Fecal Microflora in Healthy Persons in a Preindustrial Region

Abstract

Procedures for quantitating the fecal microflora of man were described. Special attention was given to criteria for characterizing the culturable aerobic, Micro-aerophilic, and anaerobic bacteria. Three groups of healthy persons were studied: wholly breast—fed infants (2 to 4 month-olds), weanlings (1 to 2 year-olds), and adults. In breast-fed children, bifidobacteria predominate and outnumber by one or several logs all other culturable bacteria. The fecal flora of wholly breast-fed infants is “simpler” and more numerous [10 11 to 10 12 per g (wet weight) of feces than that of the adult 10 2 to 10 11 per g]. In the adult, gram-negative anaerobic bacilli (bacteroides) outnumber all other groups by a factor of 1 log or more. Weanlings receiving an adult-type diet, but still breast-fed, showed a flora intermediate between that of the wholly breast-fed infant and that of the adult, but more similar to the latter. Anaerobes always constitute the predominant component of the culturable flora of children and adults and are always found in large numbers under conditions of health. The aerobes are significantly less numerous, and vary widely in their number and in the frequency with which they appear in feces.

Repertoire of human gut microbes

“…Anaerobes were considered to be the major component of gut microflora [13], however this seems biased as a great majority of studies concentrated their efforts on these specific bacteria [5].I n 1969, Hungate revolutionized the anaerobic culture in developing the roll tube technique [17], thus allowing isolation of extremely oxygen-sensitive (EOS) bacteria. Several species (within genera Bacteroides, Clostridium, Veillonella, Ruminococcus, Eubacterium, Bifidobacterium, Lactobacillus, Fusobacterium, Peptococcus and Peptostreptococcus) were considered to dominate the gut microbiota.…”

“…Several species (within genera Bacteroides, Clostridium, Veillonella, Ruminococcus, Eubacterium, Bifidobacterium, Lactobacillus, Fusobacterium, Peptococcus and Peptostreptococcus) were considered to dominate the gut microbiota. Finally, before molecular tools were incorporated, it was estimated that 400e500 different species composed the gut microflora [13,18], which remained partially characterized due to the technical limitations.…”

Probiotic therapy for gastro‐intestinal allergenic infants

“…Various pathways for early patterns of microbial colonization are enumerated as follows (Millar et al , 2003):enhancement of the mucosal protective barrier;modification of systemic immune response;competitive exclusion of less desirable microbe;protein and carbohydrate degradation;vitamin and butyrate production; andmucosal differentiation.Gut flora changes with age, most markedly by a decline in bifidobacteria population (Reuter, 2001) and the intestinal microbiota consists of a complex and diverse society of both pathogenic and non‐pathogenic bacteria (Fedorak and Madsen, 2004). Mata et al (1969) detected faecal bifidobacteria population in breast‐fed infant at a level of 10 11 , which reduced to 10 10 and 10 9 cells/g, respectively during weanling and adulthood. It has been established that an “optimum balance” in microbial population in our digestive tract is associated with good nutrition and health (Rybka and Kailasapathy, 1995) and any disturbance in the balance between beneficial and potentially harmful bacteria in the intestine may pose initiation of acute or chronic diseases (Manning and Gibson, 2004).…”

Probiotics as functional foods: gut colonization and safety concerns

“…Guemonde et al (2006) identified Bifidobacterium catenulatum and Bifidobacterium longum as the most prevalent group of bifidobacteria, respectively after five days and three weeks of age of infants. Faecal bifidobacteria population (log cfu/ml) elevated with increasing age (ten to 40 days) of infants from 9.19-9.61 to 10.67-11.04 (Ram and Chander, 2000) but reduced to a level of 10.0 and fewer during weanling (Mata et al, 1969) and adulthood (Del Piano et al, 2004), respectively. Typical composition of intestinal flora (Table I), indicated diversity in distribution of aerobic or facultative and anaerobic bacteria in stomach, jejunum, ileum and faeces (Simon and Gorbach, 1984) and is influenced by various factors such as age, nutritional requirements, susceptible to infection, immunological status of the host and the pH, transit time, interactions between flora components, presence and availability of fermentable materials in the gut (Collins and Gibson, 1999).…”