Immunoregulatory activity of rifaximin associated with a resistant mutant of Bifidobacterium infantis

Rifaximin is an antibiotic used for the treatment of intestinal disorders owing to its good luminal antibacterial activity [1]. Modern approaches for the treatment of intestinal diseases are aimed at both a reduction in pathogenic bacteria as well as immune modulation to achieve the most durable remission of disease. Probiotic bacteria exert positive effects on enteric diseases, often working through enhancement of the immune system [2,3]. Rifaximin resistance occurs spontaneously in colonic bifidobacteria during antibiotic treatment [4]. Recently, molecular and phenotypic traits of resistant Bifidobacterium mutants have been described [5,6].