History Bookmarks People Window Help Take Exam 2 ure https:J/session.masteringmi

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History Bookmarks People Window Help Take Exam 2 ure https:J/session.masteringmicrobiology ake Exam 2 m 15 ProblemiD 13669797&offseta; next 00:54:20 Hide Timer 15 of 44 Part A Scientists are concerned that bacteria will be resistant to all antbiotics within the next decade Using your knowledge of genetics, descnbe how bacterial populations can develop drug resistance in such a short time frame. Essay answers are limited to about s00 words (3800 characters maximum, including spaces) 3800 Characten(s) remaining Submit Next > Provide Feedback

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When Alexander Fleming first discovered the antibiotic penicillin, in his Nobel lecture, he had said that there will be a time when the bacteria are resistant to most antibiotics. The underlying reasons to this problem are many which is becoming clear now. Bacteria are basically smart creatures. When they are subjected to a particular antibiotic, they sense it and try to cope up with the stress in many ways. For instance, the MRSA (methicillin resistant S.aureus), has become resistant to methicillin because it targets a specific isoform of transpeptidase and the bacteria has mutated it. Also, in the process of evolution, bacteria has co-evolved to be resistant to anatibiotics by mutating the targets of the antibiotic. Mutations can result in alteration of the target, activation of drug efflux pumps, decreased drug uptake, modification of the drug as such or decreased drug uptake. Another prominent reason for antibiotic resistance is HGT (Horizontal Gene Transfer). Most of the bacteria exist in communities. So when a few bacteria die they can release their DNA into the surroundings and the immediate competent cells takes this up and acquires resistance to antibiotics. Also, bacteria 'sex' or conjugation ivolves transfer of plasmids between participating bacteria and most of these plasmids may have antibiotic resistance genes in them. Certain phages can also introduce antibiotic resistance genes in the process of transduction. Resistance to beta lactam antibiotics in gram negative bacteria is due to the production of beta lactamases. Transposons that carry antibiotic resistance genes can integrate into plasmids and thereby promote resistance.

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