Block 9 Week 2

Question 1

Narrow spectrum antibiotic examples

Answer 1

Macrolides like erythromycin which targets the large ribosomal subunit and older penicillin such as benzylpenicillin

Question 2

Sulfa drugs

Answer 2

Non antibiotic micrboial drugs which taret the folate synthesis pathway

Question 3

Target of quinolone

Answer 3

DNA gyrase

Question 4

What is DNA gyrase?

Answer 4

Enzyme for supercoiling of DNA for replicatio and transcription

Question 5

Clostridium dificile

Answer 5

Anaerobic gram negative bacteria with spores. It is a commensal bacteria at low levels butin excess causes pseudomembranous colitis

Question 6

When does innate resistance occur?

Answer 6

Bacteria lack suitable target or become impermeable to the drug

Question 7

What are the issues with broad spectrum antibiotics?

Answer 7

Resistance of bacteria

Question 8

What affects the microbiome-host relationship?

Answer 8

Diet, nutritional state and stress

Question 9

Broad spectrum antibiotics

Answer 9

Aminoglycosides, quinolones, cephalosporins and synthetic pencillin

Question 10

Tetracyclines

Answer 10

Targets both eukaryotic and prokaryotic of bacteriostatic 30s inhibitors

Question 11

Bacteria found in the upper respiratory tract

Answer 11

Staphylcoccus pneumoniae, haemophilius influenzae, staphylcoccus epididermis, staphylcoccus aureus

Question 12

Pneumonia

Answer 12

Infection of the lung tissues that results in inflammation where the alveoli fill with fluid/pus, causing pulomonary consolidation and results in respiratory distress. Nasopharyngeal colonisation is a prerequisite for the disease.

Question 13

Pneumonia causes

Answer 13

Influenza virus or bacterial causative agent is staphylococcus aurea, streptococcus pneumoniae and haemophilius influenzae. There are normally defences in the upper respiratory tract such as the nostrils, mucociliary escalator and the alveolar macrophages, and commensal bacteria that prevent this occurring.

Question 14

How is pneumonia acquired?

Answer 14

• Community acquired pneumonia is the most common type acquired outside of the hospital, caused by bacteria, viral and fungi.
• Hospital acquired pneumonia is acquired through biofilm present on ventilators and fungi.
• Aspiration pneumonia: inhaling a foreign object such as food or liquid which enters the airways causes the lung tissues to become inflamed. It occurs more in the right lung because it has greater lung capacity than the left lung.

Question 15

Risk factors for pneumonia

Answer 15

 Immunocompromised groups such as elderly and the very young
 Frequent exposure to asbestos and cigarette smoke
 Poor sanitation

Question 16

Viral cause of pneumonia

Answer 16

Influenza virus can cause pneumonia because it weakens the immune system which increases susceptibility to infection by already present bacteria in the upper URT.

Question 17

Pneumococcus pathogen

Answer 17

Pneumococcus is a gram positive cocci extracellular anaerobic bacteria with a peptidoglycan thick cell wall with lipoteichoic acid. It is absent in catalase enzyme for H202 -> H20 and O2. It is alpha haemolytic which means it partially breaks down RBC. Streptococcus pneumoniae is sensitive to bile

Question 18

Why is catalase important?

Answer 18

Catalase is important to bacteria because it provides protection against damage from the host defence signalling molecule hydrogen peroxide.

Question 19

Effects of pneumococcus

Answer 19

It inhibits the oxidative burst by neutrophils and induces activation of the classical-complement pathway. it releases the virulence factor pneumolysin to bind to cholesterol of endothelial cells and cause a pore to form. It causes partial breakdown of RBC.

Question 20

What type of bacteria is pneumococcus?

Answer 20

Streptococcus is a fastidious bacteria and the target is the alveoli have nutrient rich fluid. This causes inflammation, leading to fluid build up/pulmonary consolidation. If it enters the bloodstream, it can travel to the brain and result in meningitis.

