Antibiotics Essay Research Paper Fact Sheet No

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Antibiotics Essay, Research Paper Fact Sheet No 194May 1998 ANTIMICROBIAL RESISTANCEAntimicrobial agents (antibiotics and related medicinal products) are among the wonder drugs of the twentieth century. They have transformed our ability to treat many infectious diseases that were previously killers. However, through massive and increasing use of antimicrobials in humans, animals, fish and in agriculture, a resistance problem has been created that is rapidly moving to the forefront of public health concerns.CausesMicrobes (bacteria, fungi, parasites and viruses) are responsible for infectious diseases and antimicrobial agents (such as penicillin, erythromycin, and many others) have been developed to combat the spread and severity of many infections. However, the use of these

agents for any infection, real or feared, in any dose and over any time period, forces microbes to adapt or die (”selective pressure”). The microbes which survive are those that carry genes for resistance to antimicrobial agents and, in the medical setting, a resistant microbe is one which is not killed by an antimicrobial agent after a standard course of treatment. Antimicrobial agents are also used in agriculture such as livestock and crop production, as well as in fish farming and to treat and control animal diseases and enhance growth and yield. All these uses increase the total selective pressure exerted on the microbial world and encourage the emergence of resistance.Factors that favour the spread of resistanceBacteria are particularly efficient at enhancing the effects

of resistance, not only because of their ability to multiply very rapidly but also because they can transfer their resistance genes to other strains. Resistant microbes can spread easily from person to person. Thus in hospitals and health care facilities, where there is intensive use of antimicrobials, and many sick and susceptible people gathered together, spread of resistant bacteria (such as Staphylococcus) is common. Overcrowding and poor hygiene and sanitation also facilitate the spread of resistant organisms (such as those that cause typhoid, tuberculosis, respiratory infections and pneumonia).The enormous increase in international travel in recent years means that individuals may be exposed to resistant microbes in one country and carry them to other countries, where

resistance can then spread. For example, resistant strains of gonorrhoea that originated in Asia and Africa, have now spread throughout the world.The widespread use of antimicrobials for disease control and growth promotion in animals has been paralleled by an increase in resistance in those bacteria (such as Salmonella and Campylobacter) that can spread from animals, often through food, to cause infections in humans.Detection of resistanceResistance in bacteria is most commonly detected during standard laboratory investigations to establish the cause of a patient’s infection and the best choice of treatment. Detection depends on the collection of specimens from the patient, and on the availability of laboratory facilities for isolation, identification and susceptibility

testing of the infecting microbe. This takes time and money and thus is often foregone. In consequence, resistance may not be detected until a course of treatment fails to cure a patient’s infection. By this time it may be too late. Consequences of resistanceInfections caused by resistant microbes fail to respond to treatment, resulting in prolonged illness and greater risk of death. Treatment failures also lead to longer periods of infectivity. This increases the numbers of infected people moving in the community, augmenting opportunities for spread of resistance and exposing the general population to the risk of contracting infection with resistant strains. Prolonged illness increases the costs of treatment, both the direct costs for additional laboratory tests, treatment,