Pathology - Antibiotics History

Question 1

Antimicrobial Resistance

Answer 1

When microorganisms evolve to evade antibiotic effects through various mecahnisms

Question 2

What does Antimicrobial Resistance refer to?

Answer 2

Microorganisms adapt from medications once impacting them to a state they’re resistant.

Question 3

What are examples of Antibiotics mechanism of action?

Answer 3

Inhibit cell wall synthesis
Interfer with membranes permeability
Inhibitiion on ribosome subunits
Blockage of metabolic steps
Inhibition of nucleic acid synthesis

Question 4

Intrinsic Resistance

Answer 4

Resistance by a naturually occuring feature typical of bacteria.

Question 5

Example of Intrinsic Resistance?

Answer 5

Streptococci lack nitroreductases that convert metronidazole to active state required for its activty.

Question 6

Mutational Resistance

Answer 6

Generational or spontaneous chromosmal mutations, producing resistant strains through naturual selection.

Question 7

Acquired Resistance

Answer 7

Horizontal acquistion from other microorganisms encoding for genetic resistances through conjugation, transduction and transformation.

Question 8

Transduction

Answer 8

Translocation of DNA from bacterium to another, utilising bacteriophages

Question 9

Transformation

Answer 9

Where bacteria acquire DNA segments within the environment.

Question 10

Alexander Fleming

Answer 10

A bacteriologist whom discovered bacteria when a petri dish containing staphylococci on a bench got contaminated by a fungus affecting growth of nearby bacteria

Question 11

What fungus inhibited bacterial growth?

Answer 11

Penicillium Notatum

Question 12

What happened in 1939 after Flemings Discovery?

Answer 12

Howard Florey and Ernst Chain designed a method to culture fungu and produce it to test its antimicrobial abilities.

Question 13

What was the first experimental test of Penicilllum Notatum?

Answer 13

Injection of mice with fatal doses of streptoccous then treatment with the fungus with surivval rates.

Question 14

How does penicillin exert its effects?

Answer 14

Upon highly conserved PG cell wall

Question 15

What is the structure of penicillin

Answer 15

Contains a Beta-Lactam Ring, a Thiazoldine Ring and a 6-Aminopenicillinanic Acid Side chain.

Question 16

Beta-Lactam Ring

Answer 16

A four membered ring inhibiting transpeptidase by mimicking two of D0alanine of the peptide with irreversible binding to PBP.

Question 17

Why does Beta-Lactam binding to PBP result in?

Answer 17

Inability of PG cross-linking making cell susceptible to lysis.

Question 18

Penicillin

Answer 18

A molecule with a beta-lactam based ring

Question 19

How do Penicillin generations differ from one another?

Answer 19

Different chemical residues with different functions attached to the beta lactam ring

Question 20

What is an example of the diversity of Penicillins?

Answer 20

Benzylpenicillins are more active against GPB of cocci and bacilli shape, not so effective against GNB

Question 21

Why are penicillins commonly poor against GNB?

Answer 21

Occurence of OM and ability to produce beta-lactamases.

Question 22

Beta-Lactamases

Answer 22

Bacteria produced enzymes giving multi-resistance capabilties to beta-lactam antibiotics.

Question 23

What are some sescond generation penicillins?

Answer 23

Oxacillin, Methicillin and dicloxacillin.

Question 24

Anti-Staphylococcal Antibiotics

Answer 24

A class of second generations beta lactams used to treat bacterial infections

Question 25

Aminopenicillins

Answer 25

Third generation group of antibiotics with additional amin groups enhancing antibacterial activity.

Question 26

When did the first penicillin resistant bacteria develop?

Answer 26

E.Coli in 1940 producing penicillinase

Question 27

How many S.aureus species were resistant to penicillin by 1960?

Answer 27

80 percent.

Question 28

What is an example of early mechanisist resistance against penicillin?

Answer 28

1981 methicillin resistant chains altered original PBP to PBP-2a with reduced affinity.

Question 29

What does ROS do in bacteria?

Answer 29

Induce oxidatitve stress, affects Na/K ATPase pumps etc.

Question 30

How might genetically engineered E.Coli provide Antibiotic alternatives?

Answer 30

They can secrete antimicrobial peptides in response to quorum sensing molecules

Question 31

Phage Therapy

Answer 31

Uttilises bacteriophages to target specific bacteira.

Question 32

What are some alternatives to antibiotics?

Answer 32

Phage Therapy Metal Nanoparticles Genetically Engineerd E.Coli Hygeine