Lactobacillus fermentum CECT 5716 Reduces Staphylococcus Load in the Breastmilk of Lactating Mothers Suffering Breast Pain: A Randomized Controlled Trial

Isolation and Characterization of Probiotic Bacteria from Traditional Foods

A probiotic is a live bacterium that, when given in sufficient proportions, helps to improve the host's gut health. Kimchi and pearl millet, two traditional foods, were used to isolate probiotic bacterial strains. This study's primary goals were to isolate, identify and analyse the microorganisms for potential probiotic traits, tolerance to gastrointestinal environments, and antimicrobial activity, and produce probiotic capsule. The present investigation resulted with identification of two probiotic strains (KAC1 and PAC1) from conventional foods, such as kimchi and pearl millet porridge. The isolated probiotics were identified as Enterobacteriaceae family by 16S rRNA sequencing and are deposited in GenBank (NCBI), accession numbers OQ629827 (KAC1) and OQ629828 (PAC1), respectively. These strains exhibited the characteristics of possible probiotic traits, such as the ability to tolerate simulated gastric juice, inhibits the growth of pathogenic bacteria, auto-aggregation, co-aggregation, and hydrophobicity. Furthermore, spectroscopic analysis divulges some critical findings which corroborate the results obtained. Finally, capsules containing freeze-dried  probiotics was successfully produced.

Dose-Response Effect of Saccharomyces cerevisiae UFMG A-905 on the Prevention of Asthma in an Animal Model

Probiotics should be administered in adequate amounts to confer health benefits. Probiotic dose-response studies are still missing. Saccharomyces cerevisiae UFMG A-905 prevented asthma development; however, the ideal dose has not been investigated. We evaluated the optimal dose and administration regimen of S. cerevisiae UFMG A-905 in the prevention of asthma. Male Balb/c mice were sensitized intraperitoneally with ovalbumin (OVA) and challenged with OVA intranasally. Mice received, via gavage, daily or alternate-day S. cerevisiae UFMG A-905. In daily regimen, different concentrations (107, 108, or 109 CFU/mL) were given 10 days before OVA sensitization and during challenges. In alternate-day regimen, a concentration of 109 CFU/mL was administered three times per week for 5 weeks, starting 2 weeks prior to the first sensitization. After the last challenge, in vivo bronchial hyperresponsiveness and airway and lung inflammation were assessed. OVA-challenged mice, when compared to saline-challenged mice, presented a significant increase in bronchial hyperresponsiveness and airway and lung inflammation. Daily and alternate-day administration of 109 CFU/mL of S. cerevisiae UFMG A-905 significantly reduced bronchial hyperresponsiveness; lower concentrations of S. cerevisiae UFMG A-905 did not significantly reduce bronchial hyperresponsiveness. Daily regimen with the highest concentration significantly reduced total cell number, eosinophil count in the BAL, and the levels of IL-4, IL-5, and IL-13. Daily administration of S. cerevisiae UFMG A-905 at 107 and 108 CFU/mL and alternate-day regimen did not significantly decrease airway and lung inflammation. S. cerevisiae UFMG A-905 led to a significant attenuation of bronchial hyperresponsiveness and lung inflammation in a dose-dependent manner.

Effects of maternal probiotic supplementation on breast milk microbiome and infant gut microbiome and health: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The early-life microbiome is formed during the perinatal period and is critical for infants' lifelong health. This is established by maternal-infant microbiome crosstalk, which is mediated by the breast milk microbiome. The milk microbiome is dependent on the maternal gut microbiome, suggesting that it could potentially be restored through oral probiotic supplements. Therefore, we conducted this systematic review and meta-analysis to summarize the effect of maternal probiotic supplements on breast milk and infant gut microbiome composition and on infant health.

DATA SOURCES

The PubMed, EMBASE, Web of Science, Scopus, CINAHL, and Science Direct databases were searched until December 15, 2022.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials following the population, intervention, comparison, and outcome (population: pregnant or lactating women; intervention: probiotics; control: placebo or follow-up; outcome: breast milk and infant gut microbiome composition and infant health) principles were included.

METHODS

Using a random effect model, the standard mean difference, risk difference, and risk ratio with 95% confidence interval were used to measure each outcome. All analyses were conducted using the intention-to-treat approach. Heterogeneity was evaluated using I2 statistics.

RESULTS

The final data set included 24 randomized controlled trials with a total of 2761 mothers and 1756 infants. The overall effect of probiotics on the beneficial bacteria detection rate in breast milk had a risk difference of 24% (95% confidence interval, 0.1-0.37; P<.001; I2=91.12%). The pooled mean beneficial and pathogenic bacteria abundance in breast milk had a standard mean difference of 1.22 log10 colony forming units/mL (95% confidence interval, 0.48-1.97; P<.001; I2=95.51%) and -1.05 log10 colony forming unites/mL (95% confidence interval, -1.99 to -0.12; P=.03; I2=96.79%), respectively. The overall abundance of beneficial bacteria in the infant gut had a standard mean difference of 0.89 log10 colony forming units/g (95% confidence interval, 0.22-1.56; P=.01; I2=95.01%). It also controlled infant weight gain (standard mean difference, -0.49 kg/equivalent age; 95% confidence interval, -0.82 to -0.17; P<.001; I2=0.00%) and decreased the occurrence of infantile colic (risk ratio, 0.30; 95% confidence interval, 0.16-0.57; P<.001; I2=0.00%).

CONCLUSION

Maternal probiotic supplements effectively orchestrate the breast milk and infant gut microbiome with a wide range of clinical benefits and safety. Lactobacillus, Bifidobacterium, Streptococcus thermophilus, and S. boulardii can be used as maternal supplements to promote infant health.

Limosilactobacillus fermentum CECT5716: Clinical Potential of a Probiotic Strain Isolated from Human Milk

Breastfeeding provides the ideal nutrition for infants. Human milk contains a plethora of functional ingredients which foster the development of the immune system. The human milk microbiota predominantly contributes to this protective effect. This is mediated by various mechanisms, such as an antimicrobial effect, pathogen exclusion and barrier integrity, beneficial effects on the gastrointestinal microbiota, vitamin synthesis, immunity enhancement, secreted probiotic factors, and postbiotic mechanisms. Therefore, human milk is a good source for isolating probiotics for infants who cannot be exclusively breastfed. One such probiotic which was isolated from human milk is Limosilactobacillus fermentum CECT5716. In this review, we give an overview of available interventional studies using Limosilactobacillus fermentum CECT5716 and summarise preclinical trials in several animal models of different pathologies, which have given first insights into its mechanisms of action. We present several randomised clinical studies, which have been conducted to investigate the clinical efficacy of the Limosilactobacillus fermentum CECT5716 strain in supporting the host's health.

