Antibiotics

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Antibiotics

  1. 1. ANTIBIOTICS SURYA ANTIBIOTICS A PRESENTATION BY SURYA PRAJAPAT
  2. 2. ANTIBIOTICS INDEX 1. INTRODUCTION 2. CLASSIFICATION 3. DESCRIPTIONS & MODE OF ACTION • Β-LACTAM • AMINOGLYCOSIDES • MACROLIDES • TETRACYCLIN • CHLORAMPHENICOL • GLYCOPEPTIDES • OXAZOLIDINONE • LINCOSAMIDES • FLUOROQUINOLONES • OTHERS 4. RISISTANCE TO ANTIBIOTICS SURYA
  3. 3. ANTIBIOTICS SURYA INTRODUCTION • Antibiotics (Greek anti, “against”; bios, “life”) are chemical compounds used to kill or inhibit the growth of infectious organisms. Originally the term antibiotic referred only to organic compounds, produced by bacteria or molds, that are toxic to other microorganisms. • They are more toxic to an invading organism than they are to an animal or human host. • first antibiotic was penicillin, discovered accidentally from a mold culture. • Antibiotics only treat bacterial infections. Antibiotics are useless against viral infections (for example, the common cold) and fungal infections (such as ringworm).
  4. 4. ANTIBIOTICS • CLASSIFICATION: SURYA
  5. 5. ANTIBIOTICS SURYA • classification by their mechanism of action: 1. Inhibit bacterial cell wall synthesis: Penicillin Cephalosporin Cycloserin Vancomycin 2. Cause leakage from cell membrane: Polypeptides Polymixin Colistin Bacitracin 3. Cause misreading of m-RNA code and affect permeability : Aminoglycosides Streptomycin Gentamycin Neomycin polyenes AmphotericinB Nystatin Hamycin
  6. 6. ANTIBIOTICS 4. Inhibit protein synthesis: SURYA Tetracyclin Chloramphenicol Erythromycin Clindamycin Linezolid 5. Inhibit DNA gyrase: Fluoroquinolones Ciprofloxacin Norfloxacin Ofloxacin 6. Interfere with metabolism : Sulfonamides Ethambutol 7. Interfere with DNA function : Rifampin 8. Interfere with DNA synthesis : Metronidazole
  7. 7. ANTIBIOTICS SURYA DESCRIPTIONS: 1. Β-Lactam antibiotics: Penicillin Cephalosporin Carbapenems : Imipenem, Meropenem, Faropenem A. PENICILLIN: Penicillin was the first antibiotic to be used clinically in 1941. It was originally obtained from fungus Penicillium notatum. Mechanism of action: Binds to Penicillin-binding protein Inhibit the Transpeptidase activity in cell wall formation Transpeptidation i.e cross linking between peptides not occur. Peptidoglycan cell wall not form. bacterial cell wall synthesis inhibited.
  8. 8. ANTIBIOTICS • Eg: Penicillin G Penicillin V Naficillin Methicillin Ampicillin Amoxycillin SURYA Uses: streptococcal infection pneumococcal infection meningococcal infection gonorrhea, syphilis Diphtheria Tetanus gas gangrene
  9. 9. ANTIBIOTICS SURYA B. CEPHALOSPORIN : These are group of semisynthetic antibiotics derived from Cephalosporin-C obtained from a fungus Cephalosporium. They are chemically related to penicillin. Its nucleus consist of β-lactum ring. • Their MOA is same as penicillin, i.e inhibition of bacterial cell wall synthesis. All cephalosporins are bactericidal. Cephalosporin Ist gen: Cephalexin, cephalothin, Cephadroxil IInd gen: Cefaclor, Cefuroxime, Cefoxitin IIIrd gen: Cefixime, Cefpodoxime, Ceftriaxone, Cefdinir IVth gen: Cefepime, Cefpirome
  10. 10. ANTIBIOTICS SURYA • Ist generation: Broad spectrum than Penicillin. Active against both gram+ve and gram-ve organisms. • IInd generation: Active against many gram-ve organisms which are resistant to Ist generation. • IIIrd generation: Gram+ve : less active than Ist generation Gram -ve : more active. • IVth generation: Gram +ve : more active than IIIrd generation. Gram –ve : excellent active against gram –ve.
