Bacteria Flashcards
What is the difference between gram-positive and -negative bacteria?
Positive: thick peptidoglycan layer
Negative: Thin peptidoglycan layer but have outer membrane
Why are gram-negative bacteria more harmful?
- They’re protected by the outer membrane so harder to kill
- Higher resistance
- Release endotoxins from the membrane
What is the difference between aerobic and anaerobic bacteria?
Aerobic: produce energy with oxygen
Eg. TB, Pseudomonas, E.coli
- More common so this sample is done first
Anaerobic: without oxygen
What is acid-fast testing?
Identifies TB and other mycobacteria
How can alpha vs beta haemolytic bacteria be identified?
Using blood agar
- Alpha: incomplete haemolysis (will appear green)
- Beta: complete haemolysis (will appear white)
What is the difference between group A and B streptococcus?
A: Quite harmless. Found on the skin and inside throat
B: live digestive tract and vagina. Cause more serious infections
What are lactose fermenter bacteria?
Eg. E.coli, klebsiella, Enterobacter
They react and can be identified this way
Which bacteria can cause miscarriages?
Listeria bacteria (from uncooked pork)
Or
Strep agalactase (prophylaxis can be given for future pregnancies)
Which antibiotic is used to treat severe cellulitis?
Benzylpenicillin
Which bacteria commonly causes cellulits?
Strep pyogenes
Can turn into necrotising fasciitis
Which antibiotics can be used for urinary sepsis?
Gentamycin and co-amoxiclav
Which antibiotics can be used for a UTI?
Nitrofurantoin or Trimethoprim
Lots of UTI’s are resistant to Trimethoprim
What are the cautions with gentamycin?
It’s kidney heavy so dose needs to be appropriate for kidney function
Which antibiotic is used for neiserria meningitidis?
Ceftriaxone
Public health needs to be notified and prophylaxis is given to contacts
Which bacteria most commonly causes infective endocarditis?
Staphylococcus aureus