A systematic review of breast milk microbiota composition and the evidence for transfer to and colonisation of the infant gut

The intestinal microbiota plays a major role in infant health and development. However, the role of the breastmilk microbiota in infant gut colonisation remains unclear. A systematic review was performed to evaluate the composition of the breastmilk microbiota and evidence for transfer to/colonisation of the infant gut. Searches were performed using PUBMED, OVID, LILACS and PROQUEST from inception until 18th March 2020 with a PUBMED update to December 2021. 88 full texts were evaluated before final critique based on study power, sample contamination avoidance, storage, purification process, DNA extraction/analysis, and consideration of maternal health and other potential confounders. Risk of skin contamination was reduced mainly by breast cleaning and rejecting the first milk drops. Sample storage, DNA extraction and bioinformatics varied. Several studies stored samples under conditions that may selectively impact bacterial DNA preservation, others used preculture reducing reliability. Only 15 studies, with acceptable sample size, handling, extraction, and bacterial analysis, considered transfer of bacteria to the infant. Three reported bacterial transfer from infant to breastmilk. Despite consistent evidence for the breastmilk microbiota, and recent studies using improved methods to investigate factors affecting its composition, few studies adequately considered transfer to the infant gut providing very little evidence for effective impact on gut colonisation.

The preventive and therapeutic effects of probiotics on mastitis: A systematic review and meta-analysis

Acute mastitis is one of the main reasons why breastfeeding women stop breastfeeding, and medication should be used with caution. Considering the uncertainty of mastitis infection and the indications of antibiotic use, as well as the problem of drug resistance and the safety of medication during lactation, probiotics have become an alternative treatment choice. However, a meta-analysis of the effects of probiotics in preventing and treating lactational mastitis is still lacking. Therefore, we searched six electronic databases and the sites of clinical trial registration, a total of six randomized controlled trials were included in this meta-analysis, which showed that oral probiotics during pregnancy can reduce the incidence of mastitis (RR: 0.49, 95% CI: 0.35 to 0.69; p<0.0001). After oral administration of probiotics, the counts of bacteria in the milk of healthy people and mastitis patients were both significantly reduced (in healthy people: MD: -0.19, 95% CI: -0.23 to -0.16, p<0.00001; in mastitis patients: MD: -0.89, 95% CI: -1.34 to -0.43, p = 0.0001). These indicate that to a certain extent, probiotics are beneficial in reducing the incidence rate of mastitis during lactation and some related mastitis symptoms. However, high-quality multicenter clinical trials are still needed to support this result.

Validity of food additive maltodextrin as placebo and effects on human gut physiology: systematic review of placebo-controlled clinical trials

PURPOSE

Maltodextrin (MDX) is a polysaccharide food additive commonly used as oral placebo/control to investigate treatments/interventions in humans. The aims of this study were to appraise the MDX effects on human physiology/gut microbiota, and to assess the validity of MDX as a placebo-control.

METHODS

We performed a systematic review of randomized-placebo-controlled clinical trials (RCTs) where MDX was used as an orally consumed placebo. Data were extracted from study results where effects (physiological/microbial) were attributed (or not) to MDX, and from study participant outcomes data, before-and-after MDX consumption, for post-publication 're-analysis' using paired-data statistics.

RESULTS

Of two hundred-sixteen studies on 'MDX/microbiome', seventy RCTs (n = 70) were selected for analysis. Supporting concerns regarding the validity of MDX as a placebo, the majority of RCTs (60%, CI 95% = 0.48-0.76; n = 42/70; Fisher-exact p = 0.001, expected < 5/70) reported MDX-induced physiological (38.1%, n = 16/42; p = 0.005), microbial metabolite (19%, n = 8/42; p = 0.013), or microbiome (50%, n = 21/42; p = 0.0001) effects. MDX-induced alterations on gut microbiome included changes in the Firmicutes and/or Bacteroidetes phyla, and Lactobacillus and/or Bifidobacterium species. Effects on various immunological, inflammatory markers, and gut function/permeability were also documented in 25.6% of the studies (n = 10/42). Notably, there was considerable variability in the direction of effects (decrease/increase), MDX dose, form (powder/pill), duration, and disease/populations studied. Overall, only 20% (n = 14/70; p = 0.026) of studies cross-referenced MDX as a justifiable/innocuous placebo, while 2.9% of studies (n = 2/70) acknowledged their data the opposite.

CONCLUSION

Orally-consumed MDX often (63.9% of RCTs) induces effects on human physiology/gut microbiota. Such effects question the validity of MDX as a placebo-control in human clinical trials.

Efficacy of Direct or Indirect Use of Probiotics for the Improvement of Maternal Depression during Pregnancy and in the Postnatal Period: A Systematic Review and Meta-Analysis

The mother and infant form a unique bond, with maternal mental health affecting the interactions with the infant and infant behaviours impacting maternal mental health. One of the possible mechanisms influencing maternal mental health is the manipulation of the gut-brain axis by consuming probiotic supplements. Probiotics can also have an indirect influence on maternal mental health via the modulation of the infant microbiome and consequently improving the infant's health and thus, indirectly leading to an improvement in maternal mood. This systematic review evaluated the efficacy of probiotics on maternal mental health by searching for randomised controlled trials via international databases: Cochrane Library, PubMed, Scopus, ScienceDirect, and Web of Science until January 2022. A meta-analysis was performed using the Cochrane Collaboration methodology where possible. We found seven clinical trials that included the word probiotics and addressed maternal depression and/or anxiety. Of these, five trials investigated the influence of maternal probiotic supplementation on the gut-brain axis. Two trials investigated the indirect influence of probiotics on maternal depression via supplementation of probiotics by infants and subsequent influence on the crying of colicky infants. Meta-analysis of two studies of pregnant and postnatal women and two studies of infants consuming probiotics on the outcome of the Edinburgh Postnatal Depression Scale for mothers showed no statistical difference. The findings indicate that maternal depression is very complex and is influenced by various bidirectional factors. One of the factors that can improve maternal mental health is probiotics, however, careful consideration must be given to correct strain selection as strain-specific effectiveness was observed. Further well-designed, robust clinical studies are warranted.

Probiotics, Their Extracellular Vesicles and Infectious Diseases

Probiotics have been shown to be effective against infectious diseases in clinical trials, with either intestinal or extraintestinal health benefits. Even though probiotic effects are strain-specific, some "widespread effects" include: pathogen inhibition, enhancement of barrier integrity and regulation of immune responses. The mechanisms involved in the health benefits of probiotics are not completely understood, but these effects can be mediated, at least in part, by probiotic-derived extracellular vesicles (EVs). However, to date, there are no clinical trials examining probiotic-derived EVs health benefits against infectious diseases. There is still a long way to go to bridge the gap between basic research and clinical practice. This review attempts to summarize the current knowledge about EVs released by probiotic bacteria to understand their possible role in the prevention and/or treatment of infectious diseases. A better understanding of the mechanisms whereby EVs package their cargo and the process involved in communication with host cells (inter-kingdom communication), would allow further advances in this field. In addition, we comment on the potential use and missing knowledge of EVs as therapeutic agents (postbiotics) against infectious diseases. Future research on probiotic-derived EVs is needed to open new avenues for the encapsulation of bioactives inside EVs from GRAS (Generally Regarded as Safe) bacteria. This could be a scientific novelty with applications in functional foods and pharmaceutical industries.

