New transporter for recycling of bacterial cell wall found

A transporter which some bacteria use to recycle fragments of their cell wall has been discovered by researchers at Umeå university, Sweden. They found that the transporter controls resistance to certain kinds of cell-wall ...

Plasmids and the spread of antibiotic resistance genes

Though the harnessing of antibiotics is one of the most significant human innovations, their efficacy is continuously eroded by the craftiness of their microbial targets. Once a single bacterium mutates to become resistant ...

Perseverant bacteria challenge antibacterial treatment

Bacterial perseverance is a new phenomenon that helps explain how bacteria adapt to survive antibiotic treatments. A group of researchers at Uppsala University have studied how individual bacteria react when exposed to different ...

Declining trend in the use of antibiotics in fattening animals

Antibiotics are being used less and less in fattening animals. This is the result found by the report, "Treatment Frequency and Antibiotic Consumption Quantities 2018–2021: Trends in Cattle, Pigs, Chickens and Turkeys Kept ...

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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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