Microbial resistance Flashcards
What is tolerance/resistance associated with?
- chemical structure and potential similarity to natural compounds
- can be advantageous depending on application
The most vulnerable microbes are not exposed to ______. an example would be ______ _____
- adversity
- strict anaerobes
What is an example of an advantageous adaptation
- acidic pH and acid tolerance = survival
What is an example of a disadvantageous adaptation
- chlorine tolerance in water treatment could harm humans
What does antimicrobial resistance develop in response to?
- selective pressures
What are mechanisms of resistance?
- lack/modify target structure
- impermeability
- chemical form/metabolic alteration
- efflux pump
What alterations in cell morphology cause physiological adaptation and environmental response?
- fagella, metabolism, gene transcription, cell behaviour
Give an example of reduced permeability
- pseudomonas, penicillin (chromosomal)
- mycolic acid in cell wall structure (robust)
- waxy, gram stain doesn’t work (classic mechanisms cannot penetrate cell wall)
What does TB antimicrobial treatment use?
- structural analogs incorporated into cell wall to get waxy nature (structurally similar but not the same, breaks down)
What happens to acid fast stain when used on pseudomonas?
- melts stain to cell wall
What is scarlett fever?
- development off of another virus (strep pneumoniae)
- if not treated, worsens until death
environmental fluctuations and selective pressure involve what?
- availability of electron acceptors
- nutrient supply (C,N,P)
- osmolarity
- temperature
- liquid vs solid medium
What happens if C,N,P are not balanced?
- if lacking one, others cannot be utilized
- ex. flux of N or p = no utilization of C
What do bacteria prefer their medium to be? why?
- solid
- prefer to be attached
How can bacteria pass sterilization?
- shrivel up
- abandon flagellar production once they reach specific point
bacteria continuously monitor the environment - they have ______ ______ _____.
sophisticated detection systems
Where are signals transmitted?
- across cell membrane to specific intracellular targets
What do signalling pathways do?
- send messages to specific targets that regulate gene expression
What would happen if cytoplasmic membrane was not discriminatory to signals?
- everything would enter interior of cell (excessive nutrition) and dictate gene expression
What are the most common type of signaling systems? What bacteria are they most studied in?
- two-component
- E. coli
What does histidine kinase protein do in two-component systems?
- autophosphorylates at histidine residue, transfers phosphoryl group to aspartate residue in response regulator protein which regulates gene transcription
How does 2 component system work?
- sensor histidine kinase and response regulator protein are signal transducers
- mediate acclimation to various environmental changes by coupling environmental cues to gene expression
Give 3 examples of two-component systems
- Arc system (senses changes in oxygen)
- Che system (rotation of flagellar motion (direction, speed))
- kdpABC (potassium ion transport)
What is involved in two-component signal transduction system?
- sensor kinase protein and cytoplasmic response regulator protein