  11. 11. ANTIBIOTICS SURYA 2. AMINOGLYCOSIDES: Aminoglycosides are the drugs effective against gram-ve bacteria. All aminoglycosides are produced by soil actinomycetes. Aminoglycosides are bactericidal. Mechanism of action : Cause misreading of m-RNA code and affect permeability. Other antibiotics which inhibit protein synthesis are only static. Aminoglycosides Diffuse across outer coat of gram-ve bacteria (etransport, O2 dependent, only aerobes) Bind to 30s (streptomycin), 50s (others), 30s-50s interface. Protein synthesis initiation stopped. Cause distortion of mRNA codon recognition. Misreading of mRNA code. Wrong amino acid enters the peptide chain. Abnormality occur. Bacteria become more permeable and leak out ions, amino acids and protein.
  12. 12. ANTIBIOTICS SURYA Systemic Topical •Streptomycin •Gentamycin •Kanamycin •Tobramycin •Amikacin •Neomycin •Framycetin • Uses : Tuberculosis Subacute bacterial endocarditis pseudomonas, proteus or klebsiella infection Meningitis caused by gram-ve bacteria Neomycin is used topically for infected wounds, ulcers, burn, external ear infection, conjuctivitis, post operative infections.
  13. 13. ANTIBIOTICS SURYA 3. MACROLIDES : Macrolides are the antibiotics having a macrocyclic lactone ring with attached sugar. They are bacteriostatic. Erythromycin is the first member discovered. • Mechanism of action : Macrolides bind to 50s ribosome and interfere with translocation. When peptide bond forms between amino acid & peptide chain at acceptor site (A). The elongated chain is translocated back to peptidyl site (P). Thus site (A) becomes available for next amino acyl-t-RNA attachment. This is called translocation. Erythromycin binds to 50s ribosome and inhibit this translocation. Thus protein synthesis inhibited.
  14. 14. ANTIBIOTICS • Macrolides covers mostly gram+ve and a few gram-ve baterias. Erythromycin is highly active against: Str. Pyogenes Str. Pneumaniae N. gonorrhoeae C. diphtheriae Uses : severe campylobacter enteritis pertusis chlamydial infection pneumonia, sinusitis, bronchitis Brands : ALTHROCIN – ALEMBIC (erythromycin) EROATE – LUPIN (erythromycin) AZEE – CIPLA (azithromycin) AZRO – PIRAMAL (azithromycin) CELEX – GSK (clarithromycin) SURYA
  15. 15. ANTIBIOTICS SURYA 4. TETRACYCLINES: These are the antibiotics having a nucleus of four cyclic rings. They are obtained from soil actinomycetes. They are primarily bacteriostatic. Mechanism of action : Binds to 30s ribosomes • • • • • Tetracycline Oxytetracycline Doxycycline Domeclocycline Minocycline Attachment of aminoacyl-t-RNA to the mRNA ribosome complex is interfered Peptide chain fails to grow protein synthesis inhibited Bacteriostatic action. • Uses: Cocci : N. gonorrhoeae & N. meningitides Bacilli : Gram+ve : Corynebateria, Propionibacterium acnes, B.anthracis Gram-ve : V. cholera, Yersinia pestis , Helicobacter pylori
  16. 16. ANTIBIOTICS SURYA 5. CHLORAMPHENICOL :Chloramphenicol was initially obtained from Streptomyces venezuelae. Antibacterial spectrum: It is primarily bacteriostatic. Active against gram+ve & gram-ve organisms same as tetracyclin. Like tetracyclin it is inactive against Mycobacterium, Pseudomonas, many proteus, viruses and fungi. Mechanism of action: Chloramphenicol binds to 50s ribosome inhibit the transfer of elongated peptide chain to the newly attached aminoacyl -tRNA at ribosome mRNA complex. Protein synthesis inhibited.
