To determine the likelihood that a patient with a bacterial

To determine the likelihood that a patient with a bacterial infection who is in the intensive care unit (ICU) of a hospital could be successfully treated with antibiotic therapies, researchers investigated the frequency of antibiotic resistance in bacteria isolated from patients in ICUs in the United States from 1994 to 2000. The data from the study are shown in the table, along with the overall change in the frequency of bacterial resistance in patient samples from 1994 to 2000. A patient was admitted to the ICU in December 2000 with an uncharacterized bacterial infection. Based on the data from the study, identify the following. The antibiotic that was most likely to be effective for treating the infection The antibiotic that was least likely to be effective for treating the infection Using the data, provide justification for the claim that antibiotic resistance may arise in bacterial species. Describe THREE different processes by which antibiotic resistance develops in individual bacterial cells. Describe TWO features of natural selection that lead to the spread of antibiotic resistance in a population over many generations. Give ONE reason that the development of antibiotic resistance is an example of evolution. Giving low doses of antibiotics to beef cattle to control the population sizes of intestinal bacteria can result in more efficient uptake of food materials by the cattle. Pose an ethical question that the Food and Drug Administration (FDA) should consider when deciding whether to approve this type of antibiotic use in beef cattle.

Solution

Ans. a) The antibiotic most likely to be effective for treating bacterial infection would be imipenem. It is clear from the given table that the patient develops the least resistance towards this antibiotic. Hence it will be the most effective for the treating the patient among the given antibiotics. Ampicillin is least effective as it develop very high resistance i.e. 65%.

b) According to the data given, it is clear that antibiotic resistance may develop in bacteria as there is marked difference in their percentage when compared to previous years.

c) Process of development of antibiotic resistence in bacteria – Bacteria   can achieve antibiotic resistance by receiving a copy of a gene that produces altered protein or enzyme for example beta lactamase from other bacteria. Random mutation and horizontal gene transfer are the major causes of it. There are a several other ways to acquire a resistance gene, few of them described below -

At the time of transformation - During this process, microorganisms can join together and transfer their DNA to each other.

By plasmid - Plasmid is a small, circular, extra chromosomal piece of DNA. It has the ability to encode resistance to many different antibiotics.

By transposon - Transposons are also known as jumping genes. Basically they are small pieces of DNA that can jump from DNA molecule to other DNA molecule. They are also capable of developing antibiotic resistance in bacteria.

d) If the bacteria have a mutation in DNA those codes for one in all those proteins, the antibiotic cannot bind to the altered protein; and the mutant bacteria will survive. In the presence of antibiotics, the process of natural selection can occur, favoring the survival and reproduction of the mutant bacterium. The mutant bacteria are more capable of surviving within the presence of the antibiotic and can still cause unwellness within the patient.