Intestinal microbiota in exclusively breast-fed infants with blood-streaked stools

Intestinal microbiota in exclusively breast-fed infants with blood-streaked stools and in healthy exclusively breast-fed babies was compared. Total anaerobes, bifidobacteria, lactobacilli, coliform bacteria, enterococci and clostridia were quantified by cultivation methods in feces of 17 full-term exclusively breastfed patients (aged 16.3 ± 7.4 weeks) with blood-streaked stools and in the control group of 22 healthy fullterm exclusively breast-fed infants (13.7 ± 6.4 weeks). Specific fluorescence in situ hybridization kits for Bifidobacterium spp. were used for the quantitative detection of bifidobacteria in samples. Control samples had significantly (p < 0.05) higher counts of total anaerobes. Bifidobacteria were not detected in patients’ samples in 65 % and in controls in 36 % (p < 0.01). Bifidobacteria counts were also significantly higher in the control group (p < 0.01). Furthermore, clostridia strains were detected only in feces from bifidobacteria-negative infants reaching counts >8 log CFU/g. Lactobacilli were not detected in 65 % patients and in 45 % control samples. However, this difference was not significant as well as the difference in lactobacilli counts. Eosinophilia was observed in 35 % of patients, low IgA concentration in 71 % and also low IgG concentration in 71 %. pANCA positivity was found in 53 % of patients. In conclusion a significant low proportion of bifidobacterial microbiota in patients with blood-streaked stools was shown in comparison with controls.     

A preliminary investigation on the relationship between gut microbiota and gene expressions in peripheral mononuclear cells of infants with autism spectrum disorders

Fecal and blood samples of infants with autism spectrum disorders (ASD) and healthy infants were analyzed to investigate the association of altered gut microbiota and ASD development. 16S rRNA gene-based sequencing found that, unlike those of healthy infants, feces of ASD infants had significantly higher and lower abundance of genera Faecalibacterium and Blautia, respectively. Moreover, DNA microarray analysis of peripheral blood mononuclear cells (PBMC) detected more highly than low expressed genes in ASD infants than in healthy infants. Gene Ontology analysis revealed that differentially expressed genes between ASD and healthy infants were involved in interferon (IFN)-γ and type-I IFN signaling pathways. Finally, strong positive correlations between expression of IFN signaling-associated genes in PBMC and fecal abundance of Faecalibacterium were found. Our results strongly suggested that altered gut microbiota in infants resulted from ASD development and was associated with systemic immunity dysregulation, especially chronic inflammation.     

Microbiota Composition of the Intestinal Mucosa: Association with Fecal Microbiota?

The fecal and mucosal microbiota of infants with rectal bleeding and the fecal microbiota of healthy age-matched controls were investigated by fluorescent in situ hybridization. Bifidobacteria were the main genus in both the feces and mucosa. The other genera tested, Bacteroides, Clostridium, Escherichia coli and lactobacilli/enterococci, represented only minor constituents. No differences in fecal microbiota were observed between patients and controls. In the patients, however, four times greater numbers of bifidobacteria were observed in the feces when compared to the mucosa. Notwithstanding this difference, a strong positive correlation prevailed for bifidobacteria in feces and mucosal samples. The genera assessed accounted for 16% of total bacterial counts on mucosal samples and for 47% of total bacterial counts in feces. This indicates that the unidentified part of the microbiota, especially on the mucosa, deserves more attention.     

Correlation between lactoferrin and beneficial microbiota in breast milk and infant’s feces