Effects of Pre/Probiotic Supplementation on Breast Milk Levels of TGF-b1, TGF-b2, and IgA: A Systematic Review and Meta-Analysis of Randomized-Controlled Trial

Background: Previous studies have proposed that the maternal intake of pre/probiotics may affect the immune composition of breast milk. Nevertheless, the available findings are contradictory. This meta-analysis aimed to examine the impact of maternal supplementation with pre/probiotics on the levels of total immunoglobulin A (IgA), secretory IgA (SIgA), transforming growth factor beta 1 (TGF-β1), and TGF-2 in breast milk. Methods: PubMed and Scopus were systematically searched using a comprehensive search strategy for eligible randomized-controlled trials published up to February 2021. A random-effects model was applied to pool weighted mean difference and 95% confidence interval (CI) as effect size. Cochran's Q statistic and the I2 statistic were used to measure the between-study variance. Egger's regression test was used to assess publication bias. Results: A total of 12 different studies, with a total sample size of 1722 individuals (probiotic group: 858, placebo group: 864), were included in this meta-analysis. In the overall analysis, compared with placebo, maternal supplementation with pre/probiotics had no significant effect on concentrations of total IgA, SIgA, TGF-β1, and TGF-β2 in the breast milk. In the subgroup analysis, pre/probiotics did not affect total IgA, TGF-β1, and TGF-β2 in both colostrum/transitional and mature milk. However, a significant increase in SIgA was found in colostrum/transitional milk following pre/probiotic administration (WMD = 19.33, 95% CI: 0.83-37.83; p = 0.04), without evidence for remarkable heterogeneity (I² = 0.0, p = 0.57). Conclusions: Maternal supplementation with pre/probiotics may increase SIgA in colostrum/transitional milk, without any effect on total IgA, TGF-β1, and TGF-β2.

Genomic Analysis of Limosilactobacillus fermentum ATCC 23271, a Potential Probiotic Strain with Anti-Candida Activity

Limosilactobacillus fermentum (ATCC 23271) was originally isolated from the human intestine and has displayed antimicrobial activity, primarily against Candida species. Complete genome sequencing and comparative analyses were performed to elucidate the genetic basis underlying its probiotic potential. The ATCC 23271 genome was found to contain 2,193,335 bp, with 2123 protein-coding sequences. Phylogenetic analysis revealed that the ATCC 23271 strain shares 941 gene clusters with six other probiotic strains of L. fermentum. Putative genes known to confer probiotic properties have been identified in the genome, including genes related to adhesion, tolerance to acidic pH and bile salts, tolerance to oxidative stress, and metabolism and transport of sugars and other compounds. A search for bacteriocin genes revealed a sequence 48% similar to that of enterolysin A, a protein from Enterococcus faecalis. However, in vitro assays confirmed that the strain has inhibitory activity on the growth of Candida species and also interferes with their adhesion to HeLa cells. In silico analyses demonstrated a high probability of the protein with antimicrobial activity. Our data reveal the genome features of L. fermentum ATCC 23271, which may provide insight into its future use given the functional benefits, especially against Candida infections.

Ligilactobacillus salivarius PS2 Supplementation during Pregnancy and Lactation Prevents Mastitis: A Randomised Controlled Trial

Mastitis is considered one of the main reasons for unwanted breastfeeding cessation. This study aimed to investigate the preventive effect of the probiotic strain Ligilactobacillus salivarius PS2 on the occurrence of mastitis in lactating women. In this multicountry, multicenter, randomized, double-blind, placebo-controlled trial, 328 women were assigned to the probiotic or the placebo group. The intervention started from the 35th week of pregnancy until week 12 post-partum. The primary outcome was the incidence (hazard) rate of mastitis, defined as the presence of at least two of the following symptoms: breast pain, breast erythema, breast engorgement not relieved by breastfeeding, and temperature > 38 °C. The probability of being free of mastitis during the study was higher in the probiotic than in the placebo group (p = 0.022, Kaplan-Meier log rank test) with 9 mastitis cases (6%) vs. 20 mastitis cases (14%), respectively. The hazard ratio of the incidence of mastitis between both study groups was 0.41 (0.190-0.915; p = 0.029), indicating that women in the probiotic group were 58% less likely to experience mastitis. In conclusion, supplementation of L. salivarius PS2 during late pregnancy and early lactation was safe and effective in preventing mastitis, which is one of the main barriers for continuing breastfeeding.

Enhancement of the Antibacterial Properties of Kefir by Adding Lactobacillus fermentum grx08

ABSTRACT

Kefir is an acidic-alcoholic fermented milk that can provide probiotic benefits, such as intestinal microecological balance regulation, antibacterial activity, and anti-inflammatory activity. In this study, Lactobacillus fermentum grx08 isolated from longevous people was used to further improve the health properties of kefir. L. fermentum grx08 and kefir grains obtained from Xinjiang, People's Republic of China, were mixed at ratios of 1:1, 5:1, and 25:1 as starters. The six gram-positive and gram-negative foodborne pathogens were able to grow in the supernatant of kefir but not in the supernatant of kefir with L. fermentum grx08. With increasing amounts of inoculated L. fermentum grx08, the antibacterial activity of the mixed fermented kefir gradually increased. The contents of lactic acid, fumaric acid, and malic acid in the mixed fermented milk were significantly increased by adding L. fermentum grx08 (P < 0.05), while the content of acetic acid decreased with the increase of L. fermentum grx08 and the content of citric acid was unaffected. This study suggests that the addition of L. fermentum grx08 shortened the fermentation time, improved the acidity, and retained the quality of fermented milk. Moreover, the antibacterial properties of kefir is enhanced by increasing the production of certain acids.

