Flashcards in Immunology and Pathology Deck (106)
What are extremophiles?
Microorganisms adapted to live in harsh and extreme environments
What are thermophiles?
Bacteria with optimum growth temp >45
What are psychrophiles?
Bacteria with optimum growth temp below 20
What are bacteria that withstand high osmotic pressure environments called?
Halophiles - high salt environments and spoilage of salted foods
What are bacteria that live in acidic and alkaline environments called?
What are the 7 beneficial activities of microorganisms?
1. Environmental cycles: C, N, O, S
2. Agriculture and horticulture
3. Food and drink: brewing, wine-making, baking, cheese
4. Medicine: insulin, antibiotics
5. Energy production: ethanol, methane, H2
6. Solvent production: acetone, butanol
7. Nutritional benefits and protective in man and animal
What are the 7 mechanical antimicrobial factors which microbiota must contend with in healthy host?
1. Flushing action of liquids: saliva, urine
2. Peristalsis of gut
3. Skin: impermeable barrier
4. Cough/sneeze reflex
7. Shedding of epithelial cells
What are the 8 biochemical antimicrobial factors in health?
3. Sebaceous secretions
4. Sweat: high salt
5. Lysozyme: antibacterial enzyme
6. Digestive enzymes
7. Bile: detergent action
8. Colonisation resistance
What are the 6 immunological antimicrobial factors in health?
4. Acute phase response
6. Cell-mediated responses
Why is infection control important?
Body surfaces are heavily colonised
Inanimate surfaces, instruments, H2O, air contaminated
Patients and staff may be carrying infections
Need to protect patients and staff from risk of infection
Dentists have responsibility for ensuring safety
What are some of the infection control procedures?
Hep B immunisation
Proper aseptic techniques
Safe disposal of waste
General hygiene and cleanliness
What dental diseases are caused by microorganisms?
Dental plaque related disease: caries, periodontal disease
Other oral infections: abscess, mucosal infections, bone and sinus infections
Systemic disease: infective endocarditis, brain abscess
What are the 5 infectious agents in inc. complexity?
1. Prions: infectious proteins
2. Viruses: non-living, obligate intra-cellular parasites
3. Bacteria: prokaryote
4. Fungi: eukaryote
5. Protozoa: eukaryote
What are prokaryotes?
Single-celled, contain RNA and DNA
Lack membrane bound nucleus
Single, circular DNA molecule as chromosome
Truly nucleated: uni/multicellular containing both RNA and DNA
Membrane bound nucleus and other organelles
What are prokaryotes and eukaryotes but viruses not?
Defined as living organisms
What are parasites?
Organism that lives in/on 2nd organism (host)
May have little/no harmful affect, in apparent or bring about damage/harm (pathogen)
What are commensals?
Microbes found colonising host that benefit or are essential to them
Reproduce asexually by binary fission
V small, v diverse (aerobes, anaerobes, microaerophilic, capnophilic)
Low generation time (mins)
What are the 2 important structural features of bacteria essential for their survival?
1. Fimbriae: on surface; protect against phagocytosis, aid adherence to target
2. Pilus: share genetic material; antibiotic resistance
What are the 6 main bacteria types that interact with man?
1. Gram +ve
2. Gram -ve
4. Mycoplasma, ureaplasma
Describe gram +ve bacteria
Thick peptidoglycan cell wall, possible protein layers, stain purple
Describe gram -ve bacteria
Thin peptidoglycan layer, 2nd membrane, periplasm (space), lipid rich, fragile, stain pink
What are acid-fast bacteria?
Bacteria with mycolic acids (waxy lipid) attached to peptidoglycan
Cross linking with arabinose and galactose
Does not stain by normal procedure
What is special about mycoplasma and ureaplasma?
Cytoplasmic contents surrounded by well developed PM thus resistance to antibiotics that target cell wall e.g. penicillins
How do viruses replicate?
Depend on host
How do fungi reproduce?
Asexual - most freq. in good conditions
Sexual - fusion of gametes or gametangia
How do yeasts reproduce?
What is an important yeast in oral biology?