Lactoferrin (LF) is a natural component of human milk with antimicrobial, immunostimulatory and immunomodulatory properties. Several in vitro studies suggest that LF could promote an environment in the gut of neonates that favors colonization with beneficial bacteria. However, clinical studies on the correlation between the concentration of LF in breast milk and feces of infants and the gut microbiota in infants are lacking. In our study we analyzed the content of LF and the microbiota of breast milk and feces of infants of 48 mother–infant pairs (34 full-term and 14 pre-term infants) at birth and 30 days after delivery. In the term group, a significant decrease of mean LF concentration between colostrum (7.0 ± 5.1 mg/ml) and mature milk (2.3 ± 0.4 mg/ml) was observed. In pre-term group, breast milk LF levels were similar to those observed in full-term group. Fecal LF concentration of healthy infants was extremely high both in term and pre-term infants, higher than the amount reported in healthy children and adults. In term infants mean fecal LF levels significantly increased from birth (994 ± 1,828 μg/ml) to 1 month of age (3,052 ± 4,323 μg/ml). The amount of LF in the feces of 30 day-old term infants was significantly associated with maternal mature milk LF concentration (p = 0.030) confirming that breast milk represents the main source of LF found in the gut of infants. A linear positive correlation between colostrum and mature milk LF concentration was observed (p = 0.008) indicating that milk LF levels reflect individual characteristics. In pre-term infants higher mean concentrations of fecal LF at birth (1,631 ± 2,206 μg/ml) and 30 days after delivery (7,633 ± 9,960 μg/ml) were observed in comparison to full-term infants. The amount of fecal bifidobacteria and lactobacilli resulted associated with the concentration of fecal LF 3 days after delivery (p = 0.017 and p = 0.026, respectively). These results suggest that high levels of fecal LF in neonates, particularly in the first days of life, could represent an important factor in the initiation, development and/or composition of the neonatal gut microbiota. Since early host–microbe interaction is a crucial component of healthy immune and metabolic programming, high levels of fecal LF in neonates may beneficially contribute to the immunologic maturation and well-being of the newborn, especially in pre-term infants.     

Breast milk contains probiotics with anti-infantile diarrhoea effects that may protect infants as they change to solid foods

Infants often experience complementary food-induced diarrhoea (CFID), which occurs when infants switch from breast milk to solid foods. The relative abundances of Prevotella and Rothia were higher in stools of infants with CFID, while the relative abundances of Enterococcus and Escherichia were higher in healthy infants. The abundance of Lactobacillus spp. normally found in breast milk fed to infants with CFID was significantly reduced, and Enterococcus spp. were less abundant when diarrhoea occurred. Furthermore, Lactobacillus and Enterococcus were present as shared bacteria in both mother and infant, and they were considered potential anti-CFID probiotics as their relative abundances in breast milk were negatively correlated to infant CFID. Kyoto encyclopedia of genes and genomes (KEGG) functional analysis showed that the function of amino acid metabolism differed between infants with CFID and healthy infants. Therefore, CFID might be related to the decomposition of proteins in food supplements. The screening revealed seven hydrolytic casein and five hydrolytic casein and rice protein isolates from 320 suspected Lactobacillus and Enterococcus isolates. The animal experiments demonstrated that a mixture of five isolates effectively hydrolysed the casein and rice protein and prevented diarrhoea in young rats. Thus, the occurrence of CFID was found to be closely related to the intestinal and breast milk microbiota, and bacteria that could assist in the digestion of cereal proteins were involved in CFID.     

早期灌喂母源粪菌对新生仔猪肠道菌群发育的影响

【目的】粪菌移植(fecal microbiota transplantation,FMT)作为一种治疗手段,已在人类肠道疾病治疗中有较多应用,但在干预新生仔猪肠道菌群上的研究未见报道。本文旨在研究早期母源粪菌移植对新生仔猪肠道菌群发育的影响。【方法】选取一窝12头杜长大新生仔猪,随机分为粪菌处理组(feces treatment,FT)和对照组(control,CO)。FT组仔猪出生后1–5 d每日灌注母源粪菌接种液,CO组灌注等量生理盐水。于1、3、5、7、10、14、18和22日龄采集仔猪粪样,Miseq高通量测序分析仔猪粪便菌群。【结果】灌喂母源粪菌有增加仔猪肠道菌群丰富度的趋势;主坐标分析显示,两组仔猪粪样菌群结构簇并未分开,并在18和22日龄时靠近母猪粪样菌群结构簇;随日龄增加,两组仔猪肠道中的变形菌门丰度均显著降低,而厚壁菌门的丰度显著增加,且从10日龄起拟杆菌门和厚壁菌门之和约为90%;与对照组相比,灌喂母源粪菌增加了10日龄时Escherichia-Shigella的丰度,而降低了18日龄时该菌属的丰富度,18日龄时肠球菌属和普氏菌属的丰度则显著增加。【结论】1–3日龄口服灌喂母源粪菌液并不能影响仔猪肠道菌群的定殖,这一阶段主要受母体微生物结构的影响;灌喂粪菌液对仔猪肠道菌群定殖的影响最多持续10–14 d;而且仔猪在22 d左右,肠道菌群结构逐渐趋同于母猪肠道菌群。     

