Pleuromutilins

 Description:

Tiamulin is a semi-synthetic derivatives of pleuromutilin. Pleuromutilins are antibacterial agents that inhibit protein synthesis. They are active against Gram-positive bacteria such as streptococci and staphylococci, anaerobic bacteria and mycoplasmata.

Pleuromutilins act by inhibiting protein synthesis by binding to the 50S subunit of the bacterial ribosome. They are strong inhibitors of peptidyl transferase.

Tiamulin is authorized for chickens for the treatment and prevention of chronic respiratory disease and airsacculitis caused by Mycoplasma gallisepticum and Mycoplasma synoviae; for turkeys for the treatment and prevention of infectious sinusitis and air-sacculitis caused by M. gallisepticum, Mycoplasma meleagridis and M. synoviae. Tiamulin has also been shown to be highly active against Ornithobacterium ehinotracheale.

Animals and birds should not receive products containing monensin, narasin or salinomycin, during or for at least seven days before or after treatment. Severe growth depression or death may result. There is a strong interaction, even death, with the ionophore anticoccidials monensin, narasin and salinomycin when tiamulin is used at therapeutic levels, but this is dose-related and low doses do not interact. Tiamulin shows a milder interaction, such as temporary growth depression, with maduramicin and semduramicin but is compatible with lasalocid.

Chickens: 2 days
Turkeys: 5 days
Ducks: 6 days

Resistance derives from chromosomal mutations in the 23S rRNA and rplC genes. These chromosomal mutations emerge relatively slowly and in a stepwise fashion and are not transferred horizontally.  Resistance genes can be located on plasmids or transposons like the vga genes and the cfr gene. This type of resistance is transferable between bacteria and bacterial species. The mechanism of antimicrobial resistance varies according to the bacterial species investigated.

Tiamulin shows a milder interaction, such as temporary growth depression, with maduramicin and semduramicin but is compatible with lasalocid.
Combined administration of tiamulin and monensin may lead to intoxication manifested in severe clinical symptoms. Tiamulin metabolite complex with cytochrome P450 has been suggested to be the basis of drug-interactions. The clinical signs, pathological and biochemical changes caused by the simultaneous application of both compounds resembled to those induced by monensin alone in high doses indicating the causative role of the ionophore or its metabolite(s) in the toxic interaction.
Tiamulin shows a milder interaction, such as temporary growth depression, with maduramicin and semduramicin but is compatible with lasalocid.

Tiamulin may be used in laying and breeding birds as it has been shown to have no adverse effects on egg production, fertility and hatchability in chickens and turkeys.