Antimicrobials & Resistance Flashcards
What are the 4 ways to kill microbes?
- sterilisation
- inhibition
- decontamination
- disinfection
What are the techniques of sterilisation?
- heat
- autoclaving
- radiation
What is sterilisation?
The killing or removal of all viable organisms within a growth medium
What is inhibition?
Effectively limiting microbial growth
What is decontamination?
The treatment of an object to make it safe to handle
What is disinfection?
Directly targets the removal of all pathogens, not necessarily organisms
What is pasteurisation?
Process of using precisely controlled heat (not boiling) to reduce the microbial load in heat sensitive liquid
What is autoclaving?
Sealed chamber into which water and heat are put, because of the pressure you can raise the temp of the water above boiling. 121 degrees
What types of radiation are effective for sterilisation?
UV, microwaves, x-rays, gamma rays, and electrons can reduce microbial growth
What does UV light do to microbes?
Causes modifications and breaks in the DNA
Can the DNA damage from UV light be repaired?
Yes, if exposed to normal light. It’s a process called photoreactivation
What are the 3 classifications of antimicrobial agents?
- bacteriostatic
- bacteriocidal
- bacteriolytic
What does a bacteriostatic antimicrobial agent do?
Inhibits growth for a period of time, allows up immune system to do its job
What does a bacteriocidal antimicrobial agent do?
Causes the cell to die, is poisonous to the internal machinery of the bacteria
What does a bacteriolytic antimicrobial agent do?
Bacterial cell explosion
What are the 2 categories that microbial agents are divided into?
- control of microorganisms in commercial and industrial applications ie. chemicals in foods, air conditioning cooling towers
- prevention of the growth of human pathogens in inanimate objects and on external body surfaces ie. disinfectants, sanitizers, antiseptics
What are the 3 ways in which antimicrobial agents work?
- injury to cell membrane ie. soap and disinfectants
- inactivation of microbial enzymes ie. alcohols, phenolics, chlorine compounds
- damage to genetic material ie. formalin inactivates proteins and nucleic acids, UV light
What are the side effects of antimicrobial agents?
- allergies
- mutation
- destruction of normal flora
- toxicity
Antibiotics are broadly placed into 2 classes?
- bacteriostatic
- bacteriocidal (for nastier drugs)
What are beta-lactams?
- bacteriocidal
- inhibit bacterial cell wall synthesis
Eg, penicillins, cephalosporins
What are macrolides?
- end in mycin
- inhibits bacterial protein synthesis
- can penetrate macrophages, kills intracellular pathogens
- immune modulators
- treat Chlamydia, campylobacter, pneumonia and whooping cough
What are quinolones?
- heavy duty antibiotic
- get in the middle of the DNA/nucleic acid synthesis
- used to treat typhoid, pseudomonas respiratory infections, prostate infections
Eg. Ciprofloxacin
What are tetracyclines?
- broad spectrum agents
- alternative therapy for Chlamydia and early syphillis
- good for rickettsial infections
- commonly used for treating acne
- prevention of malaria
Eg. Doxycycline
What do antibiotics interfere with?
- cell wall synthesis
- nucleic acid synthesis
- protein synthesis