高脂饮食中添加短链菊粉对小鼠肠道菌群的影响

目的:探究高脂饮食中添加短链菊粉对小鼠肠道菌群的影响。方法:选择8周龄雄性小鼠,5只喂食高脂饲料,5只喂食10%菊粉复合型高脂饲料,喂食8周后收集小鼠粪便,检测小鼠粪便中三种主要的短链脂肪酸。同时,提取小鼠粪便中的细菌基因组,对菌群基因组16S rRNA基因V4高变区进行测序,对数据进行PCoA分析、Alpha多样性分析、LEfSe分析和16S功能预测。结果:菊粉添加后,小鼠粪便中含有的细菌DNA量增多,短链脂肪酸增加。菊粉组和对照组PCoA图可以看到明显聚类。菊粉组物种多样性低于对照组。菊粉组小鼠粪便中S24_7菌科丰度上升;Lachnospiraceae(毛螺菌科),Ruminococcaceae(瘤胃菌科)和Deferribacteraceae(脱铁杆菌科)丰度下降。16S基因功能预测发现22个第二层级的KEGG通路发生变化。结论:高脂饮食情况下短链菊粉的添加会改变小鼠肠道菌群,继而影响肠道菌群的功能。     

Immunologic aspects of human colostrum and milk. III. Fate and absorption of cellular and soluble components in the gastrointestinal tract of the newborn

A group of formula-fed infants were administered a single feed of poliovirus IgA antibody-rich human colostrum 18 to 72 hr after birth. Subsequently, the presence of IgG, IgA, and IgM immunoglobulin and poliovirus antibody activity was determined in serial serum and fecal samples of the neonates. Absorption of IgA immunoglobulin from the colostrum to the circulation was observed in three infants who were fed with colostrum between 18 and 24 hr after birth. Another group of infants of tuberculin-positive mothers who were being breast fed by their own mothers were followed for the development of in vitro correlates of cell-mediated immunity against tuberculin after prolonged breast feeding. Tuberculin-specific proliferative response was observed in the peripheral blood lymphocytes of two neonates after 5 weeks of breast feeding. The responses were undetectable after 12 weeks, although the infants continued to breast feed. No tuberculin reactivity was observed in the cord lymphocytes. These observations suggest uptake of IgA immunoglobulin and components of cellular immunity in the intestine during the immediate neonatal period.     

Survival of Lactobacillus casei strain Shirota in the intestines of healthy Chinese adults

Lactobacillus casei strain Shirota (LcS) is a widely used probiotic strain with health benefits. In this study, the survival of LcS in the intestines of healthy Chinese adults was assessed and the effects of LcS on stool consistency, stool SCFAs and intestinal microbiota evaluated. Subjects consumed 100 mL per day of a probiotic beverage containing 1.0 × 10⁸ CFU/mL of LcS for 14 days. LcS were enumerated using a culture method and the colony identity confirmed by ELISA. Fourteen days after ingestion, the amount of LcS recovered from fecal samples was between 6.86 ± 0.80 and 7.17 ± 0.57 Log₁₀ CFU/g of feces (mean ± SD). The intestinal microbiotas were analyzed by denaturing gradient gel electrophoresis. Principal component analysis showed that consuming LcS significantly changed fecal microbiota profiles. According to redundancy analysis, the amounts of 25 bacterial strains were significantly correlated with LcS intake (P < 0.05), 11 of them positively and fourteen negatively. Concentrations of acetic acid and propionic acid in feces were significantly lower during the ingestion period than during the baseline period (P < 0.05). These results confirm that LcS can survive passage through the gastrointestinal tract of Chinese people; however, they were found to have little ability to persist once their consumption had ceased. Furthermore, consumption of probiotic beverages containing LcS can modulate the composition of the intestinal microbiota on a long‐term basis, resulting in decreased concentrations of SCFAs in the gut.     

