Topic 18: Microbiology and the “One Health concept” Flashcards
1
Q
Identify and describe 5 major types of microorganisms
A
- Viruses:
+ Acellular
+ Simplest and smallest biological entities
+ Have to rely on host for reproduction and metabolism - Bacteria:
+ Unicellular
+ Smallest free-living organisms -> self-sustained
+ Have cell wall (different from that of plant - Archea: similar to bacteria without cell wall, live in extreme environment
- Fungi: first true eukaryotes
+ Large complex cells with membrane-bound organelles
+ Unicellular (yeast e.g) or multicellular (moulds e.g)
+ Some can have macroscopic and microscopic parts
+ Can be both beneficial and harmful - Protists:
+ Unicellular
+ Large complex cells with membrane-bound organelles
+ Classified as protozoa or algae (loosely classified)
+ Protozoa: predators, hunt other microbes; unicellular - Algae
+ Large complex cells with membrane-bound organelles
+ Plant-like; unicellular
+ Photosynthetic eukaryotes
2
Q
Describe the idea of cell, invention of microscopy, staining methods and agar plates
A
- The idea of cells: Robert Hooke
+ First ever microscope with 30x magnification → observe microscopic structure of blue moulds
+ First to use the world “cell” - Bacteria & protists discovery: van Leeuwenhoek
+ 300x magnification microscope → first observation - Microbiology techniques - Robert Koch:
+ Staining method for microscopy → able to observe the objects more clearly
+ Use of solid growth media (agar)
- Before that, only liquid media was used to grow microbes → unable to extract pure culture
- Solid media allows isolation of colonies with specific colors, sizes and shapes
3
Q
Describe spontaneous generation and its disproof, germ theory and Koch’s Postulates
A
- Spontaneous generation: suggests that living things can arise from non-living objects
+ Louis Pasteur discarded this theory with experiment using swan-necked flask to show that there are living things in the air that give rise to other living things in the liquid. - Germ Theory of Disease: Koch proved that microbes are the causal agents of diseases -> also disproves the spontaneous generation
- Koch’s postulates: an organism that causes disease must:
+ Be found in all cases of such disease
+ Be extracted in pure culture (not true for all cases)
+ Cause the same disease in experimentally-infected host
+ Be extracted from the experimentally-infected host
4
Q
Describe the discovery and manufacture of penicillin
A
- Flemming found there’s a mould growing in a corner on a petri dish and the bacteria cannot grow near the mould.
+ the mould is isolated and grown -> the “mould juice” is what Flemming named pure penicillin - Florey and Chain purified penicillin and discovered mass production -> first really effective antibiotic
5
Q
Discuss difference between normal flora & pathogens
A
- Normal flora: can be found everywhere in us and on us
+ Found at specific sites with unique features suitable to that location
+ Mostly bacteria
+ Have mostly positive impacts on our immune system and nutritional demands - Pathogens: disease-causing organisms
6
Q
Identify and describe benefits and downfalls of normal flora
A
- Benefits:
+ Compete with pathogens by taking over the niche and nutritional sources
+ Nutritional benefits: bacteria in our guts assist in digesting starch and synthesizing vitamins
+ Prepare immune system to fight antigens by priming the immune cells to produce antibodies - Downfalls:
+ Can cause diseases if found in unusual sites
+ Can cause diseases even at normal sites if there are external stimuli
7
Q
Identify and describe types of pathogens
A
- Obligate pathogens: ALWAYS harmful
- Opportunistic pathogens: only cause diseases when unusual things happen
+ Number: unusually high density
+ Location: normal flora found in other sites
+ Host cell: immune systems not working well
+ Virulence factor: acquire virulence factor like toxins
8
Q
Explain the concept of One Health
A
Human health has to be studied in conjunction with animal/plant and planetary/environmental health because they are interealted
9
Q
Why does human health have to be studied in conjunction with environmental and animal health?
A
- Zoonosis: many diseases in humans now are originated in animas or the environment in general
- Excessive use of antibiotics and other medications in farming and agriculture -> up the food chain to human -> increases risk of antibiotic resistance
- Globalization: spread of diseases to exotic places -> jeopardize local’s immune systems
10
Q
Why is tuberculosis becoming a more serious problem?
A
- Latent: can be infected for years before showing symptoms
- Non-specific symptoms: cannot be diagnosed early because symptoms are too general
- Excessive use of medications -> new strains of TB that can even be resistant to all antibiotics known
- Particularly significant in disadvantaged areas with poor access to health care
