A sensitive assay based on amplification of a 319-bp DNA fragment of the intracellular bacterium of swine proliferative enteritis was developed for the detection of the organism in the feces of swine. A vernacular name, ileal symbiont intracellularis (IS-intraceliularis), has recently been published for the intracellular bacterium, which was formerly known as a Campylobacter-like organism (C.

The name "Campylobacter hyointestinalis" sp. nov. is proposed for a Campylobacter species that was isolated from the intestines of pigs with proliferative enteritis. "C. hyointestinalis" is also found in the feces of cattle and has been isolated from the intestine of a hamster. "C. hyointestinalis" is distinguished from previously described catalase-positive Campylobacter species by colony morphology, ability to produce H2S in triple sugar iron agar, ability to grow anaerobically in 0.1% trimethylamine N-oxide hydrochloride, resistance to nalidixic acid, susceptibility to cephalothin and metronidazole, and hydrogenase activity. Sixteen "C. hyointestinalis" strains were highly related (.76%) by DNA-DNA hybridization (hydroxyapatite method, 50 and 65°C). Other Campylobacter species were <30% related to "C. hyointestinalis." The type strain of "C. hyointestinalis" is designated 80-4577-4 (=ATCC 35217), and its DNA has a guanine-plus-cytosine content of 36 mol%.

In a retrospective morphological and microbiological study, 39 of 55 cases of bovine fibrinous pneumonia were diagnosed as fibrinous pleuropneumonia. Twenty-nine of these 39 (74%) were associated with Pasteurella hemolytica, but only two cases (5%) with P. multocida. In contrast, of the 16 cases classified as fibrinous bronchopneumonia, one (6%) was associated with P. hemolytica, and nine (56%) with P. multocida. In eight cases Mycoplasma and Hemophilus somnus were found in association with either P. hemolytica or P. multocida but were never isolated alone. We concluded that the use of the term pasteurellosis, implying Pasteurella as the cause, is imprecise because lesions associated with P. hemolytica fulfill the criteria of a fibrinous pleuropneumonia, whereas P. multocida is more likely to cause a bronchopneumonia with moderate amounts of fibrin.

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