  17. 17. ANTIBIOTICS • Uses: Bacterial meningitis Brain abscess Gas gangrene : death & decay of wound tissues infected by soil bacterium Clostridium. Toxins produced cause tissue decay and generate gas. Whipple’s disease : less absorption of digested food in intestine, occur in males. Severe gastroenteritis Plague • Brands: CHLOREXIN CAP- CIPLA DEXOREN- INDOCO PERAXIN – PIRAMAL CHLOROMYCETIN CAP- PFIZER SURYA
  18. 18. ANTIBIOTICS SURYA 6. GLYCOPEPTIDES : It is active against MRSA. It is bactericidal to gram+ve cocci, Neisseria, clostridia and diphtheroids. • Mechanism of action: It inhibits the bacterial cell wall synthesis. vancomycin binds to terminal dipeptide 'D-ala-Dala' sequence of peptidoglycan unit prevents the assembly and cross linking of these units cell wall not form • • Uses: Staphylococcal enterocolitis Septicemia, Osteomyelitis. Brands : VANCOGEN – ALKEM VANLID – CIPLA VANCORIN – EMCURE
  19. 19. ANTIBIOTICS SURYA 7. OXAZOLIDINONE : Linezolid : active against only gram+ve bacterias. It is primarily bacteriostatic. • Mechanism of action: It inhibits bacterial protein synthesis ta an early step and different site than other. Linezolid binds to 23s fraction of 50s ribosome interfere with the formation of Nformylmethionine-tRNA-70s complex thus tRNA binding site distorts Protein synthesis not occur
  20. 20. ANTIBIOTICS • Uses : uncomplicated skin and skin structure infection. Community acquired pneumonia, Nocosomial pneumonia. • Brands: ALZOLID – ALEMBIC LIZOLID – GLENMARK LINOSPAN – CIPLA 8. LINCOSAMIDE: Clindamycin : it is similar in MOA to erythromycin (inhibit protein synthesis by binding to 50s ribosome). • Uses : Acne, Bacterial vaginosis. • Brands : ACNESOL – SYSTOPIC CLINDAC A – GALDERMA CTOP – INTAS SURYA
  21. 21. ANTIBIOTICS SURYA 9. FLOROQUINOLONES: They are quinolone antimicrobials. • Norfloxacin • Ciprofloxacin • Ofloxacin • Levofloxacin • Moxifloxacin Mechanism of action: • FQs act by inhibiting the enzyme bacterial DNA gyrase. • DNA gyrase consist of A and B subunits. • A subunit cause nicking of strand, while B subunit introduce –ve supercoil into the strand, and then A subunit reseals the strand. This is necessary to prevent the excessive positive supercoiling of DNA strands, hence DNA replication occur. • FQs bind to A subunit and interfere with the strand cutting and resealing function.
  22. 22. ANTIBIOTICS Ofloxacin uses: • Leprosy • Uncomplicated gonorrhoea • UTI • Chronic bronchitis • Traveller’s diarrhea • LRTI • Bacterial conjunctivitis • Bacterial corneal ulcer SURYA Brands: ALPROXEN- ALKEM EUFOX - LUPIN OFLOMAC- MACLEODS OFLOX - CIPLA
  23. 23. ANTIBIOTICS SURYA 10. OTHERS: A. Mupirocin B. Polypeptides i. Polymyxin-B ii. Colistin iii. Bacitracin • MUPIROCIN • It is a novel antibiotic produced through fermentation of Pseudomonas fluorescens. It inhibits isoleucyl transfer-RNA synthetase and arrestbacterial protein synthesis. • Uses: Primary skin infection- impetigo, folliculitis, furunculosis, ecthyma. Secondary skin infection- eczema, abrasion, lesions, insect bites, wounds, cuts. • Brands: BACTROBAN – GSK MPOWER- ZYDUS SUPIROCIN - GLENMARK
  24. 24. ANTIBIOTICS SURYA Polymyxin-B & COLISTIN • Active against only gram-ve bacteria. They are bactericidal. They cause distortion in bacterial cell membrane and cause pseudopore formation, so that ions, amino acids leak out. And bacteria dies. • Uses: ocular, autic and skin infections. • Brands: NEOSPORIN – GSK CADIPRIM – CADILA ORIPRIM – ZYDUS CADILA BACITRACIN Mostly active against gram+ve bacterias. Acts by inhibiting cell wall synthesis. Highly toxic so not given parenterally.
  25. 25. ANTIBIOTICS SURYA Resistance to antibiotics: Resistance of bacteria to the effects of antibiotics has become a major problem in the treatment of disease. Bacteria that are not killed or stopped by antibacterial drugs may change in form so that they resist attack against their cell walls or even produce enzymes that kill the antibiotics. Resistance: When any Types of Resistance: antibiotic does not show affect against specific microbes then it means drug resistance is developed. Natural: some antibiotics are naturally resistant to specific microbes. Eg- Penicillin is resistant to gram-ve bacteria, Tetracyclin is resistant to M. tuberculosis. Acquired: microbes become resistant due to use of antibiotics for a long period of time. Eg- Sulfonamides are resistant to Gonococci
  26. 26. THANK YOU A PRESENTATION BY SURYA PRAJAPAT

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