Abstract
Archanobacterium pyogene (Actinomyces pyogene) is an opportunistic pathogen of economically important livestock such as dairy, beef cattle and gazelles. It is also a common inhabitant of the mucous membranes of these animals. This study was aimed to investigate the epidemiology of A. pyogenes in the infected Arabian gazelles kept at King Khalid Wildlife Research Center at Thumamah, 70 km north of Riyadh, Saudi Arabia and the relationship between symptoms and infection by A. pyogenes. Samples were collected from pleural fluid of 70 infected gazelles and from upper respiratory tract of 30 healthy animals. Enrichment and isolation from the collected samples resulted in 48 bacterial strains, 8 strains from upper respiratory tract of healthy animals and 40 from infected gazelles. Biochemical tests of the 48 isolated bacterial strains revealed that all the strains were beta-hemolytic on blood agar, hydrolyzed gelatin and starch were unable to hydrolyze esculin or reduce nitrate and did not produce urease which was typical characteristics of A. pyogene. Identification of the isolated strains was further confirmed by molecular method using analysis of 16S rDNA.