Antibiotic Sensitivity Lab Essay Example for Free

Antibiotic Sensitivity Lab EssayWhy is it an important feature of antimicrobial agents? Selective toxicity is the ability of a chemical substance or drug to kill a microorganism without harming its host. Selective toxicity is important to microbial agents beca drop it en subjects these agents to inhibit or kill a microorganism by interacting with microbial functions or structures different from those of the host thereby showing little or no effect to the host. B. What are broad and narrow spectrum antimicrobials? What are the pros and cons of individually?Broad spectrum antimicrobials are drugs that are stiff against a wide variety of both gram positive and gram negative bacteria. Narrow spectrum antimicrobials are effective only against gram negative bacteria. Pros and cons of each Narrow spectrum microbial is normally better to use because they cause less(prenominal) damage to the bodys normal flora. They are less likely to cause drugs resistant strains of microorganisms bec ause they are specific in nature and are less likely to cause super infection by timeserving microorganisms like yeast infections.The main disadvantages are that Narrow spectrum microbial sometimes is more prone to allergic reaction to the host. Broad spectrum antimicrobials on the other good deal also have their own advantages in that they are able to deal with more than one kind of bacteria and as such one does non have to use drugs indiscriminately reducing chances of allergic reactions and drug toxicity. The main disadvantage is that they cause more harm to the bodys normal flora. C. What is direct selection? ingest selection is the selection of antibiotic-resistant normal floras in an individual whenever this individual is given an antibiotic.This process is normally accelerated signifi arsetly by either improper use or the overuse of antibiotics. D. What is the difference between an antibiotic and an antimicrobial chemical? Antibiotics are substances that are produced as m etabolic products of one Microorganism which are able to inhibit or kill other microorganisms. Antimicrobial chemicals are chemicals that are synthesized in a laboratory and can be used therapeutically on microorganisms. E. What is the mode of action for each of the following a. acitracin works by inhibiting peptidoglycan synthesis in actively dividing bacteria which normally results in osmotic lysis. b. nystatin exerts its fungicidal activity by binding to ergosterol found in fungal cell tissue layers. Binding to ergosterol causes the formation of pores in the membrane. Potassium and other cellular constituents leak from the pores causation cell death. c. tetracycline exert their bacteriostatic effect by inhibiting protein synthesis in bacteria.This antibiotic pr even upts transfer-RNA (tRNA) molecules from binding to the 30S fractional monetary unit of bacterial ribosomes. . ciprofloxin Contains agents that inhibit one or more enzymes in the DNA synthesis pathway F. Describe thr ee mechanisms by which microbes might become resistant to the action of an antimicrobial drug? Microbes whitethorn become resistant by producing enzymes that will detoxify or inactivate the antibiotic such as penicillinase and other beta-lactamases. Microbes may also bowdlerize the target site in the bacterium to reduce or block binding of the antibiotic in the process producing a slightly altered ribosomal subunit that still functions but to which the drug cant bind.Microbes may also prevent the transport of the antimicrobial agent into the bacterium thereby producing an altered cytoplasmic membrane or outer membrane. G. Why do you think neglecting to stop a prescribed course of antibiotics might contribute to the rise of antibiotic resistance? If you dont finish the medication, all the bacteria causing the infection may not be killed. Then, the infection could come back in that same place or even show up somewhere else. When the bacteria are undertreated, some of them may have e nough time to have these mistakes occur in their DNA.Then, when they multiply, you get a bunch of bacteria that no longer respond to the antibiotics. H. What is a tube dilution test? How is it used to determine susceptibility? Tube dilution test is one of the tests that can be used to tell which antimicrobial agent is most likely to combat a specific pathogen. This test is conducted by preparing a series of refining tubes where each tube contains a liquid medium and a different concentration of an antimicrobial agent. These tubes are then inoculated with the test organism and then incubated. subsequently the incubation they are examined for growth.