Altered Fecal Microbiota Composition Associated with Food Allergy in Infants

Increasing evidence suggests that perturbations in the intestinal microbiota composition of infants are implicated in the pathogenesis of food allergy (FA), while the actual structure and composition of the intestinal microbiota in human beings with FA remain unclear. Microbial diversity and composition were analyzed with parallel barcoded 454 pyrosequencing targeting the 16S rRNA gene hypervariable V1-V3 regions in the feces of 34 infants with FA (17 IgE mediated and 17 non-IgE mediated) and 45 healthy controls. Here, we showed that several key FA-associated bacterial phylotypes, but not the overall microbiota diversity, significantly changed in infancy fecal microbiota with FA and were associated with the development of FA. The proportion of abundant Bacteroidetes, Proteobacteria, and Actinobacteria phyla were significantly reduced, while the Firmicutes phylum was highly enriched in the FA group (P < 0.05). Abundant Clostridiaceae 1 organisms were prevalent in infants with FA at the family level (P = 0.016). FA-enriched phylotypes negatively correlated with interleukin-10, for example, the genera Enterococcus and Staphylococcus. Despite profound interindividual variability, levels of 20 predominant genera were significantly different between the FA and healthy control groups (P < 0.05). Infants with IgE-mediated FA had increased levels of Clostridium sensu stricto and Anaerobacter and decreased levels of Bacteroides and Clostridium XVIII (P < 0.05). A positive correlation was observed between Clostridium sensu stricto and serum-specific IgE (R = 0.655, P < 0.001). The specific microbiota signature could distinguish infants with IgE-mediated FA from non-IgE-mediated ones. Detailed microbiota analysis of a well-characterized cohort of infants with FA showed that dysbiosis of fecal microbiota with several FA-associated key phylotypes may play a pathogenic role in FA.     

Microbiome in Intestinal Lavage Fluid May Be A Better Indicator in Evaluating The Risk of Developing Colorectal Cancer Compared with Fecal Samples

OBJECTIVE: Intestinal microbiota plays a vital role in the pathogenesis of colorectal cancer (CRC), which is crucial for assessing the risk and prognosis of CRC. Most studies regarding human gut microbiota mainly based on the feces, but the exact composition of microbiota vary significantly due to fecal composition is easily affected by many factors. We aim to evaluate whether intestinal lavage fluid (IVF) is a better substitution mirroring the gut microbiota. METHODS: We performed 16S rRNA gene analysis on fecal and IVF samples from 30 CRC patients and 25 healthy individuals, comparison in luminal (feces) / mucosal (IVF) adherent bacterial community profiles were analyzed. RESULTS: The difference between feces and IVF were observed, including the diversity and abundance of pathogenic bacteria (either in single strain or in co-occurrence pattern). IVF group shared 605 OTUs with the fecal group, but there was 94 OTUs only observed in fecal samples, while 247 OTUs were mainly existing in the IVF group. Among them, 27 vital bacterial species detected in IVF, while 10 critical species detected in fecal samples. The co-occurrence bacteria Fusobacteria Cluster and Proteobacteria Cluster 2 significantly increased in IVF than in control (P < .01), while Firmicutes Cluster 1, Firmicutes Cluster 2 and Proteobacteria Cluster 1 were markedly lower in IVF than in control (P < .001). In CRC feces, Fusobacteria Cluster was higher than in control (P < .05), but Firmicutes Cluster 1 was of substantially less abundance than in control (P < .001). Proteobacteria Cluster 2 was increased dramatically in IVF than in feces (P < .05), Firmicutes Cluster 1 were of substantially less abundance than in feces (P < .05). CONCLUSION: Pathogenic microbiota is more abundant in IVF than in feces. Microbiota of IVF may closely be related to the mucosal-associated microbial communities, which benefit from elucidating the relationship of the intestinal microbiota and CRC carcinogenesis.     

