Week 9

Question 1

When talking about the administration and use of antibiotics it is important to understand some of the key terminology surrounding their use and clinical applications. Provide a definition of the following terms as they relation to antimicrobials.
Infection –

Answer 1

The invasion and multiplication of pathogenic microorganisms in body tissues, causing disease by local cellular injury.

Question 2

When talking about the administration and use of antibiotics it is important to understand some of the key terminology surrounding their use and clinical applications. Provide a definition of the following terms as they relation to antimicrobials.
Local Infection –

Answer 2

A localised infection involves one part of the body ie the skin

Question 3

When talking about the administration and use of antibiotics it is important to understand some of the key terminology surrounding their use and clinical applications. Provide a definition of the following terms as they relation to antimicrobials.
Systemic Infection -

Answer 3

A systemic infection involves the whole body often caused from a localised infection

Question 4

When talking about the administration and use of antibiotics it is important to understand some of the key terminology surrounding their use and clinical applications. Provide a definition of the following terms as they relation to antimicrobials.
Colonisation –

Answer 4

is the localised presence of microorganisms in the body tissues or organs; can be pathogenic or part of normal flora. It signifies the potential for infection.

Question 5

When talking about the administration and use of antibiotics it is important to understand some of the key terminology surrounding their use and clinical applications. Provide a definition of the following terms as they relation to antimicrobials.
Inflammation -

Answer 5

Protective mechanism of body tissues in response to invasion or toxins produced by colonising microorganisms.

Question 6

When talking about the administration and use of antibiotics it is important to understand some of the key terminology surrounding their use and clinical applications. Provide a definition of the following terms as they relation to antimicrobials.
Bacteraemia –

Answer 6

Is the presence of viable bacteria in the circulatory system

Question 7

When talking about the administration and use of antibiotics it is important to understand some of the key terminology surrounding their use and clinical applications. Provide a definition of the following terms as they relation to antimicrobials.
Septicaemia –

Answer 7

systemic infection caused by microorganism multiplication in the circulation.

Question 8

When talking about the administration and use of antibiotics it is important to understand some of the key terminology surrounding their use and clinical applications. Provide a definition of the following terms as they relation to antimicrobials.
Sepsis –

Answer 8

Syndrome with multiple organ involvement as a result of microorganisms or their toxins circulating in the blood.

Question 9

When talking about the administration and use of antibiotics it is important to understand some of the key terminology surrounding their use and clinical applications. Provide a definition of the following terms as they relation to antimicrobials.
Gram Stain –

Answer 9

procedure involving crystal violet and and iodine solutions followed by alcohol which allows classification of bacteria into gram positive and gram negative bacilli or cocci.

Question 10

When talking about the administration and use of antibiotics it is important to understand some of the key terminology surrounding their use and clinical applications. Provide a definition of the following terms as they relation to antimicrobials.
Bacteriostatic agents –

Answer 10

Inhibit bacterial growth, allowing intact and active host defence systems time to remove the invading microorganisms

Question 11

When talking about the administration and use of antibiotics it is important to understand some of the key terminology surrounding their use and clinical applications. Provide a definition of the following terms as they relation to antimicrobials.
Bactericidal agents –

Answer 11

Cause bacterial cell death and lysis and eradicate the infection.

Question 12

When talking about the administration and use of antibiotics it is important to understand some of the key terminology surrounding their use and clinical applications. Provide a definition of the following terms as they relation to antimicrobials.
Intrinsic Resistance –

Answer 12

Refers to the organisms’ genetic makeup that specifies the resistance.

Question 13

When talking about the administration and use of antibiotics it is important to understand some of the key terminology surrounding their use and clinical applications. Provide a definition of the following terms as they relation to antimicrobials.
Acquired Resistance –

Answer 13

Arises in the organism because of change or mutation in its genetic makeup or the acquisition of new genetic information.

Question 14

A growing problem in the health care industry in antimicrobial resistance. Discuss three distinct mechanisms by which bacteria can develop drug resistance.
• Barrier to entry –

Answer 14

change in cell wall or outer membrane composition, altered porin structure or porin synthesis.

Question 15

A growing problem in the health care industry in antimicrobial resistance. Discuss three distinct mechanisms by which bacteria can develop drug resistance.

• Efflux pump –

Answer 15

transport proteins that pump antibiotics from the inside of the bacteria to the external environment

Question 16

A growing problem in the health care industry in antimicrobial resistance. Discuss three distinct mechanisms by which bacteria can develop drug resistance.

