Excrements revealing the bacterial flore in the human intestinal tract.
If it comes to digestion, we are not alone! Among many more bacterial forms streptococci, staphylococci, enterococci, enterobacteria, mycobacteria, spirochetes, mycoplasma, corynebacteria, clostridia, or lactobacilli are living in our gastro-intestinal tract and usually help us to digest food, aid nutrient absorption, reduce dehydration or assist in the production of key vitamins. In adults, the bacterial flore makes up about five percent of the total body weight (similarlly to the brain). Altogether, more than 30’000 different species of bacteria have been classified in our intestinal tract, so far! However, it’s a fragile ecosystem. The bacterial flore is sensitive to stress, unhealthy food, alcohol or illness.
Under unfavorable circumstances it directly affects our health and e.g. causes overweight, changes our mood or makes us prone to various diseases. The small intestine normally contains relatively low numbers of bacteria compared to the large intestine. If abnormally large numbers of bacteria grow in the small intestine, they may use many of the nutrients that a person would normally absorb for their growth. Too much growth and breakdown of nutrients can damage the cells of the small intestinal wall, leading to Crohn’s disease, diabetes, scleroderma and severely influence the progression of AIDS or immunoglobulin deficiency.
This hand-colored scanning electron micrograph reveals the large number and variability of bacteria that are present in human excrements. Additionally, a plant fiber has passed the intestinal tract almost unharmed and spans across the frame (center). On the right hand side (half-cut) a large and spherical shaped structure turns out to be the cyste of a Giardia parasite (brown) – the actual reason why the person went to see a doctor… But apart from the unusual parasitic supplement the bacterial fauna looks fairly well-sorted.