Oligosaccharides from feces of preterm infants fed on breast milk

Nine neutral and five acidic oligosaccharides were isolated from feces of a preterm (30th postmenstrual week) blood group A nonsecretor infant fed on pooled breast milk. Structural analyses were carried out using sugar and methylation analyses, fast atom bombardment mass spectrometry, and 1H NMR. The acidic oligosaccharides are well-known components of human milk. The neutral oligosaccharides are characteristic of nonsecretor milk. Surprisingly, no secretor gene-dependent oligosaccharides were present in the feces. Another preterm (27th postmenstrual week) blood group A, secretor infant fed on pooled breast milk showed the same fecal oligosaccharide pattern as above during the first week after birth, despite being a secretor individual. Also notable was the absence of blood group A-active oligosaccharides in this sample. Another sample of feces collected 8 weeks later from the latter infant contained the expected blood group A-active oligosaccharides. Furthermore, free sialic acid was present at the cost of the sialyl oligosaccharides seen earlier. Thus, infants born prematurely do not show the same degree of development of oligosaccharide metabolism as their more mature counterparts.     

Vibrio cholerae/mimicus in fecal microbiota of healthy children in a cholera endemic urban slum setting in Kolkata,India

During a double‐blind, randomized, placebo‐controlled probiotic trial among 3758 children residing in an urban slum in Kolkata, India, Vibrio cholerae/mimicus was detected in fecal microbiota of healthy children. The importance of this finding in the local, regional and global transmission of cholera is discussed.     

A physiological role of breast milk leptin in body weight control in developing infants

Objective: Leptin, a hormone that regulates food intake and energy metabolism, is present in breast milk. The aim of this study was to determine whether milk leptin concentration is correlated with maternal circulating leptin and BMI and with body weight gain of infants. Research Methods and Procedures: A group of 28 non‐obese women (BMI between 16.3 and 27.3 kg/m²) who breast‐fed their infants for at least 6 months and their infants were studied. Venous blood and milk samples were obtained from mothers at 1, 3, 6, and 9 months of lactation, and leptin concentration was determined. Infant body weight and height were followed until 2 years of age. Results: During the whole lactation period, milk leptin concentration correlated positively with maternal plasma leptin concentration and with maternal BMI. In addition, milk leptin concentration at 1 month of lactation was negatively correlated with infant BMI at 18 and 24 months of age. A better negative correlation was also found between log milk leptin concentration at 1 and at 3 months of lactation and infant BMI from 12 to 24 months of age. Discussion: We concluded that, in a group of non‐obese mothers, infant body weight during the first 2 years may be influenced by milk leptin concentration during the first stages of lactation. Thus, moderate milk‐borne maternal leptin appears to provide moderate protection to infants from an excess of weight gain. These results seem to point out that milk leptin is an important factor that could explain, at least partially, the major risk of obesity of formula‐fed infants with respect to breast‐fed infants.     

Fecal antibody levels as a noninvasive method for measuring immunity to gastrointestinal nematodes in ecological studies

