Genetic Diversity and Emerging Trends of Mycoplasma synoviae in China: Insights from a 2024 Nationwide MLST Study

TL;DR

A nationwide study in China reveals the genetic diversity and antibiotic resistance patterns of Mycoplasma synoviae in poultry, offering insights for disease control.

Contribution

The study provides a comprehensive MLST-based analysis of Mycoplasma synoviae strains in China, revealing new genetic diversity and antimicrobial resistance data.

Findings

13 distinct sequence types of Mycoplasma synoviae were identified across 15 Chinese provinces.

Antimicrobial susceptibility testing revealed resistance patterns in 18 isolates against 10 antibiotics.

Infected chickens showed synovitis but no respiratory symptoms, indicating varied pathogenicity.

Abstract

Mycoplasma synoviae (MS) is a major pathogen threatening China’s poultry industry, causing severe economic losses, and clarifying its epidemiology is pivotal for disease control and flock purification. In this study, a total of 3215 chicken samples collected from 643 broiler farms across 15 provinces in China in 2024 were analyzed. PCR detected 14% positivity (450 samples), and 18 isolates obtained from these positive samples (4.0% isolation rate). Multilocus sequence typing (MLST, 7 housekeeping genes) and neighbor-joining phylogenetic analysis (integrating 425 reference sequences from public databases) identified 13 distinct sequence types (STs), demonstrating considerable genetic diversity among circulating MS strains. Pathogenicity assessment of the five isolates revealed that the infected chickens exhibited varying degrees of infectious synovitis, while no respiratory signs were observed. In addition, antimicrobial susceptibility testing against 10 commonly used antibiotics was conducted on the 18 strains, providing urgently needed guidance for rational drug use in the clinical treatment of both breeder and broiler flocks. This large-scale epidemiological study yields crucial insights into the current prevalence and genetic diversity of MS in China and lays a scientific foundation for formulating targeted prevention strategies and optimizing management practices.

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