Genetika Mikroorganisme. dr. Agus Eka Darwinata, Ph.D

Transcription

1 Genetika Mikroorganisme dr. Agus Eka Darwinata, Ph.D

2 Gene and Genome The Central Dogma Mutation TOPIC Polimerase Chain Reaction Mechanism of Antimicrobioal Resistance

3 Gene and Genome

4 Genom adalah keseluruhan informasi genetik (gen) yang dimiliki suatu sel atau organisme.

5 Human Genome

6 Bacterial Genome

7 Viral Genome 9181 bp

8 Genome-Gene Analogy

9 The Central Dogma

10 The Central Dogma of Biology

11 DNA Structure

12 Replication

13 Transcription

14 Translation

15 Translasi protein (cont.)

16 Mutation

17 Mutation Changes in base sequece of DNA and inheritable Can be: Harmful Lethal Helpful Silent

18 missense silent Mutation nonsense Point Mutation Frame Shift Mutation

19 Genetic Transfer

20 Genetic Information Flow in Bacteria

21 Genetic Transfer Transformation Conjugation Transduction Genetic transfer results in genetic variation Genetic variation needed for evolution Three ways:

22 Transformation Genes transferred from one bacterium to another by virus.

23 Conjugation Plasmid transferred from one bacterium to another via a pilus.

24 Conjugation cont

25 PCR

26 Polymerase Chain Reaction PCR allows us to produce rapidly (amplify) a billion copies of DNA without needing a living cell. These large quantities are then easily analyzed. PCR recipe:

27 Polymerase Chain Reaction Amplification of nuc gene of S. aureus

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30 Result

31 Resistance Mechanism of Antimicrobioal

32 Mechanism of Antimicrobioal Resistance Enzymatic inhibition Alteration of bacterial membranes Promotion of anntibiotic efflux Alteration of bacterial protein targets Bypass of antibiotic inhibition

33 Enzymatic inhibition bacteria produce enzymes to inhibit the activity of antibiotic Betalactamase by splitting beta-lactam ring. 340 different type of beta-lactamases. Extended spectrum beta-lactamases (ESBLs) is the most problematic. ESBL producing organism (e.g., Klebsiella, Proteus, Pseudomonas, Citrobacter, and E. coli) extremely resistant. Therapy limited to carbapenem.

34 Enzymatic inhibition bacteria produce enzymes to inhibit the activity of antibiotic 1990 s carbapenemases producer was found in Klebsiella pneumoniae (KPC), can be transmit via a plasmid to multiple other genera. In late 2010, New Delhi metallo-beta-lactamase1 (NDM-1), in E. coli and Klebsiella pneumoniae, resistant to all antibiotic except tigecycline and colistin. Carbapenemase-resistant enterobacteriaceae (CRE) is a huge health concern worldwide. Greatest risk factor: long stay in ICU with carbapenem therapy.

35 Alterations of bacterial membranes to prevent entry of antibiotics into bacteria Outer Membrane Permeability. Mutation result in alteration in porin. Pseudomonas aeruginosa resistance to imipenem. Inner Membrane Permeability. Altered the active electron t r a n s p o r t ( r a r e ). S t a p h y l o c o c c u s r e s i s t a n t t o aminoglycoside. Induced by long-term aminoglycoside therapy.

36 Promotion of Antibiotic Efflux actively pump the antibiotics out of the bacteria Pseudomonas aeruginosa and Staphylococcus aureus resistace to tetracycline. Induced by subtherapeutic concentration of tetracycline.

37 antibiotics. Alterations of bacterial protein targets which make these target unrecognizable to antibiotic Alteration of Ribosomal Target Site. Resistance to a wide variety of antiribosomal agent, including tetracyclines, macrolides, clindamycin, and aminoglycosides. Alteration of ribosomal binding sites. Staphylococcus aureus and Enterococci species resistance to macrolides. Alteration of Cell Wall Precursor Targets. vana induces the synthesis of newly modified peptidoglycan. E.coli and S. aureus resistance to vamcomycin and teicoplanin (glycopeptide antibiotics). Alteration of Critical Enzymes. Alteration in penicillin binding proteins (PBPs)/transpeptidase. Gram positive resistance to beta-lactam

38 Bypass of Antibiotic Inhibition allowing bacteria to find alternate pathways to survive when one pathway is blocked by an antibiotic Enterococci (thymidine dependent organism) utilize exogenous supplies of thymidine for enzyme activity and are thus highly resistant to trimethoprim which blocks endogenous production of thymidine by bacterial enzymes.

39 Thank you