HIGHLIGHTS

Evaluation of the Effect of Limosilactobacillus fermentum CECT5716 on Gastrointestinal Infections in Infants: A Systematic Review and Meta-Analysis

Reducing the incidence of gastrointestinal infections (GIs) that occur at early stages to mitigate hospitalizations and treatments with adverse effects is a promising strategy for providing well-being to infants and their families. This systematic review and meta-analysis explores whether the early administration of Limosilactobacillus fermentum CECT5716 might be effective as a preventive therapy for GIs. We reviewed the literature to identify randomized controlled trials (RCTs) investigating the effectiveness of milk formulas supplemented with L. fermentum CECT5716 administered to infants at early stages to reduce the incidence of GIs. The MEDLINE (via PubMed), Web of Science (WoS), and Cochrane Central Register of Controlled Trials (via CENTRAL) databases were searched up to 15 June 2021. GI data from the included studies were synthesized in a random-effects model. Three RCTs were finally selected including 435 infants. There was a significant reduction in the incidence rate of GIs for those receiving L. fermentum CECT5716 compared with those receiving placebo (IRR: 0.52, 95% CI: 0.36-0.74, p = 0.0004). Heterogeneity between studies was moderate (I² = 54.5%). Based on the present systematic review and meta-analysis, the administration of L. fermentum CECT5716 at doses from 1 × 10⁹ to 8.4 × 10⁸ cfu/day in milk formulas may prevent GIs in infants up to 12 months old. Longer-term studies including a higher number of infants are needed to determine whether the use of this probiotic during the early stages of life is an efficient way to reduce the incidence of GIs.

Impact of Maternal Nutritional Supplementation during Pregnancy and Lactation on the Infant Gut or Breastmilk Microbiota: A Systematic Review

Recent evidence indicates that maternal dietary intake, including dietary supplements, during pregnancy and lactation may alter the infant gut or breastmilk microbiota, with implications for health outcomes in both the mother and infant. To review the effects of maternal nutritional supplementation during pregnancy and lactation on the infant gut or breastmilk microbiota a systematic literature search was conducted. A total of 967 studies published until February 2020 were found, 31 were eligible and 29 randomized control trials were included in the qualitative synthesis. There were 23 studies that investigated the effects of probiotic supplementation, with the remaining studies investigating vitamin D, prebiotics or lipid-based nutrient supplements (LNS). The effects of maternal nutritional supplementation on the infant gut microbiota or breastmilk microbiota were examined in 21 and 12 studies, respectively. Maternal probiotic supplementation during pregnancy and lactation generally resulted in the probiotic colonization of the infant gut microbiota, and although most studies also reported alterations in the infant gut bacterial loads, there was limited evidence of effects on bacterial diversity. The data available show that maternal probiotic supplementation during pregnancy or lactation results in probiotic colonization of the breastmilk microbiota. There were no observed effects between probiotic supplementation and breastmilk bacterial counts of healthy women, however, administration of Lactobacillus probiotic to nursing women affected by mastitis was associated with significant reductions in breastmilk Staphylococcal loads. Maternal LNS supplementation during pregnancy and lactation increased bacterial diversity in the infant gut, whilst vitamin D and prebiotic supplementation did not alter either infant gut bacterial diversity or counts. Heterogeneity in study design precludes any firm conclusions on the effects of maternal nutritional supplementation during pregnancy and lactation on the infant gut or breastmilk microbiota, warranting further research.

Limosilactobacillus fermentum CECT5716: Mechanisms and Therapeutic Insights

Probiotics microorganisms exert their health-associated activities through some of the following general actions: competitive exclusion, enhancement of intestinal barrier function, production of bacteriocins, improvement of altered microbiota, and modulation of the immune response. Among them, Limosilactobacillus fermentum CECT5716 has become one of the most promising probiotics and it has been described to possess potential beneficial effects on inflammatory processes and immunological alterations. Different studies, preclinical and clinical trials, have evidenced its anti-inflammatory and immunomodulatory properties and elucidated the precise mechanisms of action involved in its beneficial effects. Therefore, the aim of this review is to provide an updated overview of the effect on host health, mechanisms, and future therapeutic approaches.

Protocol for probiotic therapy vs placebo for preterm prelabour rupture of membranes to prolong pregnancy duration (Pro-PPROM) trial

BACKGROUND

Preterm prelabour rupture of membranes (PPROM) is a common preterm birth antecedent. Preterm infants experience increased adverse newborn outcome risks. Infection is a risk factor for early birth in PPROM. Current management is antibiotic therapy, antenatal corticosteroids and to plan delivery at 37 weeks gestation. The microbiota and probiotics are potentially protective and may improve outcomes.

AIMS

The primary aim is to evaluate whether oral probiotic therapy (Lactobacillus fermentum CECT5716) administered during PPROM between 24 and 34 weeks gestation prolongs pregnancy duration. The secondary aim is to evaluate maternal and neonatal outcomes.

MATERIALS AND METHODS

This is a pragmatic, multicentre, double-blind, placebo-controlled randomised controlled trial in Australia. The population will be women with a singleton pregnancy and PPROM less than 34 weeks gestation. The intervention will be an oral probiotic therapy compared with a placebo control. The primary outcome will be the proportion of women still pregnant at seven days following PPROM. One-to-one randomisation will occur within 24 h of PPROM. The trial is powered (80%, alpha = 0.05) to detect an absolute percentage increase in the primary outcome of 30%, (from expected rate of 20% up to 50%).

DISCUSSION

This trial will provide evidence for the effectiveness of the probiotic in prolonging pregnancy duration. Findings will inform the feasibility of a larger trial to examine the effect of oral probiotics on clinically important maternal and neonatal outcomes in PPROM.

The Microbiota of the Human Mammary Ecosystem

Human milk contains a dynamic and complex site-specific microbiome, which is not assembled in an aleatory way, formed by organized microbial consortia and networks. Presence of some genera, such as Staphylococcus, Streptococcus, Corynebacterium, Cutibacterium (formerly known as Propionibacterium), Lactobacillus, Lactococcus and Bifidobacterium, has been detected by both culture-dependent and culture-independent approaches. DNA from some gut-associated strict anaerobes has also been repeatedly found and some studies have revealed the presence of cells and/or nucleic acids from viruses, archaea, fungi and protozoa in human milk. Colostrum and milk microbes are transmitted to the infant and, therefore, they are among the first colonizers of the human gut. Still, the significance of human milk microbes in infant gut colonization remains an open question. Clinical studies trying to elucidate the question are confounded by the profound impact of non-microbial human milk components to intestinal microecology. Modifications in the microbiota of human milk may have biological consequences for infant colonization, metabolism, immune and neuroendocrine development, and for mammary health. However, the factors driving differences in the composition of the human milk microbiome remain poorly known. In addition to colostrum and milk, breast tissue in lactating and non-lactating women may also contain a microbiota, with implications in the pathogenesis of breast cancer and in some of the adverse outcomes associated with breast implants. This and other open issues, such as the origin of the human milk microbiome, and the current limitations and future prospects are addressed in this review.

Probiotics and human lactational mastitis: A scoping review

PROBLEM

Lactational mastitis is a common condition amongst breastfeeding women. It is associated with decreased breastfeeding rates and often treated with antibiotics.

