3. Microbiology Flashcards
list types of organisms involved in microbiology
- Unicellular
- Bacteria (Prokaryotes)
- Yeast (fungi)
- Protozoa
- Multicellular
- Other fungi (mould)
- algae
- Acellular
- Virus
name a few positive impacts of microbes
Microbes
- decompose dead organic matter
- some can be eaten
- may enable food to be digested (e.g. bacteria in our gut)
- perform food / beverage fermentations
- produce antibiotics
outline importance of gram stain and bacterial cell wall structure
Gram stain test is used to classify bacteria baed on cell wall structure
important first step in identifying bacteria and determining bacteria to use (whether we use broad or narrow spectrum antibacterial treatment)
- gram positive - purple - no outer membrane around peptidoglycan cell wall
- gram negative- pink. Bacteria has outer membrane that provides barrier to some antibiotics (E.g penicillin)
briefly describe components of a vius and viral reproduction
components
- tiny / acellular
- contain either DNA/ RNA, not both
- in capsid and maybe also additional envelope
viral reproduction
- obligate intracellular parasite- needs host cell DNA and enzymes to reproduce, turn host cell into factory for virus
- cell entry + uncoating - using host cells enzymes
- replication and assembly, using host cells resources
- release / burst host cell
Distinguish between flora types and implications for handwashing
- normal resident
- relatively permanet and unchanging
- mainly commensual (harmless)- unless severely immunocomprormised
- relatively hard to remove by handwashing
- transient
- tempoary
- easmly removed via handwasying
- more likely to contain transferable pathogens
what are principal modes of disease transmission
contact (direct / indirect /droplets)
vehicles (food/ air/ water)
vectors (biological (mosquitos) / mechanical (flies with salmonella)
what is difference between prokaryote and eukaryote
Prokaryote
- cell wall with peptidoglycan
- no membrane bound organelles
- genetic material is loose in cytoplasm
Eukaryote
- membrane bound organelles
- reproduce via mitosis
- if they do have cell walls, they don’t contain peptidoglycan
- genetic material is separated from rest of cell in membrane
what are benefits of normal flora
crowd out pathogens / transient flora - e.g. breastmilk contains bifodobaterium)
stimulate immune response - developing immunity against pathogens
help process indigestable compounds and waste gut
manufacture vitamin k (blood clotting) and vit b12 (make red blood cells)
may prevent allergic response and influence brain function
Describe where it is normal / abnormal to find microbes
Normal
Connective tissue / fluid
- yes- skin
- no- semen, Cerebrospinal fluid, urine, semen, internal organs, brain, spinal cord, bone marrow, glands, organs, muscles
Respiratory
- yes- mucosa of upper respiratory tract
- no- lower respiratory tract (below larynx) and sinuses
digestive
- yes- mouth, gastrointestinal system (mainly large intestine)
- no- not many in stomach, duodenum (small intestine)
genitals
- yes- reproductive system (mainly vagina), external opening of urethra
- no - kidneys, ureter, bladder, ovaries and testes
ear
- yes - external ear
- no- middle and inner ear
Distinguish between antibiotics and other antimicrobial therapy, and between broad and narrow spectrum
Antimicrobial therapy- kill / inhibit microbes (antibacterials, antivirals, antifungals)- includes synthetic and semi synthetic drugs
Antibiotics - type of antimicrobial therapy that is sourced from one live microbe that inhibits / kills another microbe.
braod spectrum- antimicrobes that are active against number of different microbes
- advantage- useful when identity of microbe is not known
- disadvantage- many normal flora is destroyed- enables opportunistic pathogens to flourish
narrow spectrum- antimicrobes that are active against limited range of microbes - e.g. penicillin only affects gram posiitve (not gram negative as it has an additional membrane)
outline potential side effects of antibiotics
side effects
develop allergic reaction
toxic side effects for host
disrupts normal flora
explain why there are fewer antivirals than antibacterials?
- Viruses reproduce inside host cells- so it’s hard to find agents that destroy virus without damaging host cell
- bacteria are prokaryotes, so antibacterials can have more toxic specificity (target specific features of the prokaryote (e.g. cell wall) without damaging host eukaryotic cell
list ways to reduce development of resistance
complete course of antibiotics
correct antibiotic use (not for viruses)
focus on prevention rather than treatment (infection control, vaccine, better sanitation)
use narrow spectrum antibiotics
avoid food that has been fed antibiotics
