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22 Cards in this Set
- Front
- Back
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how do we treat different microbes? |
bacteria = antimicrobials viruses = vaccinations and antivirals fungi = anti-fungals (often topical) protozoa = antiprotozoal |
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routes of administration: |
- oral in mild infections - intravenous - rectally (rarely) - vaginally - topical |
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what are antibiotics? |
compounds produced by a microbe that can kill or inhibit the growth of another organism |
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what are antimicrobials? |
compounds that kill or inhibit growth of a microorganism |
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how are antibiotics classed? |
- bactericidal= directly kill bacteria - bacteriostatic= inhibit growth of the bacteria that then enables the body's defence mechanisms to remove the bacteria |
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what is selective toxicity and how does it occur? |
the ability to kill the microbe but not harm the patient. achieved by targeting the structure of the pathogen which is different in humans. |
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bacteria (____________) are structurally different to human (_____________) cells. |
prokaryotic, eukaryotic |
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why is it difficult to develop antifungal medications? |
because fungi use the same mechanisms to synthesise proteins as humans/ |
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why is it difficult to find anti-viral medications? |
because viruses multiply within host cells using host cell enzymes and machinery so it's difficult to find an antiviral medication |
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what kind of drugs treat protozoa? |
antiprotozoan drugs |
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how do antimicrobials destroy a microbe or stop it multiplying? |
- inhibit cell wall synthesis - interference with DNA replication - inhibit protein synthesis - disrupt the cell membrane - antimetabolic drugs block key metabolic reactions inside the bacteria |
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what are broad spectrum antimicrobials? |
kill a wide range of gram-positive and gram-negative bacteria but also destroy normal flora |
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what are narrow spectrum antimicrobials? |
effective against a select group of pathogens eg. penicillin which works on gram-positive bacteria |
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some adverse effects of antimicrobial agents: |
- GI upset - toxicity eg. renal toxicity or liver disease - allergy - disruption of normal flora |
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how do antibiotics reach their targets? |
- cross the cell wall - cross the cell membrane to enter the cell - bind to its target inside the cell |
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how does a pathogen develop resistance to an antibiotic? |
it develops an ability to stop one of these steps |
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what is antibiotic resistance? |
the acquired ability of a microbe to resist the effects of an antimicrobial agent to which it is normally susceptible. |
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how do microbes achieve antibiotic resistance? |
- produce enzymes that detroy/inactive penicillin/other antibiotics - changing the membrane permeability so that the antibiotic can't enter the bacterium - pumping the antibiotic out so fast that it cannot build up to toxic level inside bacterium - altering target so the antibiotic can't attach |
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how do they start developing the ability to have antibiotic resistance? |
- spontaneous mutations in critical genes - transfer of resistance genes from one bacterium to its neighbour via a pilus - use of antibiotics that kill susceptible bacteria but allow resistant bacteria to thrive |
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examples of antibiotic-resistant bacteria: |
- MRSA = methicillin resistant Staphyloccus aureus - EMRSA = a strain of MRSA - PRSP = penicillin resistant Streptococcus pneumoniae |
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how can we reduce development of resistance? |
- avoid excessive prescribing of antimicrobials - finish the full course to prevent survival and proliferation of resistant strains - never use left over antibiotics or antibiotics prescribed for someone else - prescribe most specific antibiotic available and avoid broad-spectrum antibiotics -avoid forming aerosols when drawing up antibiotics |
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what has been identified by the WHO as one of the 3 greatest threats to human health? |
antimicrobial resistance |