BACKGROUND

The anti-inflammatory effects of probiotics have been identified as a potential treatment or prevention strategy for lactational mastitis leading to increased commercial and public interest. Despite the marketing of probiotics to women, evidence is still emerging as to its efficacy.

AIM/METHODS

This scoping review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) to identify and examine the evidence around probiotic consumption and lactational mastitis. The review addressed the question; what is the evidence regarding probiotic consumption and human lactational mastitis? Studies were critically appraised using the Joanna Briggs Institute checklist for randomised control trials (RCTs).

FINDINGS

Five RCTs met the inclusion criteria; three concerned probiotic consumption for the treatment of mastitis, two for the prevention of mastitis. All reported a lower incidence of mastitis in the probiotic groups.

DISCUSSION

Although potentially promising results were reported across all studies there were significant methodological limitations concerning; appropriately described baseline characteristics, study hypotheses, lack of power calculations, definitional issues, and potential conflicts of interest.

CONCLUSION

Probiotics may have utility for the treatment or prevention of lactational mastitis. However only a few studies with significant limitations have been published to date. Well designed and conducted studies are needed before evidence-based recommendations can be made for use of probiotics in the treatment or prevention of lactational mastitis.

Interventions for preventing mastitis after childbirth

BACKGROUND

Despite the health benefits of breastfeeding, initiation and duration rates continue to fall short of international guidelines. Many factors influence a woman's decision to wean; the main reason cited for weaning is associated with lactation complications, such as mastitis. Mastitis is an inflammation of the breast, with or without infection. It can be viewed as a continuum of disease, from non-infective inflammation of the breast to infection that may lead to abscess formation.

OBJECTIVES

To assess the effectiveness of preventive strategies (for example, breastfeeding education, pharmacological treatments and alternative therapies) on the occurrence or recurrence of non-infective or infective mastitis in breastfeeding women post-childbirth.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (3 October 2019), and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials of interventions for preventing mastitis in postpartum breastfeeding women. Quasi-randomised controlled trials and trials reported only in abstract form were eligible. We attempted to contact the authors to obtain any unpublished results, wherever possible.  Interventions for preventing mastitis may include: probiotics, specialist breastfeeding advice and holistic approaches.   DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trials for inclusion and risk of bias, extracted data and assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 10 trials (3034 women). Nine trials (2395 women) contributed data. Generally, the trials were at low risk of bias in most domains but some were high risk for blinding, attrition bias, and selective reporting. Selection bias (allocation concealment) was generally unclear. The certainty of evidence was downgraded due to risk of bias and to imprecision (low numbers of women participating in the trials). Conflicts of interest on the part of trial authors, and the involvement of industry funders may also have had an impact on the certainty of the evidence. Most trials reported our primary outcome of incidence of mastitis but there were almost no data relating to adverse effects, breast pain, duration of breastfeeding, nipple damage, breast abscess or recurrence of mastitis. Probiotics versus placebo Probiotics may reduce the risk of mastitis more than placebo (risk ratio (RR) 0.51, 95% confidence interval (CI) 0.35 to 0.75; 2 trials; 399 women; low-certainty evidence). It is uncertain if probiotics reduce the risk of breast pain or nipple damage because the certainty of evidence is very low. Results for the biggest of these trials (639 women) are currently unavailable due to a contractual agreement between the probiotics supplier and the trialists. Adverse effects were reported in one trial, where no woman in either group experienced any adverse effects. Antibiotics versus placebo or usual care The risk of mastitis may be similar between antibiotics and usual care or placebo (RR 0.37, 95% CI 0.10 to 1.34; 3 trials; 429 women; low-certainty evidence). The risk of mastitis may be similar between antibiotics and fusidic acid ointment (RR 0.22, 95% CI 0.03 to 1.81; 1 trial; 36 women; low-certainty evidence) or mupirocin ointment (RR 0.44, 95% CI 0.05 to 3.89; 1 trial; 44 women; low-certainty evidence) but we are uncertain due to the wide CIs. None of the trials reported adverse effects. Topical treatments versus breastfeeding advice The risk of mastitis may be similar between fusidic acid ointment and breastfeeding advice (RR 0.77, 95% CI 0.27 to 2.22; 1 trial; 40 women; low-certainty evidence) and mupirocin ointment and breastfeeding advice (RR 0.39, 95% CI 0.12 to 1.35; 1 trial; 48 women; low-certainty evidence) but we are uncertain due to the wide CIs. One trial (42 women) compared topical treatments to each other. The risk of mastitis may be similar between fusidic acid and mupirocin (RR 0.51, 95% CI 0.13 to 2.00; low-certainty evidence) but we are uncertain due to the wide CIs. Adverse events were not reported. Specialist breastfeeding education versus usual care The risk of mastitis (RR 0.93, 95% CI 0.17 to 4.95; 1 trial; 203 women; low-certainty evidence) and breast pain (RR 0.93, 95% CI 0.36 to 2.37; 1 trial; 203 women; low-certainty evidence) may be similar but we are uncertain due to the wide CIs. Adverse events were not reported. Anti-secretory factor-inducing cereal versus standard cereal The risk of mastitis (RR 0.24, 95% CI 0.03 to 1.72; 1 trial; 29 women; low-certainty evidence) and recurrence of mastitis (RR 0.39, 95% CI 0.03 to 4.57; 1 trial; 7 women; low-certainty evidence) may be similar but we are uncertain due to the wide CIs. Adverse events were not reported. Acupoint massage versus routine care Acupoint massage probably reduces the risk of mastitis compared to routine care (RR 0.38, 95% CI 0.19 to 0.78;1 trial; 400 women; moderate-certainty evidence) and breast pain (RR 0.13, 95% CI 0.07 to 0.23; 1 trial; 400 women; moderate-certainty evidence). Adverse events were not reported. Breast massage and low frequency pulse treatment versus routine care Breast massage and low frequency pulse treatment may reduce risk of mastitis (RR 0.03, 95% CI 0.00 to 0.21; 1 trial; 300 women; low-certainty evidence). Adverse events were not reported.

AUTHORS' CONCLUSIONS

There is some evidence that acupoint massage is probably better than routine care, probiotics may be better than placebo, and breast massage and low frequency pulse treatment may be better than routine care for preventing mastitis. However, it is important to note that we are aware of at least one large trial investigating probiotics whose results have not been made public, therefore, the evidence presented here is incomplete. The available evidence regarding other interventions, including breastfeeding education, pharmacological treatments and alternative therapies, suggests these may be little better than routine care for preventing mastitis but our conclusions are uncertain due to the low certainty of the evidence. Future trials should recruit sufficiently large numbers of women in order to detect clinically important differences between interventions and results of future trials should be made publicly available.

