CASE 1-5 BLOCK 2.4
Digestion and Defence II
31 MAART 2017
MARIEKE DE JONG
ITM
,Case 1: Sense and Sensitivity ..................................................................................................................3
Antibiotics ............................................................................................................................................3
Cell Wall Targeting Antibiotics .........................................................................................................3
β-Lactams .....................................................................................................................................3
Penicillin ...................................................................................................................................3
Cephalosporins ........................................................................................................................3
Glycopeptides ..............................................................................................................................3
Ribosome Targeting Antibiotics .......................................................................................................4
Tetracyclines ................................................................................................................................4
Macrolides ...................................................................................................................................4
Aminoglycosides ..........................................................................................................................4
DNA Targeting Antibiotics ...............................................................................................................5
Quinolones ...................................................................................................................................5
Antimetabolic Antibiotics ................................................................................................................5
Trimethoprim + sulfamethoxazole ..............................................................................................5
Antibiotic Resistance ...........................................................................................................................5
Common Pathogens.............................................................................................................................6
Case 2: Stopping Malaria at the Border .................................................................................................7
Malaria .................................................................................................................................................7
Epidemiology ...................................................................................................................................7
Etiology ............................................................................................................................................7
Pathophysiology ..............................................................................................................................7
Diagnosis ..........................................................................................................................................8
Treatment and Prevention ..............................................................................................................9
Malaria Immunity ............................................................................................................................9
Case 3: Breaching the Defence .............................................................................................................10
HIV......................................................................................................................................................10
Mechanism of Infection .................................................................................................................10
Epidemiology .................................................................................................................................11
Symptoms ......................................................................................................................................12
Diagnosis ........................................................................................................................................12
Prevention......................................................................................................................................12
Treatment ......................................................................................................................................13
Antigenic shift vs. drift ...................................................................................................................14
Case 4: Soy Latte Macchiato .................................................................................................................15
Hypersensitivity .................................................................................................................................15
, Type I..............................................................................................................................................15
Type II.............................................................................................................................................16
Type III............................................................................................................................................16
Type IV ...........................................................................................................................................16
Diagnosis ............................................................................................................................................17
Treatment ..........................................................................................................................................17
Allergens Around the World ..............................................................................................................18
Case 5: Selection on Entry.....................................................................................................................19
Thymus...............................................................................................................................................19
Central and Peripheral Tolerance ......................................................................................................20
B Cell Maturation ...............................................................................................................................21
Autoimmunity ....................................................................................................................................21
Witebsky Postulates ..........................................................................................................................22
Bibliography ..........................................................................................................................................23
, Case 1: Sense and Sensitivity
Antibiotics
The outside of some bacteria is covered in complex polysaccharides. Some antibiotics cannot
penetrate this layer, and are thus ineffective on these bacteria.
Cell Wall Targeting Antibiotics
β-Lactams
Penicillin
Penicillin binds to penicillin-binding protein (PBP), which inhibits cross-linking of the peptidoglycan
layer. This only functions when the crosslinks are being formed (during growth and replication). It
also inactivates an inhibitory enzyme, which leads to autolysis.
There are natural penicillins (e.g. benzylpenicillin) and synthetic penicillins (e.g. amoxicillin).
The spectrum changes slightly between the different forms. They are most effective in gram-positive
bacteria, as the peptidoglycan layer is not covered with a membrane. However, they can sometimes
penetrate the outer membrane of gram-negative bacteria using porins.
Penicillins are bactericidal.
Cephalosporins
Cephalosporins have the same mechanism of action as penicillins.
Examples of cephalosporins are cefuroxime, cefotaxime, ceftriaxone and cefadroxil.
First and second generation cephalosporins target mostly gram-positive and some gram-negative
bacteria, while the opposite is true for third generation drugs. Fourth and fifth generation drugs
have broad spectrum coverage.
Cephalosporins are bactericidal.
Figure 1 (Brunton, Chabner et al. 2011)
Glycopeptides
Glycopeptides bind to cell wall precursor subunits. This means polymerisation cannot take place.
The most important glycopeptides are vancomycin and teicoplanin.
Glycopeptides are unable to work on gram-negative bacteria (their molecular weight is too large),
but they are effective against many gram-positive families.
