Farhan Ali :DVM
Faculty of veterinary Sciences Multan : BZU
intellifarhan390@hotmail.com
“Antimicrobials are products that kill microorganisms or keep them from multiplying (reproducing) or growing. They are most commonly used to prevent or treat disease and infections due to microorganisms”.Antimicrobial resistance mean “The result of microbes changing in ways that reduce or eliminate the effectiveness of drugs, chemicals, or other agents to cure or prevent infections”.Spectrum of antimicrobial activity is that the antimicrobial must cause more harm to the pathogen than to the host. This is called selective toxicity.Antimicrobials may work against only certain microbes. They can be: Antibacterial, Antifungal, Antiviral, Antiprotozoal.The spectrum of activity is the range of different microbes a drug is able to work against. Narrow-spectrum means that the drug works best against only a certain group or type; broad-spectrum drugs work against a wider range of microbes. If the drug works against bacteria, a broad-spectrum drug would probably do well against both gram-positive and gram-negative organisms. A narrow-spectrum drug would work only against one or the other, or possibly an even narrower group.An ideal antimicrobial would have more effect against pathogens and less on the normal flora of the body. Unfortunately, this is not always possible.Action of antimicrobial resistance include either ---cidal, which means they actually kill the pathogens, or ----static, which means they slow or prevent reproduction. 1. Inhibition of cell wall synthesis—since this attacks the cell wall, these drugs have little effect on host cells, which do not contain peptidoglycan. Penicillin, bacitracin, and vancomycin act in this way.2. Inhibition of protein synthesis---since ribosomes of procaryotic cells are slightly different from those of eucaryocytes, they can be used as a target. Chloramphenicol, erythromycin, streptomycin, and the tetracyclines act in this way.3. Injury to the plasma membrane—this is a mode of action of both some antibacterials and some antifungals. Antifungals are able to work mostly against fungus cell membranes because they contain ergosterol instead of cholesterol. However, these antibiotics are potentially quite toxic to the host. Examples are the polymixins, and antifungals such as amphotericin B, miconazole, and ketoconazole.4. Inhibition of nucleic acid synthesis---selective toxicity varies, but these interfere with DNA replication and transcription. Rifampin and the quinolones are examples.5. Inhibiting the synthesis of essential metabolites---the sulfas and trimethoprim work this way. They interfere with the pathway by which bacteria synthesize folic acid.
“Antimicrobials are products that kill microorganisms or keep them from multiplying (reproducing) or growing. They are most commonly used to prevent or treat disease and infections due to microorganisms”.Antimicrobial resistance mean “The result of microbes changing in ways that reduce or eliminate the effectiveness of drugs, chemicals, or other agents to cure or prevent infections”.Spectrum of antimicrobial activity is that the antimicrobial must cause more harm to the pathogen than to the host. This is called selective toxicity.Antimicrobials may work against only certain microbes. They can be: Antibacterial, Antifungal, Antiviral, Antiprotozoal.The spectrum of activity is the range of different microbes a drug is able to work against. Narrow-spectrum means that the drug works best against only a certain group or type; broad-spectrum drugs work against a wider range of microbes. If the drug works against bacteria, a broad-spectrum drug would probably do well against both gram-positive and gram-negative organisms. A narrow-spectrum drug would work only against one or the other, or possibly an even narrower group.An ideal antimicrobial would have more effect against pathogens and less on the normal flora of the body. Unfortunately, this is not always possible.Action of antimicrobial resistance include either ---cidal, which means they actually kill the pathogens, or ----static, which means they slow or prevent reproduction. 1. Inhibition of cell wall synthesis—since this attacks the cell wall, these drugs have little effect on host cells, which do not contain peptidoglycan. Penicillin, bacitracin, and vancomycin act in this way.2. Inhibition of protein synthesis---since ribosomes of procaryotic cells are slightly different from those of eucaryocytes, they can be used as a target. Chloramphenicol, erythromycin, streptomycin, and the tetracyclines act in this way.3. Injury to the plasma membrane—this is a mode of action of both some antibacterials and some antifungals. Antifungals are able to work mostly against fungus cell membranes because they contain ergosterol instead of cholesterol. However, these antibiotics are potentially quite toxic to the host. Examples are the polymixins, and antifungals such as amphotericin B, miconazole, and ketoconazole.4. Inhibition of nucleic acid synthesis---selective toxicity varies, but these interfere with DNA replication and transcription. Rifampin and the quinolones are examples.5. Inhibiting the synthesis of essential metabolites---the sulfas and trimethoprim work this way. They interfere with the pathway by which bacteria synthesize folic acid.
Causes of Antimicrobial resistance include selective pressure ,Mutation ,Gene Transfer,
Societal Pressures, Inappropriate Use, Inadequate Diagnostics,Hospital Use ,
and Agricultural Use respectively. In Selective
Pressure the presence of an antimicrobial, microbes are either killed or,
if they carry resistance genes, survive. These survivors will replicate, and
their progeny will quickly become the dominant type throughout the microbial
population.Mutation Most microbes reproduce
by dividing every few hours, allowing them to adapt quickly to new
environmental conditions. During replication, mutations arise and some of these
mutations may help an individual microbe survive exposure to an antimicrobial.Gene Transfer Microbes also may get
genes from each other, including genes that make the microbe drug resistant. Societal Pressures there are additional
societal pressures that act to accelerate the increase of antimicrobial
resistance. Inappropriate Use
Selection of resistant microorganisms is exacerbated by inappropriate use of
antimicrobials. Sometimes healthcare providers will prescribe antimicrobials
inappropriately, wishing to placate an insistent patient who has a viral
infection or an as-yet undiagnosed condition. Inadequate Diagnostics More often, healthcare providers must use
incomplete or imperfect information to diagnose an infection and thus prescribe
an antimicrobial just-in-case or prescribe a broad-spectrum antimicrobial when
a specific antibiotic might be better. These situations contribute to selective
pressure and accelerate antimicrobial resistance.Hospital Use Critically ill patients are more susceptible to
infections and, thus, often require the aid of antimicrobials.. The extensive
use of antimicrobials and close contact among sick patients creates a fertile
environment for the spread of antimicrobial-resistant germs. Agricultural Use Scientists also
believe that the practice of adding antibiotics to agricultural feed promotes
drug resistance. More than half of the antibiotics produced in the pakistan are
used for agricultural purposes. However, there is still much debate about
whether drug-resistant microbes in animals pose a significant public health
burden.
Antimicrobials are generally used in
animal to Control of disease, Growth promotion/feed efficiency , prevent or treat infection. Prevention for antimicrobial resistance
include appropriate medication for your illness and avoid overusing or misusing
medicines. Strictly follow prescription medication directions and never share
or take medicine that was prescribed for someone else. Communicate effectively
with your healthcare provider, so that he or she has a clear understanding of
your symptoms and can determine whether an antimicrobial drug, such as an antibiotic,
is appropriate. Do not save your antibiotic for the next time you get sick;
take all of the medication as prescribed by your healthcare provider. If the
healthcare provider has prescribed more than the required dose, discard
leftover medications once you have completed the prescribed course of
treatment. Do not share your medication with another person.Healthy lifestyle
habits always go far in preventing illness, including proper diet, exercise,
sleeping patterns, and good hygiene, such as frequent hand washing.
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