Micriobiology Flashcards
Who is louis Pasteur and what did he do ?
Germ theory of disease, microbes don’t spontaneously appear
swan neck flask experiment- sterile environemnts
Who is robert koch?
- bacillus anthracis, microbes trasmit from infection to healthy via injecting blood, browth grown microbes injected to a healthy host cause infection
What is MRSA
invades into bloodstream and produces virulence factors to protect survival or MRSA, detected via nuclei acid tests and antibiotic susceptibility
What are the symptoms of MRSA
symptoms: if via skin = swellling redness, infection, if it gets into bloodstream then infections and paneumonia
What are the treatment of MRSA and how do you prevent it:
B-lactam antibiotics, multidrug resistance treated with methicillin, non-b-lactam,
What is TB
mycobacterium tuberculosis gram positive bacterium entering lungs, airborne route of transmission, can lay dormant and then revert back to infected cells
What are the symptoms of TB
Cough, bloody phlegm, weight loss, loss of appitite, fatigue, night sweats, high temperature
What is the treatment and prevention of TB
Treatment: antibiotics - rifampin,
Prevention: vaccine at birth and or in teens
What is influenza?
Airborne droplets transmission, Influenza A + B= seasonal epidemics
C= mild illness
D= affects cattle not people
What are the symptoms of influenza
Your average ill symptoms
What is the treatment of influenza and the prevention
standard care of yourself, if bad then antiviral medication
Prevention: annual flu vaccine
Describe bacilli microbes
Rod shaped, usually singular
Describe coccus/ cocci
Spherical, berries
What does streptococci, staphylococci, dilococci mean?
- chains , 2. clusters, 3. pairs
What is Saccharmocyces cerevisae
fungi that helps ferement sugar make bread and wine
What is bacillus antracis
Orignates in soil, facultative anaerobe- can survive with or without oxygen, grows on sheep blood agar, clarify ID via bacteriophage gamma phage lysis test
What is Staphylococcus aureus
Commensal opportunistic pathoge, facultative anerobe, grown under selective media, acidity changes from red to yellow
What is mycobacterium tuberculosis
Grows in one to two weeks on agar mainly on blood, rough and irregular , Strict aerobe (no oxygen), rod shaped, orange yellow under uv light
What is escherichia coli
Found in healthy human colon, opportunistic pathogrn if relocates, growths rapidly, gram negative pink, rod shape and may form clusters
What is Chlamydia trachomatis
Highly responsive to antibiotics, if untreated can impact sperm function and block female fallopian tubes, obligate intracellular bacterium (requires host to grow)
name some attributes of prokaryotes
no nucleus, free floating dna, plasma membrane lines wall, cytoplasm holds ribosomes and granules, fast evolution + rapid mutation rate
What are the key differences between prokaryotes and eukaryotes
prokaryotes have no nucleus, prokaryotes only have 1 chromosome, prokaryotes dont have normal organelles, prokaryotes have 70 s ribosomes and e have 80s
what is the bacterial cell wall function
protection rigidity shape, formed from peptidoglycan which is NAG + NAM, created cross linkage structure
What is the structure of peptidoglycan
alternating nam and nag, nams are linked between layers, linked by peptide chain, gram psoitive and gram negative microbes
what is gram positive bacteria
bacteria with a thick peptidoglycan cell well, no outer membrane, appear purple after gram staining and hold onto dye
What is gram negative cell wall
thinner peptidoglycan cell wall, no tiechonic acid, outer membrane, has lps, appear pink after gram staining and cannot hold onto the dye
What is the capsule and slime layer
capsule: well organsied, attached to the wall, formed of polysaccharides
Slime layer: less organised, loosely attached, formed of glycoproteins and glycolipids
describe cell surface extensions:
pili or fimbriae, protein filament extensions, thin and straight, aid in attachment, aid in pathogenesis, in gram negative behaviour
what are cell inclusions
internalised storage stations, lipid phb stored in the granule, sulfur in g-, phosphate for biosynthesis
What are endospores
g + , detect via sport test, contain thick walls and little water, maybe terminal subterminal or central
What are the stages of microbial growth
lag, exponential, stationary, decline
What are the factors influencing microbial growth
chemical nutrition - carbo, nitrogen, oxygen and hydrogen from water
What are obligate aerobes
Only aerobic growth
What are facultative growth
Growth in both aerobic and anaerobic conditions
Better in oxygen conditions tho.
