Anaerobe
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Human Clostridium difficile-associated disease (CDAD) is of unquestioned importance in humans, and has been a not-uncommon cause of enteric disease in horses, dogs, and ratites. Over the past 5 years, C. difficile has emerged as a major cause of neonatal enteritis in pigs. Piglets 1-7 days of age are affected, with gross lesions frequently including mesocolonic edema. ⋯ Focal suppuration and segmental necrosis are seen on microscopic examination of cecal and colonic lamina propria, and exudation of neutrophils and fibrin into the lumen gives rise to the so-called volcano lesions. Results of one study revealed that more than one-third of piglets with enteritis were affected by C. difficile alone, while an additional quarter of affected piglets may have had mixed infections. C. difficile may be the most important uncontrolled cause of neonatal diarrhea in pigs.
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Colonic spirochetosis of colony-raised rhesus macaques associated with Brachyspira and Helicobacter.
Colonic spirochetosis is an inflammatory bowel disease that affects a broad range of hosts, including human and non-human primates. The disease in humans and non-human primates is characterized by intimate attachment of the anaerobic spirochetes Brachyspira aalborgi and B. pilosicoli, and some unclassified flagellated microbes along the apical membrane of colonic enterocytes. Although the presence of spiral-shaped bacteria with single polar flagella and blunted ends in colonic spirochetosis is well established, the identities of many of these organisms is still unknown. ⋯ The presence of flagellated bacteria alone (n=2) or together with spirochetes (n=1) in formalin-fixed and paraffin-embedded colons of three rhesus macaques with the naturally occurring disease was demonstrated by immunohistochemical staining and ultrastructural examination. Total DNA extracted from affected and control intestinal specimens was amplified by polymerase chain reaction (PCR) using Helicobacter 16S rRNA gene-specific primers. Comparative nucleotide sequence analysis of PCR products cloned from positive reactions indicated that two distinct Helicobacter genomospecies were present either alone or in combination with Brachyspira in the colons of rhesus macaques with microscopic lesions indicative of colonic spirochetosis.