"Antimicrobial Resistance Bacteria (AMRB) & Crispr System"

1. Presented by
Ali Mohamed Ibrahim
alimoh18045@gmail.com
01143257837

2. Antimicrobial Resistance (AMR)

3.  Antimicrobial resistance (AMR):
is the development of resistance in bacteria to an antimicrobial
medicine to which it was previously sensitive.
Antibiotic resistance

4. Site of Action of Antimicrobial Agents
1
3
2
4
5
6
7

5. Changes in the bacterium that enable it to resist the antibiotic occur
Naturally as a result of mutation OR as a result of Genetic recombination
Antibiotic selection of Drug resistant Bacteria

6. Resistance Mechanisms
1-Alter the membrane transport systems to prevent
entry of the antibiotic
1. By altering pores in the outer membrane of a Gram
negative bacterium
2. By altering carrier transport proteins used to transport
the drug through a bacterium's cytoplasmic membrane,
the bacterium may block entry of the drug

7. Resistance Mechanisms
2-Alter the antibiotic receptor site to reduce or
block its binding
Bacteria may become resistant to the Macrolides,
Erythromycin, Azithromycin by producing a slightly
altered 50S ribosomal subunit.
Altered antibiotic receptor

8. The bacterium may produce transporter molecules in the
cytoplasmic membrane capable of an energy-driven Efflux
Pumps the antibiotic back out of the bacterium
Bacteria use ATP-powered membrane proteins to pump
foreign molecules out of the cell.
Powerful method of resistance, because many different drugs
may be affected by these efflux pumps
Examples: Tetracycline , Macrolides, Quinolones
Resistance Mechanism
3-Multi-drug Efflux Pumps

9. Genetic recombination In Bacteria
 Genetic recombination is the transfer of DNA from
one organism to another. The transferred donor
DNA may then be integrated into the recipient's
nucleoid by various mechanisms.
Mechanisms of genetic recombination include:
1. Transformation
2. Transduction (bacteriophage )
3. Bacterial conjugation (R plasmids)

10. 1. A donor bacterium dies and is degraded.
2. A fragment of DNA from the dead donor bacterium binds to DNA binding proteins
on the cell wall of a competent, living recipient bacterium.
3. The Rec A protein promotes genetic exchange between a fragment of the donor's
DNA and the recipient's DNA
1- Transformation

11. Transformation
A donor bacterium dies and is degraded.

12. A fragment of DNA from the dead donor bacterium
binds to DNA binding proteins on the cell wall of )a
competent, living, recipient (cell.

13. The Rec A protein promotes genetic
exchange between a fragment of the
donor's DNA and the recipient's DNA.

14. Animation: Transformation in
Bacteria

15. 2-Transduction
Transfer of fragments of DNA from one bacterium to another
bacterium via a bacteriophage.

16. Types of Transduction
1- Generalized transduction
 requires lytic phage
 any section of donor chromosome can be transferred

17. Generalized Transduction by Lytic
Bacteriophage: lytic bacteriophage adsorbs to a
susceptible bacterium

18. The bacteriophage genome enters the bacterium.
The genome directs the bacterium's metabolic
machinery to manufacture bacteriophage
components and enzymes.

19. capsid assembles around a fragment of donor
bacterium's nucleoid or around a plasmid instead of
a phage genome by mistake.

20. The bacteriophages are released.

21. The bacteriophage carrying the donor
bacterium's DNA adsorbs to a recipient
bacterium

22. The bacteriophage inserts the donor
bacterium's DNA it is carrying into the
recipient bacterium

23. The donor bacterium's DNA is exchanged
for some of the recipient's DNA.

24. Generalized Transduction by Lytic
Bacteriophage

25. 2- Specialized Transduction by Temperate
Bacteriophage. bacteriophage adsorbs to a
susceptible bacterium and injects its genome

26. The bacteriophage inserts its genome
nto the bacterium's nucleoid to
become a prophage.

27. A small piece of the donor bacterium's DNA is picked up
as part of the phage's genome in place of some of the phage
DNA which remains in the bacterium's nucleoid.

28. As the bacteriophage replicates, the segment of
bacterial DNA replicates as part of the phage's
genome. Every phage now carries that segment
of bacterial DNA.

29. The bacteriophage adsorbs to a recipient
bacterium and injects its genome.

30. The bacteriophage genome carrying the donor
bacterial DNA inserts into the recipient
bacterium's nucleoid.

31. Specialized Transduction by Temperate
Bacteriophage

32. 3- Conjugation
 Bacterial conjugation: transfer of DNA from a living donor bacterium
to a recipient bacterium.
 In Gram negative bacteria, a sex pilus produced by the donor
bacterium binds to the recipient. The sex pilus then retracts, bringing
the two bacteria in contact. Both bacteria make a complementary
strand of the R-plasmid and both are now multiple antibiotic resistant
and capable of producing a sex pilus.
sex pilus

33. Animation: F+ Conjugation

34. Multiple drug resistant organisms
Multiple organisms are resistant to treatment with
several, often unrelated, antimicrobial agents
If an organism carries several resistant genes, it is called
multiresistant or, informally, a superbug.

35. Antimicrobial resistance is A Global
Concern
 AMR is a growing public health threat of huge concern to
countries and to many sectors as:
 AMR threatens the effective prevention and treatment of
infectious agents.
Loosing effective antibiotics compromises success of major
surgery and cancer chemotherapy and increasing their risks,
morbidities and mortalities .
Increasing the health care cost (longer duration of illness,
additional tests and use of more expensive drugs).
Threat of returning to the pre-antibiotic Era .

36. Global action plan of antimicrobial resistance (AMR )
To improve awareness and understanding of
antimicrobial resistance through effective
communication, education and training.
To strengthen the knowledge and evidence base
through surveillance and research.
To reduce the incidence of infection through effective
sanitation, hygiene and infection prevention measures.
To optimize the use of antimicrobial medicines in
human and animal health.
To develop the economic case for sustainable
investment that takes account of the needs of all
countries and to increase investment in new medicines,
diagnostic tools, vaccines and other interventions.

37. Crispr System

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O’Connor C., 2008, Nature Education
First report about transformation

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Griffith Fred, 1928, J. Hygiene
First report about transformation
Something inside of S type bacteria induced “R--->S” transformation
Experiment Result
S
R
Dead S + R
S
R
S

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Experiment Result
S
R
DNA S
RProtein
Lipid
Carbohydrate
R
R
Avery O. T., 1944, J. Expt. Med.
S
DNA could be a “Gene”

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The “Gene” is DNA only
Hershey A. D. and Chase M., 1952, J. General Physiology.

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And then…

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And then…

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And then…

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And then…

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And then…

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Identification of CRISPR
Clustered Regularly-Interspaced Short Palindromic Repeats
CRISPR
Spacer

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short palindromic sequences

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74. Applications
Part II: Harnessing CRISPR

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Dumpier nematodes Zebra fish embryos Fruit flies
Pennisi E. 2013. Science, (6148):833-6.
Rice
Models generated by CRISPR/Cas9 system
Monkey

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Questions?

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