Study Objectives 1. Define: chemotherapy, antimicrobial drug, antibiotic, select
ID: 210835 • Letter: S
Question
Study Objectives 1. Define: chemotherapy, antimicrobial drug, antibiotic, selective toxicity, broad spectrum, narrow spectrum, bacteriocidial, and bacteriostatic. 2. Describe how antibacterial drugs inhibit/attack cell walls, membranes, protein synthesis, nucleic acid synthesis and give at least 2 examples. 3. Describe the mechanism of inhibition of sulfa drugs. 4. What organisms are killed by the following drugs: Polyenes, Miconazole. 5. Describe the antiviral activity of acyclovir, AZT, and protease inhibitors. 6 7. Explain how the misuse of antibiotics selects for resistance mutants Describe the 4 mechanisms of antibiotic resistance.Explanation / Answer
1) Chemotherapy - It is a type of treatment, which includes combination of medications to treat cancer. The aim of this treatment is to stop or slow the development of cancer cells. It is a systemic therapy, because it affects the entire body. This medications attack speedily growing cancer cells, but it can also affect healthy cells, which develops rapidly.
Antimicrobial drug: It is an agent, which kills microorganisms or stops their development. This drugs can be grouped according to the microorganisms they act primarily against. They treat a microbial infection. It is a group of drugs, which includes antibiotics, antifungals, antiprotozoals and antivirals.
Antibiotics - They are a type of antimicrobial drug, which are used in the treatment and prevention of bacterial infections. They may either kill or inhibit the development of bacteria. Antibiotics fight bacterial infections. They either kill bacteria or keep them from reproducing.
Selective Toxicity - It is the ability of the drug to targets areas. They are relative specific to the microorganism , which is responsible for infection. Antimicrobial drugs are chemicals that are proposed to have selective toxicity against microbes. They kill microbial cells but not the host's cells.
Mechanisms of selective toxicity are:
Inhibition of cell wall synthesis
Inhibition of pathogen's attachment to or recognition of host
Inhibition of DNA or RNA synthesis
Disruption of cytoplasmic memebrane
And inhibition of protein synthesis.
Broad-spectrum - They are active against a wide range of microorganisms. They develop a broad-spectrum antiviral, which treat the cold, influenza and other viruses. It acts on the two major bacterial groups, gram-positive and gram-negative or any antibiotic . It acts against a wide range of disease-causing bacteria. These medications are used when a bacterial infection is suspected but the group of bacteria is unknown or when infection with multiple groups of bacteria is suspected.
Narrow spectrum - It is active against a selected group of bacterial types. It has limited activity andis useful against particular species of microorganisms. It is used for the specific infection when the causative organism is known. It causes less resistance of the bacteria as it will deal with only specific bacteria.
Bacteriostatic- It is a biological and chemical agent, which stops bacteria from reproducing. It depends on their application, bacteriostatic antibiotics, disinfectants, antiseptics and preservatives. When they are used, the duration of therapy must be sufficient to permit host defense mechanisms to eliminate the bacteria. Upon removal of the bacteriostat, the bacteria starts to grow again. It is used in plastics to prevent development of bacteria on surfaces. It limits the growth of bacteria by interfering with bacterial protein production, DNA replication and other aspects of bacterial cellular metabolism.