Table 1.

Alterations in the gut microbiota of preterm infants related to different factors

Factors	Alterations	Reference
PROM a and chorioamnionitis	↑ Staphylococcus ↑ Streptococcus ↑ Serratia ↑ Parabacteroides	Chernikova, et al. (2016)
Pre-eclampsia	↓ Escherichia/Shigella	Westaway, et al. (2021)
GDM	↑ Firmicutes ↓ Alpha-diversity ↓ Proteobacteria ↓ Prevotella ↓ Lactobacillus	Chen, et al. (2021), Su, et al. (2018)
C-section	↑ Firmicutes ↑ Actinobacteria ↑ Clostridium sensu stricto ↓ Bacteroides	Pammi, et al. (2017), Rutayisire, et al. (2016), Gregory, et al. (2015), Hill, et al. (2017)
Prenatal antibiotic	↓ Bifidobacterium	Zou, et al. (2018)
IAP	↓ Alpha-diversity ↓ Bacteroidetes ↑ Proteobacteria ↑ Bifidobacteria ↑ Staphylococcaceae ↑ Unclassified bacilli ↓ Enterobacteriaceae ↑ Comamonadaceae	Arboleya, et al. (2015), Diamond, et al. (2021), Dierikx, et al. (2020)
Postnatal antibiotic (PTIs)	↑ Enterococcus ↓ Bifidobacteria ↓ B. fragilis ↓ Bacteroidetes	Zou, et al. (2018), Penders, et al. (2006), Chang, et al. (2021)
MOM	↑ Alpha-diversity ↑ Bacteroides ↑ Bifidobacterium ↑ Enterococcus	Ford, et al. (2019), Gregory, et al. (2016)

^aPTIs, preterm infants; PROM, premature rupture of the fetal membrane; GDM, gestational diabetes mellitus; C-section, cesarean section; IAP, Intrapartum antibiotic prophylaxis; MOM, mother’s own milk