Bacterial Growth, Human Milk Microbiome
Conditions
Keywords
human milk, breast milk, expressed human milk, bacterial communities, microbiome, breast pump, bacterial growth
Brief summary
The MiLC trial is a randomized control trial of two different breast pump set-ups: mother's own and sterile. The objective of this trial is to investigate the bacterial composition of human milk pumped and stored in real-life conditions. To meet this objective, lactating mothers will fully express breast milk from one breast on two consecutive pumping sessions at home, once with the participant's own pumps and collection kits (own pump set-up) and once with a hospital-grade pump and disposable, sterile collection kits (sterile pump set-up). Randomization will be used to determine which pump participants use first. From the total volume of milk pumped during each pumping session, the researchers will collect 1 oz. Milk from both pumps will be stored at home and sampled on days 0, 2, 4, and 30 after expression for analysis of its bacterial composition.
Detailed description
Participants will donate 1 oz of human milk during each of two consecutive pumping sessions, for a total volume of 2 oz donated on one day. To collect this human milk, participants will be asked to fully express one breast during each pumping session. Participants will pump once with the participant's own pump set-up and once with the sterile pump set-up (provided by the research team). Women will be randomized to which pump is used first. Randomization will be done using stratified randomization as follows: participants were stratified by how their infants were fed, namely whether infants were fed human milk only vs. human milk and complementary foods). Then, randomization was conducted within each strata. The researchers aim to have a minimum of 25 participants in each stratum. All human milk collections will occur at participants' homes between 0700 and 1100 hours. The second pumping session must begin 3 hours (+/-30 minutes) after the beginning of the first pumping session (e.g. the first pumping session at 7:30 am and the second at 10:30 am). Participants will elect from which breast to donate human milk and that breast will be used for both pumping sessions. Participants will be asked not to nurse from or pump that breast during the 2 hours before the first pumping session and not until after the second pumping session (a total of \ 5.5 hours). From the milk produced during each pumping session (which could be up to \ 6 oz), researchers will collect 1 oz using a sterile, plastic syringe. Participants will keep the remaining volume of milk. Each ounce of milk collected will be separated into 5 sterile containers (provided). Participants will store donated milk at home until it is picked up by a researcher 2, 4, and 30 days after pumping.
Interventions
DEVICESterile pump set-up
Medela symphony breast pump (model number 0240108) and disposable, sterile collection kits (model number 67399S).
DEVICEMother's Own pump set-up
Mother's own electric breast pump and own collection kit (previously used and cleaned at home using her usual practices).
Sponsors
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
University of Idaho
United States Department of Agriculture (USDA)
Cornell University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
All participants will pump their milk with two pump set-ups: own and sterile supplies. The pump set-up each woman used first was randomized according to infant feeding status (human milk only vs. human milk and complementary foods).
Eligibility
Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Lactating women over the age of 18 years * Self-reported as healthy women and infants * Use an electric breast pump * Confident of ability to donate 1 oz of milk from one breast during each of two consecutive pumping sessions where pumping sessions are 3 hours (+/- 30 minutes) apart and between 0700-1100 hours. * Able to store donated milk at home for 30 days * Have infants who do not consume formula or only consume formula episodically as long as the most recent formula-feeding occurred \> 2 weeks before the day milk is pumped for this study.