What are obligate anaerbobes
Only grow without oxygen conditions
What is Aerotolerant
Can live in the presence of oxygen but they are better off without
What is microaerophiles
Only in areobic conditions but a low concentration
What is bacterial nutrition
Phosphorus - nucleic acids and phospholipids
Sulfur- amino acid/ vitamins
Potassium - enzymes
Magnesium - stabilizes ribosomes/ membranes/ nucleic acid enzymes
Calcium
Na
what are micro-nutrients for bacteria
Iron, Trace metals, growth factors
What are: psychrophiles, mesophiles, thermophiles, hyperthermophiles
Colder to warmer temperatures
Does osmotic pressure affect microbial growth
yes
What type of stains are used for microscopic counts
Fluorescent
None-fluorescent
What are the issues with using stains for microscopic counts
Live + dead cant be distinguished
accuracy is hard
small cells overlooked
low density suspensions hard to count
motile cells need to be immobilised
debris can be mistaken
what is the pour plate method
- pipette inoculum onto sterile plate
- add sterile medium
- swirl to mix and incubate
- colonies grow in and on medium
What is the spread plate method
Pipette inoculumonto the surface of agar plate
2. spread evenly over the agar surface
3. incubate
4. colonies grow only on the surface
What are turbidimetric methods
cell suspensions turbid because cells scatter light
measured with a spectrophotometer
What is the wobble hypothesis
how one amino acid can be coded for by different codons
why would alterations in the bacterial genome occur
for variation, evolutionary purposes, genomic stability, have competitiveness in environment
how do alterations in the bacterial genome occur
random errors in dna replication
dna damage
mutation
horizontal gene transfer( swith of genes)
what is a wild type strain in bacterial genetics
isolated from the environment/ nature = wild type genome
what is spontaneous mutation
occasional
framshift or point
What are induced mutations
via radiation
what is the clinical significance of mutations
antibiotic resistance
what are the different types of genetic transfer in bacteria
transforamation, transduction, conjugation
describe transforamtion of genetic tranfer in bacteria
free dna released from the donor cell and incorporated into the recipient cell to br
transduction method in genetic transfer in bacteria
generalised
=1. lytic cycle
specialised transduction
what types of normal flora are there
resident - stays
- and transient - temporary
what is normal flora
the cells belonging to our body
do foetus have microbiota
no
when does the flora in the intestine first develop
after a persons first meal
define pathogenicity
ability to produce pathologic changes or disease
What is a pathogen
disease producing microorganism
what is virulence
measure of pathoenicity. Also involves invasiveness
What is toxigenicity
the ability to produce toxins
what is invasion
entry into host cells
what are primary pathogens
cause disease
e.g e.coli
- produces toxinm inhibit proteins synthesis resulting in severe bloody diarrhoea, inflammation, renal failure
What are opportunistic pathogens
disease caused in compromised hosts
s.epidermidis
- cause endocarditis
grows on catheters and implants
What are the general steps of infection
- exposure 2. adherence 3. invasion 4. evade host defenses 5.multiply and grow 6. damage the host 7. leave the host
what is an endotoxin
released on bacterial death and sometimes during growth, heat stable
systematic effects produced
- fever, intestinal hemorrhage, inflammation, simulates the immune system
what is an exotoxin
produced within bacteria, mainly gram positive organisms, may travel away from site of infection
four types: AB toxin, site specific (neurotoxin ect / membrane disrupting), superantigens
Describe the botulinum toxin
AB toxin the toxin enters the neural synapse, it blocks the release of ACh, this means you will have permanent muscle relaxation and result in organ failure
Describe the tetanus toxin
ab toxin, prevents the release of glycine and gaba, contraction occurs constantly
describe the cholera entertoxin
food borne, cholera binds to epthithelial cells releasing the toxin, this results in over expression of adenyl cyclase, this prevents na movement into the blood
what are the types of membrane disrupting toxins
haemolysin
leukocidin
what are superantigens
cuases excessive and non specific release of cytokines, most characterised is toxic shock syndrome. streptoccocus also able to produce it
what are the types of growth and colonisation of pathogens
Local- a small area(near entry site), extensive tissue damage but local
Focal- spread to secondary location, leading to secondary infection
Systemic-spread throughout the body
whata re the symptoms of having a disease
vital signs- 37 temp, heart rate (60-100) blood pressure(90/60 and 120/80)
nausea loss of appetite, pain
what are the classifications of diseases
Infectious
latrogenic
nosocomial
zoonotic
noncommunicable
non-infectious
What are the types of pathogen carries
active = showing symptoms and can pass it on to someone
convalescent = when someones who has had the disease and recovered but may still be able to pass it on
healthy/passive = has pathogen w no signs or symptoms
Incubatory = has pathogen, not developed symptoms but is facilitating the growth of it
what are the type of transmission
vertical = mother to child, e.g hiv
horizontal = indirect e.g sneezing or touching it
are the types of horizontal transmission
airborne = air, droplets, dust
contact = direct: respiratory (salivary), faecal, venereal, skin. indirect: via fomites
what is vehicle transmission
vehicle = material or object involved in pathogen transmission
spread over long distances e.g food and water
What is vector transmission
insects, ticks or mites
external = passive
internal =
hwo do we fight infection
Innate
adaptive methods
What is innate immunity
physical = cell junctions, skin, endothelia, microbiome, mucous membrane
chemical = enzymes, antimicrobial peptides, plasma protein mediators, inflammation - eliciting
What is the complement system
classical pathway
lectin pathway
alternative pathway
what are cellular defenses
white blood cells (neutrophils and macrophages)
t cells and b cells
What are the characteristics of protozoa
What is the basic life cycle of a protozoa
trophozoite, cyst, direct, indirect
What type of reproduction do protozoa under
asexual
- binary fission (mitosis of nucleus, cytokensesis of cytoplasm)
budding
schizogany
and sexual
- gamonts, syngamy, conjugation, autogamy
Describe radiolaria
silica based- skeletal makeup
non-motile
feed by endocytosis using folopodia
part of zooplankton
What are some examples of pathogenic protozoa
Entamoeba histolytica
Balantidium coli
Giardia lamblia
Trypanosoma brucei
Plasmodium
Toxoplasma
