Table 1:

Demographic data of cohort with opportunistic sampling.

Demographics	All Patients (n=23)a	Cefepime (n=10)	Meropenem (n=7)	Piperacillin/Tazobactam (n=9)
Age, years Mean ± Standard Deviation	12.7 ± 8.3	15.2 ± 9.0	15.4 ± 7.4	8.0 ± 7.1
Weight, kg	45.5	45.1	60.6	18.1
Median [range]	[10.6–94.8]	[16.1–69.4]	[10.6–94.8]	[10.6–55.9]
Males, n (%)	11 (48)	2 (20)	4 (57)	7 (78)
Comorbid conditionsb, n (%)	21 (91)	9 (90)	7 (100)	8 (89)
Sepsisc, n (%)	10 (43)	6 (60)	3 (43)	4 (44)
Culture positive, n (%)	2 (20)	1 (17)	1 (33)	1 (25)
Culture negative, n (%)	8 (80)	5 (83)	2 (67)	3 (75)

^aOne patient received an organ transplant, readmitted post-op to the PICU, was administered a different β-lactam on PICU readmission, and was considered as 2 separate encounters. Three patients were initiated on one of the 3 β-lactams of interest and switched to one of the other 2 β-lactams within 7 days during index PICU admission; patients who received 2 of the 3 β-lactam antibiotics sequentially were included each respective antibiotic group.

^bcomorbid condition defined as condition requiring medications or subspecialty care

^csepsis: defined as meeting pediatric-specific consensus criteria for sepsis and received at least seven days of antibiotics.