• Formation of biofilm –

Answer 16

delays penetration of antibiotic through extracellular glycocalyx

Question 17

A growing problem in the health care industry in antimicrobial resistance. Discuss three distinct mechanisms by which bacteria can develop drug resistance.

• Enzymatic inactivation –

Answer 17

inactivation of drug by bacterial enzymes

Question 18

A growing problem in the health care industry in antimicrobial resistance. Discuss three distinct mechanisms by which bacteria can develop drug resistance.

• Target site modification –

Answer 18

results in reduced effectiveness of antibiotic

Question 19

A growing problem in the health care industry in antimicrobial resistance. Discuss three distinct mechanisms by which bacteria can develop drug resistance.

• Increased synthesis of target –

Answer 19

increased production of drug target results in reduced effectiveness of drug

Question 20

A growing problem in the health care industry in antimicrobial resistance. Discuss three distinct mechanisms by which bacteria can develop drug resistance.

• Target adaptation –

Answer 20

conversion of key bacterial substrate to essential cell product is inhibited by antibiotic. Bacteria develop a bypass pathway to ensure supply of the essential product.

Question 21

3. Antibiotics generally fall into four distinct groups defined by their mechanisms of action or how they exert their bactericidal or bacteriostatic effect. Discuss how the following classes of antibiotics exert their effects and give examples from each class.
   Inhibitors of Bacterial Cell Wall Synthesis
   Penicillins

Answer 21

Penicillins – Weaken the cell wall by inhibiting the trans-peptidase enzymes responsible for cross linking the glycan strands; resulting in cell lysis.

– Benzyl-penicillin and Phenoxy-methyl-penicillin

Question 22

3. Antibiotics generally fall into four distinct groups defined by their mechanisms of action or how they exert their bactericidal or bacteriostatic effect. Discuss how the following classes of antibiotics exert their effects and give examples from each class.
   Bacterial Protein Synthesis Inhibitors

Macrolide Antibiotics

Answer 22

Macrolide Antibiotics – Inhibit bacterial RNA-dependant protein synthesis by binding to the 50S ribosomal subunit. Macrolides are bacteriostatic that is they inhibit growth of microorganisms and in high concentrations with selected organisms may be bactericidal. AZITHROMYCIN CLARITHROMYCIN ERYTHROMYCIN ROXITHROMYCIN

Question 23

3. Antibiotics generally fall into four distinct groups defined by their mechanisms of action or how they exert their bactericidal or bacteriostatic effect. Discuss how the following classes of antibiotics exert their effects and give examples from each class.

Inhibitors of DNA Synthesis

Answer 23

Fluoroquinolones – They interfere with bacterial topoisomerase II and topoisomerase IV, the enzymes involved in the supercoiling of the DNA that is necessary for the duplication, transcription and repair of bacterial DNA. CIPROFLOXACIN MOXIFLOXACIN NORFLOXACIN OFLOXACIN

Question 24

3. Antibiotics generally fall into four distinct groups defined by their mechanisms of action or how they exert their bactericidal or bacteriostatic effect. Discuss how the following classes of antibiotics exert their effects and give examples from each class.

Miscellaneous

Answer 24

Metronidazole – They inhibit bacterial synthesis and cause cell death. They are selectively toxic to many anaerobic bacteria and protozoa. METRONIDAZOLE

Trimethoprim-sulfamethoxazole – Sulfonimide that is primarily bacteriostatic. They competitively inhibit the bacterial enzyme, dihydropteroate synthetase, necessary for incorporating PABA into dihydrofolic acid; resulting in a decrease of tetrahydrofolic acid, which interferes with synthesis of purines, thymidine and DNA. Also blocks a further step in the synthesis of folic acid, which bacteri need to synthesise.

Question 25

4. Explain why the plasma drug concentration of the aminoglycoside gentamicin is monitored

Answer 25

To ensure therapeutic levels are maintained without risk of adverse reactions. These drugs exhibit a significant post-antibiotic effect, inhibiting the growth of organisms after the plasma concentration has fallen below the minimal inhibitory concentration.

Question 26

5. Why are antiretroviral drugs often used in combination for the treatment of HIV?

Answer 26

Usually three or more of these drugs are used in combination due to rebound viral replication, development of resistance and inadequate drug potency.

