Antimicrobial Agents & Antibiotics

TYPES OF ANTIBIOTIC RESISTANCE

Bacteria have evolved to survive in diverse environments. They survive exposure to harsh chemicals including antibiotics, and they also survive difficult growth conditions. They have learned to “detoxify” harmful substances e.g. antibiotics. Antibiotic resistance can either be intrinsic or acquired. INTRINSIC (INNATE) RESISTANCE Some bacteria are said to possess innate/intrinsic resistance against antibacterial action put […]

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BRIEF HISTORY OF ANTIBIOTIC RESISTANCE

Antimicrobial agents, particularly antibiotics are the most significant class of pharmaceuticals and are one of the most influential medical inventions of the twentieth century. They have undeniably been a boon to human society in the fight against bacteria, saving millions of lives. Nonetheless, the number of infections caused by multidrug-resistant (MDR) bacteria is increasing across

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ANTIMICROBIAL (ANTIBIOTIC) RESISTANCE: definition, selective pressure and clonal selection

Antibiotic or antimicrobial resistance (AMR) is a phenomenon that occurs when bacteria are not killed or inhibited by usually achievable systemic concentration of an antibiotic (drug) with normal dosage schedule and/or fall in the minimum inhibitory concentration ranges of the drug in question. It is the ability of bacteria to resist the killing or inhibitory

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DRUG INTERACTION

To be clinically effective for the treatment of infectious diseases, every drug must reach a certain level of bioavailability in vivo; and this is critical because drugs contain other constituents aside the actual portion of the medicine which is necessary to express antimicrobial action in the recipient host. The bioavailability of a drug is the

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ERYTHROMYCIN

Erythromycin is a protein synthesis inhibitor that binds to the 50S ribosomal subunit of the bacterial ribosome. It is found in the family of antibiotics known as the macrolides; and antibiotics in this group are generally protein synthesis inhibitors. Other macrolides include azithromycin and clarithromycin. Lincomycin and clindamycin are antibiotics that inhibit protein synthesis in

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CHARACTERISTICS/FEATURES OF ANTIBIOTICS

Antibiotics including antibacterial agents, antiviral agents, antiprotozoal agents, and antifungal agents have some specific characteristics that distinguish them from other antimicrobial agents that are used for the treatment of microbial infections as well as in the control of microbes on inanimate surfaces. Some of these features are highlighted in this unit. References Ashutosh Kar (2008).

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OTHER BETA-LACTAM ANTIBIOTICS AND NON-BETA-LACTAMS THAT INTERFERE WITH CELL WALL SYNTHESIS

Aside penicillins and cephalosporins, other beta-lactam antibiotics used for clinical applications also exist. These beta-lactam antibiotics have expanded antibacterial activity, and they are often used to treat infections caused by bacterial pathogens that are resistant to the penicillins and cephalosporins. Antibiotics in this category are generally cell wall synthesis inhibitors, and they possess similar mechanisms

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MECHANISM OF ACTION OF ANTIBIOTICS: Antibacterial Agents

The antibiotics described above including those not described in this work are used to treat infections caused by disease causing microorganisms (bacteria). Majority of them exert a highly selective toxic action upon their target microbial cells but have little or no toxicity towards mammalian cells. These antibiotics can therefore be administered at concentrations sufficient enough

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CEPHALOSPORINS

Cephalosporins are beta-lactam antibiotics that are penicillinase-resistant, and with related mode of action to the penicillins. Drugs in this category are clinical substitutes for penicillins due to the development of resistance to the later by pathogenic bacteria. Cephalosporins are classified into four (4) generations based on their spectrum of activity, side chain modifications and clinical

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PENICILLINS

Penicillins are beta-lactam drugs that inhibit the cross-linking of N-acetyl glucosamine (NAG) and N-acetyl muramic acid (NAM) required for the formation of peptidoglycan in bacterial cells. They are generally bacterial cell wall synthesis inhibitors. Penicillin, the first member of the penicillins is a general purpose antibiotic used in clinical medicine even till date. They specifically

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