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 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.
Antimicrobial resistance (AMR) occurs when microbes evolve mechanisms that protect them from the effects of antimicrobials. All classes of microbes can evolve resistance. Fungi evolve antifungal resistance. Viruses evolve antiviral resistance. Protozoa evolve antiprotozoal resistance, and bacteria evolve antibiotic resistance. Bacteria that are considered extensively drug resistant (XDR) or totally drug-resistant (TDR) are sometimes referred to as a superbug. Although antimicrobial resistance is a naturally-occurring process, it is often the result of improper usage of the drugs and management of the infections.
A urinary tract infection (UTI) is an infection that affects part of the urinary tract. When it affects the lower urinary tract it is known as a bladder infection (cystitis) and when it affects the upper urinary tract it is known as a kidney infection (pyelonephritis). Symptoms from a lower urinary tract infection include pain with urination, frequent urination, and feeling the need to urinate despite having an empty bladder. Symptoms of a kidney infection include fever and flank pain usually in addition to the symptoms of a lower UTI. Rarely the urine may appear bloody. In the very old and the very young, symptoms may be vague or non-specific.
β-lactam antibiotics are antibiotics that contain a beta-lactam ring in their chemical structure. This includes penicillin derivatives (penams), cephalosporins and cephamycins (cephems), monobactams, carbapenems and carbacephems. Most β-lactam antibiotics work by inhibiting cell wall biosynthesis in the bacterial organism and are the most widely used group of antibiotics. Until 2003, when measured by sales, more than half of all commercially available antibiotics in use were β-lactam compounds. The first β-lactam antibiotic discovered, penicillin, was isolated from a strain of Penicillium rubens.
This is the timeline of modern antimicrobial (anti-infective) therapy. The years show when a given drug was released onto the pharmaceutical market. This is not a timeline of the development of the antibiotics themselves.
Neomycin is an aminoglycoside antibiotic that displays bactericidal activity against gram-negative aerobic bacilli and some anaerobic bacilli where resistance has not yet arisen. It is generally not effective against gram-positive bacilli and anaerobic gram-negative bacilli. Neomycin comes in oral and topical formulations, including creams, ointments, and eyedrops. Neomycin belongs to the aminoglycoside class of antibiotics that contain two or more amino sugars connected by glycosidic bonds.
Gentamicin is an antibiotic used to treat several types of bacterial infections. This may include bone infections, endocarditis, pelvic inflammatory disease, meningitis, pneumonia, urinary tract infections, and sepsis among others. It is not effective for gonorrhea or chlamydia infections. It can be given intravenously, by intramuscular injection, or topically. Topical formulations may be used in burns or for infections of the outside of the eye. It is often only used for two days until bacterial cultures determine what specific antibiotics the infection is sensitive to. The dose required should be monitored by blood testing.
ATC code D06Antibiotics and chemotherapeutics for dermatological use is a therapeutic subgroup of the Anatomical Therapeutic Chemical Classification System, a system of alphanumeric codes developed by the World Health Organization (WHO) for the classification of drugs and other medical products. Subgroup D06 is part of the anatomical group D Dermatologicals.
Gramicidin, also called gramicidin D, is a mix of ionophoric antibiotics, gramicidin A, B and C, which make up about 80%, 5%, and 15% of the mix, respectively. Each has 2 isoforms, so the mix has 6 different types of gramicidin molecules. They can be extracted from Brevibacillus brevis soil bacteria. Gramicidins are linear peptides with 15 amino acids. This is in contrast to unrelated gramicidin S, which is a cyclic peptide.
Novobiocin, also known as albamycin or cathomycin, is an aminocoumarin antibiotic that is produced by the actinomycete Streptomyces niveus, which has recently been identified as a subjective synonym for S. spheroides a member of the class Actinomycetia. Other aminocoumarin antibiotics include clorobiocin and coumermycin A1. Novobiocin was first reported in the mid-1950s.
Dalfopristin is a semi-synthetic streptogramin antibiotic analogue of ostreogyrcin A. The combination quinupristin/dalfopristin was brought to the market by Rhone-Poulenc Rorer Pharmaceuticals in 1999. Synercid is used to treat infections by staphylococci and by vancomycin-resistant Enterococcus faecium.
Any cause that reduces or increases reproductive success in a portion of a population potentially exerts evolutionary pressure, selective pressure or selection pressure, driving natural selection. It is a quantitative description of the amount of change occurring in processes investigated by evolutionary biology, but the formal concept is often extended to other areas of research.
Streptogramins are a class of antibiotics.
Virginiamycin is a streptogramin antibiotic similar to pristinamycin and quinupristin/dalfopristin. It is a combination of pristinamycin IIA and virginiamycin S1. Virginiamycin is used in the fuel ethanol industry to prevent microbial contamination. It is also used in agriculture, specifically in livestock, to accelerate the growth of the animals and to prevent and treat infections. Antibiotics also save as much as 30% in feed costs among young swine, although the savings fade as pigs get older, according to a USDA study.
Polypeptide antibiotics are a chemically diverse class of anti-infective and antitumor antibiotics containing non-protein polypeptide chains. Examples of this class include actinomycin, bacitracin, colistin, and polymyxin B. Actinomycin-D has found use in cancer chemotherapy. Most other polypeptide antibiotics are too toxic for systemic administration, but can safely be administered topically to the skin as an antiseptic for shallow cuts and abrasions.
Streptogramin A is a group of antibiotics within the larger family of antibiotics known as streptogramins. They are synthesized by the bacteria Streptomyces virginiae. The streptogramin family of antibiotics consists of two distinct groups: group A antibiotics contain a 23-membered unsaturated ring with lactone and peptide bonds while group B antibiotics are depsipeptides. While structurally different, these two groups of antibiotics act synergistically, providing greater antibiotic activity than the combined activity of the separate components. These antibiotics have until recently been commercially manufactured as feed additives in agriculture, although today there is increased interest in their ability to combat antibiotic-resistant bacteria, particularly vancomycin-resistant bacteria.
Avoparcin is a glycopeptide antibiotic effective against Gram-positive bacteria. It has been used in agriculture as an additive to livestock feed to promote growth in chickens, pigs, and cattle. It is also used as an aid in the prevention of necrotic enteritis in poultry.
Streptomyces antibioticus is a gram-positive bacterium discovered in 1941 by Nobel-prize-winner Selman Waksman and H. Boyd Woodruff. Its name is derived from the Greek "strepto-" meaning "twisted", alluding to this genus' chain-like spore production, and "antibioticus", referring to this species' extensive antibiotic production. Upon its first characterization, it was noted that S. antibioticus produces a distinct soil odor.
Streptomyces virginiae is a bacterium species from the genus of Streptomyces which has been isolated from soil. Streptomyces virginiae produces actithiazic acid, virginiamycins and cycloserine. Streptomyces virginiae also produces monensin A, monensin B, monensin C, monensin D, actithiazic acid.
Medicated feed is an American legal terminology. As of 2019, it was defined in 21 CFR § 558.3.
