Solution CTQ 04:
Fundamental Concept:
An agent lethal to bacteria is bactericidal and which inhibits the growth of bacteria is bacteriostatic.
Effectiveness of control agent depends on its concentration, time of exposure and its activity (cidal or static)
Solution:
• Microbial control agents are of two types based on their effect on microbial cells which are either bactericidal or bacteriostatic.
• Bactericidal antibiotics kill (cidal) the bacteria Ex: Polymixin B is a bactericidal agents which disrupts the plasma membrane resulting in leaking the contents creating imbalance in the cell.
• Bacteriostatic antibiotics suppress the growth of bacteria Ex: tetracycline is a bacteriostatic agent which stops the protein synthesis by inhibiting the role of ribosomes. The bacteria will be surviving with the already available proteins in the cell but cannot replicate.
• In evaluating the effectiveness of selected antimicrobial agents, the concentration, length of contact, and whether it is cidal or static at that concentration and exposure are the important criteria to be known.
• …show more content…
Ex: In the agar diffusion method, single bacterial species is uniformly swabbed onto a nutrient agar plate. Control agent of different concentrations is placed on paper disks. These paper discs are kept on the surface of the agar. Control agent diffuses from the paper disk into the surrounding agar. Based on the zones of inhibition size around the disks, it can be evident that an effective agent will inhibit bacterial growth and the relative effectiveness of a compound is determined by comparing standard antibiotic values. The minimum concentration which inhibits the bacteria is called as Minimum inhibitory concentration
Fundamental Concept:
An agent lethal to bacteria is bactericidal and which inhibits the growth of bacteria is bacteriostatic.
Effectiveness of control agent depends on its concentration, time of exposure and its activity (cidal or static)
Solution:
• Microbial control agents are of two types based on their effect on microbial cells which are either bactericidal or bacteriostatic.
• Bactericidal antibiotics kill (cidal) the bacteria Ex: Polymixin B is a bactericidal agents which disrupts the plasma membrane resulting in leaking the contents creating imbalance in the cell.
• Bacteriostatic antibiotics suppress the growth of bacteria Ex: tetracycline is a bacteriostatic agent which stops the protein synthesis by inhibiting the role of ribosomes. The bacteria will be surviving with the already available proteins in the cell but cannot replicate.
• In evaluating the effectiveness of selected antimicrobial agents, the concentration, length of contact, and whether it is cidal or static at that concentration and exposure are the important criteria to be known.
• …show more content…
Ex: In the agar diffusion method, single bacterial species is uniformly swabbed onto a nutrient agar plate. Control agent of different concentrations is placed on paper disks. These paper discs are kept on the surface of the agar. Control agent diffuses from the paper disk into the surrounding agar. Based on the zones of inhibition size around the disks, it can be evident that an effective agent will inhibit bacterial growth and the relative effectiveness of a compound is determined by comparing standard antibiotic values. The minimum concentration which inhibits the bacteria is called as Minimum inhibitory concentration