Table 2 Antibiotic exposure among case and control infants.

From: Associations between antibiotic exposure intensity, intestinal microbiome perturbations, and outcomes in premature neonates with bacteremia

Cumulative ASIa by subject, mean

Case (n = 40)

Control (n = 39)

p-value

ASI at 7 days of life

22.7

8.4

<0.001

ASI at 30 days of life

94.8

10.8

<0.001

ASI at time of bacteremia

110.6

n/a

 

ASI at NICU discharge

252.4

11.4

<0.001

Preceding ASIb by sample, mean

Case (n = 199 stools)

Control (n = 199 stools)

 

ASI in 7 days preceding stool collection

11.3

0.5

0.001

ASI in 14 days preceding stool collection

21.8

1.7

<0.001

Total exposed to antibiotic, n (%)c

Case (n = 40)

Control (n = 39)

 

Ampicillin

37 (92.5)

27 (69.2)

0.01

Gentamicin

37 (92.5)

26 (66.7)

0.005

Vancomycin

32 (80)

3 (8.0)

<0.001

Cefepime

28 (70)

2 (5.0)

<0.001

Metronidazole

19 (47.5)

2 (5.0)

0.0

Cefotaxime or ceftriaxone

18 (45)

0 (0)

Cefazolin

17 (42.5)

0 (0)

Piperacillin-tazobactam

11 (27.5)

0 (0)

  1. P-values calculated using independent t-test for ASI, chi-square or Fisher Exact Test for categorical antibiotic exposures, with statistical significance defined as p < 0.05.
  2. aCumulative ASI is the sum of all antibiotics up to that timepoint in the subject’s NICU admission while bpreceding ASI is the sum of antibiotics received only during a specific interval prior to individual stool collections.
  3. cTotal exposed is the number of subjects who received the listed antibiotic at any point during admission. More details including ASI calculations available in supplemental methods.