Microbiology - Principles Flashcards
to pass the formative :)))
3 domains of life
archaea
eukaryotes
bacteria
protozoa
single celled animals
fungi
higher plant like organisms
bacteria
usually small, unicellular organisms
viruses
very small obligate parasites
eukaryote vs prokaryote
eukaryotes are much bigger, more complex, have linear chromosomes, no flexible cell wall and a cell cycle
structure of a nucleoid
contains DNA and proteins
no nuclear membrane
chromosomes are single, circular molecules
basic DNA
gram positive
thick, multilayer peptidoglycan
target of penicillin
gram negative
outer membrane
periplasm (gel like matrix between membranes)
thinner peptidoglycan
target of penicillin
order of prokaryote protein synthesis
gene mRNA ribosome protein 2nd, 3rd, 4th structure export
prokaryote food
c source organic e.g. protein/sugar
N source
O&H source
vitamins`
prokaryotic growth
food temperature hydrogen ion conc osmotic protection oxygen
identification of microorganisms
microscopy
measures shape, size, grouping
flagella, spores
staining
common shapes of bacteria
cocci - spheres
bacilli - rods
spiral shaped
cocci division in one plane
produce chains 4-20 cocci e.g. streptococcus
cocci division in three planes
produce clumps. eg staphylococcus
obligate aerobes
require oxygen
obligate anaerobes
killed by oxygen
facultative anaerobes
can tolerate oxygen
selective media
a media that selects the growth of specific prokaryotes
differential media
incorporations of chemicals produces visible changes in colonies that facilitate identification
metabolic profiling
utilisation of carbon sources
utilisation of amino acids
agglutination
clumping of an antigen and antibody
DNA technology
specific primers amplify specific pieces of DNA
allows precise identification
16sRNA
RNA component of holoenzyme
multi locus sequence typing (MLST)
increasing resolution
entire genome sequencing
MALDI-TOF
powerful, rapid, precise, cost effective
separates ions according to mass and charge
detects the spectrum of proteins released from a sample
haemolysis
streptococci ONLY
virulence
the capacity of a microbe to cause damage to a host
pathogen
harmful organism that produces a pathology
commensal bacteria
organism part of the normal flora
often mutualistic relationship
endogenous
opportunistic pathogen
organism that causes infection when opportunity/change in natural immunity arises
examples of gram negative organisms
Neisseria spp
Escherichia spp
examples of gram positive organisms
streptococcus
staphylococcus
enterococcus
clostridium
coliform
species of gram negative bacilli that look like E.coli
grow best aerobically
are coliforms dangerous?
yes. any coliform that gets into a normally sterile tract can cause infection. e.g. UTI
antibiotic used to treat infections from coliforms
gentamicin
mechanism of fever production
antigen interacts with macrophages
macrophages release cytokines into the blood stream
cytokines travel to the anterior hypothalamus
prostaglandin E is released which increases the bodies thermal set point
the body now perceives itself as cold and starts to shiver in order to conserve heat
normal body temperature
37 degrees
fever temperature
38>
alpha haemolysis
partial haemolysis
beta haemolysis
full haemolysis
gamma haemolysis
no haemolysis
antibiotics
a drug used to treat or prevent infections caused by microorganisms
bacteriostatic
inhibits the growth of bacteria
bacteriocidal
kills bacteria
ideal antibiotic
long half life cidal (kills bacteria) minimal damage to host good tissue distribution no side effects
excretion of antibiotics
through urine, liver, biliary tract and faeces
antibiotic targets
cell wall ribosomes DNA replication DNA gyrases metabolic pathways
commonly prescribed cell wall antimicrobials
penicillin
cephalosporins
glycopeptides
advantages of penicillin
safe to use when pregnant
very few side effects
range from narrow spectrum to broad spectrum
disadvantages of penicillin
excreted very quickly through kidneys
many people are allergic
many strains are resistant
cephalosporins
broad spectrum antibiotics that effect the bowel flora
broad spectrum antibiotics
acts against both gram positive and gram negative bacteria
narrow spectrum antibiotics
acts against specific families of bacteria
how do antibiotics inhibit protein synthesis
they attach to bacterial ribosomes
protein synthesis resumes once the antibiotic is removed
the exception to this is aminoglycosides which is lethal when the antibiotic binds to the bacterial ribosome
what does SICP’s stand for?
standard infection control procedures
5 ways infection can spread
inhalation inoculation intercourse ingestion mother to infant
what does BBE stand for?
bare below the elbows
