Efficacy of tiamulin alone or in combination with chlortetracycline against experimental Mycoplasma gallisepticum infection in chickens

Abstract

Mycoplasma gallisepticum (M. gallisepticum) remains one of the most important diseases in poultry production. Controlling the impact of the disease is done by eradication of positive breeder flocks or by vaccination and medication. A widely used molecule in medication programs is tiamulin, a pleuromutilin antibiotic. Since recent data on the in vivo efficacy of this molecule are scarce, 2 challenge studies were conducted using a recently isolated M. gallisepticum strain belonging to the wildtype population with regard to its tiamulin and tetracycline minimum inhibitory concentration (MIC). In the first challenge study, the dose rate of tiamulin was tested. For this, broilers were infected with M. gallisepticum and treated with 10 mg or 25 mg tiamulin hydrogen fumarate (hf)/kg body weight (BW) for 5 successive days. In a second challenge study, the dose rate of tiamulin combined with chlortetracycline was tested. For this, broilers were infected with M. gallisepticum and treated with 6.25 mg tiamulin hf/18.75 mg chlortetracycline hydrochloride (hcl)/kg BW or 12.5 mg tiamulin hf/37.5 mg chlortetracycline hcl/kg BW for 5 successive days. Clinical scoring of respiratory signs, macroscopic scoring of respiratory tract lesions, M. gallisepticum isolation from the respiratory organs, weight gain, and mortality were the monitored efficacy parameters. The first study demonstrated that a 5-day 10 mg/kg BW tiamulin hf treatment provided significant protection against the M. gallisepticum infection. However, since the 5-day 25 mg/kg BW group was significantly better than the 10 mg/kg BW for reducing the post-treatment clinical signs and the M. gallisepticum numbers in the respiratory organs, the 25 mg/kg BW treatment is recommended for clinical M. gallisepticum infections. In the second study, the combined 12.5 mg tiamulin hf/37.5 mg chlortetracycline hcl/kg BW resulted in a significant reduction of the severity of clinical respiratory disease post treatment and a significant reduction of the M. gallisepticum numbers in the respiratory tract.

Synthesis, biological activities and docking studies of pleuromutilin derivatives with piperazinyl urea linkage

“…Four semi-synthesised marketed drugs based on its structure have already been developed. Tiamulin and valnemulin ( Figure 1, 2 and 3) can effectively prevent and control swine dysentery, mycoplasmal diseases such as enzootic pneumonia and chronic respiratory disease in poultry 10,11 . Retapamulin (Figure 1, 4) is used for the treatment of skin impetigo 12,13 .…”

A mini-review on antimycoplasma antibiotics

“…Valnemulin was found to be active against M. hyopneumoniae (Hanan et al 1997). Tiamulin @ 10-25mg/kg has been used in poultry against Mycoplasma gallisepticum infection and resulted in a significant reduction in the severity of clinical respiratory disease post-treatment (Garmyn et al 2017). Lefamulin is the first semisynthetic pleuromutilin antibiotic and is highly active against multidrug-resistant mycoplasma genitilium strains (Jensen et al 2017).…”

Antimicrobial prescribing guidelines for poultry

“…With the exception of avilamycin, the antimicrobial agents listed in Appendix 2 with antibacterial indications (amoxicillin, apramycin, bacitracin, chlortetracycline, erythromycin, flavophospholipol, lincomycin, neomycin, oxytetracycline, spectinomycin, sulfadiazine, sulfadimidine, tiamulin, trimethoprim, tylosin, virginiamycin) were available for use in poultry in Australia in 1989. Because of the age of the antimicrobial agents available for use and their availability in most cases from a range of generic sources, there has been very little recent investigation of their pharmacology or efficacy, or optimal dosage regimens [57][58][59][60][61][62][63][64][65][66][67][68][69][70] for these agents.…”