Individual variations in intestinal microbiota were higher in preterm infants with necrotising enterocolitis than healthy controls

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Establishment and development of the intestinal microbiota of preterm infants in a Lebanese tertiary hospital

© 2016 The Authors The establishment and development of the intestinal microbiota is known to be associated with profound short- and long-term effects on the health of full-term infants (FTI), but studies are just starting for preterm infants (PTI). The data also mostly come from western countries and little information is available for the Middle East. Here, we determined the composition and dynamics of the intestinal microbiota during the first month of life for PTI (n = 66) and FTI (n = 17) in Lebanon. Fecal samples were collected weekly and analyzed by quantitative PCR (q-PCR) and temporal temperature gradient gel electrophoresis (TTGE). We observed differences in the establishment and composition of the intestinal microbiota between the two groups. q-PCR showed that PTI were more highly colonized by Staphylococcus than FTI in the first three weeks of life; whereas FTI were more highly colonized by Clostridium clusters I and XI. At one month of life, PTI were mainly colonized by facultative anaerobes and a few strict anaerobes, such as Clostridium cluster I and Bifidobacterium. The type of feeding and antibiotic treatments significantly affected intestinal colonization. TTGE revealed low species diversity in both groups and high inter-individual variability in PTI. Our findings show that PTI had altered intestinal colonization with a higher occurrence of potential pathogens (Enterobacter, Clostridium sp) than FTI. This suggests the need for intervention strategies for PTI to modulate their intestinal microbiota and promote their health

Typage moléculaire de souches du genre bifidobacterium : Polymorphisme génétique intraspécifique et intragénérique

Non disponible / Not availableL'identification des espèces ou des souches bactériennes repose sur la mise en évidence du polymorphisme génétique interspécifique et intra générique. Le but de ce travail a donc été de rechercher diverses méthodes de révélation du polymorphisme génétique, applicables au genre bifidobacterium. La réalisation de profils de restriction a d'abord permis une caractérisation des différentes souches du laboratoire, comprenant des souches de collection, des souches industrielles ainsi que des souches d'origine humaine provenant d'une expérience clinique. Cette première méthode révèle un polymorphisme de la taille des fragments de restriction aussi bien interspécifique qu'intra spécifique chez ce genre bactérien. Par ailleurs, une comparaison plus rapide des souches a été réalisée en utilisant une sonde nucléique spécifique des gènes d'ARN ribosomiques. Les profils obtenus ont notamment permis de caractériser toutes les souches de bifidobacterium et de procéder à des regroupements en espèces. Nous rapportons également l'identification de quatre espèces de bifidobacterium par la sélection de sondes nucléiques spécifiques d'espèces, isolées des mini-banques d'ADN des souches b. Adolescentis cip64.59t, b. Animalis atcc25527#t, b. Bifidum cip64.65 et b. Longum atcc15707#t. La spécificité d'espèce de ces fragments a été testée par hybridation sur les ADN natifs des souches du genre. Le polymorphisme de restriction existant entre les différentes souches de la même espèce a ensuite été visualisé par hybridation du fragment cloné sur les profils de restriction de l'ADN total. Ainsi, la sonde l6/45, spécifique de 13 des 15 souches classées dans l'espèce b. Longum uniquement, est répétée chez certaines de ces souches. Le séquençage de ce fragment a mis en évidence une partie d'orf. La séquence protéique déduite de cette orf présente des similarités significatives avec une classe de recombinases site-spécifiques représentées par la protéine Int du bactériophage lambda

Genetic diversity among dairy lactococcal strains investigated by polymerase chain reaction with three arbitrary primers.

International audienceRandomly amplified polymorphic DNA (RAPD) has been used for the rapid typing of Lactococcus lactis strains isolated from raw milk from the Camembert region of Normandy. It is thought that the diversity and perhaps the area strain specificity due to climatic and geographical factors of such wild-type lactococcal strains could contribute to the flavour differences and specific features detected for the same product in different areas. The patterns from 58 isolates were analysed by UPGMA dendrograms. At a similarity level of 50%, four RAPD clusters were distinguished. Clusters 1 and 2 contained strains of subspecies lactis and cluster 3 contained strains related to the C2 strain which is genetically cremoris but phenotypically lactis. The type strain of cremoris subspecies was significantly differentiated from these strains with primers P2 and P3. Thus, there was a real genetic diversity in pattern, making it possible to detect potential typical RAPD fragments

Genetic diversity among dairy lactococcal strains investigated by polymerase chain reaction with three arbitrary primers.

