Medical research

New evidence links gut bacteria and neurodegenerative conditions

Neurodegenerative diseases such as Alzheimer's, Parkinson's and ALS affect millions of adults, but scientists still do not know what causes these diseases, which poses a significant roadblock to developing treatments or preventative ...

Immunology

Early-life exposure to antibiotics linked to atopic dermatitis

Exposure to antibiotics in utero and during the first year of life is associated with an increased risk for atopic dermatitis, with the correlation partially attenuated after adjustment for familial factors, according to ...

Diseases, Conditions, Syndromes

Tailor-made therapy of multi-resistant tuberculosis

Globally, tuberculosis is the most common bacterial infectious disease leading to death. The pathogen causing tuberculosis, Mycobacterium tuberculosis, has a number of peculiarities. One is that it is growing very slowly. ...

Diseases, Conditions, Syndromes

Mean cumulative incidence of tick bite ED visits 49 per 100,000

(HealthDay)—The mean cumulative incidence of emergency department tick bite visits was 49 per 100,000 visits in January 2017 to December 2019, according to research published in the April 30 issue of the U.S. Centers for ...

Medications

Developing antiviral drugs is not easy—here's why

The UK prime minister, Boris Johnson, recently announced the creation of an antivirus taskforce to "supercharge" the development of new antiviral drugs. At a Downing Street press conference, Johnson said: "The majority of ...

Medications

For deprescribing medications, what the doctor says is key

When an older patient no longer needs a medication or requires less dosage, doctors may consider "deprescribing" the medicine. Deprescribing enables clinicians to stop or reduce medications that are no longer beneficial or ...

Medical research

Using nanobodies to block a tick-borne bacterial infection

Tiny molecules called nanobodies, which can be designed to mimic antibody structures and functions, may be the key to blocking a tick-borne bacterial infection that remains out of reach of almost all antibiotics, new research ...

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Antibiotic

In common usage, an antibiotic (from the Ancient Greek: ἀντί – anti, "against", and βίος – bios, "life") is a substance or compound that kills bacteria or inhibits their growth. Antibiotics belong to the broader group of antimicrobial compounds, used to treat infections caused by microorganisms, including fungi and protozoa.

The term "antibiotic" was coined by Selman Waksman in 1942 to describe any substance produced by a microorganism that is antagonistic to the growth of other microorganisms in high dilution. This original definition excluded naturally occurring substances that kill bacteria but are not produced by microorganisms (such as gastric juice and hydrogen peroxide) and also excluded synthetic antibacterial compounds such as the sulfonamides. Many antibiotics are relatively small molecules with a molecular weight less than 2000 Da.[citations needed]

With advances in medicinal chemistry, most antibiotics are now semisynthetic—modified chemically from original compounds found in nature, as is the case with beta-lactams (which include the penicillins, produced by fungi in the genus Penicillium, the cephalosporins, and the carbapenems). Some antibiotics are still produced and isolated from living organisms, such as the aminoglycosides, and others have been created through purely synthetic means: the sulfonamides, the quinolones, and the oxazolidinones. In addition to this origin-based classification into natural, semisynthetic, and synthetic, antibiotics may be divided into two broad groups according to their effect on microorganisms: those that kill bacteria are bactericidal agents, while those that only impair bacterial growth are known as bacteriostatic agents.

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