The development of the gut microbiome and temperament during infancy and early childhood: A systematic review

Effects of early-life gut microbiota on the neurodevelopmental outcomes of preterm infants: a multi-center, longitudinal observational study in China

To prospectively investigate associations between the features of gut microbiota at the fourth week after birth in preterm infants and neurodevelopment from 1 month of corrected age to 6 months of corrected age (MCA). Seventy-seven preterm infants were recruited from three NICUs of three tertiary hospitals between Apr 2021 to Sep 2022. Stool samples were collected during the fourth week after birth. Illumina MiSeq high-throughput sequencing technology was used to detect the composition and diversity of gut microbiota. Neurodevelopment assessments of preterm infants were conducted at 1, 3, and 6 MCA using the Ages and Stages Questionnaire, the third edition (ASQ-3). Spearman correlation, a generalized linear mixed model (GLMM), and permutational multivariate analysis of variance (PERMANOVA) analysis were used to horizontally and prospectively explore the associations between gut microbial and ASQ-3 dimension scores at each time point. The GLMM showed no significant associations between the alpha diversity and neurodevelopmental trajectory from 1 to 6 MCA. The beta diversity was significantly associated with gross motor scores at 1, 3, and 6 MCA (R2 = 0.067, p = 0.001; R2 = 0.039, p = 0.020; R2 = 0.031, p = 0.047); communication scores at 3 MCA (R2 = 0.030, p = 0.040); and fine motor scores at 6 MCA (R2 = 0.035, p = 0.022). After adjusting for covariates, the GLMM showed that the relative abundance of Klebsiella was negatively associated with gross motor score trajectory from 1 to 6 MCA (β =  - 1.449; 95% CI, - 2.275 to - 0.572; p = 0.001), while the relative abundance of Lactobacillus displayed a positive association (β = 1.421; 95% CI, 0.139 to 2.702; p = 0.030). Moreover, the relative abundance of Streptococcus was negatively associated with fine motor trajectory from 1 to 6 MCA (β =  - 1.669; 95% CI, - 3.305 to - 0.033; p = 0.046).

CONCLUSION

Our results suggest a possible association between the neonatal gut microbial diversity; the relative abundance of Klebsiella, Streptococcus, and Lactobacillus; and neurodevelopment from 1 to 6 MCA. In the future, clinical staff can focus on the window period of gut microbiota colonization, and implement probiotics targeted at the dominant genera to improve the neurodevelopment of preterm infants.

WHAT IS KNOWN

• In the fields of biology and medicine, current studies suggest that gut microbiota may play an important role in the critical window period of neurodevelopment through the gut-brain axis pathway. • Extensive preclinical research has implied the vital role of the initial gut colonization in the long-term neurodevelopment of children.

WHAT IS NEW

• The early-life gut microbiota was associated with neurodevelopment in preterm infants within 6 months of corrected age (MCA).

Psychobiotics and the Microbiota-Gut-Brain Axis: Where Do We Go from Here?

The bidirectional relationship between the gut microbiota and the nervous system is known as the microbiota-gut-brain axis (MGBA). The MGBA controls the complex interactions between the brain, the enteric nervous system, the gut-associated immune system, and the enteric neuroendocrine systems, regulating key physiological functions such as the immune response, sleep, emotions and mood, food intake, and intestinal functions. Psychobiotics are considered tools with the potential to modulate the MGBA through preventive, adjunctive, or curative approaches, but their specific mechanisms of action on many aspects of health are yet to be characterized. This narrative review and perspectives article highlights the key paradigms needing attention as the scope of potential probiotics applications in human health increases, with a growing body of evidence supporting their systemic beneficial effects. However, there are many limitations to overcome before establishing the extent to which we can incorporate probiotics in the management of neuropsychiatric disorders. Although this article uses the term probiotics in a general manner, it remains important to study probiotics at the strain level in most cases.

Bacterial community analysis identifies Klebsiella pneumoniae as a native symbiotic bacterium in the newborn Protobothrops mucrosquamatus

BACKGROUND

The study of the native microbiome of organisms is crucial. The connection between the native microbiome and the host affects the formation of the innate immune system and the organism's growth. However, the native microbiome of newborn venomous snakes has not been reported. Therefore, we aimed to determine the oral and skin microbiomes of newborn Protobothrops mucrosquamatus.

RESULTS

We performed 16 S full-length sequencing on 14 samples collected from 7 newborn P. mucrosquamatus individuals, specifically targeting their oral and skin microbiomes. In terms of the oral and skin microbiome, the main species were Klebsiella pneumoniae lineages. According to subspecies/species analysis, the proportion from highest to lowest was K. quasipneumoniae subsp. similipneumoniae, K. pneumoniae subsp. pneumoniae, and K. pneumoniae subsp. rhinoscleromatis. These three bacteria accounted for 62.5% and 85% of the skin and oral activity, respectively. The oral microbiome of newborn P. mucrosquamatus did not comprise common bacteria found in snakebite wounds or oral cultures in adult snakes. Therefore, the source of other microbiomes in the oral cavities of adult snakes may be the environment or prey. Functional Annotation of the Prokaryotic Taxa analysis showed that the skin/oral native microbiome metabolism was related to fermentation and human infection owing to the dominance of K. pneumoniae lineages. The characteristics of K. pneumoniae may impact the development of venom in venomous snakes.

CONCLUSION

The results of the native microbiome in the oral cavity and skin of newborn P. mucrosquamatus demonstrated that the habitat environment and prey capture may affect the composition of bacteria in adult snakes. We hypothesized that the native microbiome influences newborn venomous snakes and that K. pneumoniae lineages related to citrate fermentation may play a role in venom growth. However, further verification of this is required.