4. Microbiome, Biofilms, AMR (Steph) Flashcards
define microbiome**
collection of genomes from all microorganisms within any given environment
define microbiota
collection of microorganisms within a specific environement
why is microbiome important**
proper function of the immune system, heart and other aspects of health (PRODUCTION OF ANTIMICROBIAL PEPTIDES –> OVERGROWTH OF PATHOGENS)
list 3 factors that may affect the microbiome***
age, lifestyle (diet), medication, maternal microbiota
define dysbiosis***
disruption of the microbiome resulting in an imbalance in microbiota
how does dysbiosis happen
gain or loss in community members or changes in relative abundance of microbes
what is dysbiosis associated with
disease
what can disturb the microbiome
antibiotics, acidosis, stres***
describe the significance of C. perfringens in poultry
agent of avian necrotising enteritis, most common and economically devestating enteric disease in poultry
describe how poultry can develop necrotizing enteritis via dysbiosis (aka. describe one dysbiosis problem in veterinary medicine**)
eimeria infection, feeding indigestible non-starch polysaccarides or high protein diet, immunosupression –> reduce abundance of certain bacteria such as lactic acid producing ones –> promote C.perfringens or Enterobacteriaeceae in chicken intestine
describe how dysbiosis plays a role in IBD in dogs and cats (aka. describe one dysbiosis problem in veterinary medicine**)
stress/allergies/genetic component –> disrupts intestinal microbiota –> reduces bacteria from phylum Firmicutes –> reduced diversity of pathogenic bacteria
describe how dysbiosis plays a role in colitis in horses***
sudden change in diet/antimicrobials –> disrupts intestinal microbiota (red. bacteria from phylum Firmicutes) –> promotes proliferation of colitis associated bacteria (ex. salmonella, C. difficile, ecoli etc)
what are biofilms**
assemblage of surface associated microbial cells that is enclosed in an extracellular polymeric substance matrix –> aka. the population that is attached to the surface and all the substance that envelops it
how are biofilms formed (5)*** For sure a test question
- reversible adhesion: bacteria can be removed in this stage although surface type predicts how successful this will be)
- irreversible adhesion (critical stage )
- biofilm proliferation: matrix produced
- biofilm maturation: attracts other bacteria
- ## deadhesion-
- - biofilm rupture and return to planktonic cells which adhere to surface again
why do some bacteria form biofilms and others do not*
associated with genes
describe a biofilm problem in veterinary medicine * –> ex. dairy cows
biofilms on milking equipment –> contact teats and propagate contagious mastitis and corrosion of equipment, spoilage of milk,
why are biofilms important*
biofilms protect bacteria from harmful environement: dehydration, UV light, Immune system, Disinfectants, antimicrobials
describe a biofilm problem in veterinary medicine * –> oral plaques
plaque = biofilm on teeth –> hardens into tartar, associated with gingivitis, tooth decay, oral infections and systemic infections
how do antimicrobials act*
- inhibition of cell wall synthesis
- damage to cell membrane
- inhibition of protein synthesis
- inhibition of nucleic acid synthesis or function
how do bacteria become resistant*
can acquire resistance mechanisms –> AMR genes via horizontal gene transfer of mobile genetic elements (plasmids, transposons) OR bacteria develops resistance through mutations
how do resistance mechanisms work*
- development of alternative pathways (sulfonamides)
- drug inactivation (beta lactams)
- decreased permeability
- efflux pumps
- target modification
what are the most pressing AMR related issues in human medicine*
- increase in “ESKAPE” pathogens and a few others (Enterococcus, Stapph., Acinetobacter., Pseudomonas, Enterobacter)
- Clostridioides difficile infections following antimicrobial therapy
- Increasing AMR in community aquired bacteria
what are the most pressing AMR related issues in vet medicine*
- dogs and cats: methicilin resistant Staphylococcus
- beef cattle: BRD associated bacteria resistance to macrolides
- horse: MRSA skin infection
Fish and shrimp: antimicrobial resistant Edwardsiella sp. infections - pigs, chickens: zoonotic concern (salmonella, Campylobacter
can antimicrobial use in animals affect human health*
yes, although most AMR in humans are consequences of use in humans
what are some of the best practices related to antimicrobial use in vet med*
- prescribe the most appropriate tx
- right dose, time, reason, route, duration
- first choice should be a vet drug
- opt for drug category of lower importance
- use diganostic and complementary tests
