Gut and Lung Microbiota in Preterm Infants: Immunological Modulation and Implication in Neonatal Outcomes

Abstract

In recent years, an aberrant gastrointestinal colonization has been found to be associated with an higher risk for postnatal sepsis, necrotizing enterocolitis (NEC) and growth impairment in preterm infants. As a consequence, the reasons of intestinal dysbiosis in this population of newborns have increasingly become an object of interest. The presence of a link between the gut and lung microbiome's development (gut-lung axis) is emerging, and more data show as a gut-brain cross talking mediated by an inflammatory milieu, may affect the immunity system and influence neonatal outcomes. A revision of the studies which examined gut and lung microbiota in preterm infants and a qualitative analysis of data about characteristic patterns and related outcomes in terms of risk of growing impairment, Necrotizing Enterocolitis (NEC), Bronchopulmonary Dysplasia (BPD), and sepsis have been performed. Microbiota take part in the establishment of the gut barrier and many data suggest its immune-modulator role. Furthermore, the development of the gut and lung microbiome (gut-lung axis) appear to be connected and able to lead to abnormal inflammatory responses which have a key role in the pathogenesis of BPD. Dysbiosis and the gut predominance of facultative anaerobes appear to be crucial to the pathogenesis and subsequently to the prevention of such diseases.

Temporal dynamics of the gut microbiome and metabolome in preterm and term infants from birth through the first year of life

“…The homogenisation effect observed might be a natural response of the gut microbiome towards the changes from womb to birth in which a smaller subset of available microbial populations was preferentially selected. It is notable that the higher Tenericutes observed in preterms' meconium compared to the terms is consistent with the composition of placental microbiome in preterm neonates (29,30). It is interesting to note that the divergence in preterm and term microbiomes was strongest at month 12.…”

Preterm birth and sustained inflammation: consequences for the neonate

“…Hence, distinct identifiable differences in functionality may predict subsequent infection-mediated outcomes [43]. Intriguingly, there is evidence that the developing organ systems at risk for long-term sequelae have a significant cross talk via the microbiome-immune interaction (gut-brain axis, gutlung axis, gut-heart axis) [44]. This emerging field of research offers new targets for microbiota stabilization in order to strengthen the ability to downregulate or resolve immune responses.…”

Impact of Probiotic B. Infantis EVC001 Feeding in Premature Infants on the Gut Microbiome, Nosocomially Acquired Antibiotic Resistance, and Enteric Inflammation

“…Therefore, the importance of early microbiome development on host health and morbidity and the relative plasticity of this community presents a need and an opportunity to colonize the preterm gut microbiome with beneficial organisms that maximize ecosystem services to the host [23]. These services include increased availability of nutrients from human milk, improved maturation of the intestinal epithelium, reduced enteric inflammation, and mitigated risk of infection in hospitalized infants [3,21,43,44,46]. In this study, we found preterm infants in two hospitals were colonized by nosocomially acquired bacteria despite a human milk diet, and the resulting gut microbiomes, absent intervention with B. infantis EVC001, developed comparably to reports in the literature on the preterm infant gut microbiome [1,2,10].…”