Question 27

6. There are four characteristics of inflammation name them and outline the three basic events that account for these characteristics

Answer 27

Swelling (oedema) Redness (erythema) Pain and heat which are accounted for by 3 basic events 1. Blood vessel vasodilation and increased capillary permeability 2. Cellular infiltration and 3. Tissue repair.

Question 28

7. Define the following terms as they relate to immunity and the immune system;
   Natural Immunity –

Answer 28

The inherited and innate ability to resist antigens. Physiological factors- gastric acidity, resp tract cilia, bactericidal lysozyme in tears. General defences – rest, nutrition, exercise, lack of stress.

Question 29

7. Define the following terms as they relate to immunity and the immune system;

Acquired Immunity –

Answer 29

Custom made immunoglobulins or antibodies provide acquired immunity to specific type of antigen for varying lengths of time

Question 30

7. Define the following terms as they relate to immunity and the immune system;

Passive Immunity –

Answer 30

when antibodies are made by the mothers body are passively transferred by placenta or breast milk..

Question 31

7. Define the following terms as they relate to immunity and the immune system;

Artificially Acquired Active Immunity –

Answer 31

evoked by the deliberate admin of antigens which may be live or partially modified organisms or their toxins.

Question 32

7. Define the following terms as they relate to immunity and the immune system;
   Natural Immunity – The inherited and innate ability to resist antigens. Physiological factors- gastric acidity, resp tract cilia, bactericidal lysozyme in tears. General defences – rest, nutrition, exercise, lack of stress.

Artificially Acquired Passive Immunity –

Answer 32

Is conferred by the parenteral admin of antibody containing immune plasma from immune humans or animals.

Question 33

8. Non-Steroidal Anti-inflammatory Drugs (NSAIDs) are one of the most commonly administered drug groups worldwide. Discuss the reasons why NSAIDs cause gastric ulceration and nephrotoxicity.

Answer 33

NSAIDs causes renal and GI toxicity because of the inhibition of prostaglandin which account for all the therapeutic effects of analgesic anti-inflammatory and antipyretics effects of NSAIDs.

Question 34

9. Anti-histamines are some of the most common over the counter medication utilised to overcome motion sickness, vertigo and allergic or skin disorders. Discuss the effect that histamine has on the systems and symptoms listed below to explain why anti-histamines are utilised as they are;

Vascular Effects –

Answer 34

Stimulation of H1 and H2 receptors dilates the capillaries, increasing blood flow, capillary permeability, erythema and oedema. By activating the H1 and H2 receptors on the smooth muscles of the arterioles, histimine is also capable of eliciting a systemic response – vasodilation of the arterioles which can result in a profound fall in blood pressure- Therefore antihistimines can be used to raise blood pressure.

Question 35

9. Anti-histamines are some of the most common over the counter medication utilised to overcome motion sickness, vertigo and allergic or skin disorders. Discuss the effect that histamine has on the systems and symptoms listed below to explain why anti-histamines are utilised as they are;

Smooth Muscle Effects –

Answer 35

Produces a powerful relaxing effect on the smooth muscle of the arterioles and contractile action on the smooth muscles of many non-vascular organs i.e bronchi and GI tract. In sensitised individuals activation of the H1 receptors of the lungs can cause bronchial muscle contraction leading to dyspnoea and airway obstruction – therefore antihistimines are used for reducing contractions of non-vascular organs.

Question 36

9. Anti-histamines are some of the most common over the counter medication utilised to overcome motion sickness, vertigo and allergic or skin disorders. Discuss the effect that histamine has on the systems and symptoms listed below to explain why anti-histamines are utilised as they are;

Exocrine Glandular Effects -

Answer 36

Histamine stimulates the gastric, salivary, pancreatic and lacrimal glands. Stimulation of H2 receptors in the exocrine glands of the stomach increases acid production attributed to the activity of the parietal cells, causes the development of peptic ulcers. Therefore anti-histamines reduce gastric acid production.

Question 37

9. Anti-histamines are some of the most common over the counter medication utilised to overcome motion sickness, vertigo and allergic or skin disorders. Discuss the effect that histamine has on the systems and symptoms listed below to explain why anti-histamines are utilised as they are;

Central Nervous System Effects –

Answer 37

The activation of H1 receptors of the semicircular canals associated with motion sickness. Therefore antihistamine prevents the action of histamine.

