Anti-Microbials Module
Antimicrobials
Anti-bacterials
* Need a drug selectively toxic to bacterial cells but won’t harm human cells * Many drugs that achieve this still have side effects as every drug is a poison
Bacterial Infections * Immunocompromised especially vulnerable * Opportunistic infection – Infection caused by pathogens that usually do not cause disease in a healthy immune system. A compromised immune system however presents ‘opportunity’ for pathogen to infect * Prophylaxis (procedure used to prevent disease) especially important here * Breakdown of barriers allows for disease transmission 1. International travel and immigration 2. Overpopulation leading to crowding 3. Nosocomial (hospital acquired) infections * Hospitals known to have most resilient strains of microbes
Chemotherapy * Use of drugs, selectively toxic to pathogenic organism (or cancer) but harmless or minimal effects on host * Infections organisms: * Prokaryotes – cells without nuclei – bacteria * Viruses – which utilise biochemical machinery of host * Cancer cells – eukaryotic cells similar to host cells
Bacteriostatic vs. Bacteriocidal * Bacteriostatic – antibiotics that inhibit growth and reproduction of bacteria without killing them * Relies on immune system to destroy bacteria * Bacteriocidal – antibiotic that kills bacteria * CFU = colony forming units
Primary mechanism of Action of Antimicrobials 1. Inhibition of synthesis or damage to peptidoglycan cell wall * E.g. β-lactams e.g. penicillin 2. Inhibition of synthesis or damage to cytoplasmic membrane * Polymyxins and daptomycin 3. Modification in synthesis or metabolism of nucleic acids * Quinolones (inhibit DNA gyrase), Rifampin (inhibits RNA polymerase) 4. Inhibition or modification of protein synthesis * Aminoglycosides, tetracyclines, etc. – Inhibit 5. Modification in energy
Anti-bacterials
* Need a drug selectively toxic to bacterial cells but won’t harm human cells * Many drugs that achieve this still have side effects as every drug is a poison
Bacterial Infections * Immunocompromised especially vulnerable * Opportunistic infection – Infection caused by pathogens that usually do not cause disease in a healthy immune system. A compromised immune system however presents ‘opportunity’ for pathogen to infect * Prophylaxis (procedure used to prevent disease) especially important here * Breakdown of barriers allows for disease transmission 1. International travel and immigration 2. Overpopulation leading to crowding 3. Nosocomial (hospital acquired) infections * Hospitals known to have most resilient strains of microbes
Chemotherapy * Use of drugs, selectively toxic to pathogenic organism (or cancer) but harmless or minimal effects on host * Infections organisms: * Prokaryotes – cells without nuclei – bacteria * Viruses – which utilise biochemical machinery of host * Cancer cells – eukaryotic cells similar to host cells
Bacteriostatic vs. Bacteriocidal * Bacteriostatic – antibiotics that inhibit growth and reproduction of bacteria without killing them * Relies on immune system to destroy bacteria * Bacteriocidal – antibiotic that kills bacteria * CFU = colony forming units
Primary mechanism of Action of Antimicrobials 1. Inhibition of synthesis or damage to peptidoglycan cell wall * E.g. β-lactams e.g. penicillin 2. Inhibition of synthesis or damage to cytoplasmic membrane * Polymyxins and daptomycin 3. Modification in synthesis or metabolism of nucleic acids * Quinolones (inhibit DNA gyrase), Rifampin (inhibits RNA polymerase) 4. Inhibition or modification of protein synthesis * Aminoglycosides, tetracyclines, etc. – Inhibit 5. Modification in energy