Microbial resistance Flashcards
What is normal Microbiota?
The normal bacterial flora of the body that colonizes surfaces without causing disease
what is contamination?
The presence of microbes in or on the body
What is infection?
When organisms overcome bodily defenses, multiplies and becomes established in the body
What is the definition of disease?
When injury occurs as a result of a significant amount of microorganisms that disrupt normal functioning of the body.
What are the two portals of entry, explain each.
Skin - Usually acts a barrier to bacteria, but cuts or openings can allow pathogens to enter.
Mucous membranes - Lines cavities that are open to outside world, composed of tightly packed cells but is fairly thin; making an easy port of entry.
What are the methods of transmission for pathogens? (4)
Airborne
Droplet
Insects/rodents
Direct Contact
Endospores originate from which type of Bacteria?
Gram - bacteria
Released upon cellular death
How does Microbial adaptation play a role in the emergence of disease?
Bacteria can become resistant to drugs used to treat them -> therefore allowing them to re-emerge
How does human behaviour play a role in the emergence of disease?
International travel can help spread infectious diseases & Sexual activity can transmit bacteria and illness that is otherwise difficult to transmit.
(SEX & TRAVEL)
How does human susceptibility to infection play a role in the emergence of disease?
Certain circumstances can increase the risk of human infection:
Poverty
Malnutrition
Poor Sanitation
How does our changing ecosystem play a role in the emergence of disease?
Global warming -> melting ice caps exposing ancient bacterial strands
Climate and weather (Mosquitos heading north)
Why does antimicrobial resistance typically occur?
Low drug concentration or short duration of exposure
Explain the inactivation of antimicrobials.
When bacterial cells produces enzymes that alter the drug’s function.
What is Clavulanic acid and how does it prevent bacterial resistance?
It binds to beta-lactamase and prevents its action of destroying the beta-lactam ring of Penicillins
What is an Antibiotic-Efflux pump? How is it powered?
Pump inside bacterial cells that ejects antimicrobials before they can take action. Powered by ATP and able to pump out more than one type of antimicrobial.
Explain multiple resistance of pathogens. Where do they typically occur?
When bacteria possess a resistance to more than one type of antimicrobial at the same time.
Typically manifest in Hospitals and nursing homes were antimicrobials are common
Multiple resistance to antimicrobials is common when \_\_\_\_ is present. A/ R-Plasmids B/ Beta-plasmids C/ Beta-lactamase D/ RNA polymerase
A/ R-Plasmids
Explain Cross-resistance of antimicrobials
Pathogens acquire resistance to a drug and it’s similar “sister” drugs.
i.e. - Penicillin & Amoxicillin
This drug binds to the 30S ribosome and inhibits binding of tRNA to the acceptor site of 70S ribosomes.
Tetracycline
This drug is extremely toxic to humans and is rarely used as it has limited selectability.
Polymyxin
