Bifidobacterium longum subsp. infantis 157F

Bifidobacterium longum is an anaerobic, non-halophilic, Gram-positive bacterium that is commonly found in the intestines of humans and most animals and insects. They were first isolated and described over one hundred years ago from human feces and were quickly associated with a healthy gastrointestinal tract (GIT) due to their numerical dominance in breast fed infants compared to bottle fed infants. In the neonate their numerical advantage confers a substantial health benefit by hindering pathogen colonization through competitive exclusion. It is important for establishing and maintaining homeostasis of the intestinal ecosystem to allow for normal digestion. B. longum is characterized by a unique hexose metabolism that occurs via a phosphoketolase pathway often termed the bifid shunt. Fructose-6-phosphate phosphoketolase (F6PPK) is a key enzyme of the bifid shunt and its presence is the most common diagnostic test for this genus, as it is not present in other Gram-positive intestinal bacteria. B. longum is often the dominant species detected in humans and is the only species to regularly harbor plasmids. It is a leading member of the probiotic bacteria due to numerous studies that have provided a growing body of evidence for its role in a myriad of potential health benefits. These include diarrhea prevention in antibiotic treated patients, cholesterol reduction, alleviation of lactose intolerance symptoms, immune stimulation and cancer prevention. The stabilizing effect on GIT microflora is attributed to the capacity of bifidobacterium to produce bacteriocins, which are bacteriostatic agents with a broad spectrum of action, and to their pH-reducing activity. Selection of suitable strains for probiotic purposes is very difficult as inherent characteristics of strains of B. longum that are necessary for its survival and competition in the human large intestine are currently very poorly understood. The use of the sequenced genome in microarray analysis reveals pertinent traits that are important to attain dominance in these complex ecosystems. (EBI Integr8)