Table 3.

Influence of antibiotic exposure (broad^* vs. narrow) on taxonomic composition in all preterm infants (both PEP- and NPVP-infants) with fecal samples and who received antibiotics after first week of life.

	Microbiota at 28 days			Microbiota at 4 months
	Median relative abundance			Median relative abundance
Antibiotic regimen	Broad*	Narrow	P	Broad*	Narrow	P	FDR Q
	(n = 7**)	(n = 15**)		(n = 9**)	(n = 13**)
BACTERIAL GENERA
Bifidobacterium	14.4	28.9	0.783	14.3	41.5	0.096	0.512
Escherichia	44.5	1.40	0.368	17.4	9.9	0.209	0.669
Klebsiella	0.00	0.00	0.680	0.25	0.57	0.845	0.623
Enterobacter	0.00	0.45	0.123	0.00	0.00	0.235	0.627
Staphylococcus	0.42	0.08	0.783	0.00	0.00	1.00	1.00
Veilonella	0.00	0.00	0.945	1.25	6.01	0.001	0.016
Enterococcus	2.73	0.68	0.783	0.64	0.39	0.647	1.00
Streptococcus	0.00	0.00	0.630	0.07	0.18	0.126	0.504
Lactobacillus	0.00	0.00	0.891	0.00	0.87	0.071	0.568

PEP, probiotic extremely preterm; NPVP, non-probiotic very preterm.

^*We defined regimens including third-generation cephalosporins or carbapenems as a broad-spectrum regimen.

^**Number of fecal samples included in these analyses.

Median relative abundance of Bacteroides, Morganella, Akkermansia, Prevotella, Acinetobacter, Haemophilus, and Serratia were < 0.001 at 28 days and 4 months of age and there were no statistical difference between groups.

Bold indicate significant difference between broad- and narrow-spectrum antibiotic exposure.

FDR, false discovery rate; only calculated for comparisons with P < 0.05.