Question 38

9. Anti-histamines are some of the most common over the counter medication utilised to overcome motion sickness, vertigo and allergic or skin disorders. Discuss the effect that histamine has on the systems and symptoms listed below to explain why anti-histamines are utilised as they are;

Inflammatory effects –

Answer 38

Histamine is a chemical mediator and type 1 anaphylactic reaction is the one associated with the release of histamine. Symptoms range from mild urticaria to anaphylactic shock. Therefore anti histamines are used to treat anaphylactic shock.

Question 39

9. Anti-histamines are some of the most common over the counter medication utilised to overcome motion sickness, vertigo and allergic or skin disorders. Discuss the effect that histamine has on the systems and symptoms listed below to explain why anti-histamines are utilised as they are;

Urticaria –

Answer 39

Is a vascular reaction of the skin, contact with external irritant causes histamine release from the mast cells into the skin. The local vasodilation causes the red flare. Increased permeability of the capillaries causes inflammation. Antihistamine drugs administered before exposure will prevent the response.

Question 40

9. Anti-histamines are some of the most common over the counter medication utilised to overcome motion sickness, vertigo and allergic or skin disorders. Discuss the effect that histamine has on the systems and symptoms listed below to explain why anti-histamines are utilised as they are;
   #
   Atopy –

Answer 40

Occurs in susceptible people and is caused by seasonal pollen. This disorder is manifested in the upper respiratory known as allergic rhinitis or hay fever. Histimine is produced causing local vascular dilation and increased capillary permeability. Resulting in swelling in the nasal linings. Anti-histamine drugs can prevent the reaction if administered before antigen exposure.

Question 41

9. Anti-histamines are some of the most common over the counter medication utilised to overcome motion sickness, vertigo and allergic or skin disorders. Discuss the effect that histamine has on the systems and symptoms listed below to explain why anti-histamines are utilised as they are;

Food Allergies –

Answer 41

Involves release of histamine in the mast cells of the intestine in response to ingested antigens. If upper GI vomiting occurs. If lower GI cramps and diarrhoea occurs. Can cause anaphylaxis if large amount of antigen is ingested. Antihistamines are used to prevent allergies.

Question 42

9. Anti-histamines are some of the most common over the counter medication utilised to overcome motion sickness, vertigo and allergic or skin disorders. Discuss the effect that histamine has on the systems and symptoms listed below to explain why anti-histamines are utilised as they are;

Bronchial Asthma –

Answer 42

inhaled antigen causes histamine release in the lower respiratory tract causing the bronchioles to contract however antihistamine does not relieve bronchoconstriction because more potent chemical mediators are responsible for causing the reaction.

Question 43

9. Anti-histamines are some of the most common over the counter medication utilised to overcome motion sickness, vertigo and allergic or skin disorders. Discuss the effect that histamine has on the systems and symptoms listed below to explain why anti-histamines are utilised as they are;

Systemic Anaphylaxis –

Answer 43

mediator response in the basophils and mast cells in the connective tissue. Usually caused by drugs, foods, stings. Causes the massive release of histamine causing major vasodilation and increased capillary permeability. This causes blood pressure drop and death can be caused by laryngeal oedema.

Question 44

10. The development of cancerous cells or carcinogenesis in the body typically follows process that leads to the development of clusters of cancerous cells. In the space below list the 8 steps that result in cancerous growth within the body.

Answer 44

1. Exposed of a cell to a mutagen, inheritance of a mutated gene, leads to:
2. -alteration of the cellular DNA, which:
3. • changes a proto-oncogene into an oncogene, or inactivates tumour suppressor gene, so that:
4. -the transformed cell (clone) is no longer subject to cell-cycle control end thus:
5. • has growth advantages over non-transformed cells and proliferates which:
6. • activates others proto oncogenes and:
7. -produce more growth factors and tumour-specific proteins, leading to:
8. • uncontrolled cancer growth such that cells become invasive and metastatic.

Question 45

11. Cancer growth is enhanced by an increased rate of cell proliferation due to a lack of regulating mechanisms. Approximately how many cancer cells are present before clinical symptoms begin to appear?

