Introduction and Medical Uses of Antibiotics
- Etymology: Antibiosis was first observed in 1877 by Louis Pasteur and Robert Koch. The term antibiotic was first used in 1942 by Selman Waksman.
- Usage: Antibiotics are used to treat or prevent bacterial and sometimes protozoan infections. Empiric therapy and definitive therapy are two approaches to antibiotic treatment.
- Routes of Administration: Antibiotics can be taken orally, intravenously, or topically depending on the severity and location of the infection.

Antibiotic Resistance
- Impact of Resistance: Overuse and easy access to antibiotics have led to the emergence of antibiotic resistance. The World Health Organization considers antimicrobial resistance a widespread serious threat. Global deaths attributable to antimicrobial resistance numbered 1.27 million in 2019.
- Types of Antibiotics: Antibiotics can be classified into different types, such as penicillins, cephalosporins, tetracyclines, macrolides, and fluoroquinolones. Combination therapy may be necessary for certain infections or to prevent the emergence of resistance.

Side Effects and Interactions
- Side Effects: Antibiotics can have mild to severe side effects, including fever, nausea, and allergic reactions. Common side effects of oral antibiotics include diarrhea and overgrowth of pathogenic bacteria. They can also affect the vaginal flora and lead to yeast overgrowth.
- Interactions: Some antibiotics may interact with oral contraceptives, potentially increasing the risk of contraceptive failure. Alcohol can also interact with certain antibiotics, causing serious side effects or reducing their efficacy.

Pharmacodynamics and Combination Therapy
- Pharmacodynamics: The successful outcome of antimicrobial therapy depends on various factors, including the bactericidal activity of antibiotics and their pharmacokinetic profile.
- Combination Therapy: Combination therapy is used to delay or prevent the emergence of resistance and can improve treatment outcomes through synergistic effects. However, some combinations may be antagonistic and less effective than monotherapy.

Antibiotic Production, Misuse, and Impact on Health
- Antibiotic Production: Most modern antibiotics are semisynthetic modifications of natural compounds. Antibacterials are produced through fermentation in aerobic conditions.
- Misuse: Inappropriate antibiotic treatment and overuse contribute to antibiotic-resistant bacteria. Common forms of misuse include self-prescribing and excessive prophylactic use.
- Impact on Health: Antibiotic-resistant strains contribute to the emergence of diseases that were previously controlled. Multidrug-resistant tuberculosis and newly identified enzymes like NDM-1 are examples of antibiotic resistance.

Antibiotic (Wikipedia)

"Antibacterial" redirects here. For other uses, see Antibacterial (disambiguation).

This article is about treatment of bacterial infection. For anti-tumor antibiotics, see Chemotherapy § Cytotoxic antibiotics.

An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of such infections. They may either kill or inhibit the growth of bacteria. A limited number of antibiotics also possess antiprotozoal activity. Antibiotics are not effective against viruses such as the ones which cause the common cold or influenza; drugs which inhibit growth of viruses are termed antiviral drugs or antivirals rather than antibiotics. They are also not effective against fungi; drugs which inhibit growth of fungi are called antifungal drugs.

Antibiotic
Drug class
Testing the susceptibility of Staphylococcus aureus to antibiotics by the Kirby-Bauer disk diffusion method – antibiotics diffuse from antibiotic-containing disks and inhibit growth of S. aureus, resulting in a zone of inhibition.
Legal status
In Wikidata

Sometimes, the term antibiotic—literally "opposing life", from the Greek roots ἀντι anti, "against" and βίος bios, "life"—is broadly used to refer to any substance used against microbes, but in the usual medical usage, antibiotics (such as penicillin) are those produced naturally (by one microorganism fighting another), whereas non-antibiotic antibacterials (such as sulfonamides and antiseptics) are fully synthetic. However, both classes have the same goal of killing or preventing the growth of microorganisms, and both are included in antimicrobial chemotherapy. "Antibacterials" include bactericides, bacteriostatics, antibacterial soaps, and chemical disinfectants, whereas antibiotics are an important class of antibacterials used more specifically in medicine and sometimes in livestock feed.

Antibiotics have been used since ancient times. Many civilizations used topical application of moldy bread, with many references to its beneficial effects arising from ancient Egypt, Nubia, China, Serbia, Greece, and Rome. The first person to directly document the use of molds to treat infections was John Parkinson (1567–1650). Antibiotics revolutionised medicine in the 20th century. Alexander Fleming (1881–1955) discovered modern day penicillin in 1928, the widespread use of which proved significantly beneficial during wartime. However, the effectiveness and easy access to antibiotics have also led to their overuse and some bacteria have evolved resistance to them. The World Health Organization has classified antimicrobial resistance as a widespread "serious threat [that] is no longer a prediction for the future, it is happening right now in every region of the world and has the potential to affect anyone, of any age, in any country". Global deaths attributable to antimicrobial resistance numbered 1.27 million in 2019.