Question 21

Ve+ bacteria

Answer 21

Gram + has thick peptidoglycan cell wall with teichoic acid. It is divided into cocci and bacilli. Cell membrane is below the cell wall.

Question 22

What is teichoic acid?

Answer 22

Teichoic acid binds to fibronectin on endothelial cells for host colonisation. for hydrophobicity and maintaining structure.

Question 23

Ve- bacteria

Answer 23

Outer membrane of lipopolysaccharide containing endotoxins such as polysaccharide O which maintains membrane integrity. It has a thin cell wall of peptidoglycan. It contains a periplasmic space between inner membrane and peptidoglycan cell wall.

Question 24

What is the role of IL-1?

Answer 24

Acute inflammatory mediators

Question 25

What is the role of TNF?

Answer 25

Recruiting WBC and activating endothelium

Question 26

Meningitis

Answer 26

Caused by pneumococcus meningitis bacteria crossing the blood brain barrier through the release of the virulence factor pneumolysin. This results in the inflammation of the brain and spinal cord meningeal layers.

Question 27

Meningitis symptoms

Answer 27

Fever, chills, hearing loss, vision loss, photosensitivity

Question 28

Neisseria Meningitidis

Answer 28

Gram negative bacterium which causes meningitis in older children and adults commonly.

Question 29

What is the most common cause of community acquired pneumonia?

Answer 29

Streptococcus pneumoniae which becomes pathogenic when immunosuppression occurs

Question 30

What is the most common cause of pneumonia in infants?

Answer 30

Streptococcus agalctaei which is gram positive transmitted during birth

Question 31

Macrolide

Answer 31

Bind to the P site of the subunit of the 50s ribosomal subunit. This prevents peptidyltransferase allowing attachment between peptide and another amino acid on tRNA.

Question 32

Why has antibiotic resistance occurred?

Answer 32

Increased global availability, uncontrolled sale in low/middle income countries
During pharmaceutical manufacturing, antibiotic is released into environment

Question 33

What is the choroid plexus?

Answer 33

Network of blood vessels in the brain which produce CSF

Question 34

Which space is affected by meningitis?

Answer 34

Bacteria enter the subarachnoid space where the blood-brain barrier is vulnerable in the choroid plexus. Due to the immune response of inflammation, causes oedema of the brain called vasogenic cerebral oedema.

Question 35

Which immune cells are present in the brain?

Answer 35

Astrocytes and microglia

Question 36

What is the effect of meningitis on the brain?

Answer 36

Vasogenic cerebral oedema, cerebral vasculitis which reduces blood flow to the brain which both decreases BP and increases intracranial pressure, leading to brain cell apoptosis

Question 37

What is the common bacterial cause of meningitis in infants?

Answer 37

E.Coli, listeria monocytogenes and Streptococcus agalactiae

Question 38

What is the common bacterial cause of meningitis in children?

Answer 38

Streptococcus pneumonia, neisseria meningitidis

Question 39

What is the common bacterial cause of meningitis in adult?

Answer 39

Streptococcus pneumonia, neisseria meningitidis, listeria monocytogenes

Question 40

What are the viral causes of pneumonia?

Answer 40

Enterovirus, herpes and its subtype varicella zoster virus, HIV, mumps

Question 41

How is meningitis transmitted?

Answer 41

Respiratory secretions from close contact only, not simply breathing the air near a person

Question 42

What are the vaccinations for meningitis?

Answer 42

Pneumococcal vaccine, MenB, MMR.

Question 43

What is the target of first gen cephalosporins?

Answer 43

Inhibiting cell wall synthesis of gram positive bacteria

Question 44

What is the target of second gen cephalosporins?

Answer 44

Inhibiting cell wall synthesis of gram negative bacteria

Question 45

Side effects of tetracyclines

Answer 45

Photosensitivity