Among‐individual variation in antibody‐associated immunity to gastrointestinal nematode parasites (GIN) is known be associated with life‐history traits and vital rates in wild vertebrate systems. To date, measurement of levels of antibodies against GIN antigens in natural populations has exclusively been based on invasive blood sampling techniques. Previous work in laboratory rodents and ruminant livestock suggests that antibody measures from feces may provide a viable noninvasive approach. We measured total and anti‐GIN antibodies of different isotypes (immunoglobulin (Ig) G, IgA and IgE) from paired samples of plasma and feces from free‐living Soay sheep of different ages and sexes. We tested the correlations among these measures as well as their associations with body mass and Strongyle nematode fecal egg counts (FEC). Significant positive correlations were present among plasma and fecal anti‐GIN antibody levels for IgG and IgA. Generally, correlations between total antibody levels in plasma and feces were weaker and not significant. No significant relationships were found between any antibody measures and body mass; however, fecal anti‐GIN antibody levels were significantly negatively correlated with FEC. Our data clearly demonstrate the feasibility of measuring anti‐GIN antibodies from fecal samples collected in natural populations. Although associations of fecal antibody levels with their plasma counterparts and FEC were relatively weak, the presence of significant correlations in the predicted direction in a relatively small and heterogeneous sample suggests fecal antibody measures could be a useful, noninvasive addition to current eco‐immunological studies.     

Construction of a Model Culture System of Human Colonic Microbiota to Detect Decreased Lachnospiraceae Abundance and Butyrogenesis in the Feces of Ulcerative Colitis Patients

Compositional alteration of the gut microbiota is associated with ulcerative colitis (UC). Here, a model culture system is established for the in vitro human colonic microbiota of UC, which will be helpful for determining medical interventions. 16S ribosomal RNA sequencing confirms that UC models are successfully developed from fecal inoculum and retain the bacterial species biodiversity of UC feces. The UC models closely reproduce the microbial components and successfully preserve distinct clusters from the healthy subjects (HS), as observed in the feces. The relative abundance of bacteria belonging to the family Lachnospiraceae significantly decreases in the UC models compared to that in HS, as observed in the feces. The system detects significantly lower butyrogenesis in the UC models than that in HS, correlating with the decreased abundance of Lachnospiraceae. Interestingly, the relative abundance of Lachnospiraceae does not correlate with disease activity (defined as partial Mayo score), suggesting that Lachnospiraceae persists in UC patients at a decreased level, irrespective of the alteration in disease activity. Moreover, the system shows that administration of Clostridium butyricum MIYAIRI restores butyrogenesis in the UC model. Hence, the model detects deregulation in the intestinal environment in UC patients and may be useful for simulating the effect of probiotics.     

Bacterial Diversity in Meconium of Preterm Neonates and Evolution of Their Fecal Microbiota during the First Month of Life

The establishment and succession of bacterial communities in infants may have a profound impact in their health, but information about the composition of meconium microbiota and its evolution in hospitalized preterm infants is scarce. In this context, the objective of this work was to characterize the microbiota of meconium and fecal samples obtained during the first 3 weeks of life from 14 donors using culture and molecular techniques, including DGGE and the Human Intestinal Tract Chip (HITChip) analysis of 16S rRNA amplicons. Culture techniques offer a quantification of cultivable bacteria and allow further study of the isolate, while molecular techniques provide deeper information on bacterial diversity. Culture and HITChip results were very similar but the former showed lower sensitivity. Inter-individual differences were detected in the microbiota profiles although the meconium microbiota was peculiar and distinct from that of fecal samples. Bacilli and other Firmicutes were the main bacteria groups detected in meconium while Proteobacteria dominated in the fecal samples. Culture technique showed that Staphylococcus predominated in meconium and that Enterococcus, together with Gram-negative bacteria such as Escherichia coli, Escherichia fergusonii, Klebsiella pneumoniae and Serratia marcescens, was more abundant in fecal samples. In addition, HITChip results showed the prevalence of bacteria related to Lactobacillus plantarum and Streptococcus mitis in meconium samples whereas those related to Enterococcus, Escherichia coli, Klebsiella pneumoniae and Yersinia predominated in the 3^rd week feces. This study highlights that spontaneously-released meconium of preterm neonates contains a specific microbiota that differs from that of feces obtained after the first week of life. Our findings indicate that the presence of Serratia was strongly associated with a higher degree of immaturity and other hospital-related parameters, including antibiotherapy and mechanical ventilation.     

