Diet and faecal flora in the newborn: nucleotides.

Breast milk contains nucleotide salts that are only present in minimal amounts in modern infant formulas prepared from cows' milk. Nucleotides have been suggested as cofactors for the growth of bifidobacteria in vitro. Bifidobacteria are found to be more numerous in the faeces of breast fed babies compared with those of formula fed babies. Faecal flora were examined at 2 weeks of age in 32 babies who from birth had been fed a whey based formula supplemented with nucleotide monophosphate salts, 33 babies fed an unsupplemented formula, and 21 breast fed babies. Faecal flora were also examined at 4 weeks, and 7 weeks but with fewer babies in each group. Most differences were found at 2 weeks of age when more babies fed the nucleotide supplemented formula were colonised with Escherichia coli and more had E coli as the dominant organism in their faecal flora. Fewer of these babies were colonised with bifidobacteria. The counts of bifidobacteria and enterococci were reduced in the nucleotide supplemented group but bacteroides accounted for a higher percentage of the total flora in this group of babies. Supplementation of a formula with nucleotide salts did not make the faecal flora closer to that of breast fed infants as the growth of bifidobacteria was discouraged. While there may be arguments to support the addition of nucleotides to infant formula the results of this study do not support their addition for the enhancement of bifidobacteria in the faecal flora.     

Diet and faecal flora in the newborn: iron.

The faecal flora of a baby receiving a modern infant formula is substantially different from that of a breast fed baby. This difference is a little less when whey based formulas are used. The addition of bovine lactoferrin has no effect and there is some evidence that the presence of added iron in a formula moved the faecal flora further away from that of a breast fed baby. the iron content of currently used infant formulas is much higher than that of breast milk. The effect of the addition of iron to both whey and casein based formulas on the faecal flora was examined in further detail. Faecal flora were examined at 14 days of age in 33 babies receiving a whey formula fortified with iron, 29 babies receiving a whey formula without iron, 29 babies receiving a casein formula fortified with iron, and 24 babies receiving casein formula without iron. Subsequently fewer babies in each group were examined at week 7, 11, and 15. The addition of iron to both casein and whey formulas discouraged colonisation and growth of staphylococci and bacteroids but encouraged the colonisation and growth of clostridia and enterococci. The type of protein and not the iron content had more effect upon the growth of bifidobacteria; both whey formulas, fortified or not, encouraged the colonisation by bifidobacteria. If an infant formula, for use in the first few months, is to mimic the physiological effects of breast milk, there may be microbiological arguments for not fortifying it with iron. However, large empirical trials would be necessary before advocating such a policy.     

Diet and faecal flora in the newborn: casein and whey proteins.

Despite the extensive modifications of cows'' milk to make an infant formula resemble human breast milk, we showed in a previous study that the faecal flora of breast fed babies still differs substantially from that of formula fed babies. This paper describes the effects that differences in the distribution of whey proteins and caseins exert on the faecal flora. Faecal flora was examined in 33 babies receiving a whey formula, 29 babies receiving a casein formula, and 38 breast fed babies. Subsequently fewer babies in each group were studied at weeks 7, 11, and 15. More whey fed babies were colonised with bifidobacteria at 14 days compared with the casein fed group, more casein fed babies were colonised with bacteroides (at 14 days), and more had a dominant growth of enterococci (at week 7). It seems therefore that during the first two months that the whey predominant formula induced a faecal flora generally closer to that of breast fed babies than did a casein formula.     

Diet and faecal flora in the newborn: breast milk and infant formula.

This study examined the faecal flora on days 4, 14, and 28 of 17 breast fed babies and 26 bottle fed babies receiving a modern infant formula based on demineralized whey. Generally among breast fed babies bifidobacteria and staphylococci were the predominant organisms, whereas in the formula fed babies the predominant organisms were enterococci, coliforms, and clostridia. Despite the extensive modification of cows'' milk to make an infant formula resemble human breast milk, the results are very similar to those previously reported with unmodified cows'' milk baby feeds. The exact dietary factor responsible for these microbiological differences is unclear and in succeeding papers we have looked at the effects of protein quality, in particular the content of whey proteins, casein, and lactoferrin.     

Supplementation of an adapted formula with bovine lactoferrin: 1. Effect on the infant faecal flora

The development of the infant faecal flora was studied over the first three months of life in infants receiving breast milk, a modern adapted formula and adaptations of this formula. Breast-fed infants developed a flora rich in Bifidobacterium sp. Facultative anaerobes were ubiquitous, but in relatively small numbers within the diet group. Other obligate anaerobes, such as Clostridium sp. and Bacteriodes sp. were rarely isolated. Standard formula produced a flora rich in bifidobacteria, but the growth of facultative organisms was not suppressed by this diet. Clostridium sp. and Bacteroides sp. were more common in this feeding group. After the addition of lactoferrin at 10 mg/100 ml to the formula diet, a flora similar to that of the standard formula-fed babies was achieved. Lactoferrin at 100 mg/100 ml was able to establish a "bifidus flora" in half of the babies given this formula, but only at age three months. Clostridium sp. and Bacteroides sp. were common faecal isolates from babies receiving both the lactoferrin diets.     

