Infectious Diseases (basics) Flashcards
(46 cards)
Define Eukaryotes?
cells containing membrane bound organelles e.g. nucleus, mitochondria or chloroplasts, can be unicellular e.g. fungi, or part of a complex multicellular organism e.g. a human
Define prokaryotes?
cells lack any membrane bound organelles – usually unicellular e.g. bacteria and archaea
What are archaea?
- Archaea are a domain of single cell organisms that live at extremes (type of prokaryote)
Describe difference in way DNA is organised in prokaryotes vs eukaryotes?
- DNA in prokaryotes and therefore bacteria is circular including the circular chromosome and plasmids – this is in contrast to eukaryotes where DNA is arranged in a linear fashion e.g. in chromosomes
- prokaryotes can do co-transcriptional translation (all happening at the same time) because nothing is membrane bound
Proteins are synthesised in the ______
ribosome
What is essential for synthesis and regulation of DNA within the bacteria?
folic acid
Explain the process of gram staining and what it involves?
- This allows organisms to be classed as gram positive or negative
- Atypical organisms cannot be classed this way – definition = organisms that cannot be stained or cultured in normal ways
- Gram staining involves first using a crystal violet stain which will stain gram positive organisms purple, then a counterstain which will stain gram negative organisms pink
- Gram staining is to do with differences in thickness of peptidoglycan cell walls
Name 6 gram positive rods?
- Propionibacterium
- Clostridium
- Lactobacillus
- Corneybacteria
- Actinomyces
- Listeria
2 genus of gram positive cocci? How can you differentiate?
streptococci - grow in chains - catalase negative
staphylococci - grow in clusters - catalase positive
2 species of staph that are clinically relevant?
aureus and epidermidis
Describe classification of streptococci?
Alpha haemolytic – viridans and pneumonia
Beta haemolytic (complete) – Group A and Group B
Gamma haemolytic – Enterococcus
Describe neisseria genus?
gram negative cocci in pairs
includes neisseria meningitidis and neisseria gonorrhoea
What are the coliforms? List 3?
COLIFORMS- gram negative non spore forming bacilli
E. coli
Klebsiella
Enterobacter
Pseudomonas shape and gram stain?
gram negative rod
Moraxella Catarrhalis shape and gram stain?
gram negative diplococcus
List 4 gram positive anaerobes?
Clostridium, lactobacillus, actinomyces, Propionibacterium
Name a gram negative anaerobe?
Bacteroides
Define bacteriostatic vs bacteriacidal?
- Bacteriostatic – stops reproduction and growth of the bacteria
- Bacteriacidal – kills the bacteria directly
Antibiotics that inhibit cell wall synthesis?
- Antibiotics that inhibit cell wall synthesis can be split into beta lactam and non beta lactam antibiotics
- Beta lactam – penicillins, carbapenems and cephalosporins
- Non beta lactam – vancomycin and teicoplanin
Antibiotics that inhibit folic acid metabolism?
- Antibiotics that inhibit folic acid metabolism – sulfamethoxazole, trimethoprim, co-trimoxazole (combination of the above 2)
Antibiotic that affects nucleic acid synthesis?
- Antibiotic that affects nucleic acid synthesis – metronidazole – this only converts to active form in anaerobic cells so is only effective against anaerobes
Antibiotics that affect protein synthesis by targetting the ribosome?
- Inhibition of protein synthesis by targeting the ribosome – macrolides, clindamycin, tetracyclines, gentamicin, chloramphenicol
Amoxicillin coverage
widely covers gram positive and some gram negative organisms, covers most strep, enterococcus and listeria
Co-amoxiclav coverage?
widely covers gram positive, gram negative and anaerobes
