Hi John and Shauna,

A quick look at Wikipedia under 'gut flora' will show that we can't live with out our gut flora.
"The metabolic activities performed by these bacteria resemble those of an organ, leading some to liken gut bacteria to a 'forgotten' organ"

I doubt those transgenic mice kept in a germ free environment and lacking gut flora would last long.
For a person whose gut lining is functioning normally the immune system is in effect blind to the existence of the hundreds of different species in the gut. It's only in a condition like AS where gut mucosal lining integrity is compromised (and the patient has a number of predisposing genetic factors like HLA B27 IL 23R ERAP1 KIR and others) that the immune system is triggered to look at a commensal bacteria like Klebsiella (assuming they are the driver of AS) and mount a dysregulated immunological cascade culminating in an inflammatory disease.

Cheers David

Dx Oct 2006 B27+ undifferentiated spondlyarthropathy (uSpA) with mild sebhorrhoeic dermatitis and mild Inflammatory Bowel Disease (IBD) controlled by NSD since 2007.