Breast Milk, a Source of Beneficial Microbes and Associated Benefits for Infant Health

Human breast milk is considered the optimum feeding regime for newborn infants due to its ability to provide complete nutrition and many bioactive health factors. Breast feeding is associated with improved infant health and immune development, less incidences of gastrointestinal disease and lower mortality rates than formula fed infants. As well as providing fundamental nutrients to the growing infant, breast milk is a source of commensal bacteria which further enhance infant health by preventing pathogen adhesion and promoting gut colonisation of beneficial microbes. While breast milk was initially considered a sterile fluid and microbes isolated were considered contaminants, it is now widely accepted that breast milk is home to its own unique microbiome. The origins of bacteria in breast milk have been subject to much debate, however, the possibility of an entero-mammary pathway allowing for transfer of microbes from maternal gut to the mammary gland is one potential pathway. Human milk derived strains can be regarded as potential probiotics; therefore, many studies have focused on isolating strains from milk for subsequent use in infant health and nutrition markets. This review aims to discuss mammary gland development in preparation for lactation as well as explore the microbial composition and origins of the human milk microbiota with a focus on probiotic development.

Lactobacillus fermentum CECT5716 supplementation in rats during pregnancy and lactation affects mammary milk composition

Lactobacillus fermentum CECT5716 has shown immunomodulatory action and reduction of infections; therefore, it is suggested to be appropriate for use in early life. The present study aimed to assess the effects of the supplementation of L. fermentum CECT5716 in rats during gestation and lactation periods on the composition of some mammary milk components such as microbiota, fatty acid (FA) profile, and immunoglobulins. Wistar rats were supplemented by oral gavage with 1010 cfu/d of Lactobacillus fermentum CECT5716 (n = 6) or vehicle (n = 6) for 5 wk, comprising the 3 wk of gestation and the first 2 wk of lactation. At the end of the intervention, milk, mammary glands, and cecal contents were obtained for the tracking of the probiotic strain by nested PCR-quantitative PCR. Additionally, milk samples were used for the analysis of microbiota by 16S rRNA sequencing, FA by gas chromatography-flame ionization detector, and immunoglobulin by Luminex (Luminex Corporation, Austin, TX). Although L. fermentum CECT5716 administration did not modify the overall composition of milk microbiota, the strain was detected in 50% of the milk samples of rats supplemented with the probiotic. Moreover, probiotic administration induced beneficial changes in the FA composition of milk by increasing total PUFA, including linoleic and α-linolenic acids, and decreasing the proportion of palmitic acid. Finally, the milk of the rats treated with the probiotic showed a 2-fold increase of IgA levels. The supplementation with L. fermentum CECT5716 during pregnancy and lactation periods improved the milk composition of FA and immunoglobulins. These effects were not linked to the presence of the strain in milk, thus suggesting that the mechanism is connected to intestinal compartment. These findings provide novel insight into a potential new approach for infants to benefit from better nutrition, development of a healthy immune system and microbiota, and protection from gastrointestinal infections.

Lactobacillus fermentum CECT5716 Supplementation in Rats during Pregnancy and Lactation Impacts Maternal and Offspring Lipid Profile, Immune System and Microbiota

Probiotics have shown potential for their use in early life. This study aimed to investigate whether the administration of Lactobacillus fermentum CECT5716 during pregnancy and lactation periods impacts maternal and offspring plasma lipid profile, immune system and microbiota. Rats were supplemented with the probiotic during gestation and two weeks of lactation. After supplementation, although the microbiota composition was not affected, the probiotic strain was detected in all cecal contents of dams and in some of their pups. Dams showed reduced proportion of T cytotoxic cells in the mesenteric lymph nodes, modulation of intestinal cytokines (IL-10 and IL-12) and changes in plasma fatty acids (20:0, 22:0, 20:5 n-3, and 18:3 n-6). Pups showed changes in immunoglobulins (intestinal IgA and plasmatic IgG2a and IgG2c) and fatty acid profile (17:0, 22:0, and 18:2 n-6). Overall, Lactobacillus fermentum CECT5716 supplementation contributed to beneficially modulating the immune system of the mother and its offspring.

Milk Microbiota: What Are We Exactly Talking About?

The development of powerful sequencing techniques has allowed, albeit with some biases, the identification and inventory of complex microbial communities that inhabit different body sites or body fluids, some of which were previously considered sterile. Notably, milk is now considered to host a complex microbial community with great diversity. Milk microbiota is now well documented in various hosts. Based on the growing literature on this microbial community, we address here the question of what milk microbiota is. We summarize and compare the microbial composition of milk in humans and in ruminants and address the existence of a putative core milk microbiota. We discuss the factors that contribute to shape the milk microbiota or affect its composition, including host and environmental factors as well as methodological factors, such as the sampling and sequencing techniques, which likely introduce distortion in milk microbiota analysis. The roles that milk microbiota are likely to play in the mother and offspring physiology and health are presented together with recent data on the hypothesis of an enteromammary pathway. At last, this fascinating field raises a series of questions, which are listed and commented here and which open new research avenues.

Genetic and Biochemical Characterization of an Exopolysaccharide With in vitro Antitumoral Activity Produced by Lactobacillus fermentum YL-11

In the present study, the whole genome sequence of Lactobacillus fermentum YL-11, a novel exopolysaccharide (EPS)-producing lactic acid bacteria (LAB) strain isolated from fermented milk, was determined. Genetic information and the synthetic mechanism of the EPS in L. fermentum YL-11 were identified based on bioinformatic analysis of the complete genome. The purified EPS of YL-11 mainly comprised galactose (48.0%), glucose (30.3%), mannose (11.8%), and arabinose (6.0%). In vitro, the EPS from YL-11 exhibited inhibition activity against HT-29 and Caco-2 colon cancer cells, suggesting that EPS from strain YL-11 might be used as an antitumoral agent. EPS at 600 and 800 μg/mL achieved inhibition rates of 46.5 ± 3.5% and 45.6 ± 6.1% to HT-29 cells, respectively. The genomic information about L. fermentum YL-11 and the antitumoral activity of YL-11 EPS provide a theoretical foundation for the future application of EPS in the food and pharmaceutical industries.

Novel Innovations and Recent Findings in Lactation Support

Rationale

Staying current with the burgeoning amount of breastfeeding research can be a daunting task. It is incumbent upon the IBCLC and other lactation care providers to be cognizant of new research and innovations in lactation support.

Method

Recent products and findings regarding neonatal jaundice, hypoglycemia, mastitis, and therapeutic taping are presented.

Findings

New research findings, techniques, and products have been gathered to augment the provider's knowledge and skill set regarding a broad range of items relevant to clinical lactation practice. Most are affordable options for practitioners and parents, and represent safe and effective options for screening and treatment.

