Isolation and Identification of Potential Probiotic Bacteria from Human Milk.

Breast milk was long considered a sterile environment, but now it is known to harbor many bacteria that will shape the newborn microbiota. The benefits of breastfeeding to newborn health are, on some level, related to the presence of beneficial bacteria in human milk. Therefore, this study aims to investigate and isolate potential probiotics present in human milk that might be associated with improved health in infants, being potential candidates to be used in simulated human milk formula. Milk samples of 24 healthy mothers were collected at three time points: 30 min (colostrum), 5-9 days (transitional milk), and 25-30 days (mature milk) postpartum. Samples were evaluated by culturing, and the isolated bacteria were identified by MALDI-TOF MS and 16S DNA sequencing. In vitro screening for probiotics properties was performed, and the potential probiotics were mono-associated with germ-free mice to evaluate their ability to colonize the gastrointestinal tract. The microorganisms were submitted to the spray-drying process to check their viability for a potential simulated milk formula production. Seventy-seven bacteria were isolated from breast milk pertaining to four bacterial genera (Staphylococcus, Streptococcus, Leuconostoc, and Lacticaseibacillus). Four potential probiotics were selected: Lacticaseibacillus rhamnosus (n = 2) and Leuconostoc mesenteroides (n = 2). Isolates were able to colonize the gastrointestinal tract of germ-free mice and remained viable after the spray-drying process. In conclusion, breast milk harbors a unique microbiota with beneficial microorganisms that will impact the newborn gut colonization, being an essential source of probiotic candidates to be used in a formula of simulated maternal milk.

Antarctic Strain of Rhodotorula mucilaginosa UFMGCB 18,377 Attenuates Mucositis Induced by 5-Fluorouracil in Mice.

Mucositis is one of the most strenuous side effects caused by chemotherapy drugs, such as 5-fluorouracil (5-FU), during the treatment of several types of cancers. The disease is so prevalent and aggressive that many patients cannot resist such symptoms. However, despite its frequency and clinical significance, there is no effective treatment to prevent or treat mucositis. Thus, the use of probiotics as an adjuvant for the treatment has gained prominence. In the present study, we evaluated the effectiveness of oral administration of the Antarctic strain of Rhodotorula mucilaginosa UFMGCB 18,377 as an alternative to minimize side effects of 5-FU-induced mucositis in mice. Body weight, food consumption, stool consistency, and presence of blood in the feces were assessed daily in mice orally treated or not with the yeast and submitted or not to experimental mucositis. Blood, bones, and intestinal tissues and fluid were used to determine intestinal permeability and immunological, microbiological, and histopathological parameters. Treatment with R. mucilaginosa UFMGCB 18,377 was able to decrease clinical signs of the disease, such as reduction of food intake and body weight loss, and also decreased the number of intestinal enterobacteria and intestinal length shortening. Additionally, treatment was able to decrease the levels of MPO and EPO activities and inflammatory infiltrates, as well as the histopathological lesions characteristic of mucositis in the jejunum and ileum. Results of the present study showed that the oral administration of R. mucilaginosa UFMGCB 18,377 protected mice against mucositis induced by 5-FU.

Treatment with selenium-enriched Saccharomyces cerevisiae UFMG A-905 partially ameliorates mucositis induced by 5-fluorouracil in mice.

PURPOSE: Gastrointestinal mucositis is a major problem associated with cancer therapy. To minimize these deleterious effects, simultaneous administration of antioxidant components, such as selenium, can be considered. There is a growing interest in the use of yeasts because they are able to convert inorganic selenium into selenomethionine. In the present study, oral administration of Saccharomyces cerevisiae UFMG A-905 enriched with selenium was evaluated as an alternative in minimizing the side effects of 5FU-induced mucositis in mice. METHODS: Mice body weight, food consumption, faeces consistency and the presence of blood in faeces were assessed daily during experimental mucositis induced by 5-fluorouracil (5FU). Blood was used for intestinal permeability determination, and small intestine for oxidative stress, immunological and histopathological examination. RESULTS: The increased intestinal permeability observed with mucositis induction was partially reverted by S. cerevisiae and selenium-enriched yeast. Both treatments were able to reduce myeloperoxidase activity, but only selenium-enriched yeast reduced eosinophil peroxidase activity. CXCL1/KC levels, histopathological tissue damage and oxidative stress (lipid peroxidation and nitrite production) in the small intestine were reduced by both treatments; however, this reduction was always higher when treatment with selenium-enriched yeast was evaluated. CONCLUSIONS: Results of the present study showed that the oral administration of S. cerevisiae UFMG A-905 protected mice against mucositis induced by 5-FU, and that this effect was potentiated when the yeast was enriched with selenium.

Evaluation of Potential Probiotics Isolated from Human Milk and Colostrum.

