Vancomycin is a glycopeptide antibiotic medication used to treat a number of bacterial infections. It is recommended intravenously as a treatment for complicated skin infections, bloodstream infections, endocarditis, bone and joint infections, and meningitis caused by methicillin-resistant Staphylococcus aureus. Blood levels may be measured to determine the correct dose. Vancomycin is also taken by mouth as a treatment for severe Clostridium difficile colitis. When taken by mouth it is poorly absorbed.
Drug resistance is the reduction in effectiveness of a medication such as an antimicrobial or an antineoplastic in treating a disease or condition. The term is used in the context of resistance that pathogens or cancers have "acquired", that is, resistance has evolved. Antimicrobial resistance and antineoplastic resistance challenge clinical care and drive research. When an organism is resistant to more than one drug, it is said to be multidrug-resistant.
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.
Methicillin (USAN), also known as meticillin (INN), is a narrow-spectrum β-lactam antibiotic of the penicillin class.
Puromycin is an antibiotic protein synthesis inhibitor which causes premature chain termination during translation.
Aminoglycoside is a medicinal and bacteriologic category of traditional Gram-negative antibacterial medications that inhibit protein synthesis and contain as a portion of the molecule an amino-modified glycoside (sugar). The term can also refer more generally to any organic molecule that contains amino sugar substructures. Aminoglycoside antibiotics display bactericidal activity against Gram-negative aerobes and some anaerobic bacilli where resistance has not yet arisen but generally not against Gram-positive and anaerobic Gram-negative bacteria.
Micromonospora is a genus of bacteria of the family Micromonosporaceae. They are gram-positive, spore-forming, generally aerobic, and form a branched mycelium; they occur as saprotrophic forms in soil and water. Various species are sources of aminoglycoside antibiotics with spellings that end with -micin, such as gentamicin, mutamicin, netilmicin, retymicin, sisomicin, verdamicin, calicheamicin, and the recently found turbinmicin. Potent new antifungal drugs discovered in the microbiome of marine animals, unlike most other aminoglycoside names that end with -mycin.
Neomycin/polymyxin B/bacitracin, also known as triple antibiotic ointment, is an antibiotic medication used to reduce the risk of infections following minor skin injuries. It contains the three antibiotics neomycin, polymyxin B, and bacitracin. It is for topical use.
Kanamycin A, often referred to simply as kanamycin, is an antibiotic used to treat severe bacterial infections and tuberculosis. It is not a first line treatment. It is used by mouth, injection into a vein, or injection into a muscle. Kanamycin is recommended for short-term use only, usually from 7 to 10 days. As with most antibiotics, it is ineffective in viral infections.
Tobramycin is an aminoglycoside antibiotic derived from Streptomyces tenebrarius that is used to treat various types of bacterial infections, particularly Gram-negative infections. It is especially effective against species of Pseudomonas.
Enterococcus faecalis – formerly classified as part of the group D Streptococcus system – is a Gram-positive, commensal bacterium inhabiting the gastrointestinal tracts of humans. Like other species in the genus Enterococcus, E. faecalis is found in healthy humans and can be used as a probiotic. The probiotic strains such as Symbioflor1 and EF-2001 are characterized by the lack of specific genes related to drug resistance and pathogenesis. As an opportunistic pathogen, E. faecalis can cause life-threatening infections, especially in the nosocomial (hospital) environment, where the naturally high levels of antibiotic resistance found in E. faecalis contribute to its pathogenicity. E. faecalis has been frequently found in reinfected, root canal-treated teeth in prevalence values ranging from 30% to 90% of the cases. Re-infected root canal-treated teeth are about nine times more likely to harbor E. faecalis than cases of primary infections.
Netilmicin (1-N-ethylsisomicin) is a semisynthetic aminoglycoside antibiotic, and a derivative of sisomicin, produced by Micromonospora inyoensis. Aminoglycoside antibiotics have the ability to kill a wide variety of bacteria. Netilmicin is not absorbed from the gut and is therefore only given by injection or infusion. It is only used in the treatment of serious infections particularly those resistant to gentamicin.
Hygromycin B is an antibiotic produced by the bacterium Streptomyces hygroscopicus. It is an aminoglycoside that kills bacteria, fungi and higher eukaryotic cells by inhibiting protein synthesis.
Aminoglycoside-3'-phosphotransferase, also known as aminoglycoside kinase, is an enzyme that primarily catalyzes the addition of phosphate from ATP to the 3'-hydroxyl group of a 4,6-disubstituted aminoglycoside, such as kanamycin. However, APH(3') has also been found to phosphorylate at the 5'-hydroxyl group in 4,5-disubstituted aminoglycosides, which lack a 3'-hydroxyl group, and to diphosphorylate hydroxyl groups in aminoglycosides that have both 3'- and 5'-hydroxyl groups. Primarily positively charged at biological conditions, aminoglycosides bind to the negatively charged backbone of nucleic acids to disrupt protein synthesis, effectively inhibiting bacterial cell growth. APH(3') mediated phosphorylation of aminoglycosides effectively disrupts their mechanism of action, introducing a phosphate group that reduces their binding affinity due to steric hindrances and unfavorable electrostatic interactions. APH(3') is primarily found in certain species of gram-positive bacteria.
Sisomicin, is an aminoglycoside antibiotic, isolated from the fermentation broth of Micromonospora inositola. It is a newer broad-spectrum aminoglycoside most structurally related to gentamicin.
16S rRNA (guanine1405-N7)-methyltransferase (EC 2.1.1.179, methyltransferase Sgm, m7G1405 Mtase, Sgm Mtase, Sgm, sisomicin-gentamicin methyltransferase, sisomicin-gentamicin methylase, GrmA, RmtB, RmtC, ArmA) is an enzyme with systematic name S-adenosyl-L-methionine:16S rRNA (guanine1405-N7)-methyltransferase. This enzyme catalyses the following chemical reaction
Nourseothricin (NTC) is a member of the streptothricin-class of aminoglycoside antibiotics produced by Streptomyces species. Chemically, NTC is a mixture of the related compounds streptothricin C, D, E, and F. NTC inhibits protein synthesis by inducing miscoding. It is used as a selection marker for a wide range of organisms including bacteria, yeast, filamentous fungi, and plant cells. It is not known to have adverse side-effects on positively selected cells, a property cardinal to a selection drug.
Hygromycin A is a modified cinnamic acid flanked by a furanose sugar and aminocyclitol. It is produced by Streptomyces hygroscopicus, first described in the 1950s.
Selectivity factor is a quantifiable measure of how efficient an antibiotic is during the process of gene selection. It measures of the capacity an antibiotic to select for transfected (resistant) cells that contain a selectable marker, while killing untransfected (sensitive) cells that do not contain a selectable marker. A selectivity factor higher than 10 is optimal. This means the concentration of antibiotic is sufficient to kill untransfected cells but not toxic enough to kill transfected cells. A selectivity factor lower than 10 means the concentration of antibiotic needed for selection is too close to the toxic concentration for the transfected cells. As a result, fewer transfected cells survive and more untransfected cells survive. In this case an alternative antibiotic should be considered.