Unfolding the Human Milk Microbiome Landscape in the Omics Era

Studies conducted in the last years have demonstrated that human milk represents a continuous supply of beneficial bacteria to the infant gut, which contribute to the maturation of the digestive and immune functions in the developing infant. Nevertheless, the origin of bacterial populations in milk is not fully understood yet and they have been proposed to originate from maternal skin, infant’s mouth, and (or) endogenously, from the maternal digestive tract through a mechanism involving immune cells. Understanding the composition, functions and assembly of the human milk microbiota has important implications not only for the infant gut microbiota establishment, but also for the mammary health since dysbiosis in the milk bacteria may lead to mastitis. Besides, host, microbial, medical and environmental factors may affect the composition of the human milk microbiome, with implications for the mother-infant health. Application of both culture-dependent and -independent techniques to assess the milk microbiome faces some practical limitations but, together, have allowed providing novel and complementary views on its origin, composition and functioning as summarized in this minireview. In the next future, the application of the ultimate advances in next-generation sequencing and omics approaches, including culturomics, will allow a detailed and comprehensive understanding of the composition and functions of these microbial communities, including their interactions with other milk components, expanding the opportunities to design novel microbiome-based modulation strategies for this ecosystem.

Strong Multivariate Relations Exist Among Milk, Oral, and Fecal Microbiomes in Mother-Infant Dyads During the First Six Months Postpartum

BACKGROUND

Neonatal gastrointestinal (GI) bacterial community structure may be related to bacterial communities of the mother, including those of her milk. However, very little is known about the diversity in and relationships among complex bacterial communities in mother-infant dyads.

OBJECTIVE

Our primary objective was to assess whether microbiomes of milk are associated with those of oral and fecal samples of healthy lactating women and their infants.

METHODS

Samples were collected 9 times from day 2 to 6 mo postpartum from 21 healthy lactating women and their infants. Milk was collected via complete breast expression, oral samples via swabs, and fecal samples from tissue (mothers) and diapers (infants). Microbiomes were characterized using high-throughput sequencing of the 16S ribosomal RNA (rRNA) gene. Alpha and beta diversity indices were used to compare microbiomes across time and sample types. Membership and composition of microbiomes were analyzed using nonmetric multidimensional scaling and canonical correlation analysis (CCA). The contribution of various bacterial communities of the mother-infant dyad to both milk and infant fecal bacterial communities were estimated using SourceTracker2.

RESULTS

Bacterial community structures were relatively unique to each sample type. The most abundant genus in milk and maternal and infant oral samples was Streptococcus (47.1% ± 2.3%, 53.9% ± 1.3%, and 69.1% ± 1.8%, respectively), whereas Bacteroides were predominant in maternal and infant fecal microbiomes (22.9% ± 1.3% and 21.4% ± 2.4%, respectively). The milk microbiome was more similar to the infant oral microbiome than the infant fecal microbiome. However, CCA suggested strong associations between the complex microbial communities of milk and those of all other sample types collected.

CONCLUSIONS

These findings suggest complex microbial interactions between breastfeeding mothers and their infants and support the hypothesis that variation in the milk microbiome may influence the infant GI microbiome.

Strategies for the Preservation, Restoration and Modulation of the Human Milk Microbiota. Implications for Human Milk Banks and Neonatal Intensive Care Units

Studies carried in the last years have revealed that human milk contains a site-specific microbiota and constitutes a source of potentially beneficial bacteria to the infant gut. Once in the infant gut, these bacteria contribute to the assembly of a physiological gut microbiota and may play several functions, contributing to infant metabolism, protection against infections, immunomodulation or neuromodulation. Many preterm neonates are fed with pasteurized donor's human milk (DHM) or formula and, therefore, are devoid of contact with human milk microbes. As a consequence, new strategies are required to allow the exposition of a higher number of preterm infants to the human milk microbiota early in life. The first strategy would be to promote and to increase the use of own mother's milk (OMM) in Neonatal Intensive Care Units (NICUs). Even small quantities of OMM can be very valuable since they would be added to DHM in order to microbiologically "customize" it. When OMM is not available, a better screening of donor women, including routine cytomegalovirus (CMV) screening of milk, may help to avoid the pasteurization of the milk provided by, at least, a relevant proportion of donors. Finally, when pasteurized DHM or formula are the only feeding option, their supplementation with probiotic bacteria isolated from human milk, such as lactic acid bacteria or bifidobacteria, may be an alternative to try to restore a human milk-like microbiota before feeding the babies. In the future, the design of human milk bacterial consortia (minimal human milk microbiotas), including well characterized strains representative of a healthy human milk microbiota, may be an attractive strategy to provide a complex mix of strains specifically tailored to this target population.

Mammary Dysbiosis

Mastitis can be an unwelcome and debilitating visitor to breastfeeding mothers. The mammary gland has its own microbiome that can be affected by reduced polymorphonuclear neutrophil recruitment during the first 3 months postpartum, as well as the receipt of antibiotics during the last trimester of pregnancy. This can leave the breast vulnerable to pathologic bacterial overgrowth. Mammary dysbiosis is a process whereby the population of potential pathogens increases at the expense of the normal mammary microbiota. Multiresistance to antibiotics plus tricky evasion techniques engaged in by bacterial agents can result in microbes that are elusive to antibiotic therapy. Therefore, new strategies are needed for the treatment of this threat to continued breastfeeding. Bacteriotherapy, targeting harmless bacteria to displace pathologic organisms, is an emerging therapeutic intervention that uses probiotics instead of antibiotics. Once more high-quality clinical trials of strain-specific probiotics have been conducted, bacteriotherapy may move into mainstream mastitis treatment.

Breastfeeding-associated microbiota in human milk following supplementation with Lactobacillus rhamnosus GG, Lactobacillus acidophilus La-5, and Bifidobacterium animalis ssp. lactis Bb-12

Breastfeeding is one of the major factors affecting the early development of the infant gut microbiota, and weaning is associated with a shift in the gut microbiota toward a more adult composition. Through breastfeeding, infants receive bioactive components that shape their microbiota while also being exposed to the breast milk and breast surface microbial communities. Recent studies have suggested the possibility of an entero-mammary route of microbial transfer, opening the possibility of infant gut microbiota modulation through maternal probiotic supplementation. In this study, we have analyzed breast milk samples collected at 10 d and 3 mo postpartum from women participating in the Probiotics in the Prevention of Allergy among Children in Trondheim placebo controlled trial. Women who were randomized to the probiotic arm of the Probiotics in the Prevention of Allergy among Children in Trondheim trial received a fermented milk supplemented with Lactobacillus rhamnosus GG, Lactobacillus acidophilus La-5, and Bifidobacterium animalis ssp. lactis Bb-12, consuming this daily from 4 wk before their expected due date until 3 mo after birth. In total, 472 breast milk samples were assessed for the administered bacteria using quantitative real-time PCR and the microbiota transferred during breastfeeding was analyzed using 16S ribosomal RNA gene sequencing of 142 samples. We found that breastfeeding is unlikely to be a significant source of L. rhamnosus GG, L. acidophilus La-5, and B. animalis ssp. lactis Bb-12 for infants in the probiotic arm of the trial. Furthermore, maternal supplementation did not significantly affect the overall composition of the breast milk microbiota transferred during breastfeeding. We also present a descriptive analysis of this microbiota, which was largely dominated by Streptococcus and Staphylococcus genera at both 10 d and 3 mo postpartum. Samples collected at 3 mo postpartum had a statistically significant lower presence and relative abundance of the Staphylococcus genus. These samples also had a greater number of observed species and diversity, including more operational taxonomic units from the Rothia, Veillonella, Granulicatella, and Methylbacterium genera.

