INFLAMMATORY BOWEL DISEASE Lactobacillus GG prevents recurrence of colitis in HLA-B27 transgenic rats after antibiotic treatment

rats while broad spectrum antibiotics prevent and treat colitis in specific pathogen free (SPF) TG rats although disease recurs after treatment ends. Lactobacilli treat human pouchitis and experimental coli-tis. We investigated if Lactobacillus rhamnosus GG (L GG) can prevent colitis in TG rats monoassoci-ated with B vulgatus and if L GG or Lactobacillus plantarum 299v (LP 299v) can treat established colitis in SPF TG rats and prevent recurrent disease after antibiotics were stopped. Methods: Germfree B27 TG rats were monoassociated with B vulgatus for four weeks following two weeks of colonisation with L GG or no bacteria. SPF B27 TG rats received oral vancomycin and imi-penem for two weeks, or water alone, followed by four weeks of treatment with oral L GG, LP 299v, or water only. Disease activity was quantified by blinded gross and histological scores, caecal myeloper-oxidase (MPO) activity, and levels of interleukin (IL)-1β, tumour necrosis factor (TNF), transforming growth factor β, and IL-10. Results: L GG did not prevent colitis in B vulgatus co-associated TG rats or treat established disease in SPF rats. However, L GG but not LP 299v prevented colitis relapse in antibiotic treated rats with reduced gross and histological scores, caecal MPO, IL-1β, and TNF whereas caecal IL-10 was increased