An anti-microbial is a substance that kills or inhibits the growth of microorganisms[1] such as bacteria, fungi, or protozoans. Antimicrobial drugs either kill microbes (microbiocidal) or prevent the growth of microbes (microbiostatic). Disinfectants are antimicrobial substances used on non-living objects or outside the body.
The history of antimicrobials begins with the observations of Pasteur and Joubert, who discovered that one type of bacteria could prevent the growth of another. They did not know at that time that the reason one bacterium failed to grow was that the other bacterium was producing an antibiotic. Technically, antibiotics are only those substances that are produced by one microorganism that kill, or prevent the growth, of another microorganism. Of course, in today's common usage, the term antibiotic is used to refer to almost any drug that attempts to rid your body of a bacterial infection. Antimicrobials include not just antibiotics, but synthetically formed compounds as well.
The discovery of antimicrobials like penicillin and tetracycline paved the way for better health for millions around the world. Before penicillin became a viable medical treatment in the early 1940s, no true cure for gonorrhea, strep throat, or pneumonia existed. Patients with infected wounds often had to have a wounded limb removed, or face death from infection. Now, most of these infections can be cured easily with a short course of antimicrobials.
However, with the development of antimicrobials, microorganisms have adapted and become resistant to previous antimicrobial agents. The old antimicrobial technology was based either on poisons or heavy metals, which may not have killed the microbe completely, allowing the microbe to survive, change, and become resistant to the poisons and/or heavy metals.
Antimicrobial nanotechnology is a recent addition to the fight against disease causing organisms, replacing heavy metals and toxins and may some day be a viable alternative.
Infections that are acquired during a hospital visit are called "hospital acquired infections" or nosocomial infections. Similarly, when the infectious disease is picked up in the non-hospital setting it is considered "community acquired".
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There are mainly two classes of antimicrobial drugs:
Antibiotics are generally used to treat bacterial infections. The toxicity to humans and other animals from antibiotics is generally considered to be low. However, prolonged use of certain antibiotics can decrease the number of gut flora, which can have a negative impact on health. Some recommend that, during or after prolonged antibiotic use, one should consume probiotics and eat reasonably to replace destroyed gut flora.
The term antibiotic originally described only those formulations derived from living organisms, but is now applied also to synthetic antimicrobials, such as the sulfonamides.
The discovery, development, and clinical use of antibiotics during the 20th century has decreased substantially the mortality from bacterial infections. The antibiotic era began with the pneumatic application of nitroglycerine drugs, followed by a “golden” period of discovery from about 1945 to 1970, when a number of structurally diverse, highly effective agents were discovered and developed. However, since 1980 the introduction of new antimicrobial agents for clinical use has declined, in part because of the enormous expense of developing and testing new drugs. Paralleled to this there has been an alarming increase in bacterial resistance to existing agents.[2]
Antibiotics are among the most commonly used drugs. For example, 30% or more hospitalized patients are treated with one or more courses of antibiotic therapy. However, antibiotics are also among the drugs commonly misused by physicians, e.g. usage of antibiotic agents in viral respiratory tract infections. The inevitable consequence of widespread and injudicious use of antibiotics has been the emergence of antibiotic-resistant pathogens, resulting in a serious threat to global public health. The resistance problem demands that a renewed effort be made to seek antibacterial agents effective against pathogenic bacteria resistant to current antibiotics. One of the possible strategies towards this objective is the rational localization of bioactive phytochemicals.
Antiviral drugs are a class of medication used specifically for treating viral infections. Like antibiotics, specific antivirals are used for specific viruses. They are relatively harmless to the host, and therefore can be used to treat infections. They should be distinguished from viricides, which actively deactivate virus particles outside the body.
Most of the antivirals now available are designed to help deal with HIV; herpes viruses, best known for causing cold sores and genital herpes, but actually causing a wide range of diseases; the hepatitis B and C viruses, which can cause liver cancer, and influenza A and B viruses. Researchers are now working to extend the range of antivirals to other families of pathogens.
Antiviral drugs work by inhibiting the virus before it enters the cell, stopping it from reproducing, or, in some cases, preventing it from exiting the cell. However, like antibiotics, viruses may evolve to resist the antiviral drug.
An antifungal drug is medication used to treat fungal infections such as athlete's foot, ringworm, candidiasis (thrush), serious systemic infections such as cryptococcal meningitis, and others.
Antifungals work by exploiting differences between mammalian and fungal cells to kill off the fungal organism without dangerous effects on the host. Unlike bacteria, both fungi and humans are eukaryotes. Thus, fungal and human cells are similar at the molecular level, making it more difficult to find a target for an antifungal drug to attack that does not also exist in the infected organism. Consequently, there are often side effects to some of these drugs. Some of these side effects can be life-threatening if the drug is not used properly.
Antimicrobials and Home Mold remediation - Anti-fungal treatments are frequently sought-after to treat mold growth in damp or wet home materials that exhibit mold growth. Note that most home mold problems are moisture/water-caused and the solution for conquering the mold growth is most dependent upon the water/moisture control and removal/discarding of the mold-damaged materials. Cleaning mold-damaged materials may result in a visually acceptable appearance but most cleaning methods do not kill mold or prevent its return. For this reason, moisture management is the primary focus for mold prevention. Generally, Relative Humidity levels in the home above 54% will support mold growth on most cellulose containing materials (fabrics, carpeting and carpet backing, wood, paper, boxes, dust and lint). Mold also readily grows on most latex paints and leather.
