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. Antibiotics are also not effective against fungi. Drugs which inhibit growth of fungi are called antifungal drugs.
Linezolid is an antibiotic used for the treatment of infections caused by Gram-positive bacteria that are resistant to other antibiotics. Linezolid is active against most Gram-positive bacteria that cause disease, including streptococci, vancomycin-resistant enterococci (VRE), and methicillin-resistant Staphylococcus aureus (MRSA). The main uses are infections of the skin and pneumonia although it may be used for a variety of other infections including drug-resistant tuberculosis. It is used either by injection into a vein or by mouth.
Clostridioides difficile infection, also known as Clostridium difficile infection, is a symptomatic infection due to the spore-forming bacterium Clostridioides difficile. Symptoms include watery diarrhea, fever, nausea, and abdominal pain. It makes up about 20% of cases of antibiotic-associated diarrhea. Antibiotics can contribute to detrimental changes in gut microbiota; specifically, they decrease short-chain fatty acid absorption which results in osmotic, or watery, diarrhea. Complications may include pseudomembranous colitis, toxic megacolon, perforation of the colon, and sepsis.
Clindamycin is a lincosamide antibiotic medication used for the treatment of a number of bacterial infections, including osteomyelitis (bone) or joint infections, pelvic inflammatory disease, strep throat, pneumonia, acute otitis media, and endocarditis. It can also be used to treat acne, and some cases of methicillin-resistant Staphylococcus aureus (MRSA). In combination with quinine, it can be used to treat malaria. It is available by mouth, by injection into a vein, and as a cream or a gel to be applied to the skin or in the vagina.
Aztreonam, sold under the brand name Azactam among others, is an antibiotic used primarily to treat infections caused by gram-negative bacteria such as Pseudomonas aeruginosa. This may include bone infections, endometritis, intra abdominal infections, pneumonia, urinary tract infections, and sepsis. It is given by intravenous or intramuscular injection or by inhalation.
Tigecycline, sold under the brand name Tygacil, is a tetracycline antibiotic medication for a number of bacterial infections. It is a glycylcycline class drug that is administered intravenously. It was developed in response to the growing rate of antibiotic resistant bacteria such as Staphylococcus aureus, Acinetobacter baumannii, and E. coli. As a tetracycline derivative antibiotic, its structural modifications has expanded its therapeutic activity to include Gram-positive and Gram-negative organisms, including those of multi-drug resistance.
Carbapenems are a class of very effective antibiotic agents most commonly used for treatment of severe bacterial infections. This class of antibiotics is usually reserved for known or suspected multidrug-resistant (MDR) bacterial infections. Similar to penicillins and cephalosporins, carbapenems are members of the beta-lactam antibiotics drug class, which kill bacteria by binding to penicillin-binding proteins, thus inhibiting bacterial cell wall synthesis. However, these agents individually exhibit a broader spectrum of activity compared to most cephalosporins and penicillins. Furthermore, carbapenems are typically unaffected by emerging antibiotic resistance, even to other beta-lactams.
Fecal microbiota transplant (FMT), also known as a stool transplant, is the process of transferring fecal bacteria and other microbes from a healthy individual into another individual. FMT is an effective treatment for Clostridioides difficile infection (CDI). For recurrent CDI, FMT is more effective than vancomycin alone, and may improve the outcome after the first index infection.
2-Oxazolidone is a heterocyclic organic compound containing both nitrogen and oxygen in a 5-membered ring.
Dalbavancin, sold under the brand names Dalvance in the US and Xydalba in the EU among others, is a second-generation lipoglycopeptide antibiotic medication. It belongs to the same class as vancomycin, the most widely used and one of the treatments available to people infected with methicillin-resistant Staphylococcus aureus (MRSA).
Ramoplanin (INN) is a glycolipodepsipeptide antibiotic drug derived from strain ATCC 33076 of Actinoplanes. It is effective against Gram-positive bacteria.
Tedizolid, sold under the brand name Sivextro is an oxazolidinone-class antibiotic. Tedizolid phosphate is a phosphate ester prodrug of the active compound tedizolid. It was developed by Cubist Pharmaceuticals, following acquisition of Trius Therapeutics, and is marketed for the treatment of acute bacterial skin and skin structure infections.