Influence of two infant formulas and human milk on the development of the faecal flora in newborn infants

The establishment of the faecal flora of 39 full-term infants fed exclusively on breast milk (n = 20) or with two different modern adapted cow's milk formulas (n = 19) was studied during the first 3 months of life. One formula investigated was based on 100% bovine casein as the protein source whereas the other formula contained bovine milk proteins with a whey/casein ratio of 60:40. A faecal flora rich in bifidobacteria was found in all study groups; the growth of putrefactive bacteria (especially Bacteroides spp.), however, was limited. In formula-fed infants, significantly higher bacterial counts of enterococci and Clostridia were detected compared to breast milk-fed infants. Similarities and differences due to the feeding regimen were particularly reflected in the pattern of the anaerobic bacterial species. Bifidobacterium bifidum, B. infantis and B. breve constituted the majority of the bifidobacterial flora independent of the type of milk feeding. Other bifidobacterial species such as B. longum, B. adolescentis, B. parabifidum and B. pseudo-catenulatum were detected in high numbers and at low frequencies in breastfed infants. The latter three were observed in infants fed the whey/casein formula as well. It seems that infants fed a casein formula develop a faecal flora more like that of breastfed infants concerning Lactobacillus spp. (especially L. fermentum and L. brevis).     

Experimental milk formulae with reduced protein content and desialylated milk proteins: influence on the faecal flora and the growth of term newborn infants

We have assessed the growth, tolerance and the faecal flora composition in healthy infants on different feeding regimens. Four groups of infants were fed exclusively on mother's milk, a standard formula and two experimental formulae. The first experimental formula consisted of a milk with a reduced protein content (1.2 g/100 ml), the second in a formula with the same protein content and with milk proteins desialylated by mild acid hydrolysis. The aim of the study was to test whether lowering the protein content and/or modifying the proteins by desialylation would favour the development of a bifidus flora. A bifidus flora was detected in 60% of breastfed infants at 1 month of life. All formulae employed during the study failed to induce a prevalence of colonization with bifidobacteria at 1 month of age. The two experimental milk formulae were well tolerated, but the infant growth rate was slightly lower as compared to the breastfed infants and the infants fed the standard formula. The presence in milk formulae of pre-digested and desialylated proteins can offer some advantages in term of digestibility and mimic a physiological intestinal mechanism of the infant.     

A simplified method for the evaluation of human faecal flora in clinical practice.

Qualitative and quantitative evaluation of aerobic and anaerobic faecal flora was determined by a new and easy method. 10 microliter of 12 ten-fold dilutions in saline of samples of faeces were plated on the surface of culture media solidified in wells of sterile virology plexiglass plates (diameter 16 mm; 0.5 ml culture media) and incubated at 37 degrees C for 24 h. The same dilutions and the same plexiglass plates were used under anaerobic conditions for analysis of anaerobic flora (under atmosphere of N2 85%, CO2 10%, H2 5%, negative pressure, at 37 degrees C for 48 h). The analysis was performed on 35 healthy breast-fed newborn infants, 1--6 days old. After birth, the meconium in sterile; already at 25 h of life some bacterial species (Lactobacilli, Bifidobacteria, Bacteroides) show the maximal concentration in faeces and do not grow afterwards; other bacterial species (Coliforms, aerobic and anaerobic Streptococci) increase gradually during the first week of life. This method gives the same results as the conventional techniques (i.e. Petri dishes), but in an easier and quicker way; therefore it seems useful in clinical practice.     

High faecal calprotectin concentrations in newborn infants

BACKGROUND: Calprotectin, a major component of soluble cytosolic proteins in human neutrophil granulocytes, is excreted in excess in stools during inflammatory bowel disease in adults and children. Faecal calprotectin concentrations are also higher during the first year of life than in adults. OBJECTIVES: To measure faecal calprotectin concentrations in the neonatal period and define reference values according to the mode of feeding: standard infant formula, prebiotic infant formula (Calisma, Blédina SA, France), or breast feeding.Patients and methods: A prospective study was carried out over three months in 69 full term, healthy newborns with a median gestational age of 39.8 weeks (range 37-41.5) and a birth weight of 3300 g (range 2600-4460). Three groups were formed depending on the mode of feeding: group 1 (n = 18) received a standard infant formula, group 2 (n = 19) the prebiotic infant formula, and group 3 (n = 32) was breast fed. One stool sample was taken from each newborn on day 4 (3-7), and faecal calprotectin analysed using a commercial enzyme linked immunoassay (Calprest, Eurospital, Italy). RESULTS: Faecal calprotectin concentrations (median 167 micro g/g) were higher than reference values in healthy adults. The concentration was below the upper reference limit for adults (50 micro g/g) for three infants only, one fed the standard formula and two fed the prebiotic formula. Concentrations did not differ significantly according to method of feeding. CONCLUSIONS: Compared with healthy adults, newborns have high calprotectin concentrations in the first days of life. There is no obvious influence of the mode of feeding.     

