Antibiotic Use in Infants


Antibiotics are very effective and safe drugs that have saved millions of lives worldwide. However, we are still learning how antibiotics affect the normal/good bacteria in your child’s stomach. These bacteria collectively are called a microbiome. To understand more, we are conducting a study that looks at your baby’s bacteria before and after antibiotics are administered to determine how they are affected by antibiotic use.


Currently recruiting participants: Yes

Eligible gender: Male, Female, Transgender, Other

Inclusion criteria:

1. Must be admitted as an in-patient to the Alberta Children’s Hospital or to the Peter Lougheed Centre.
2. Must have been administered an IV dose of antibiotics.
3. Age 0 to 3.99 months.

Exclusion criteria:

1. Currently taking oral antibiotics or have been taking oral antibiotics within the past 2 weeks.

2. Born very prematurely.
(Before 31 weeks + 6 days, or any time before 32 weeks)

3. Have gastrointestinal anomalies or have a history of gastrointestinal surgery.
(e.g. Gastroesophageal reflux, meconium plug syndrome, intestinal obstruction)

4. Have necrotizing enterocolitis (NEC).
(The intestinal wall is infected by bacteria)

5. Have neonatal cholestasis or gastroenteritis.
(Excess bilirubin; Presence of diarrhea or vomiting, ≥ 3 episodes in a 24-hour period)

6. Reside outside of the Calgary city limits.

7. Previously enrolled in this study.

8. Unable to provide all requested specimens or complete follow-up.

9. Unable to understand English.

10. Currently (most recent complete blood count) known to be neutropenic
(Neutrophils <1000), or at high-risk of being neutropenic (receiving chemotherapy)
at present.
(Rectal swabs in neutropenic patients are not performed due to potential for bacteremia.)


Fill out the following form if you want to participate in this research

Method of contact

Additional information

Contact information

Recruitment is only through hospital admission. However, if you have any questions in regards to participating in the research study, please contact Karen Lowerison, the ANTIBIO Team lead, at 403-955-3197 or

Principal investigator:

Marie Arrieta

Clinical trial: