Bacterial infection Flashcards
What percentage of in-patients are on antibiotics?
25%
What percentage of patients in care will need antibiotics?
33.3%
What proportion of the drug budgets spent on antibiotics?
30%
What proportion of antibiotic usage occurs in primary care?
80%
What type of pathogen causes a) thrush b) malaria and c) tape worm?
Fungi
Protozoa
Helminths (worm-like organisms living in and feeding on living hosts, receiving nourishment and protection while disrupting their hosts’ nutrient absorption, causing weakness and disease)
State the general name for bacteria colonies that form a) spheres b) rods.
a) Coccus
b) Bacillus
What is a peptidoglycan ?
What is the difference between a gram positive and a gram negative bacteria?
A mixture of charged amino acids and N-acylated hexose sugars which are cross linked by transpeptidase enzymes.
Gram positive - cell wall made from peptidoglycan (20-80nm) therefore highly hydrophilic and therefore resistant to the action of bile. Secrete endotoxins and exotoxins.PURPLE
Gram negative - cell wall contains less peptidoglycan (5-10nm) lipoproteins and lipopolysaccharides theres outer layer has hydrophobic properties. Secrete endotoxins.PINK
Describe the processes involved in gram staining.
- Preparing and fixing the slide
Use sterilised loop to place culture on glass slide mounted on water.
Fix by drying out water using heat from bunsen burner - Stain with crystal violet and set with iodine
- Decolourise with alcohol
- Counterstain with safranin (pink)
What does fixation of culture on slide accomplish?
- kill the bacteria
- firmly affix the smear to the microscope slide
- allow the sample to more readily take up the stain
Give 6 examples of gram positive bacteria.
Cocci
Staphylococcus aureus
Streptococcus pyogenes
Streptococcus pneumoniae
Bacillus Bacillus cereus Bacillus anthraces Listeria Clostridium difficile
Give 6 examples of gram negative bacteria.
Cocci
Neisseria meningitidis
Neisseria gonorrhoeae
Bacillus
Haemophilus influenza
Enterobacteriaciae (e.g. Salmonella, Shigella, Escherichia coli)
Vibrio cholerae
How can bacteria growth differ between species?
What is the clinical significance of bacteria that grow in spores?
Grow in different nutrients and atmosphere
Grow in different patterns e.g. colonies or chains
Resistant to drying, temperature, disinfection and digestion.
How do aerobes, anaerobes and facultative bacteria grow?
AEROBES
Use oxygen as terminal electron acceptor
Oxidation of glucose to produce CO2 and H2O
ANAEROBES
Organic molecules acts as final electron acceptor
Glucose converted to lactic acid
FACULTATIVE
do both
Why do some bacteria take from their extracellular environment in order to grow?
They cannot make vitamins, amino acids, purines and pyrimidines.
Describe the special requirements needed for E.Coli and Triponema palladium (syphillis) to grow.
E.Coli - requires inorganic salts and glucose
Triponema palladium- fastidious so only grows under strict conditions.
