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... g to one or more of the classes listed here, including miscellaneous. To keep up with evolving bacteria, scientists are attacking efflux pumps. Efflux pumps are what microbes use to rid themselves of toxic materials and drugs. The way science is perusing this is to attach these pumps with compounds called efflux-pump inhibitors. These compounds have no infection fighting power but can make current antimicrobial drugs more effective (Christensen).
Microbes that caused sickness in the pre antibiotic era are again making people sick because some of these microbes have become resistant to antibiotics. Various bacterium are now resistant to one or more classes of antibiotics; penicillins, cephalosporins, tetracycline's, quinol ones, amino glycosides, and macrolides. These Bacteria can resist the drugs in several ways. They can alter it so that it's no longer toxic. Or they can modify their own components so that the antimicrobial compound can't bind to them nor have an effect on them (Garrett 432). Recently microbiologists have found that bacteria can also expel drugs, thus lowering the internal concentration enough that the microbes escape the treatment's intended effects (Christensen).
Most efflux pumps probably evolved to handle toxins in the environment and only by luck pump out antibiotics, and it is still unknown how these pumps work. Each pump is made up of one or several proteins that span the cell membrane of the microbe. Two theories on how efflux pumps actively expel a drug is through a local channel or by propelling the drug across the cell membrane. Efflux pumps are known to be responsible for a moderate level of resistance in many different species of bacteria and against several drugs. Not all microbes have efflux pumps, and the ones that do employ widely varying numbers and types. Some microbes always have abundant pumps, and others manufacture additional pumps after exposure to drugs (Christensen).
Efflux pumps help explain why some bacteria are less susceptible to drugs than others are. Some species of bacteria seem to use efflux pumps to resist tetracycline's, macrolides, and fluoroquinolones well enough to often make these antibiotics useless weapons. Since efflux pumps can act on more than just one kind of antimicrobial agent, microbes may develop resistance against several different drugs simultaneously (Tulkens in Christen). Between 40 and 90 percent of some bacterial pathogens carry efflux pumps for most of the major classes of available antibiotics (Christensen). With the information now known, efflux pumps opens up opportunities for pharmaceutical companies to find compounds that will disrupt this microbial activity. As drugs, efflux-pump inhibitors aren't expected to have a significant antimicrobial effect on their own and companies are now developing these compounds.
They are expected to reverse acquired drug resistance in microbes that are susceptible to antibacterial and antifungal drugs. Also efflux-pump inhibitors might make some microbes that are intrinsically drug resistant vulnerable to antibiotics, and those efflux-pump inhibitors will reduce the chance that bacteria will successfully reproduce enough times to select for a drug-resistance mutation (Christensen). Efflux pumps are not the only problem, many bacteria were capable of using sporulation to their advantage in the face of' antibiotics and other threats. Like plant seeds, they would go dormant, toughen their cell walls to a nearly impermeable state, and wait. When conditions were favorable, the bacteria would reactivate, their cell walls once again becoming permeable. Some forms of resistance involved the bacteria's use of genes that triggered sporulation when the microbes were threatened, or created an even less vulnerable cell wall at the time of sporulation (Garrett 428).
Under such conditions, microbes could drift about unharmed in solutions designed specifically to kill them. Sporulation mutants can withstand all disinfectants, such as chlorine- and ammonia-based cleansers, soaps, extremely salty or acid solutions, and even high heat. An example of this would be a number of organisms, including strains of cholera, E. colt, and the Legionnaires' disease bacteria, had developed some resistance, through such sporulation mechanisms, and other means, to chlorine.
They are partially tolerant, not all together resistant, because the microbes were able to survive in doses of chlorine that usually killed their species. To ensure safe drinking water in the presence of such bugs, higher doses of chlorine were needed (Garnett 428) At drug and biotech companies across the United States, scientists have set their sights on a most elusive target: drug-resistant microbes. Working in pharmaceutical- biotechnology partnerships, researchers are trying every trick in the book-including high-tech drug discovery, genome sequencing, and development of new vaccines-to overcome resistant pathogens. Successful companies stand to gain a significant share of the $ 23 billion antibiotics market (Brown). A handful of new or improved antibiotics geared to resistant bugs are in various stages of clinical trials, and ideas for novel therapeutics abound. Like, resistance-related genes may lie within human and bacterial genomes currently being sequenced in various large-scale projects.
According to a newly released World Health Organization (WHO) annual report, drug-resistant strains of microbes have evaded common treatments for tuberculosis (TB), malaria, cholera, and pneumonia. The widespread use of antibiotics contributes to drug resistance. The longer bacteria are exposed to a drug, the more likely they are to evolve a way around it. Today, 160 antibiotics, all based on a few basic chemical structures, are on the market. Researchers suggest these drugs may be overprescribed.
Patients often fail to complete antibiotic therapy; they stop taking drugs as soon as they feel better. Bacteria still in the body can rebound, developing resistance to the drug at hand in the host's system. Such misuse of prescriptions, combined with societal conditions-such as the growth of day-care centers and increased long-term care in hospitals-provides an environment where drug-resistant microbes can emerge and thrive (Brown). Science, is many fields, is working on a varying answer for this problem.
But they must work fast to counteract the problem, because is the microbes become resistant to are antibiotics, where does that leave us? Extinct (Magee)! Bibliography: Brown, Kathryn. The Scientist, Vol: 10, # 12, p. 1, 8 - 9, June 10, 1996. Christensen, Damages. Keeping Bugs from Pumping Drugs.
Science News 157 no 7 F 12 2000. Garrett, Laurie. The Coming Plague. New York: Farrar, 1994. Levy, Stuart B. Antimicrobial resistance.
British Medical Journal, Sept 5, 1998 v 317 p 612. Magee, J T. Antibiotic Prescribing and Antibiotic Resistance in Community Practices. British Medical Journal, Nov 6, 1999 v 319 i 7219 p 1239. Stapleton, Stephanie. Counterattack (Antibiotics and Bacteria).
American Medical News, June 1, 1998 v 41 n 21 p 31 (1).
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Research essay sample on British Medical Journal Cell Membrane