Age-dependent changes in the gut microbiota and serum metabolome correlate with renal function and human aging

Human aging is invariably accompanied by a decline in renal function, a process potentially exacerbated by uremic toxins originating from gut microbes. Based on a registered household Chinese Guangxi longevity cohort (n = 151), we conducted comprehensive profiling of the gut microbiota and serum metabolome of individuals from 22 to 111 years of age and validated the findings in two independent East Asian aging cohorts (Japan aging cohort n = 330, Yunnan aging cohort n = 80), identifying unique age-dependent differences in the microbiota and serum metabolome. We discovered that the influence of the gut microbiota on serum metabolites intensifies with advancing age. Furthermore, mediation analyses unveiled putative causal relationships between the gut microbiota (Escherichia coli, Odoribacter splanchnicus, and Desulfovibrio piger) and serum metabolite markers related to impaired renal function (p-cresol, N-phenylacetylglutamine, 2-oxindole, and 4-aminohippuric acid) and aging. The fecal microbiota transplantation experiment demonstrated that the feces of elderly individuals could influence markers related to impaired renal function in the serum. Our findings reveal novel links between age-dependent alterations in the gut microbiota and serum metabolite markers of impaired renal function, providing novel insights into the effects of microbiota-metabolite interplay on renal function and healthy aging.     

Comparison of intestinal microflora in healthy infants and infants with allergic colitis

Twenty-eight exclusively breast-fed healthy infants and 16 infants also exclusively breast-fed with allergic colitis (aged 85 +/- 60 and 98 +/- 58 d, respectively) were screened for differences in fecal flora. Bifidobacteria were detected in 23 healthy infants and only in 4 fecal samples of infants with allergic colitis. All bifidobacteria-free infants possessed Gram-positive regular rods as a major group of their fecal flora. These bacteria were identified as clostridia using genus-specific FISH probe. Infants with allergy colitis possessed significantly lower counts of bifidobacteria and total anaerobes and significantly higher counts of clostridia in their feces. In healthy infants, Bifidobacterium longum was the most frequently found species (54.5% of the samples), followed by B. adolescentis (20.0), B. breve (18.2), B. bifidum (16.4), B. dentium (10.9) and B. pseudocatenulatum (1.80). Bifidobacterial isolates from two babies with allergic colitis were identified as B. longum, one child from patients group contained species B. dentium and one baby B. adolescentis. Our results suggest that there are significantly lower counts of bifidobacteria in infants with allergic colitis than in healthy infants.     

Taxonomic Lactobacillus Composition of Feces from Human Newborns during the First Few Days

Abstract Intestinal microbiota comprise a complex ecosystem whose equilibrium is crucial for the health of animal species. For humans, data exist on the microbiota composition in adult subjects, but few studies have addressed the microbiota composition in infants. In particular, data on the presence and species distribution of members of the genus Lactobacillus in newborns (less than one week old) are lacking. In the present work, the feces of healthy newborns were sampled to determine the taxonomic composition of Lactobacillus in the intestinal microbiota in a group of 16 neonates. In total, 1640 colony-forming units (CFU) were isolated, of which 420 grouped in the Lactobacillus genus by means of primary phenotypic characterization. The 420 isolates were further grouped into 125 strains on the basis of identical plasmid profiles. Of these 125 strains, 21 turned out to be permanent, i.e., they were identified in the feces of the same subject on several consecutive days. Sugar fermentation, DNA/DNA hybridization, and S-layer protein determination enabled us to classify 52 of the 125 strains as follows: L. paracasei (40 strains), L. delbrueckii sp. (1 strain), and L. acidophilus (sensu stricto) (11 strains). Based on the same criteria, the remaining 73 strains were tentatively allotted to the Johnson subgroup B, although hybridization experiments with probes specific for L. gasseri and L. johnsonii species were not performed. The presence of new species among these 73 strains cannot be excluded. Surprisingly, the obligately heterofermentative lactobacilli, L. reuteri in particular, were entirely absent from the feces of healthy newborns. Received: 26 March 1997; Accepted: 24 July 1997