated microbial cells that is enclosed in an extracellular polymeric substance matrix. AKA, the population that is attached to a surface and all the substance that envelops it

Question 12

extracellular polymeric matrix protects bacteria from what 5 things:

Answer 12

• dehydration
• UV light
• immune system
• disinfectants
• antimicrobials

Question 13

what phases are the most important in the formation of a biofilm and why?

Answer 13

the reversible and irreverisble phases because they are easier to treat/get rid of in these stages, before they proliferate and are not yet matured

Question 14

why do some bacteria form biofilms and others do not?

Answer 14

it is a virulence factor, so they must have the genes in order to form biofilms

Question 15

what are 3 common hospital acquired infections in humans?

Answer 15

• ventilator associated pneumonia
• surgical site infections
• catheter associated infections

Question 16

in the dairy industry, biofilms can be found on milking equipment, water sprinklers, and bulk tanks. Why is this bad?

Answer 16

if the equipment comes in contact with the cows it may cause mastitis, especially if it is contagious mastitis. this can also cause corrosion of the equipment.

Question 17

in food production areas, biofilms are signs that…

Answer 17

the area is unsanitary and needs proper cleaning. if not cleaned, food products may be contaminated which can reduce shelf life and make it not safe for consumption

Question 18

what are the 5 stages of biofilm production?

Answer 18

reversible adhesion, irreversible adhesion, biofilm proliferation, biofilm maturation, deadhesion

Question 19

how do biofilms relate to gingivitis?

Answer 19

plaque on the teeth is a biofilm that can harden into tartar, which causes gingivitis and eventually periodental disease. this may progress to tooth decay, abscesses, infections, and even systemic infections if severe enough

Question 20

why are biofilms important?

Answer 20

because it is estimated that 80% of infections and infectious processes involves biofilms.

Question 21

true or false: most antimicrobial use occurs in animals

Answer 21

true

Question 22

true or false: AMR can lead to treatment failure

Answer 22

true

Question 23

what are 4 broad ways in which antimicrobials act?

Answer 23

• inhibition of cell wall synthesis (beta lactams)
• damage to the cell membrane
• inhibition of protein synthesis
• inhibition of nucleic acid synthesis or function

Question 24

the bacterial cell wall consists mainly of _____

Answer 24

peptidoglycan, NAG and NAM

Question 25

the bacteria cell wall is organized in layers and held together by

Answer 25

transpeptidases (these are where penicillins bind to)

Question 26

bacteria acquire resistance mechanisms through AMR genes, which they can get a variety of ways. list them

Answer 26

• mobile genetic elements (plasmids, transposons)
• horizontal gene transfer
• mutations

Question 27

what are the three processes by which bacteria can acquire new DNA?

Answer 27

conjugation (from another bacteria cell)
transduction (from bacteriophage)
transformation (from free DNA entering the cell)

Question 28

what are the 5 resistance mechanisms?

Answer 28

• development of alternative pathways (find a new way to make the cell wall or the proteins, etc)
• drug inactivation (have an enzyme or something that deactivates the drug)
• decreased permeability (drug can’t get into the cell)
• efflux pumps (drug gets in but is spit back out)
• target modifcation (modify where the drug is trying to bind/target)

Question 29

what are 3 pressing AMR related issues in human medicine?

Answer 29

• increase AMR in ESKAPE pathogens (you get these ones in hospitals, nursing homes, etc, anywhere antimicrobials are being used a ton)
• clostridium difficile infections following antimicrobial therapy
• AMR in community acquired bacteria like E coli, strep, salmonella

Question 30

name an AMR related issue in vet med regading each of the following species:
- dogs and cats
- beef cattle
- horses
- fish and shrimp
- chickens and pigs

Answer 30

dogs and cats: MRSA
beef cattle: BRD associated bacteria resistance
horses: MRSA skin infections
fish and shrimp: AMR Edwardsiella spp
chickens and pigs: zoonotic conern, salmonella and campylobacter

Question 31

how do you decide what antimicrobial to use?

Answer 31

they are split into classes and ranked for “importance” by government agencies. “Important” classes are classes of drug in which are commonly used/preferred in the treatment of serious human bacterial infections. These are the drugs you should avoid using if possible. Important drugs are also those in which there are no alternative treatments for a specific bacterial infection. For example, if drug A is really specific for fighting off a specific bacteria, you shoulnd’t use that drug unless you are sure you have an infection with that specific bacteria.

Question 32

is it ok to use extra label antimicrobials in veterinary medicine?

Answer 32

yes, extra label is preferred when it results in the use of a categoryof drug of lower impotance to human medicine. it is legal in Canada to use extra label antimicrobials