Antibiotics 6.14-6.15 and CP15 Flashcards
What are antibiotics?
Chemicals that kill or inhibit the growth of microorganisms
What is the difference between bacteriostatic and bactericidal antibiotics?
- Bactericidal antibiotics can kill bacteria
- Bacteriostatic antibiotics prevent the growth of bacteria
How do antibiotics work?
They interfere with metabolic reactions that are crucial for growth and life of the cell
Describe the two ways that antibiotics inhibit bacterial metabolism
1) Inhibit enzymes that make chemical bonds in bacterial cell walls which prevents them from growing - weakened cell wall cannot withstand pressure as water moves in by osmosis so cell bursts = death
2) Inhibit protein production by binding to bacterial ribosomes, all enzymes are proteins so important metabolic processes can’t take place
Describe an experiment to investigate the effects of antibiotics on bacterial growth:
1) Use a sterile pipette to transfer bacteria onto an agar plate - spread using a sterile spreader
2) Use sterile forceps to place paper disks soaked in different antibiotics onto the plate - various concentrations should be used and a disk soaked with water acts as a control
3) Lightly tape a lid onto the Petri dish, turn upside down and incubate for 1-2 days at a temperature of 25 degrees Celsius
4) Observe
What name is given to an area of the bacterial ‘lawn’ where it is clear?
Zone of inhibition (the larger the zone, the more effective the bacteria)
Why is it important to use aseptic techniques? x2
1) To prevent bacteria becoming contaminated with unwanted organisms,s which could affect the results by interfering with growth of bacteria
2) Human pathogens can make us ill
Give three examples of aseptic techniques:
1) Using disinfectant
2) Using sterile equipment
3) Working near a Bunsen burner so any airborne microbes are drawn away from the cultures
What are HAIs?
Infections that are caught while a patient is being treated in hospital
How are HAIs transmitted? x3
1) Hospital staff and visitors not washing their hands
2) Coughs and sneezes
3) Equipment and surfaces not being disinfected
Why are people more likely to catch infections in hospital?
Weakened immune systems and surrounded by sick people
Ways to prevent HAIs
1) Visitors and staff should wash their hands
2) Doctors should remove ties, watches etc.
3) Disinfecting surfaces
4) Isolation wards
5) Testing for bacterial infections before surgery
Give an example of a antibiotic-resistant bacteria
MRSA
Why are antibiotic-resistant bacteria common in hospitals?
More antibiotics are used so more likely to have evolved resistance against them
Ways of preventing antibiotic-resistant bacteria:
- Antibiotics should not be prescribed for viral infections
- Narrow-spectrum antibiotics should be used
- Doctors should rotate the use of antibiotics
- Patients should finish the antibiotic course so all infections is cleared