Fidaxomicin, sold under the brand name Dificid among others, is the first member of a class of narrow spectrum macrocyclic antibiotic drugs called tiacumicins. It is a fermentation product obtained from the actinomycete Dactylosporangium aurantiacum subspecies hamdenesis. Fidaxomicin is minimally absorbed into the bloodstream when taken orally, is bactericidal, and selectively eradicates pathogenic Clostridioides difficile with relatively little disruption to the multiple species of bacteria that make up the normal, healthy intestinal microbiota. The maintenance of normal physiological conditions in the colon may reduce the probability of recurrence of Clostridioides difficile infection.
Actelion Pharmaceuticals Ltd. is a pharmaceuticals and biotechnology company established in December 1997, headquartered in Allschwil near Basel, Switzerland.
Rifalazil is an antibiotic substance that kills bacterial cells by blocking off the β-subunit in RNA polymerase. Rifalazil is used as a treatment for many different diseases. The most common are Chlamydia infection, Clostridioides difficile associated diarrhea (CDAD), and tuberculosis (TB). Using rifalazil and the effects that coincide with taking rifalazil for treating a bacterial disease vary from person to person, as does any drug put into the human body. Food interactions and genetic variation are a few causes for the variation in side effects from the use of rifalazil. Its development was terminated in 2013 due to severe side effects.
Nemonoxacin is a non-fluorinated quinolone antibiotic undergoing clinical trials. It has the same mechanism of action as fluouroquinolones; it inhibits DNA gyrase, preventing DNA synthesis, gene duplication, and cell division. At the end of 2016, it had reached market in Taiwan, Russia, the Commonwealth Independent States, Turkey, mainland China, and Latin America under the brand name Taigexyn. Nemonoxacin has completed phase 2 trials in the US and has moved on to phase 3 trials. The U.S. Food and Drug Administration (FDA) has granted nemonoxacin qualified infectious disease product (QIDP) and fast track designations for community-acquired bacterial pneumonia (CAP) and acute bacterial skin and skin-structure infections (ABSSSI).
Surotomycin was an investigational oral antibiotic. This macrolide antibiotic was under investigation by Merck & Co for the treatment of life-threatening diarrhea, commonly caused by the bacterium Clostridioides difficile. After reaching phase III in clinical trials, its production was discontinued in 2017 due to its non-superiority to current therapies.
Clostridioides difficile is a bacterium known for causing serious diarrheal infections, and may also cause colon cancer. It is known also as C. difficile, or C. diff, and is a Gram-positive species of spore-forming bacteria. Clostridioides spp. are anaerobic, motile bacteria, ubiquitous in nature and especially prevalent in soil. Its vegetative cells are rod-shaped, pleomorphic, and occur in pairs or short chains. Under the microscope, they appear as long, irregular cells with a bulge at their terminal ends. Under Gram staining, C. difficile cells are Gram-positive and show optimum growth on blood agar at human body temperatures in the absence of oxygen. C. difficile is catalase- and superoxide dismutase-negative, and produces up to three types of toxins: enterotoxin A, cytotoxin B and Clostridioides difficile transferase. Under stress conditions, the bacteria produce spores that are able to tolerate extreme conditions that the active bacteria cannot tolerate.
Ridinilazole is an investigational small molecule antibiotic being evaluated for oral administration to treat Clostridioides difficile infection (CDI). In vitro, it is bactericidal against C. difficile and suppresses bacterial toxin production; the mechanism of action is thought to involve inhibition of cell division. It has properties which are desirable for the treatment of CDI, namely that it is a narrow-spectrum antibiotic which exhibits activity against C. difficile while having little impact on other normal intestinal flora and that it is only minimally absorbed systemically after oral administration. At the time ridinilazole was developed, there were only three antibiotics in use for treating CDI: vancomycin, fidaxomicin, and metronidazole. The recurrence rate of CDI is high, which has spurred research into other treatment options with the aim to reduce the rate of recurrence.
SCHEMBL19952957 is an oxadiazole based antibiotic, originally developed in 2014 as a potential treatment for infections with methicillin-resistant Staphylococcus aureus (MRSA) and other antibiotic-resistant bacteria. Subsequently, it has been found to be useful against Clostridioides difficile as it not only kills active bacteria but also inhibits the germination of the dormant spores which can otherwise often lead to persistent infections that repeatedly recur upon cessation of antibiotic treatment. While it is still only being researched in animals at this stage, this dual action is a significant advance over existing antibiotics, and it is likely that drugs from this class may be developed as new medications for the treatment of antibiotic-resistant infections in humans.
