Diseases, Conditions, Syndromes

Drug-resistant tuberculosis reversed in lab

About 1.5 million people died of tuberculosis (TB) in 2017, making it the most lethal infectious disease worldwide. A growing rise in drug-resistant TB is a major obstacle to successfully treating the illness.

Medical research

A 'shocking' new way to treat infections

Titanium has many properties that make it a great choice for use in implants. Its low density, high stiffness, high biomechnanical strength-to-weight ratio, and corrosion resistance have led to its use in several types of ...

Diseases, Conditions, Syndromes

Transient and long-term disruption of gut microbes after antibiotics

Trillions of microbes in the intestine aid human health, including digestion of breast milk, breaking down fiber and helping control the immune system. However, antibiotic treatment is known to disrupt the community structure ...

Medications

Why does tuberculosis find a 65-year-old drug so hard to resist?

Since its discovery in 1954, there have been almost no recorded cases of tuberculosis becoming resistant to the antibiotic drug D-cycloserine (DCS) in patients. With resistance to many other drugs on the rise, a team of ...

Medical research

Resistance can spread even without the use of antibiotics

Antibiotic resistance does not spread only where and when antibiotics are used in large quantities, ETH researchers conclude from laboratory experiments. Reducing antibiotic use alone is therefore not sufficient to curtail ...

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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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