Answer 45

A tumour cell burden of 10⁹ (1000 000 000) one billion, that is physically palpable, about the size of a small grape,

Question 46

12. Discuss the following principles of cancer chemotherapy that are important to consider when determining the best course of treatment for a patient.
    Selective Toxicity –

Answer 46

chemotherapy usually relies on finding and exploiting a difference in biochemical pathway between the normal cell and the neoplastic cells ( or host cells and the microbial cell)

Question 47

12. Discuss the following principles of cancer chemotherapy that are important to consider when determining the best course of treatment for a patient.
    Selective Toxicity –

Answer 47

chemotherapy usually relies on finding and exploiting a difference in biochemical pathway between the normal cell and the neoplastic cells ( or host cells and the microbial cell)

Question 48

12. Discuss the following principles of cancer chemotherapy that are important to consider when determining the best course of treatment for a patient.
    Drug Delivery -

Answer 48

cancer chemotherapy is most effective against small tumours because they usually have an efficient blood supply and therefore drug delivery to the cancer site is increased. (Drug delivery directly into the cancer site)

Question 49

12. Discuss the following principles of cancer chemotherapy that are important to consider when determining the best course of treatment for a patient.

Cell-Kill Fraction –

Answer 49

drug given in adequate doses tend to kill a constant proportion of the cancer cells

Question 50

12. Discuss the following principles of cancer chemotherapy that are important to consider when determining the best course of treatment for a patient.

Growth Fraction –

Answer 50

the term growth fraction was created to distinguish the cell population , in the tumour that is actively engaged in cell cycling from the fraction that is not

Question 51

12. Discuss the following principles of cancer chemotherapy that are important to consider when determining the best course of treatment for a patient.

Courses of Treatment -

Answer 51

each cycle of cancer treatment (chemo, or radiation) to achieve total cancer cell kill if possible.

Question 52

12. Discuss the following principles of cancer chemotherapy that are important to consider when determining the best course of treatment for a patient.

Adjuvant Therapy - :

Answer 52

also called adjuvant care, is treatment that is given in addition to the primary, main or initial treatment

Question 53

12. Discuss the following principles of cancer chemotherapy that are important to consider when determining the best course of treatment for a patient.

Cell Cycle Specificity - :

Answer 53

agents that are most effective in one specific phase are referred to as a cell-cycle-specifics agents.

Question 54

13. As a nurse who may be administering cytotoxic agents to patients within various healthcare settings, an understanding of how to handle these medications appropriately is essential. Cytotoxic drugs are inherently toxic and many can be absorbed through the skin during handling. List some of the precautions that maybe necessary when handling this type of medication.

Answer 54

a. - Staff handling the drugs use protective clothing and equipment, including masks and gloves: techniques must be developed to avoid inhaling droplets or powders or spilling solutions.
b. -excess drug, waste secretions and contaminated equipment are disposed of by high temperature incineration.
c. - after administration of the cytotoxic agents , the patient ‘s body fluids are treated as id mutagenic.

Question 55

14. Breast and Prostate cancer are common examples of hormone dependent cancers. Discuss the possible treatment options available using either breast or prostate cancer as an example.

Answer 55

prostate cancer may be treated by:
Surgical removal of the prostate Radiation administration of antiandrogenic drugoestrogenic hormones ( as the female hormones have antiandrogenic effects) gonadotrophin-releasing hormone (GnRH) analogues (to suppress gonadotrphin releases.

Question 56

Carcinomas are tumours that originate in:

a. Mesenchyme
b. Bone marrow
c. Striated muscle
d. Epithelial cells

Answer 56

d. Epithelial cells

Question 57

Antineoplastic drugs destroy human cells. They are most likely to cause cell death among healthy cells that:

a. Have poor cell membranes
b. Are rapidly turning over
c. Are in dormant tissues
d. Cross the blood-brain barrier

Answer 57

b. Are rapidly turning over

Question 58

Cancer treatment usually occurs in several different treatment phases. In assessing the appropriateness of another round of chemotherapy for a particular person, which of the following would be evaluated as the most important

a. Hair loss
b. Bone marrow function
c. Anorexia
d. Heart rate

Answer 58

b. Bone marrow function

Question 59

A bacteriostatic substance is one that:

a. Directly kills any bacteria it comes in contact with
b. Directly kills any bacteria that are sensitive to the substance
c. Prevents the growth of bacteria
d. Prevents the growth of specific bacteria that are sensitive to the substance

Answer 59

d. Prevents the growth of specific bacteria that are sensitive to the substance

Question 60

The goal of antibiotic therapy is:

a. to eradicate all bacteria from the system
b. To suppress resistant strains of bacteria
c. To reduce the number of invading bacteria so that the immune system can deal with the infection
d. To stop the drug as soon as the person feels better

Answer 60

c. To reduce the number of invading bacteria so that the immune system can deal with the infection

