Comparison of oral fluids, environmental swabs, and pooled feces for detection of dysentery-associated Brachyspira spp. in pigs

摘要

Brachyspira spp. are anaerobic spirochetes that colonize the large intestine of many species including humans and swine. There are several recognized species of Brachyspira that colonize pigs, including three species capable of causing swine dysentery(B hyody-senteriae, B hampsonii, and B suanatina) and the agent of porcine intestinal spirochetosis (Bpilosicoli)}1 Brachyspira are classified as strongly and weakly beta-hemolytic, with strongly hemolytic species such as B hyodysenteriae considered more virulent.4 All known agents of swine dysentery (SD) are strongly beta-hemolytic. These bacteria typically colonize the crypts of the colon and cecum, affecting goblet cells and causing an excessive amount of mucus production. This is accomplished by chemotaxis and motility of flagella to penetrate the mucus. The classical sign of SD, muco-hemorrhagic diarrhea, is the result of cytotoxic factors produced by the bacteria that cause necrosis of superficial colonic epithelium and mucus excretion. While multiple factors are likely involved, the hemolysin encoded by the dyA gene has been shown to impact virulence.