microbiology revision Flashcards
complement system leads to
phagocytosis of c3b coated bacteria
inflammation
lysis of microbe
stages of sample processing bacteriology
sample
plate onto enrichment media
pick off colonies
plate onto selective/differential agars
pick off colonies
gram stain
definitive ID
catalase test
positive for staphylococcus
negative for streptococcus
following a positive catalase test which test would you do
coagulase
coagulase test
positive staph aureus
following negative coagulase test which test
novobiocin sensitivity
positive novobiocin test
staph epidermis
negative novobiocin test
staph saprophyticus
following negative catalase test which test
hemolysis
testing for strep pneumoniae
negative catalase
alpha hemolysis positive
testing for s pyogenes
negative catalase
beta hemolysis positive
testing for s agalactiae
negative catalase
beta hemolysis negative
why do we want to identify pathogens
improved treatment and outcomes
more appropriate use of antibiotics
managing outbreaks
what are many class 3 reactions for
selective toxicity
antibacterial drug for cell wall synthesis
cephalosporins
antibacterial drug for cell wall integrity
beta lactamases
antibacterial drug for DNA synthesis
metronidazole
antibacterial drug for DNA gyros
quinolones
antibacterial drug for RNA polymerase
rifampicin
antibacterial drug for phospholipid membrane
polymyxins
antibacterial drug for protein synthesis, 30S inhibitors
tetracyclins
antibacterial drug for protein synthesis, 50S inhibitors
clindamycin
drugs that may overcome resistance
co amoxiclav
antiviral drugs targeting attachment and entry inhibitors
maraviroc
antiviral drugs targeting ion channel blockers
rimantadine
antiviral drugs targeting polymerase inhibitors
acyclovir
antiviral drugs targeting integrase inhibitors
raltegravir
antiviral drugs targeting protease inhibitors
ritonavir
antiviral drugs targeting neuraminidase inhibitors
oseltamivir
infectious disease control
environment
behaviour change
antimicrobial agents
vaccination
public health awareness
surveillance
infection control measures
factors in viral pathogenesis
effects of viral infection on cells
entry into host
course of infection
cell tropism
cell damage
host immune response
virus clearance or persistence
how can cells respond to viral infections
no change
death
transformation
direct cell damage from viral infection may result from
diversion of cells energy
shut off of cell macromolecular synthesis
competition of viral mRNA for cellular ribosomes
competition of viral promotors and transcriptional nhances
indirect cell damage can result from
integration of viral genome
induction of mutations in host genome
inflammation
host immune response
COVID-19 replication
spike protein binds to ACE2 receptors
TMPRSS2 and cathepsin cleaves S glycoprotein
enables cell membrane viral fusion and viral RNA release
may create a pore so viral RNA can enter
or may be internalised by endocytosis and uncoated in lysosomal environment
which would release ssRNA into cytosol
viral genome replicated and translated into viral proteins
envelope glycoproteins and process in Golgi
released by vesicular exocytosis
what is the influenza a virus
enveloped
negative sense
ssRNA
influenza viral replication
virus adsorbs to respiratory epithelium by hem agglutinin spikes
fuses with the membrane
virus is endocytose into vacuole
releases 8 nucleocapsid segments into cytoplasm
nucleocapsids transported to nucleus
negative sense ran is transcribed t positive sense
translated into viral proteins
positive sense rna synthesises glycoprotein spikes inserted into the host membrane
positive sense rna synthesises new negative sense, assembled into nucleocapsids
transported out of nucleus to cell membrane
release of mature virus, budded off with spiked envelope
how would strep pyogenes be identified in the lab
sputum sample taken
cultured on general medium, blood agar
look for beta haemolytic colonies
pick off colonies
make smear on slide
gram stain
look for gram positive cocci chains
definitive ID based on API or MALDI
alpha hemolysis
partial hemolysis
green
beta hemolysis
complete hemoylsis
clear