The Postpartum Maternal and Newborn Microbiomes

Biological and environmental changes to maternal and newborn microbiomes in the postnatal period can affect health outcomes for the mother-baby dyad. Postpartum sleep deprivation and unmet dietary needs can alter commensal bacteria within the body and disrupt gut-brain communication. Perineal injury and breast infections also change microbial community composition, potentiating an environment favoring pathogen growth. The gut microbiome refers to the collection of microorganisms working in harmony. Disruptions within the gut microbiome and gut-brain communication may lead to postpartum depression, a potentially devastating sequela. Postnatal newborn changes to the gut and skin microbiome materialize quickly after birth and are profoundly influenced by mode of birth, feeding method, and bathing and skin care practices. During the newborn period, infant microbiomes are highly vulnerable and susceptible to multiple influences. Maternal-newborn nurses have a valuable role in helping mothers and newborns promote healthy microbiomes. Factors that influence the rapidly changing postnatal microbiome of the mother and her newborn, and the role nurses have to positively influence immediate and long-term health outcomes are presented.

Lactobacillus fermentum CECT 5716 and a reduction of the Staphylococcus load in breast milk which reduces the risk of infectious mastitis: evaluation of a health claim pursuant to Article 14 of Regulation (EC) No 1924/2006

Following an application from Biosearch Life, submitted for authorisation of a health claim pursuant to Article 14 of Regulation (EC) No 1924/2006 via the Competent Authority of France, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to Lactobacillus fermentum CECT 5716 and decreases the Staphylococcus load in breast milk. High Staphylococcus load in breast milk is a risk factor for infectious mastitis. The scope of the application was proposed to fall under a health claim referring to disease risk reduction. The Panel considers that Lactobacillus fermentum CECT 5716 is sufficiently characterised. In the context of this application, the Staphylococcus load in breast milk can be considered a risk factor for the development of infectious mastitis, as long as evidence is provided that the consumption of Lactobacillus fermentum CECT 5716 reduces the Staphylococcus load in breast milk as well as the incidence of infectious mastitis. Three human intervention studies investigated the effect of Lactobacillus fermentum CECT 5716 on the Staphylococcus load of breast milk in lactating women. One of these studies was conducted in lactating women free of infectious mastitis at baseline. The Panel considers that no conclusions can be drawn from this study for the scientific substantiation of the claim owing to important methodological limitations. The other two studies were conducted in lactating women with infectious mastitis and, therefore, the effect of the intervention on the incidence of infectious mastitis cannot be assessed. The Panel concludes that a cause and effect relationship has not been established between the consumption of Lactobacillus fermentum CECT 5716 and a reduction of the Staphylococcus load in breast milk which reduces the risk of infectious mastitis.

Oral Administration to Nursing Women of Lactobacillus fermentum CECT5716 Prevents Lactational Mastitis Development: A Randomized Controlled Trial

Objective: The objective of this study is to evaluate the preventive effect of oral administration of Lactobacillus fermentum CECT5716 on mastitis incidence in lactating women.

Methods: A randomized double-blinded controlled trial that included 625 women was conducted. Women who received preventive dose of antibiotic in the context of delivery were recruited 1–6 days after childbirth and randomly assigned to a group. Probiotic group received 1 capsule/day containing L. fermentum 3 × 10⁹ CFU, control group received 1 placebo capsule/day containing maltodextrin. The intervention period was 16 weeks. The primary outcome of the study was the incidence of clinical mastitis defined as at least two out of the three breast symptoms (pain, redness, and lump) and at least one of fever or flu-like symptoms (shivering, hot sweats, or aches).

Results: Two hundred ninety-one women completed 16 weeks of treatment. Sixteen women in the probiotic group developed mastitis versus 30 women in the control group (odds ratio = 0.531; p = 0.058). Incidence rate of mastitis in the probiotic group was significantly lower than that in the control group (IR = 0.130 in the probiotic group versus IR = 0.263 in the control group; p = 0.021). Therefore, the oral administration of L. fermentum CECT5716 during lactation decreased by 51% the incidence rate of clinical mastitis. Staphylococcus spp. load at the end of intervention was significantly lower in breast milk of women in the probiotic group than in breast milk of women in the control group (p = 0.025).

Conclusion: Consumption of the probiotic strain L. fermentum CECT5716 might be used during breastfeeding as an efficient strategy to prevent development of lactational mastitis in women.

Trial registration: NCT02203877.

A review of dose-responses of probiotics in human studies

The probiotic definition requires the administration of an 'adequate amount' in order to obtain a health benefit. What that amount should be is not indicated. Here, an overview is given of studies that investigated the dose-response relation of probiotics in human interventions. Studies were divided in; meta-analyses, meta-analyses on specific probiotic strains, and studies testing two or more doses of a probiotic (combination) in the same study. Meta-analyses on the effect of probiotics on antibiotic associated diarrhoea (AAD) suggest a dose-response effect; for Clostridium difficile-associated diarrhoea on the other hand no dose-response was observed. For other end-points; such as necrotising enterocolitis, prevention of atopic dermatitis and slow intestinal transit, no dose-response relation was identified in meta-analyses. For prophylaxis in colorectal cancer and relief of irritable bowel syndrome, no dose-response relation was determined. However, for blood pressure, a meta-analysis observed that higher doses (greater than 10¹¹ cfu) were more effective than lower doses. Meta-analyses of specific strains suggest a break-point for effectiveness of Lactobacillus rhamnosus GG in the treatment of acute gastroenteritis in children; no dose-response was observed for two other probiotics assessed. Studies comparing two or more doses indicate that faecal recovery and risk reduction of AAD follow a positive dose-response relationship. Other end-points such as immune markers, general health, and bowel function did not exhibit clear dose-response relations. For AAD, the findings are very compelling; both meta-analyses and dedicated dose-response studies observe a positive correlation between dose and AAD risk. These findings do not allow for extrapolation, but suggest that studying higher doses for this end-point would be worthwhile. The lack of a clear dose-response for other end-points, does not mean it does not exist; present data does just not allow drawing any conclusions.