Psychobiotics; A Promise for Neurodevelopmental Therapy

Microbes are ubiquitous as they are found everywhere on the planet. It is therefore not surprising that the human body is made of 90% bacteria cells and only 10% human cells making us a cocktail of human and bacteria cells tightly associated in a mutualistic relationship. These microbes may play very essential roles in the development of the fetus andthat may be why they are present in amniotic fluids, amniotic cord blood, andeven in healthy neonatal meconium. The human gut microbiome (the collection of all the microorganisms living in association with the human gut) consists of three enterotypes namely, Bacteroides (most abundant and most variable genus), Prevotella and Ruminococcus. Over 1500 gut bacteria species are present in the human body with more than 95% of them residing in the gut. 

These bacteria contain over 8 million distinct genes encoding for several enzymes and proteins which influence host metabolism. A balance in the richness of the gut bacteriais therefore required for homeostasis. In various pathological conditions such as chronic anxiety, depression, autism and celiac disease, disease-associated dysbiosis are characterized by an imbalance in the levels, the reciprocal abundance, the presence and/or localization of normal gut bacteria species, rather than an overgrowth of well-defined pathogenic bacteria (as observed in C. difficile infection). Such disease-associated alterations in the microbiome are usually caused by genetic and environmental factors such as drugs, diet, toxins and pathogens.