Arcanobacterium pyogenes: Virulence factors, importance in mastitis etiology and therapeutic (im)possibilities

Abstract

Arcanobacterium pyogenes is an opportunistic pathogen, a causative agent of suppurative infections of organs and tissues in economically important livestock species. Most frequently this bacteria is isolated from inflamed lung lesions in pigs and cattle, in samples of uterine mucus of cows with endometritis and milk from cows with clinical mastitis. A. pyogenes possesses a number of virulence factors: cholesterol-dependent cytolysin (pyolysin), two neuraminidases, several proteases, extracellular matrix-binding proteins, DNases, fimbriae. The virulence factors are well studied in laboratory conditions, but the role of these factors in the pathogenesis of A. pyogenes infections remains to be elucidated. Lately, the ability of A. pyogenes to form biofilm in vivo has also been implicated as a virulence factor and a possible cause of therapeutic failure. Despite the fact that A. pyogenes milk isolates in cows with mastitis in vitro are very sensitive to β-lactam drugs and tetracycline, experience has shown that therapy is usually ineffective, prognosis is poor and the affected quarter is lost for milk production

Selected parameters of immune response in pregnant sows vaccinated against Trueperella pyogenes

“…Moreover, pyolysin activates the complement system, stimulates the production of cytokines, and inhibits oxygen burst and bactericidal activities of neutrophils and monocytes (1,6). T. pyogenes is also able to adhere to the alimentary and respiratory epithelial mucosa of a host.…”

“…They are involved in invasion and destruction of tissues. T. pyogenes escapes from the host immune control and modulation of the immune system during infection and inflammation (3,6). A wide array of T. pyogenes virulence factors results in various disease symptoms, such as subcutaneous, intramuscular, and internal organ abscesses, and inflammatory lesions in the lungs, joints, mammary glands, and central nervous system (1,4,6).…”