Tylosin is a

macrolide The Macrolides are a class of natural products that consist of a large macrocyclic lactone ring to which one or more deoxy sugars, usually cladinose and desosamine, may be attached. The lactone rings are usually 14-, 15-, or 16-membered. Ma ...

antibiotic 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 ...

and bacteriostatic feed additive used in veterinary medicine. It has a broad spectrum of activity against

Gram-positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bact ...

organisms and a limited range of

Gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wa ...

organisms. It is found naturally as a fermentation product of ''

Streptomyces fradiae ''Streptomyces fradiae'' is a species of Actinomycetota. Different strains of ''S. fradiae'' are known to produce the antibiotics neomycin, tylosin, and fosfomycin Fosfomycin, sold under the brand name Monurol among others, is an antibiotic p ...

''. Tylosin is used in veterinary medicine to treat bacterial infections in a wide range of species and has a high margin of safety. It has also been used as a growth promotant in some species, and as a treatment for colitis in companion animals.

Mode of action

Like other macrolides, tylosin has a

bacteriostatic A bacteriostatic agent or bacteriostat, abbreviated Bstatic, is a biological or chemical agent that stops bacteria from reproducing, while not necessarily killing them otherwise. Depending on their application, bacteriostatic antibiotics, disinfect ...

effect on susceptible organisms, caused by inhibition of protein synthesis through binding to the 50S subunit of the bacterial

ribosome Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to fo ...

Spectrum of activity

Tylosin has a wide spectrum of activity against Gram-positive bacteria including ''

Staphylococcus ''Staphylococcus'' is a genus of Gram-positive bacteria in the family Staphylococcaceae from the order Bacillales. Under the microscope, they appear spherical ( cocci), and form in grape-like clusters. ''Staphylococcus'' species are faculta ...

'', '' Streptococcus'', ''

Corynebacterium ''Corynebacterium'' () is a genus of Gram-positive bacteria and most are aerobic. They are bacilli (rod-shaped), and in some phases of life they are, more specifically, club-shaped, which inspired the genus name ('' coryneform'' means "club- ...

'', and ''

Erysipelothrix ''Erysipelothrix'' is a genus of bacteria containing four described species, ''Erysipelothrix rhusiopathiae'', ''Erysipelothrix tonsillarum'', ''Erysipelothrix inopinata'' and ''Erysipelothrix larvae''.Verbarg, S., et al. (2004)''Erysipelothrix ...

''. It has a much narrower Gram-negative spectrum of activity, but has been shown to be active against ''

Campylobacter coli ''Campylobacter coli'' is a Gram-negative, microaerophilic, non-endospore-forming, S-shaped bacterial species within genus ''Campylobacter''. In humans, it ''C. coli'' can cause campylobacteriosis, a diarrhoeal disease which is the most freque ...

'', and certain

spirochaete A spirochaete () or spirochete is a member of the phylum Spirochaetota (), (synonym Spirochaetes) which contains distinctive diderm (double-membrane) gram-negative bacteria, most of which have long, helically coiled (corkscrew-shaped or s ...

s.Tylosin
drugs.com It has also been shown to be extremely active against ''Mycoplasma'' species isolated from both mammalian and avian hosts. The following represents MIC susceptibility data for a few medically significant pathogens: * ''Mycoplasma bovis'': 0.06 - 4 μg/ml * ''Staphylococcus aureus'': 0.5 - >128 μg/ml

Clinical use

Tylosin has been used to treat a variety of different diseases throughout the world. Differing formulations and licensing conditions mean it may not be a recognized method of treatment for certain conditions in certain countries. In general, tylosin is licensed for the treatment of infections caused by organisms susceptible to the drug, but it has also been used as a treatment of

colitis Colitis is swelling or inflammation of the large intestine ( colon). Colitis may be acute and self-limited or long-term. It broadly fits into the category of digestive diseases. In a medical context, the label ''colitis'' (without qualification ...

in small animals, as a growth promotant in food-producing animals, and as a way of reducing epiphora (tear staining) around the eyes of white-faced dogs. In these cases, the result is positive only when using the tylosin in the form of tartrate, a chelating porphyrin. No marketing authority exists for the use of other tylosin forms as a tear-stain remover, thus it is not legal to use it for such purposes; the exception is as a prescription-only medicine of last resort by veterinarians under the cascading rule (UK) or the extra-label use rule (US). Examples of bacterial infections that could potentially be treated with tylosin include respiratory infections, metritis, and acute

mastitis Mastitis is inflammation of the breast or udder, usually associated with breastfeeding. Symptoms typically include local pain and redness. There is often an associated fever and general soreness. Onset is typically fairly rapid and usually occurs ...

in cattle; mastitis in sheep and goats;

enteritis Enteritis is inflammation of the small intestine. It is most commonly caused by food or drink contaminated with pathogenic microbes,Dugdale, David C., IIII, and George F Longretc"Enteritis" MedlinePlus Medical Encyclopedia, 18 October 2008. Access ...

pneumonia Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severit ...

erysipelas Erysipelas () is a relatively common bacterial infection of the superficial layer of the skin ( upper dermis), extending to the superficial lymphatic vessels within the skin, characterized by a raised, well-defined, tender, bright red rash, ...

, and infectious

arthritis Arthritis is a term often used to mean any disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, swelling, and decreased range of motion of the affected joints. In som ...

in swine; and soft-tissue infections in small animals. While tylosin may be one appropriate therapeutic choice in theory for the conditions listed above, many other antibiotics may be preferable for treating a specific infection, and tylosin will not be the first choice. It is also used as a growth promoter for a variety of terrestrial and aquatic animals grown for human consumption.

Available forms

Tylosin is available in injectable, intramammary, and oral formulations with different product ranges available in different countries.

Composition

Tylosin is a mixture of four major components: tylosins A, B, C, and D. Tylosin A is considered the major component of tylosin (comprises about 90% of tylosin); however, tylosins B, C, and D contribute to the overall potency of tylosin.

Precautions and contraindications

Administration of tylosin should be avoided in animals with a known hypersensitivity to the product, or to other macrolides. Oral administration can result in diarrhoea and gastrointestinal disturbance. This is particularly true of horses, such that it can be fatal. Tylosin also has a foul taste that is difficult to disguise. The injectable formulations of tylosin can cause pain, inflammation, and itchiness around the injection site. Since tylosin has a relatively poor spectrum of activity against Gram-negative organisms, it may not be a sensible therapeutic choice in the treatment of infections caused by unknown, potentially unsusceptible organisms.

Drug interactions

Tylosin may increase digitalis blood levels, thus its toxicity, and may be antagonistic to

chloramphenicol Chloramphenicol is an antibiotic useful for the treatment of a number of bacterial infections. This includes use as an eye ointment to treat conjunctivitis. By mouth or by injection into a vein, it is used to treat meningitis, plague, chole ...

lincosamide Lincosamides are a class of antibiotics, which include lincomycin, clindamycin, and pirlimycin. Structure Lincosamides consist of a pyrrolidine ring linked to a pyranose moiety (methylthio-lincosamide) via an amide bond. Hydrolysis of lincosam ...

s. Colorimetric assays of serum ALT and AST may be falsely elevated by macrolide antibiotics.

References

Tylosin (Tylan)
{{Protein synthesis inhibitor antibiotics Macrolide antibiotics Veterinary drugs