Introduction to Microbes Flashcards
Where does angular chelitis present?
at the angles of the mouth
What bacteria causes angular chelitis?
staphylococcus aureus
What is minimum inhibitory concentration?
lowest concentration of an anti-microbial that will inhibit visible growth of microorganism
What does a leukocidin do?
Kills white blood cells
What does capnophilic mean?
carbon dioxide
What does facultative mean?
with and without oxygen
what does aerobic mean?
oxygen
What does anaerobic mean?
without oxygen
What does microaerophilic mean?
small amounts of oxygen
What are the stages of bacterial growth?
Lag, log, stationary, death
What happens in the lag phase?
bacteria get used to surroundings
What happens in log phase?
replicate exponentially
What happens in stationary phase?
growth rate = death rate
What happens in death phase?
no growth mediums so cell death
What is the D-value?
The time taken to kill 90% of bacteria
What are the different shapes of bacteria?
Rod shaped = BACILLI round shaped = COCCI spiral shape
What are the steps of gram staining?
primary stain, fixative (iodine), decoloriser (alcohol/acetone), counterstain
What is the colour of gram+ bacteria after staining?
purple
What is the colour of gram- bacteria after staining?
pink/red
Why do gram+ cells stain violet?
due to the presence of a thick layer of peptidoglycan
Why do gram- cells stain pink?
thinner peptidoglycan wall
what makes up the cell wall of gram- cells?
lipopolysaccharide
what is a lipopolysaccharide?
an endotoxin
Where do endotoxins come from?
produced by gram- bacteria
