Gut Microbiota and Immune System in Necrotizing Enterocolitis and Related Sepsis

Intestinal Microbiota Dysbiosis Role and Bacterial Translocation as a Factor for Septic Risk

The human immune system is closely linked to microbiota such as a complex symbiotic relationship during the coevolution of vertebrates and microorganisms. The transfer of microorganisms from the mother's microbiota to the newborn begins before birth during gestation and is considered the initial phase of the intestinal microbiota (IM). The gut is an important site where microorganisms can establish colonies. The IM contains polymicrobial communities, which show complex interactions with diet and host immunity. The tendency towards dysbiosis of the intestinal microbiota is influenced by local but also extra-intestinal factors such as inflammatory processes, infections, or a septic state that can aggravate it. Pathogens could trigger an immune response, such as proinflammatory responses. In addition, changes in the host immune system also influence the intestinal community and structure with additional translocation of pathogenic and non-pathogenic bacteria. Finally, local intestinal inflammation has been found to be an important factor in the growth of pathogenic microorganisms, particularly in its role in sepsis. The aim of this article is to be able to detect the current knowledge of the mechanisms that can lead to dysbiosis of the intestinal microbiota and that can cause bacterial translocation with a risk of infection or septic state and vice versa.

Gut Pathogen Colonization: A Risk Factor to Bloodstream Infections in Preterm Neonates Admitted in the Neonatal Intensive Care Unit - A Prospective Cohort Study

INTRODUCTION

Gut pathogen colonization, where pathogens disrupt the normal gut microbiota, has been implicated in the development of bloodstream infections (BSIs). This study investigates the association between gut pathogen colonization and BSI, hypothesizing that species causing BSI primarily originated from gut.

METHODS

A prospective cohort study was conducted in the neonatal intensive care unit (NICU) of tertiary care hospital in Karnataka, India, from January 2021 to September 2023. Inborn preterm infants were enrolled. The study population was divided into two groups: group A (neonates without sepsis) and group B (neonates with sepsis). Demographic details and blood culture results were collected. Stool samples were taken on day 4 and day 14 for group A, and on day 4 and the day of sepsis diagnosis for group B.

RESULTS

Group B had a lower mean birthweight (1,649.6 ± 652.1 g) compared to group A (1,757 ± 656 g). Klebsiella pneumoniae was the most common pathogen causing BSIs (44.1%). The analysis revealed a high abundance of potential pathogens in the gut microbiome of group B neonates, with a concurrent decrease in beneficial gut flora.

CONCLUSION

This study provides strong evidence for the association between gut pathogen colonization and BSI development in preterm neonates in NICUs. Gut microbiota modulation may serve as preventive strategy against BSIs, emphasizing the need for further research in this area to improve outcomes in vulnerable population.

INTRODUCTION

Gut pathogen colonization, where pathogens disrupt the normal gut microbiota, has been implicated in the development of bloodstream infections (BSIs). This study investigates the association between gut pathogen colonization and BSI, hypothesizing that species causing BSI primarily originated from gut.

METHODS

A prospective cohort study was conducted in the neonatal intensive care unit (NICU) of tertiary care hospital in Karnataka, India, from January 2021 to September 2023. Inborn preterm infants were enrolled. The study population was divided into two groups: group A (neonates without sepsis) and group B (neonates with sepsis). Demographic details and blood culture results were collected. Stool samples were taken on day 4 and day 14 for group A, and on day 4 and the day of sepsis diagnosis for group B.

RESULTS

Group B had a lower mean birthweight (1,649.6 ± 652.1 g) compared to group A (1,757 ± 656 g). Klebsiella pneumoniae was the most common pathogen causing BSIs (44.1%). The analysis revealed a high abundance of potential pathogens in the gut microbiome of group B neonates, with a concurrent decrease in beneficial gut flora.

CONCLUSION

This study provides strong evidence for the association between gut pathogen colonization and BSI development in preterm neonates in NICUs. Gut microbiota modulation may serve as preventive strategy against BSIs, emphasizing the need for further research in this area to improve outcomes in vulnerable population.