Alberto Cresci

Differences in Fecal Microbiota in Different European Study Populations in Relation to Age, Gender, and Country: a Cross-Sectional Study

ABSTRACT A cross-sectional study on intestinal microbiota composition was performed on 230 healthy subjects at four European locations in France, Germany, Italy, and Sweden. The study participants were assigned to two age groups: 20 to 50 years (mean age, 35 years; n = 85) and >60 years (mean age, 75 years; n = 145). A set of 14 group- and species-specific 16S rRNA-targeted oligonucleotide probes was applied to the analysis of fecal samples by fluorescence in situ hybridization coupled with flow cytometry. Marked country-age interactions were observed for the German and Italian study groups. These interactions were inverse for the predominant bacterial groups Eubacterium rectale-Clostridium coccoides and Bacteroides-Prevotella. Differences between European populations were observed for the Bifidobacterium group only. Proportions of bifidobacteria were two- to threefold higher in the Italian study population than in any other study group, and this effect was independent of age. Higher proportions of enterobacteria were found in all elderly volunteers independent of the location. Gender effects were observed for the Bacteroides-Prevotella group, with higher levels in males than in females. In summary, age-related differences in the microbiota makeup were detected but differed between the study populations from the four countries, each showing a characteristic colonization pattern.

Resistant starch modifies gut microflora and microbial metabolism in human flora-associated rats inoculated with faeces from italian and UK donors

The effect of sucrose and resistant starch (‘CrystaLean’– a retrograded, amylose starch) on human gut microflora and associated parameters was studied in human flora‐associated (HFA) rats, colonized with microfloras from UK or Italian subjects, to determine whether such floras were affected differently by dietary carbohydrates. Consumption of the resistant starch diet resulted in significant changes in four of the seven main groups of bacteria enumerated. In both the UK and Italian flora‐associated rats, numbers of lactobacilli and bifidobacteria were increased 10–100‐fold, and there was a concomitant decrease in enterobacteria when compared with sucrose‐fed rats. The induced changes in caecal microflora of both HFA rat groups were reflected in changes in bacterial enzyme activities and caecal ammonia concentration. Although it had little effect on caecal short‐chain fatty acid concentration, CrystaLean markedly increased the proportion of n‐butyric acid in both rat groups and was associated with a significant increase in cell proliferation in the proximal colon of the Italian flora‐associated rats. CrystaLean appeared to play a protective role in the colon environment, lowering caecal ammonia concentration, caecal pH and β‐glucuronidase activity.

Administration of probiotic strain to improve sea bream wellness during development

Two bacterial strains Lactobacillus fructivorans (AS17B), isolated from adult sea bream (Sparus aurata) gut, and Lactobacillus plantarum (906), isolated from human faeces, were administered contemporaneously, during sea bream development using Brachionus plicatilis and/or Artemia salina and dry feed as vectors. The probiotic treatment influenced gut colonization: at 35 days post-hatching (p.h.) L. fructivorans was not present in the gut, but the treatment induced colonization by L. plantarum. At 66 days p.h., L. fructivorans was evident also in the control; moreover, when suitable environmental conditions appeared in the post-metamorphosis gastro-intestinal tract, competition between L. plantarum and L. fructivorans occurred. At 90 days p.h., L. plantarum was displaced by L. fructivorans that became significantly higher with respect to the control. In treated groups, probiotic administration significantly decreased larvae and fry mortality.

EU project Crownalife: functional foods, gut microflora and healthy ageing isolation and identification of Lactobacillus and Bifidobacterium strains from faecal samples of elderly subjects for a possible probiotic use in functional foods

A new EU-funded project called “Crownalife” has been set up both to assess structural and functional alterations of the intestinal microflora with ageing in Europe, and to validate functional foods that promote health by improving the function of the intestinal microflora in the elderly. Species of bifidobacteria and lactobacilli were isolated from faecal samples of healthy elderly Italian subjects and identified for a possible probiotic use in functional foods. Total anaerobic and aerobic, Lactobacillus and Bifidobacterium counts were performed on the faecal samples. Colonies grown on selective media were identified using enzymatic tests. Lactobacillus fermentum and Bifidobacterium longum were the most represented species and could be considered good candidates to be further characterized and then utilized to design appropriate dietary strategies. Some of the identification results related to Bifidobacterium species were validated by using PCR procedure based on 16S rRNA gene sequences species-specific primers showing a good concordance rate with the enzymatic method.

