Mycoplasma gallisepticum (MG)

Mycoplasma gallisepticum is a wall-less bacterium belonging to the class Mollicutes and is the most pathogenic avian mycoplasma species (Merck Veterinary Manual, 2023). It primarily affects the respiratory tract of poultry, leading to chronic respiratory disease in chickens and infectious sinusitis in turkeys, which results in significant economic losses in the poultry industry (Ley, 2003). The organism lacks a peptidoglycan cell wall, making it naturally resistant to beta-lactam antibiotics like penicillin (Gautier-Bouchardon, 2018). Instead, therapeutic interventions focus on drugs that target its internal machinery, such as macrolides and tetracyclines that inhibit the 50S and 30S ribosomal subunits, or fluoroquinolones that target DNA gyrase (Nascimento et al., 2005). MG is characterized by its specialized attachment organelle, which facilitates adherence to host epithelial cells and is essential for colonization and pathogenicity (Papazisi et al., 2003). As a whole organism rather than a specific molecular target, it represents a pathogen targeted by various antimicrobial classes to manage infection and reduce transmission (Ley, 2003). Control measures include biosecurity, vaccination, and strategic antimicrobial treatment to manage outbreaks and reduce economic impact (Merck Veterinary Manual, 2023).

Other names

MGPleuropneumonia-like organismPPLOAvian mycoplasmosis agentChronic respiratory disease agent

Inhibition of bacterial protein synthesis by binding to the 50S ribosomal subunit (macrolides, lincosamides, pleuromutilins) or the 30S ribosomal subunit (tetracyclines, aminoglycosides), and inhibition of DNA replication by targeting DNA gyrase and topoisomerase IV (fluoroquinolones) (Gautier-Bouchardon, 2018; Nascimento et al., 2005).