Enterococcus spp are gram-positive cocci that are part of the commensal intestinal microbiota but can also be opportunistic pathogens. Some strains have the capacity to adhere to the mucosal surface of the intestinal villi and have been associated with diarrhea in suckling piglets. Disease is typically confirmed via a combination of lesion assessment and cultural confirmation.
Etiology and Pathogenesis of Enterococcus spp Enteritis in Pigs
The three species most commonly associated with enterococcal diarrhea in piglets are Enterococcus durans, E hirae, and E villorum. A study of the microbiota in neonatal piglets has demonstrated significant increases in the abundance of Enterococcus spp in the intestines of neonatal piglets with diarrhea versus healthy piglets (1). However, the pathogenesis of enteric disease associated with adherent enterococci is unclear, because diarrhea is not associated with enterotoxin production or substantial mucosal injury.
Clinical Findings of Enterococcus spp Enteritis in Pigs
Piglets with Enterococcus spp enteritis develop acute watery to creamy diarrhea. Postmortem examination typically shows a full stomach containing large amounts of milk curd, and the intestines appear dilated and fluid-filled. Microscopically, intestinal villi have many adhered cocci, often in pairs, along the apical surface of enterocytes in the jejunum and ileum. Gram staining will confirm that the attached bacteria are gram-positive.
Diagnosis of Enterococcus spp Enteritis in Pigs
Diagnosis of Enterococcus spp enteritis requires a combination of clinical signs, characteristic microscopic lesions showing adherent cocci, and bacterial culture results.
Treatment and Control of Enterococcus spp Enteritis in Pigs
Antimicrobial susceptibility testing should be performed before choosing an antimicrobial because enterococci are often resistant to common antimicrobial agents. Farrowing house sanitation is important to prevent the spread of Enterococcus spp enteritis, as well as other causes of neonatal diarrhea, among litters.
Key Points
Enterococcus spp are part of the commensal microbiota, but some members of the genus are potential pathogens in suckling pigs.
E durans, E hirae, and E villorum are the most common species implicated in neonatal piglet diarrhea.
Because clinical signs overlap with other causes of neonatal diarrhea, culture and histological evaluation are required to confirm a diagnosis.
For More Information
Cheon DS, Chae C. Outbreak of diarrhea associated with Enterococcus durans in piglets. J Vet Diagn Invest. 1996;8(1):123-124.
Jang S, Shin S, Kim SH, Kim H, Moon C. Diagnosis of Enterococcus hirae infection in association with piglet diarrhea. J Biomed Transl Res. 2019;20(4):115-120.
Vancanneyt M, Snauwaert C, Cleenwerck I, et al. Enterococcus villorum sp. nov., an enteroadherent bacterium associated with diarrhoea in piglets. Int J Syst Evol Microbiol. 2001;51(pt 2):393-400.
References
Gryaznova MV, Dvoretskaya YD, Syromyatnikov MY, et al. Changes in the microbiome profile in different parts of the intestine in piglets with diarrhea. Animals 2022;12(3):320. doi:10.3390/ani12030320