International audienceRandomly amplified polymorphic DNA (RAPD) has been used for the rapid typing of Lactococcus lactis strains isolated from raw milk from the Camembert region of Normandy. It is thought that the diversity and perhaps the area strain specificity due to climatic and geographical factors of such wild-type lactococcal strains could contribute to the flavour differences and specific features detected for the same product in different areas. The patterns from 58 isolates were analysed by UPGMA dendrograms. At a similarity level of 50%, four RAPD clusters were distinguished. Clusters 1 and 2 contained strains of subspecies lactis and cluster 3 contained strains related to the C2 strain which is genetically cremoris but phenotypically lactis. The type strain of cremoris subspecies was significantly differentiated from these strains with primers P2 and P3. Thus, there was a real genetic diversity in pattern, making it possible to detect potential typical RAPD fragments

Long-term changes in human colonic Bifidobacterium populations induced by a 5-day oral amoxicillin-clavulanic acid treatment.

International audienceThe objective of this study was to assess the possible modifications due to amoxicillin-clavulanic acid (AMC) treatment on total bacteria and on Bifidobacterium species balance in human colonic microbiota. Eighteen healthy volunteers (19 to 36 years old) were given a 875/125 mg dose of AMC twice a day for 5 days. Fecal samples were obtained before and after antibiotic exposure. After total DNA extraction, total bacteria and bifidobacteria were specifically quantified using real-time PCR. Dominant species were monitored over time using bacterial and bifidobacterial Temporal Temperature Gradient gel Electrophoresis (TTGE). At the end of AMC exposure, total bacterial concentrations as well as bifidobacteria concentrations were significantly reduced compared to before AMC exposure:10.7±0.1 log(10) 16S rRNA gene copies/g vs 11.1±0.1 log(10) (p = 0.003) and 8.1±0.5 log(10) 16S rRNA gene copies/g vs 9.4±0.3 log(10) (p = 0.003), respectively. At the same time, the mean similarity percentages of TTGE bacteria and TTGE bifidobacteria profiles were significantly reduced compared to before AMC exposure: 51.6%±3.5% vs 81.4%±2.1% and 55.8%±7.6% vs 84.5%±4.1%, respectively. Occurrence of B. adolescentis, B. bifidum and B. pseudocatenulatum/B. catenulatum species significantly decreased. Occurrence of B. longum remained stable. Moreover, the number of distinct Bifidobacterium species per sample significantly decreased (1.5±0.3 vs 2.3±0.3; p = 0.01). Two months after AMC exposure, the mean similarity percentage of TTGE profiles was 55.6% for bacteria and 62.3% for bifidobacteria. These results clearly demonstrated that a common antibiotic treatment may qualitatively alter the colonic microbiota. Such modifications may have potential long-term physiological consequences

Amoxicillin treatment modifies the composition of Bifidobacterium species in infant intestinal microbiota

Objectives: Amoxicillin is a beta-lactam antibiotic largely used in childhood. However only few studies described its impact on composition of children gut microbiota, in particular on Bifidobacterium populations considered as beneficial microorganisms. In this study, the impact on faecal Bifidobacterium species of a seven-day amoxicillin treatment was quantitatively and qualitatively assessed in infants during an episode of acute respiratory infection. Methods: Faecal samples from 31 infants were obtained on day 0 (just before amoxicillin therapy) and on day 7 (the end of therapy). Total DNA was extracted and bifidobacteria were quantified using real-time PCR. Predominant Bifidobacterium species were then identified using specific PCR-TTGE. Results: Bifidobacteria concentrations were not significantly altered by amoxicillin compared to the healthy group. However, amoxicillin treatment induced a complete disappearance of Bifidobacterium adolescentis species (occurrence rate of 0% versus 36.4% in healthy group, P < 0.001), a significant decrease in the occurrence rate of Bifidobacterium bifidum (23% versus 54.5% in healthy group, P < 0.05), but did not affect Bifidobacterium longum (93.5% versus 100% in healthy group) and Bifidobacterium pseudocatenulatum/B. catenulatum (about 55% in both groups). The number of Bifidobacterium species per microbiota significantly decreased from 2.5 1 for healthy group to 1.8 0.9 for treated infants (P < 0.05). Conclusions: This study showed that a 7 day amoxicillin treatment did not alter the counts of Bifidobacterium. However amoxicillin can have an impact by changing the microbiota at the species level and decreased the diversity of this population.This work was supported by Ecos (grant number C01S03)

Juvenile ferric iron prevents microbiota dysbiosis and colitis in adult rodents

AIM: To assess whether juvenile chronic ferric iron ingestion limit colitis and dysbiosis at adulthood in rats and mice

Oral administration of viable Bifidobacterium pseudolongum strain Patronus modified colonic microbiota and increased mucus layer thickness in rat

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Mean similarity coefficients of specific <i>Bifidobacterium</i> TTGE profiles of samples collected before and after AMC exposure (day0–day5) and calculated according to the reference period (day-12 day-6 day 0; n = 17).

<p>Mean similarity coefficients of specific <i>Bifidobacterium</i> TTGE profiles of samples collected before and after AMC exposure (day0–day5) and calculated according to the reference period (day-12 day-6 day 0; n = 17).</p