Biology Investigatory Project

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Antibiotic resistance is a form of drug resistance whereby some (or, less commonly, all) sub-populations of a microorganism, usually a bacterial species, are able to survive after exposure to one or more antibiotics; pathogens resistant to multiple antibiotics are considered multidrug resistant (MDR) or, more colloquially, superbugs.[1]Antibiotic resistance is a serious and growing phenomenon in contemporary medicine and has emerged as one of the pre-eminent public health concerns of the 21st century, in particular as it pertains to pathogenic organisms (the term is especially relevant to organisms that cause disease in humans). A World Health Organization report released April 30, 2014 states, "this serious threat is no longer a prediction for the future, it is happening right now in every region of the world and has the potential to affect anyone, of any age, in any country. Antibiotic resistance–when bacteria change so antibiotics no longer work in people who need them to treat infections–is now a major threat to public health."[2]In the simplest cases, drug-resistant organisms may have acquired resistance to first-line antibiotics, thereby necessitating the use of second-line agents. Typically, a first-line agent is selected on the basis of several factors including safety, availability, and cost; a second-line agent is usually broader in spectrum, has a less favourable risk-benefit profile, and is more expensive or, in dire circumstances, may be locally unavailable. In the case of some MDR pathogens, resistance to second- and even third-line antibiotics is, thus, sequentially acquired, a case quintessentially illustrated by Staphylococcus aureus in some nosocomial settings. Some pathogens, such as Pseudomonas aeruginosa, also possess a high level of intrinsic resistance.It may take the form of a spontaneous or induced genetic mutation, or the acquisition of resistance genes from other bacterial species by horizontal gene transfer via conjugation, transduction, or transformation. Many antibiotic resistance genes reside on transmissible plasmids, facilitating their transfer. Exposure to an antibiotic naturally selects for the survival of the organisms with the genes for resistance. In this way, a gene for antibiotic resistance may readily spread through an ecosystem of bacteria. Antibiotic-resistance plasmids frequently contain genes conferring resistance to several different antibiotics. This is not the case for Mycobacterium tuberculosis, the bacteria that causes Tuberculosis, since evidence is lacking for whether these bacteria have plasmids.[3] Also M. tuberculosis lack the opportunity to interact with other bacteria in order to share plasmids.[3][4]Genes for resistance to antibiotics, like the antibiotics themselves, are ancient.[5] However, the increasing prevalence of antibiotic-resistant bacterial infections seen in clinical practice stems from antibiotic use both within human medicine and veterinary medicine. Any use of antibiotics can increase selective pressure in a population of bacteria to allow the resistant bacteria to thrive and the susceptible bacteria to die off. As resistance towards antibiotics becomes more common, a greater need for alternative treatments arises. However, despite a push for new antibiotic therapies, there has been a continued decline in the number of newly approved drugs.[6] Antibiotic resistance therefore poses a significant problem.The growing prevalence and incidence of infections due to MDR pathogens is epitomised by the increasing number of familiar acronyms used to describe the causative agent and sometimes the infection; of these, MRSA is probably the most well-known, but others including VISA (vancomycin-intermediate S. aureus), VRSA (vancomycin-resistant S. aureus), ESBL (Extended spectrum beta-lactamase), VRE (Vancomycin-resistant Enterococcus) and MRAB (Multidrug-resistant A. baumannii) are prominent examples. Nosocomial infections overwhelmingly dominate

Text of Biology Investigatory Project

BIOLOGY INVESTIGATORY PROJECT TOPIC: STUDY OF DRUG RESISTANCE IN BACTERIA USING ANTIBIOTICS NAME: ________________________________________________ SCHOOL: ______________________________________________ ROLL NO: YEAR: 2014-15 INDEX CONTENTS PAGE NO. 1. Certificate of Authenticity2. Acknowledgement3. Aim of the project4. Introduction5. Need of the Experiment6. Material Required for the experiment7. Experimental Procedure8. Observation and Conclusions9. References CERTIFICATE OF AUTHENTICITY

This is to certify that, __________________________ student of class XII has successfully completed the research project on the topic STUDY OF DRUG RESISTANCE IN BACTERIA USING ANTIBIOTICS under the guidance of _____________________________ (Biology Teacher). This project is absolutely genuine and does not indulge in plagiarism of any kind. The references taken in making this project have been declared at the end of this Report.