Glycopeptides are bactericidal.
Digestion and Defence II
31 MAART 2017
MARIEKE DE JONG
ITM
,Case 1: Sense and Sensitivity ..................................................................................................................3
Antibiotics ............................................................................................................................................3
Cell Wall Targeting Antibiotics .........................................................................................................3
β-Lactams .....................................................................................................................................3
Penicillin ...................................................................................................................................3
Cephalosporins ........................................................................................................................3
Glycopeptides ..............................................................................................................................3
Ribosome Targeting Antibiotics .......................................................................................................4
Tetracyclines ................................................................................................................................4
Macrolides ...................................................................................................................................4
Aminoglycosides ..........................................................................................................................4
DNA Targeting Antibiotics ...............................................................................................................5
Quinolones ...................................................................................................................................5
Antimetabolic Antibiotics ................................................................................................................5
Trimethoprim + sulfamethoxazole ..............................................................................................5
Antibiotic Resistance ...........................................................................................................................5
Common Pathogens.............................................................................................................................6
Case 2: Stopping Malaria at the Border .................................................................................................7
Malaria .................................................................................................................................................7
Epidemiology ...................................................................................................................................7
Etiology ............................................................................................................................................7
Pathophysiology ..............................................................................................................................7
Diagnosis ..........................................................................................................................................8
Treatment and Prevention ..............................................................................................................9
Malaria Immunity ............................................................................................................................9
Case 3: Breaching the Defence .............................................................................................................10
HIV......................................................................................................................................................10
Mechanism of Infection .................................................................................................................10
Epidemiology .................................................................................................................................11
Symptoms ......................................................................................................................................12
Diagnosis ........................................................................................................................................12
Prevention......................................................................................................................................12
Treatment ......................................................................................................................................13
Antigenic shift vs. drift ...................................................................................................................14
Case 4: Soy Latte Macchiato .................................................................................................................15
Hypersensitivity .................................................................................................................................15
, Type I..............................................................................................................................................15
Type II.............................................................................................................................................16
Type III............................................................................................................................................16
Type IV ...........................................................................................................................................16
Diagnosis ............................................................................................................................................17
Treatment ..........................................................................................................................................17
Allergens Around the World ..............................................................................................................18
Case 5: Selection on Entry.....................................................................................................................19
Thymus...............................................................................................................................................19
Central and Peripheral Tolerance ......................................................................................................20
B Cell Maturation ...............................................................................................................................21
Autoimmunity ....................................................................................................................................21
Witebsky Postulates ..........................................................................................................................22
Bibliography ..........................................................................................................................................23
, Case 1: Sense and Sensitivity
Antibiotics
The outside of some bacteria is covered in complex polysaccharides. Some antibiotics cannot
penetrate this layer, and are thus ineffective on these bacteria.
Cell Wall Targeting Antibiotics
β-Lactams
Penicillin
Penicillin binds to penicillin-binding protein (PBP), which inhibits cross-linking of the peptidoglycan
layer. This only functions when the crosslinks are being formed (during growth and replication). It
also inactivates an inhibitory enzyme, which leads to autolysis.
There are natural penicillins (e.g. benzylpenicillin) and synthetic penicillins (e.g. amoxicillin).
The spectrum changes slightly between the different forms. They are most effective in gram-positive
bacteria, as the peptidoglycan layer is not covered with a membrane. However, they can sometimes
penetrate the outer membrane of gram-negative bacteria using porins.
Penicillins are bactericidal.
Cephalosporins
Cephalosporins have the same mechanism of action as penicillins.
Examples of cephalosporins are cefuroxime, cefotaxime, ceftriaxone and cefadroxil.
First and second generation cephalosporins target mostly gram-positive and some gram-negative
bacteria, while the opposite is true for third generation drugs. Fourth and fifth generation drugs
have broad spectrum coverage.
Cephalosporins are bactericidal.
Figure 1 (Brunton, Chabner et al. 2011)
Glycopeptides
Glycopeptides bind to cell wall precursor subunits. This means polymerisation cannot take place.
The most important glycopeptides are vancomycin and teicoplanin.
Glycopeptides are unable to work on gram-negative bacteria (their molecular weight is too large),
but they are effective against many gram-positive families.
Glycopeptides are bactericidal.
