Intestinal Emphysema and Gut Bacterial Microbiota Composition

Pneumatosis cystoides intestinalis, or intestinal emphysema, is a condition characterized by the presence of multiple cystic structures within the gut wall and on the serosal surface of the intestine. Intestinal emphysema represents an accidental finding in swine, although it can be clinically relevant in humans. Its etiology is unknown, and many theories have been proposed. Among them, a bacterial etiology is considered the most likely. Therefore, in this study, the V3-V4 region of the 16S rRNA gene was sequenced from 19 swine ileal tracts, 12 with intestinal emphysema and 7 without lesions, to detect a possible bacterial agent. In parallel, prevalence was estimated. Escherichia-Shigella (13.15%), Clostridium_sensu_stricto_1; s__uncultured_bacterium (7.09%), and Fusobacterium; s_uncultured bacterium (6.60%) were the most abundant species identified. No statistically relevant differences were observed between the pathological and physiological groups. Prevalence ranged from 1.25 to 5.12% depending on the batch. Our results suggest that the gut wall bacterial microbiota greatly match the normal gut microbiota, and that the etiological agent of intestinal emphysema may be (1) undetectable due to the chronicity of the lesions, (2) not considered statistically relevant in comparing the two groups (p < 0.05) and likewise in causing lesions, and (3) undetectable due to contamination. Regarding prevalence, the condition is moderately frequent.