Signature (Subject Teacher) Signature (Examiner)

ANCKNOWLEDGEMENTIwould like to express my special thanks of gratitude to our Biology teacher Mr. _________________________ as well as our Principal Mr. ___________________________ who gave me the golden opportunity to do this wonderful project on the topic STUDY OF DRUG RESISTANCE IN BACTERIA USING ANTIBIOTICS which also helped me in doing a lot of Research and I came to know about so many new things I am really thankful to them.Secondly I would also like to thank my parents and friends who helped me a lot in finalizing this project within the limited time frame.

Aim of the Project

To study the Drug resistance in bacteria using Antibiotics.

Introduction

What is Antibiotic?Anantibioticis an agent that either kills or inhibits the growth of amicroorganism.The termantibioticwas first used in 1942 bySelman Waksmanand his collaborators in journal articles to describe any substance produced by a microorganism that isantagonisticto the growth of other microorganisms in high dilution.[3]This definition excluded substances that kill bacteria but that are not produced by microorganisms (such asgastric juicesandhydrogen peroxide). It also excludedsyntheticantibacterial compounds such as the sulfonamides. Many antibacterial compounds are relativelysmall moleculeswith amolecular weightof less than 2000atomic mass units.With advances inmedicinal chemistry, most modern antibacterial aresemi syntheticmodifications of various natural compounds.[4]These include, for example, thebeta-lactam antibiotics, which include thepenicillin(produced by fungi in the genusPenicillium), thecephalosporin, and thecarbapenems. Compounds that are still isolated from living organisms are theamino glycosides, whereas other antibacterialfor example, thesulfonamides, the quinolones, and theoxazolidinonesare produced solely by chemical synthesis. In accordance with this, many antibacterial compounds are classified on the basis of chemical/biosyntheticorigin into natural, semi synthetic, and synthetic. Another classification system is based on biological activity; in this classification, antibacterial are divided into two broad groups according to their biological effect on microorganisms:Bactericidalagents kill bacteria, and bacteriostatic agentsslow down or stall bacterial growth.What is Antibiotic Resistance?Antibiotic resistanceis a form ofdrug resistancewhereby some (or, less commonly, all) sub-populations of amicroorganism, usually a bacterial species, are able to survive after exposure to one or moreantibiotics; pathogens resistant to multiple antibiotics are consideredmultidrug resistant(MDR) or, more colloquially,superbugs. Antibiotic resistance is a serious and growing phenomenon in contemporary medicine and has emerged as one of the pre-eminent public health concerns of the 21st century, in particular as it pertains to pathogenic organisms (the term is especially relevant to organisms that cause disease in humans). AWorld Health Organizationreport released April 30, 2014 states, "this serious threat is no longer a prediction for the future, it is happening right now in every region of the world and has the potential to affect anyone, of any age, in any country. Antibiotic resistancewhen bacteria change so antibiotics no longer work in people who need them to treat infectionsis now a major threat to public health." In the simplest cases, drug-resistant organisms may have acquired resistance to first-line antibiotics, thereby necessitating the use of second-line agents. Typically, a first-line agent is selected on the basis of several factors including safety, availability, and cost; a second-line agent is usually broader in spectrum, has a less favorable risk-benefit profile, and is more expensive or, in dire circumstances, may be locally unavailable. In the case of some MDR pathogens, resistance to second- and even third-line antibiotics is, thus, sequentially acquired, a case quintessentially illustrated byStaphylococcus aureusin somenosocomialsettings. Some pathogens, such asPseudomonas aeruginosa, also possess a high level of intrinsic resistance.It may take the form of a spontaneous or induced geneticmutation, or the acquisition of resistancegenesfrom other bacterial species byhorizontal gene transferviaconjugation, transduction, ortransformation. Many antibiotic resistance genes reside on transmissibleplasmids, facilitating