Chemical composition and antimicrobial activity of the essential oil from Ferula glauca L. (F. communis L. subsp. glauca) growing in Marche (central Italy)

The essential oil obtained from different parts of Ferula glauca L. (formerly considered as a subspecies of F. communis) growing in Marche (central Italy), was analyzed for the first time by GC-FID and GC-MS. The major volatiles were (E)-caryophyllene and caryophyllene oxide in leaves, alpha-pinene, myrcene and germacrene D in flowers, alpha- and beta-pinene in fruits, (E)-beta-farnesene, myristicin and elemicin in roots, respectively. The differences in composition detected with respect to F. communis, made the volatile fraction a reliable marker to distinguish between them, and confirm the botanical data at the base of their discrimination. Furthermore, the oil was assayed for its antimicrobial activity by the broth microdilution method. B. subtilis was found to be the most sensitive microorganism, with the lowest MIC values.

Efficacy of antimicrobial filter treatments on microbial colonization of air panel filters

Aims: To assess the activity of biostatic agents on the microbial colonization of panel filters.

Pilot-scale production and viability analysis of freeze-dried probiotic bacteria using different protective agents.

The functional food industry requires an improvement of probiotic strain stability during storage, especially when they are stored at room temperature. In this study, the viability of freeze-dried Lactobacillus rhamnosus IMC 501(®) and Lactobacillus paracasei IMC 502(®) using different protective agents (i.e., glycerine, mannitol, sorbitol, inulin, dextrin, Crystalean(®)) was determined and compared with semi skimmed milk (SSM) control. No significant differences were observed between the tested protectants and the control (SSM) during storage at refrigerated conditions. During storage at room temperature, only glycerine was found to stabilize viability better than other tested substances.

Composition and biological activity of essential oil of Achillea ligustica All. (Asteraceae) naturalized in central Italy: Ideal candidate for anti-cariogenic formulations

Essential oil from flowers (FL) and vegetative parts (VP) of Achillea ligustica (Asteraceae), naturalized after cultivation in central Italy, was investigated by GC-FID and GC-MS. The most abundant components were linalool, viridiflorol, beta-pinene, 1,8-cineole and terpinen-4-ol. The antioxidant assays (DPPH and ABTS radical scavenging assays, and beta-carotene bleaching test) demonstrated a moderate activity of essential oils. The antimicrobial activity was evaluated by the broth micro-dilution method on 6 microbial strains and showed to be quite strong against the cariogenic Gram-positive Streptococcus mutans, suggesting that this essential oil could be a valid candidate for anti-cariogenic formulations. Moderate cytotoxic activity was observed in assays on four tumour cell lines by MTT assay.

The effect of sucrose or starch‐based diet on short‐chain fatty acids and faecal microflora in rats

An investigation was carried out to determine whether variations of dietary carbohydrates could modify the colonic flora in rats. Sprague‐Dawley rats were fed with two equicaloric diets based on the AIN‐76 diet ( American Institute of Nutrition 1977 ) but differing from that diet in content of carbohydrates, i.e. high sucrose (64%) or high corn starch (64%). Feeding was continued for 9 months ad libitum and no variation in weight gain was recorded among the different diets. A prevalence of aerobes, and a significant reduction in the ratio anaerobes/aerobes in the faeces of rats on the high starch diet compared with the high sucrose diet, was observed. The anaerobe genera identified included Actinomyces, Bacteroides, Bifidobacterium, Clostridium, Eubacterium, Lactobacillus and Propionibacterium. Bacteroides was the most prevalent genus in both dietary groups (51·2 and 29·5% in the faeces of rats fed the sucrose and starch diets, respectively). In contrast, clostridia were prevalent in the starch‐fed group (23·8%) and less so in the sucrose diet (11·5%), as propionibacteria were prevalent in faeces of rats fed the starch diet (15·5%), and low in the sucrose diet (3·9%). The remaining genera were scarce in faeces from rats on either diet. Total short‐chain fatty acids (SCFA) were significantly higher in the faeces of animals fed the starch diet compared with those fed the sucrose diet. The relative concentrations of acetic, propionic and butyric acids were not significantly different between the two dietary groups. In conclusion, high starch diet can markedly modify the composition of faecal flora and alter considerably the faecal concentration of SCFAs, compounds which might have a health‐promoting effect.

In vitro evaluation of antimicrobial activity of Lactobacillus rhamnosus IMC 501®, Lactobacillus paracasei IMC 502® and SYNBIO® against pathogens

Probiotic lactobacilli have a great potential to produce antimicrobial compounds that inhibit and control the microbial pathogen growth. The antimicrobial and antifungal activities of two probiotic strains, Lactobacillus rhamnosus IMC 501® and Lactobacillus paracasei IMC 502®, and their 1 : 1 combination, named SYNBIO®, were studied using four different methods.