Question 61

The penicillins

a. Are bacteriostatic
b. Are bactericidal, interfering with bacteria cell walls
c. Are effective only if given intravenously
d. Do not produce cross-sensitivity within their class

Answer 61

b. Are bactericidal, interfering with bacteria cell walls

Question 62

In general all people receiving antibiotics should receive teaching that includes which of the following points?

a. The need to complete the full course of drug therapy
b. The possibility of oral contraceptive failure
c. When to take the drug related to food and other drugs
d. The need for assessment of blood tests
e. Advisability of saving any leftover medication for future use
f. How to detect super infections and what to do if they occur

Answer 62

a. The need to complete the full course of drug therapy
b. The possibility of oral contraceptive failure
c. When to take the drug related to food and other drugs

Question 63

While teaching the client about taking oral tetracycline, which of the following does the nurse advise the client to do?

a. Consume calcium rich products to decrease the duration of the antibacterial effect
b. Use a soft toothbrush and floss teeth gently to remove staining on teeth
c. Report any ringing in the ears or dizziness
d. Avoid direct exposure to sunlight and apply sun block when outdoors.

Answer 63

d. Avoid direct exposure to sunlight and apply sun block when outdoors.

Question 64

3. Antibiotics generally fall into four distinct groups defined by their mechanisms of action or how they exert their bactericidal or bacteriostatic effect. Discuss how the following classes of antibiotics exert their effects and give examples from each class.

Inhibitors of Bacterial Cell Wall Synthesis
Cephalosporins

Answer 64

Cephalosporins - inhibit bacterial cell wall synthesis and are bactericidal because they inhibit cell division and growths, rapidly dividing bacteria are affected most. CEFEPIME, CEFACLOR

Question 65

3. Antibiotics generally fall into four distinct groups defined by their mechanisms of action or how they exert their bactericidal or bacteriostatic effect. Discuss how the following classes of antibiotics exert their effects and give examples from each class.

Inhibitors of Bacterial Cell Wall Synthesis
Carbapenems

Answer 65

Carbapenems – Bind to penicillin binding proteins thus inhibiting bacterial cell wall synthesis. Carbapenems have the broadest spectrum against gram negative and gram positive aerobic and anaerobic organisms. ERTAPENEM IMIPENEM MEROPENEM

Question 66

3. Antibiotics generally fall into four distinct groups defined by their mechanisms of action or how they exert their bactericidal or bacteriostatic effect. Discuss how the following classes of antibiotics exert their effects and give examples from each class.

Inhibitors of Bacterial Cell Wall Synthesis
Glycopeptides

Answer 66

Glycopeptides – Inhibit bacterial wall synthesis and are primarily active against gram positive bacteria. VANCOMYCIN TEICOPLANIN

Question 67

3. Antibiotics generally fall into four distinct groups defined by their mechanisms of action or how they exert their bactericidal or bacteriostatic effect. Discuss how the following classes of antibiotics exert their effects and give examples from each class.
   Bacterial Protein Synthesis Inhibitors

Lincosamides

Answer 67

Lincosamides – inhibits protein synthesis by binding to the bacterial 50S ribosomal subunit and preventing peptide bond formation. It is primarily bacteriostatic although it may be bactericidal in high doses against selected organisms LINCOMYCIN CLINDAMYCIN

Question 68

3. Antibiotics generally fall into four distinct groups defined by their mechanisms of action or how they exert their bactericidal or bacteriostatic effect. Discuss how the following classes of antibiotics exert their effects and give examples from each class.
   Bacterial Protein Synthesis Inhibitors

Aminoglycosides

Answer 68

Aminoglycosides – Irreversible binding to the 30S ribosomal subunit of susceptible bacteria thus inhibiting protein synthesis leading to cell death. Bactericidal antibiotics effective against gram negative bacteria and limited activity against gram positive bacteria. NEOMYCIN GENTAMICIN AMIKACIN

Question 69

3. Antibiotics generally fall into four distinct groups defined by their mechanisms of action or how they exert their bactericidal or bacteriostatic effect. Discuss how the following classes of antibiotics exert their effects and give examples from each class.
   Bacterial Protein Synthesis Inhibitors

Tetracyclines

Answer 69

Tetracyclines – Bacteriostatic for gram negative and positive. They inhibit protein synthesis by reversibly blocking 30S subunit of the ribosome and preventing access of tRNA to the mRNA ribosome complex. DOXYCYCLINE MINOCYCLINE TIGECYCLINE