their transfer. Exposure to an antibioticnaturally selectsfor the survival of the organisms with the genes for resistance. In this way, a gene for antibiotic resistance may readily spread through an ecosystem of bacteria. Antibiotic-resistance plasmids frequently contain genes conferring resistance to several different antibiotics. This is not the case forMycobacterium tuberculosis, the bacteria that causesTuberculosis, since evidence is lacking for whether these bacteria have plasmids.AlsoM. tuberculosislack the opportunity to interact with other bacteria in order to share plasmids. Genes for resistance to antibiotics, like the antibiotics themselves, are ancient.However, the increasing prevalence of antibiotic-resistant bacterial infections seen in clinical practice stems from antibiotic use both within human medicine andveterinary medicine. Any use of antibiotics can increaseselective pressurein a population of bacteria to allow the resistant bacteria to thrive and the susceptible bacteria to die off. As resistance towards antibiotics becomes more common, a greater need for alternative treatments arises. However, despite a push for new antibiotic therapies, there has been a continued decline in the number of newly approved drugs.Antibiotic resistance therefore poses a significant problem.The growing prevalence and incidence of infections due to MDR pathogens is epitomized by the increasing number of familiar acronyms used to describe the causative agent and sometimes the infection; of these,MRSAis probably the most well-known, but others including VISA (vancomycin-intermediateS. aureus), VRSA (vancomycin-resistantS. aureus), ESBL (Extended spectrum beta-lactamase), VRE (Vancomycin-resistantEnterococcus) and MRAB (Multidrug-resistantA. baumannii) are prominent examples.Nosocomial infectionsoverwhelmingly dominate cases where MDR pathogens are implicated, but multidrug-resistant infections are also becoming increasingly common in the community.Although there were low levels of preexisting antibiotic-resistant bacteria before the widespread use of antibiotics,[7][8]evolutionary pressure from their use has played a role in the development of multidrug-resistant varieties and the spread of resistance between bacterial species.[9]In medicine, the major problem of the emergence of resistant bacteria is due to misuse and overuse of antibiotics.[10]In some countries, antibiotics are sold over the counter without a prescription, which also leads to the creation of resistant strains. Other practices contributing to resistance includeantibiotic use in livestockfeed to promote faster growth.[11][12]Household use of antibacterial in soaps and other products, although not clearly contributing to resistance, is also discouraged (as not being effective at infection control).[13]Unsound practices in the pharmaceutical manufacturing industry can also contribute towards the likelihood of creating antibiotic-resistant strains.[14]The procedures and clinical practice during the period of drug treatment are frequently flawed usually no steps are taken to isolate the patient to prevent re-infection or infection by a new pathogen, negating the goal of complete destruction by the end of the course[15](seeHealthcare-associated infectionsandInfection control).Certain antibiotic classes are highly associated with colonization with "superbugs" compared to other antibiotic classes. A superbug, also called multiresistant, is a bacterium that carries several resistance genes.[16]The risk for colonization increases if there is a lack of susceptibility (resistance) of the superbugs to the antibiotic used and high tissue penetration, as well as broad-spectrum activity against "good bacteria". In the case ofMRSA, increased rates of MRSA infections are seen withglycopeptides,cephalosporins, and especiallyquinolones.[17][18]In the case of colonization withClostridium difficile, the high-risk antibiotics include cephalosporins and in particular quinolones andclindamycin.[19][20]Of antibiotics used in the United States in 1997, half were used in humans and half in animals; in 2013, 80% were used in animals.

Need of this Experiment

Antibiotic resistance is becoming more and more common. Antibiotics and antimicrobial agents are drugs or chemicals that are used to kill or hinder the growth ofbacteria,viruses, and other microbes. Due to the prevalent use of antibiotics, resis