Pro- and pre-biotics administration in preterm infants: colonization and influence on faecal flora

Prolonged administration of probiotic in preterm babies induce a rise of specific IgA and IgM antibodies against probiotic. This fact explains why presence of living germs in stools almost disappeared in spite of continuous administration. However some positive influences were observed: decreased ratio of aerobic/anaerobic. Increased ratio of gram +/gram - germs. Prebiotic administration induces after 28 days a significant increase of faecal bifidobacteria and frequency and consistency of stools were more similar to those observed in subjects fed with human milk.     

Pro- and pre-biotics administration in preterm infants: colonization and influence on faecal flora

Prolonged administration of probiotic in preterm babies induce a rise of specific IgA and IgM antibodies against probiotic. This fact explains why presence of living germs in stools almost disappeared in spite of continuous administration. However some positive influences were observed: decreased ratio of aerobic/anaerobic. Increased ratio of gram +/gram – germs. Prebiotic administration induces after 28 days a significant increase of faecal bifidobacteria and frequency and consistency of stools were more similar to those observed in subjects fed with human milk.     

Protein nutrition, faecal flora and iron metabolism: the role of milk-based formulae

This paper explores the role of milk-based formulae in achieving four aspects of nutritional health in infants and toddlers: in the suckling, to mimic the amino acid metabolism and the faecal flora of a breast-fed baby; in the weanling, to achieve adequate protein intakes in later infancy and beyond and to achieve satisfactory haemoglobin concentrations in the early toddler years. Milk-based formulae have two roles in infant nutrition: as so-called breast milk substitutes and as a safety net during the weaning period; the latter role may be the more important.     

Sorrento studies of diet and fecal flora in the newborn

The fecal flora of a breast-fed baby is very different from that of a bottle-fed baby. This paper reviews five previous studies, performed at this hospital concerning the effect of various dietary components (whey proteins, casein, lactoferrin, iron, nucleotides) on the fecal flora. The babies received either breast milk or one of the test formulas from birth. Fecal samples were examined by quantitative microbiological methods at 4 and 14 days and at various intervals thereafter. By 14 days differences in the fecal flora were established. Among breast-fed babies bifidobacteria, lactobacilli and staphylococci were predominant organisms, whereas in the formula-fed babies the predominant organisms were enterococci, coliforms, and Bacteroides. A whey-based formula without bovine lactoferrin, iron or nucleotides gave a flora a little closer to but still remote from the breast-fed one. Despite extensive modification of cow's milk in the manufacture of a modern infant formula, the fecal flora of bottle-fed babies remains substantially different from that of breast-fed babies.     

Effect of diet and bacteria on the faecal amino acid pattern in the newborn

Serial changes in the amino acid pattern given by meconium and faeces from normal babies and a baby kept in a sterile environment were studied. The effect of diet and bacteria on the amino acid pattern are discussed.Two substances, tentatively identified as lactose-lysine and glucose-lysine, are thought to be derived from processed milks.     

Aerobic and anaerobic bacterial flora of the maternal cervix and newborn gastric fluid and conjunctiva: a prospective study.

Aerobic and anaerobic cultures were performed on cervical swabs from 35 mothers and their newborn infants' gastric aspirates and conjunctival sacs. Four hundred seventy-nine isolates were obtained; 287 were aerobes and 192 were anaerobes. The cervical and gastric cultures overall yielded a similar flora, but this was not always the case when one compared mothers with their own newborn infants. The conjunctival cultures yielded about half of the number of bacteria per specimen that the gastric contents yielded, and a repeat conjunctival culture done 48 hours later showed a marked reduction in the number of potentially pathogenic bacteria isolated. The predominant aerobes isolated were Staphylococcus epidermidis, diphtheroids, viridans streptococci and Haemophilus vaginalis. The predominant anaerobes were the Bacteroides fragilis group, Propionibacterium acnes, Peptococcus, other Bacteroides and Peptostreptococcus organisms. Statistical analysis revealed significant positive correlation between the isolation of certain groups of organisms and increased duration of pregnancy, increased baby's weight, and prolonged duration of labor.     

Effects of a new mixture of prebiotics on faecal flora and stools in term infants

A double-blind, randomized, controlled study was performed in 90 full term infants to evaluate dose-related bifidogenic effects of a new synergistic mixture of galacto-oligosaccharides (GOS) and fructo-oligosacharides (FOS). The GOS/FOS mixture showed a dose-dependent stimulatory effect on the intestinal growth of bifidobacteria. Also stool consistency and faecal pH were positively affected.     

Effects of a new mixture of prebiotics on faecal flora and stools in term infants

A double-blind, randomized, controlled study was performed in 90 full term infants to evaluate dose-related bifidogenic effects of a new synergistic mixture of galacto-oligosaccharides (GOS) and fructo-oligosacharides (FOS). The GOS/FOS mixture showed a dose-dependent stimulatory effect on the intestinal growth of bifidobacteria. Also stool consistency and faecal pH were positively affected.