Prudent Use of Tylosin for Treatment of Mycoplasma gallisepticum Based on Its Clinical Breakpoint and Lung Microbiota Shift

Abstract

The aim of this study was to explore the prudent use of tylosin for the treatment of chronic respiratory infectious diseases in chickens caused by Mycoplasma gallisepticum (MG) based on its clinical breakpoint (CBP) and its effect on lung microbiota. The CBP was established based on the wild-type/epidemiological cutoff value (COWT/ECV), pharmacokinetics-pharmacodynamics (PK-PD) cutoff value (COPD), and clinical cutoff value (COCL) of tylosin against MG. The minimum inhibitory concentration (MIC) of tylosin against 111 MG isolates was analyzed and the COWT was 2 μg/ml. M17 with MIC of 2 μg/ml was selected as a representative strain for the PK-PD study. The COPD of tylosin against MG was 1 μg/ml. The dosage regimen formulated by the PK-PD study was 3 days administration of tylosin at a dose of 45.88 mg/kg b.w. with a 24-h interval. Five different MIC MGs were selected for clinical trial, and the COCL of tylosin against MG was 0.5 μg/ml. According to the CLSI decision tree, the CBP of tylosin against MG was set up as 2 μg/ml. The effect of tylosin on lung microbiota of MG-infected chickens was analyzed by 16S rRNA gene sequencing. Significant change of the lung microbiota was observed in the infection group and treatment group based on the principal coordinate analysis and the Venn diagrams of the core and unique OTU. The phyla Firmicutes and Proteobacteria showed difference after MG infection and treatment. This study established the CBP of tylosin against MG. It also provided scientific data for the prudent use of tylosin based on the evaluation of MG infection and tylosin treatment on the lung microbiota.

Mycoplasma galliscepticum: An overview

“…However, chickens infected with MG and treated with tylosin not only show effectiveness against MG but also undergo significant changes in lung microbial communities. When treating MG infections, we need to consider not only the effects of tylosin but also its impact on the host's microbial community (Huang et al, 2021).…”

Mycoplasma gallisepticum Infection, A Perpetual Problem

“…It can be transmitted by both horizontal (from infected to healthy birds by infectious aerosols and by the contamination of feed, water etc.) and vertical routes (by poultry eggs from infected breeder yolk to progeny) as shown in Figure 1 (Huang et al, 2021;Marois et al, 2008;Thomas et al, 2008).…”

“…There is a great risk to transfer mycoplasma in a highly-populated poultry area, and it is very difficult to maintain a flock free from infection (Lysnyansky et al, 2005). (Huang et al, 2021;Marois et al, 2008;Thomas et al, 2008) diaGnoses…”

“…Among the major poultry disease, CRD in chicken is the most common respiratory disorder with the causative agent Mycoplasma gallisepticum (MG) and M. synoviae that cause a huge economical loss (Rehman et al, 2018;Shoaib, 2019). MG is the main pathogenic mycoplasma that causes reproductive and respiratory disease in poultry (Huang et al, 2021). Due to its highly aerobic character, MG is chiefly encountered in the upper respiratory tract of poultry birds (Büyüktanir et al, 2008).…”

“…Figure 1: Pathogenesis of Mycoplasma gallisepticum(Huang et al, 2021;Marois et al, 2008;Thomas et al, 2008) …”