ANTIBIOTIKA

Aryan MoritaBiomedika KG

DEFINITION

• Low molecular weight microbial metabolites which can kill or inhibit the growth of susceptible bacteria.

• Synthetic antimicrobial agents which may or may not be derived from microbial metabolites

HISTORY

HISTORY

ANTIMICROBIAL AGENTS DERIVED FROM MICROORGANISMS

Microorganism Antimicrobial agent

Bacillus colistinus Colistin (polymyxin E)

B.subtilis Bacitracin

Penicillium notatum Penicillin G

Streptomyces sp Spectinomycin, Tetracylines

S.erythreus Erythromycin

S.griseus Streptomycin

CLASSIFICATION

BACTERICIDAL

•Cause irreparable damage and bacterial cell death•Binding irreversibly to target structure

BACTERIOSTATIC

•Inhibit growth of bacteria•Allowing host immune defenses to eliminate infection

SPECTRUM

Narrow Broad

MODE AND SITE OF ACTION

INHIBITION OF CELL WALL SYHTHESIS

• Prevent cross-linking of peptdoglycan chain• Penicillin & cephalosporine β lactam ring• Mode of action: involves binding to cell

receptors (PBPs) inhibition of transpeptidation reaction inactivation of an inhibitor of autolytic enzym in the cell wall

INHIBITION OF CELL MEMBRANE FUNCTION

• Cell membrane disrupted macromolecules and ion escape from the cell cell damage and death

INHIBITION OF PROTEIN SYNTHESIS

• Attachment to a spesific receptor blocks normal activity of initiation complex of peptide formation mRNA missread break up polysome to monosome incapable to synthesis protein

INHIBITION OF NUCLEIC ACID SYNTHESIS

• Disruption of DNA structure• Inhibition of DNA dependent RNA polymerase• Interface with DNA gyrase• Interface with DNA synthesis by blocking folic

acid production

RESISTANCE TO ANTIMICROBIAL DRUGS

Mo produce enzym that destroy active drug

Mo change their permeability to the drug

Mo develop an altered stuctural target for the drugs

Mo develop an altered metabolic pathway

Mo develop an altered enzyme that can still perform metabolic function

ANTIMICROBIAL ACTIVITY IN VITRO

Potency of an antibacterial agent in solution

Concentration in body fluids or tissue

Susceptibility of a given mo to known concentrations of the drugs

FACTORS AFFECTING ANTIMICROBIAL ACTIVITY

pH Component of medium

Stability of drug

Size of inoculum

Length of incubation

Metabolic activity of mo

Chemical Structure

• Sulfonamides and related drugs• Diaminopyrimidines trimetropin• Quinolone ciprofloxacin, norfloxacin, etc• Beta lactam penicilin, cephalosphorine• Tetracycline minocycline, doxycycline, etc

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Con’t

• Nitrobenzene derivates chloramphenicol• Aminoglycosides stepromycine,

gentamycin,etc• Macrolide erythromycine, dll• Polypeptide antibiotics polymyxin,

bacitracin, dll• Glycopeptides vancomycine

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Con’t

• Oxazolidinone linezoid• Nitrofuran derivates furazolidone• Nitroimidazole metronidazole• Nicotinic acid derivates isoniasid• Polyene antibiotics nystatine• Azole derivates miconazole• Others rifampin

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Kriteria Penggunaan antibiotik

• Tepat indikasi• Tepat penderita• Tepat obat• Tepat dosis, rute, waktu, dan lama pemberian• Waspada efek samping

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Penggunaan yg tidak tepat• Viruses• Dosis yg tidak tepat• Informasi yg Inadequate• Tidak dilakukannya drainase ketika operasi

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Seleksi antimikroorganisme• Identifikasi MO• Menggunakan obat yg sensitif thd MO• Pertimbangkan host factors – tempat tjdnya infeksi– Sistem pertahanan inang– allergies, – Ketidakmampuan dari drug of choice untuk menembus

tempat infeksi– Kerentanan pasien thd tjdnya toksisitas

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ANTIMICROBIAL COMBINATION

• To give prompt treatment in desperately ill patients suspected serious microbial infection

• To delay the emergence of microbial mutants resistant

• To treat mixed infection• To achieve bactericidal synergism or to

provide bacterial action

MECHANISM

synergism antagonism

THANK YOU...SAYONARA