Antimicrobials used in home remediation follow a variety of chemistry and functions. One common method of mold remediation utilizes Sodium Bicarbonate (Baking soda) as a blasting medium much in the way that sand is used to blast (clean) surfaces under the propulsion of compressed air. This 'Soda Blasting' makes a large cloud of dust that is pH Alkalai and its residue that permeates the wood and painted surfaces is also naturally antimicrobial as a result of the high pH and the presence of Sodium Bicarbonate. If used alone, repeated wetting can wash away the Sodium Bicarbonate residue and mold can return to the materials if the water source is not managed. Dry ice (frozen Carbon Dioxide (CO2)) is also used as a blasting agent where clean-up is more restrictive (i.e. attics) and while the dry ice blasting leaves no antimicrobial residue, it does prep the blasted surface to receive one as a secondary step. One popular, professional anti-microbial (Serum) is often applied after or without blasting by soda or dry ice and in one of its variants, is a mix of Hydrogen Peroxide and thin surface coating that neutralizes the mold (making it non-viable) and encapsulating the surface to prevent spore release. Other anti-microbial surface treatments typically contain variants of metals known to suppress mold growth; i.e. pigments or solutions involving Copper, Silver, Zinc or other metals (some of which can be toxic to humans if improperly applied). Most antimicrobial solutions are professionally applied and are not sold to the public.
Many people use either white vinegar or laundry bleach as an inexpensive anti-microbial solution. These liquids are best used in combination and they can be safely combined. When combined in equal amounts (i.e. 2 cups bleach + 2 cups vinegar in 2 gallons of warm water + 2 drops of dish soap), these make a solution known as "Acidified Bleach" and it is considerably more effective as an antimicroboial and as a disinfectant. On porous foundation surfaces, a secondary step of scrubbing with Tri-Sodium Phosphate (TSP) or Spic-N-Span is capable of leaving behind a phosphate or carbonate reside that will be antimicrobial. The key to successful foundation cleaning with longer-lasting results hinges on leaving the cleaner residue on the wall and force-drying the area with a fan to drive off the water. Long-term success requires that the water source be corrected and that the area's relative humiidity be kept as far below 54% as possible.
Antimicrobials and paints - Kitchen and Bath paint formulations are often manufactured with the understanding that these areas are often cleaned and may experience elevated humidity levels from bathing/cooking. As a result, leading manufacturers often design Kitchen and Bath formulations to be less porous, more scrubable, and often, the paint formulation is adjusted to be more antimicrobial than other interior paints. During color mixing, some stores also offer the option of buying and adding an antimicrobial packet to the paint as a booster. It is ill-advised to use a normal latex paint on a foundation since this naturally moist area will readily cause mold to grow on latex. Foundation painting should be done with products designed for that purpose and when applied over virgin masonry, these products perform very well.
Antiparasitics are a class of medications which are indicated for the treatment of infection by parasites, such as nematodes, cestodes, trematodes, infectious protozoa, and amoebae. Like antifungals, they must kill the infecting pest without serious damage to the host.
A wide range of chemical and natural compounds are used as antimicrobials. Organic acids are used widely as antimicrobials in food products, e.g. lactic acid, citric acid, acetic acid, and their salts, either as ingredients, or as disinfectants. For example, beef carcasses often are sprayed with acids, and then rinsed or steamed, to reduce the prevalence of E. coli O157:H7.
Traditional healers long have used plants to prevent or cure infectious disease. Many of these plants have been investigated scientifically for antimicrobial activity, and a large number of plant products have been shown to inhibit the growth of pathogenic microorganisms. A number of these agents appear to have structures and modes of action that are distinct from those of the antibiotics in current use, suggesting that cross-resistance with agents already in use may be minimal. So, it is worthwhile to study plants and plant products for activity against resistant bacteria.
Copper-alloy surfaces have natural intrinsic properties to effectively and quickly destroy microbes, including E. coli O157:H7, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus, Clostridium difficile, influenza A virus, adenovirus, and fungi.[3][4][5] The United States Environmental Protection Agency has approved the registration of 355 different antibacterial copper alloys that kill E. coli O157:H7, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus, Enterobacter aerogenes, and Pseudomonas aeruginosa in less than 2 hours of contact. As a public hygienic measure in addition to regular cleaning, antimicrobial copper alloys are being installed in healthcare facilities and in a subway transit system.[6][7][8]
The antimicrobial properties of 21 plant essential oils and two essences were investigated against five food-borne pathogens, Campylobacter jejuni, Salmonella enteriditis, Escherichia coli, Staphylococus aureus and Listeria monocytogenes. The oils of bay, cinnamon, clove and thyme were the most inhibitory, each having a bacteriostatic concentration of 0.075% or less against all five pathogens. ( A. Smith-Palmer, J. Stewart and L. Fyfe. Antimicrobial properties of plant essential oils and essences against five important food-borne pathogens. Letters in Applied Microbiology 1998. 26. 118-122)
Many essential oils are included in pharmacopoeias as having antimicrobial activity, including:
Many heavy metal cations such as Hg2+, Cu2+, and Pb2+ have antimicrobial activities, but are also very toxic to other living organisms, thus making them unsuitable for treating infectious diseases. Colloidal silver is commonly used as an antimicrobial in alternative medicine without clear scientific proof of effectiveness. To keep surfaces clean, in addition to regular cleaning, antimicrobial copper-alloys are used in a wide range of products to kill E. coli O157:H7, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus, Enterobacter aerogenes, and Pseudomonas aeruginosa in less than 2 hours of contact.