Children and dogs in a household share gut microbes – and these microbes are modified by a canine probiotic

From longtime family pets to ‘pandemic puppies’, dog ownership is seemingly more popular than ever. In households with children, scientists have found that a pet dog is one of the environmental factors that influences the gut microbiota in early life – but can the microbes that children and dogs share be modified?

A new study from ISAPP president Prof. Seppo Salminen (University of Turku, Finland) and colleagues recently explored the impact of a household dog on children’s gut microbiota, before and after the dogs were given a canine probiotic. Not only did the gut microbiota of dogs and children in the same household share features in common, but also the gut microbes of both shifted after dogs received a probiotic.

The study, which was part of a larger investigation, looked at families with at least one member who had allergic disease. Thirty-one of the families in the current study had dogs, and 18 families (the control group) did not. From each household, the fecal microbiota of one child (aged 5 or under) was tested. The fecal microbiota of the dogs was tested, and further, they received either a probiotic containing 3 canine-derived strains, or placebo.

The data supported previous observations that dogs and children share gut microbes: the children living with dogs had a distinct fecal microbiota composition. The most striking microbiota differences were a higher abundance of Bacteroides and short-chain fatty acid producing bacteria.

Moreover, when the household dogs were given a probiotic, both the dogs and the children living with them showed a gut microbiota shift, with a reduction in Bacteroides. (The exact probiotic strains were not tracked in the feces of either the dogs or the children.)

Were the changes beneficial? It’s not certain, since health outcomes in the children were not part of the study. But these findings provide more evidence for the effect of home environments and pets on the gut microbiota of children, and highlight the modifiability of both the dog’s and children’s gut microbiota. The ability to modify a child’s gut microbiota is of particular interest in the early years, when gut microbiota / immune interactions have the potential to shape health through the lifespan.

The study authors conclude, “Our promising data invite the idea that the compositional development of the gut microbiota in children is potentially modifiable by indirect changes in household pets and justify the further search of novel modes of intervention during critical period when the scene is set for the consolidation of the child later health.”

Probiotics to Prevent Necrotizing Enterocolitis: Moving to Evidence-Based Use

By Ravi Mangal Patel, MD, Msc, Associate Professor of Pediatrics, Emory University School of Medicine and Children’s Healthcare of Atlanta. Twitter: @ravimpatelmd

Necrotizing enterocolitis (NEC) is one of the most lethal neonatal diseases, yet most people have never heard about it. The disease primarily affects preterm infants and is characterized by the development of intestinal inflammation. Clinically, the disease often manifests with an infant developing feeding intolerance or abnormal abdominal exam findings. The diagnosis is confirmed by abdominal x-ray or ultrasound. One of the key diagnostic radiographic findings is pneumatosis, which is air in the lumen of the bowel caused by gas-producing bacteria.

Dr Ravi Mangal Patel

NEC accounts for 1 out of every 10 deaths in US neonatal intensive care units. Among extremely preterm infants (those born at 22-28 weeks’ gestation) in the US, NEC is the most common single cause of death between 2 weeks and 2 months of age. Many infants with NEC undergo surgery to remove diseased bowel and those who recover and survive are at risk for long-term neurodevelopmental impairment and short bowel syndrome.

Decades of research into NEC have identified several key risk factors, including formula feeding, inconsistent feeding, abnormal intestinal oxygenation and [gut microbiota] dysbiosis. Studies have shown that dysbiosis, or abnormal intestinal colonization, is an important antecedent risk factor for the development of NEC. These studies have found that infants who develop NEC have an increase or bloom in the relative abundance of proteobacteria, compared to those who do not develop NEC. These proteobacteria, which contain a lipopolysaccharide coating, may lead to inflammation through their interaction with Toll-like receptor 4.

Given the role of dysbiosis in NEC, efforts to intervene by provision of probiotics to prevent NEC is a rational and extensively studied intervention, with over 63 randomized trials enrolling ~15,000 infants to date. The aforementioned meta-analysis, along with several others (Table 1), show probiotic supplementation results in large magnitude reductions in the risks of NEC and death and more modest reductions in the risks of late-onset sepsis. However, there is more limited data on extremely preterm infants and the quality or certainty of evidence for probiotics for the prevention of NEC was low in a recent Cochrane review.



In the United States, an increasing number of centers have begun to routinely provide probiotics, with the greatest increase in use beginning in 2015. Observational studies evaluating routine probiotic use show benefits that are similar in magnitude to those from randomized trials, supporting the external validity of the results from the trials. This includes a large recent evaluation of probiotic use in the United States. Around the world, probiotic use is highly variable, from 100% of NICUs in New Zealand, 68% of NICUs in Germany, to 12% in the UK, 21% in Canada and 14% in the United States. Some of the variability in clinical use may be related to the uncertainty regarding the quality of commercially available probiotic products and need for clarity regarding strain-specificity of effects. There are many considerations both for and against routine use of probiotics to prevent NEC (Table 2). Current probiotic dietary supplements do not undergo FDA’s premarket review and approval requirements for safety and effectiveness or have to meet manufacturing and testing standards for drugs, and the potential risks were highlighted by a case of an infant death from a contaminated supplement. There is currently no FDA-approved live biotherapeutic product to prevent NEC.

Source: doi: 10.1016/j.earlhumdev.2019.05.009

Recent recommendations and guidance from ESPHGAN and the AGA also demonstrate that some medical organizations recognize the strength of the data in support of probiotic use to prevent NEC. It has been over two decades since the first study demonstrating the benefit of probiotic supplementation to prevent NEC in preterm infants. Now, more than ever, the evidence continues to accumulate regarding the beneficial effects of probiotic use in preterm infants as a compelling strategy to reduce the risks of both NEC and death. Therefore, considering the balance of potential risks and benefits including data from both randomized trials and routine implementation studies, my opinion is that the cumulative evidence to date supports routine probiotic use to prevent NEC and death in preterm infants.

As important is considering the parent voice regarding probiotic use. The NEC Society is a non-profit focused on NEC that has worked to incorporate the voice of the patient-family in clinical decisions.

Disclosures: Dr. Patel serves on the data-safety monitoring board of the Connection Study, which is a trial examining the use of an investigational probiotic to decrease the risk of NEC.

For further information, see this seminar by Dr. Patel: Practical Consideration for Probiotics in the NICU