Several studies have demonstrated a diversity of bacterial species in human milk, even in aseptically collected samples. The present study evaluated potential probiotic bacteria isolated from human milk and associated maternal variables. Milk samples were collected from 47 healthy women and cultured on selective and universal agar media under aerobic and anaerobic conditions. Bacterial isolates were counted and identified by Biotyper Matrix-Assisted Laser Desorption Ionization-Time of Flight mass spectrometry and then tested for probiotic properties. Total bacteria in human milk ranged from 1.5 to 4.0 log10 CFU/mL. The higher bacterial counts were found in colostrum (mean = 3.9 log10 CFU/mL, 95% CI 3.14-4.22, p = 0.00001). The most abundant species was Staphylococcus epidermidis (n = 76). The potential probiotic candidates were Lactobacillus gasseri (n = 4), Bifidobacterium breve (n = 1), and Streptococcus salivarius (n = 4). Despite the small sample size, L. gasseri was isolated only in breast milk from mothers classified into a normal weight range and after a vaginally delivered partum. No potential probiotics showed antagonism against pathogens, but all of them agglutinated different pathogens. Nine bacterial isolates belonging to the species L. gasseri, B. breve, and S. salivarius were selected as potential probiotics. The present study confirms the presence in breast milk of a bacterial microbiota that could be the source of potential probiotic candidates to be used in the formula of simulated maternal milk.

Dietary glutamine prevents the loss of intestinal barrier function and attenuates the increase in core body temperature induced by acute heat exposure.

Dietary glutamine (Gln) supplementation improves intestinal function in several stressful conditions. Therefore, in the present study, the effects of dietary Gln supplementation on the core body temperature (T core), bacterial translocation (BT) and intestinal permeability of mice subjected to acute heat stress were evaluated. Male Swiss mice (4 weeks old) were implanted with an abdominal temperature sensor and randomly assigned to one of the following groups fed isoenergetic and isoproteic diets for 7 d before the experimental trials: group fed the standard AIN-93G diet and exposed to a high ambient temperature (39°C) for 2 h (H-NS); group fed the AIN-93G diet supplemented with l-Gln and exposed to a high temperature (H-Gln); group fed the standard AIN-93G diet and not exposed to a high temperature (control, C-NS). Mice were orally administered diethylenetriaminepentaacetic acid radiolabelled with technetium (99mTc) for the assessment of intestinal permeability or 99mTc-Escherichia coli for the assessment of BT. Heat exposure increased T core (approximately 41°C during the experimental trial), intestinal permeability and BT to the blood and liver (3 h after the experimental trial) in mice from the H-NS group relative to those from the C-NS group. Dietary Gln supplementation attenuated hyperthermia and prevented the increases in intestinal permeability and BT induced by heat exposure. No correlations were observed between the improvements in gastrointestinal function and the attenuation of hyperthermia by Gln. Our findings indicate that dietary Gln supplementation preserved the integrity of the intestinal barrier and reduced the severity of hyperthermia during heat exposure. The findings also indicate that these Gln-mediated effects occurred through independent mechanisms.

Treatment with Selemax®, a selenium-enriched yeast, ameliorates experimental arthritis in rats and mice.

Rheumatoid arthritis (RA) is a chronic inflammatory disease that mainly targets the synovial membrane, cartilage and bone. It affects 1 % of the population and is associated with significant morbidity and increased mortality. Se is an essential trace element with antioxidant properties and the ability to modulate the immune responses. Selemax® is an inactive yeast (Saccharomyces cerevisiae) enriched with organic Se. The aim of the present study was to investigate the effects of Selemax® administration in models of an antigen-induced arthritis (AIA) in C57BL/6 mice, and of an adjuvant-induced arthritis (AdIA) in Holtzman rats. As control, the animals were treated with the same inactivated yeast species that was not enriched for Se. In the AIA model, treatment with different doses of Selemax® (0·01, 0·1, 1 and 10 % added to food) significantly decreased the number of inflammatory cells recruited to the knee cavity, essentially by reducing the number of neutrophils. Levels of proinflammatory cytokines, including TNF-α, IL-1ß and chemokine (C-X-C motif) ligand 1/keratinocyte chemoattractant (CXCL1/KC), were also reduced in the peri-articular tissue of mice treated with Selemax® at the tested dose (1 %). In the AdIA model in rats, Selemax® treatment decreased paw oedema and hypernociception. This reduction was associated with inhibition of the influx of proinflammatory cells. Therefore, treatment with Selemax® is associated with amelioration of several inflammatory and functional parameters in models of arthritis, suggesting that this Se-enriched yeast should be evaluated further in patients with RA.

Carica papaya seed macerate as inhibitor of conjugative R plasmid transfer from Salmonella typhimurium to Escherichia coli in vitro and in the digestive tract of gnotobiotic mice.

In this study, the effect of Carica papaya seed macerate on conjugal R plasmid transfer from Salmonella typhimurium to Escherichia coli was investigated in vitro and in the digestive tract of gnotobiotic mice. Twenty-five micrograms per milliliter and 430 mg (administered intragastrically twice a day) of papaya seed macerate concentrations were used during conjugation for in vitro and in vivo assays, respectively. High frequency of conjugation inhibition by macerate was observed for both in vitro and in vivo experiments, independently of bacterial growth and mating conditions. Papaya seed macerate caused a reduction of the transconjugant population ranging from 71% to about 100%. There was no lethal effect of the seed macerate on donor or recipient cells in the concentrations used. Once the mechanisms and magnitude of resistance gene transfer are clearly understood, strategies to reduce or minimize the dissemination of these genes could be relevant. The data here obtained show a clinical potential use of papaya seed macerate on this transfer.