Exclusion criteria
* Not confident of ability to donate 1 oz of milk from one breast during each of two consecutive pumping sessions, 3 hours (+/- 30 minutes) apart and between the hours of 0700-1100 hours. * Infant consumption of formula in the past 2 weeks * Current indication of breast infection (e.g., breast pain, discomfort, lumps, mastitis with fever, red streaks, or hard red portions of the breast) * Breast pain that the woman does not consider normal for lactation/breastfeeding * Signs/symptoms of acute illness in woman or infant in past 7 days including fever (rectal or temporal temperature ≥99.5 F), dark green nasal discharge, diarrhea (abrupt onset of 3 or more excessively loose stools in one day), vomiting (where infant vomiting is not associated with feeding), or severe cough.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Bacterial Community Richness | 0 days after pumping | Richness is the total number of different bacterial taxa detected in the sample. This metric will be assessed on data collected via high-throughput sequencing of the bacterial 16S rRNA gene present in milk. |
| Bacterial Community Diversity | 0 days after pumping | Bacterial community diversity will be assessed using the the Shannon diversity index. The Shannon diversity index is a type of entropy measure and is a function of the distribution of the total number of organisms across all of the species. If S is the total number of species in the sample and p\_i is the number of organisms in the i-th species divided by the total number of organisms, then Diversity = -Σ p\_i log(p\_i). This metric will be assessed on data collected via high-throughput sequencing of the bacterial 16S rRNA gene present in milk. |
| Total Live Aerobic Bacterial Counts | 0 days after pumping | Number of live total aerobic bacteria in milk assessed by aerobic culturing of milk on plate count agar. Reported as colony-forming units (CFU)/mL. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Sterile Pump Set-up First Participants will pump with sterile pump set-ups first. Approximately 3 hours later, participants will pump with their own pump set-ups. | 27 |
| Mother's Own Pump Set-up First Participants will pump with their own pump set-ups first. Approximately 3 hours later, participants will pump with sterile pump set-ups. | 25 |
| Total | 52 |
Baseline characteristics
| Characteristic | Sterile Pump Set-up First | Mother's Own Pump Set-up First | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 27 Participants | 25 Participants | 52 Participants |
| Age, Continuous | 33.6 years STANDARD_DEVIATION 4.1 | 33.6 years STANDARD_DEVIATION 4 | 33.6 years STANDARD_DEVIATION 4 |
| Infant feeding status, number fed human milk only | 13 Participants | 14 Participants | 27 Participants |
| Race/Ethnicity, Customized African American/black | 0 Participants | 1 Participants | 1 Participants |
| Race/Ethnicity, Customized Asian or Pacific Islander | 2 Participants | 1 Participants | 3 Participants |
| Race/Ethnicity, Customized Caucasian/white | 23 Participants | 22 Participants | 45 Participants |
| Race/Ethnicity, Customized Native American | 1 Participants | 0 Participants | 1 Participants |
| Race/Ethnicity, Customized Other | 0 Participants | 2 Participants | 2 Participants |
| Region of Enrollment United States | 27 participants | 25 participants | 52 participants |
| Sex: Female, Male Female | 27 Participants | 25 Participants | 52 Participants |
| Sex: Female, Male Male | 0 Participants | 0 Participants | 0 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 0 | 0 / 0 |
| other Total, other adverse events | 0 / 0 | 0 / 0 |
| serious Total, serious adverse events | 0 / 0 | 0 / 0 |
Outcome results
Primary
Bacterial Community Diversity
Bacterial community diversity will be assessed using the the Shannon diversity index. The Shannon diversity index is a type of entropy measure and is a function of the distribution of the total number of organisms across all of the species. If S is the total number of species in the sample and p\_i is the number of organisms in the i-th species divided by the total number of organisms, then Diversity = -Σ p\_i log(p\_i). This metric will be assessed on data collected via high-throughput sequencing of the bacterial 16S rRNA gene present in milk.
Time frame: 0 days after pumping
Population: Data analyzed from all participants.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Sterile Pump Set-up First | Bacterial Community Diversity | In Milk Collected with Sterile Pump Set-Up | 3.89 Shannon Diversity Index | Standard Deviation 1.18 |
| Sterile Pump Set-up First | Bacterial Community Diversity | In Milk Collected with Mother's Own Pump Set-Up | 3.84 Shannon Diversity Index | Standard Deviation 1.08 |
| Mother's Own Pump Set-up First | Bacterial Community Diversity | In Milk Collected with Sterile Pump Set-Up | 3.56 Shannon Diversity Index | Standard Deviation 1.13 |
| Mother's Own Pump Set-up First | Bacterial Community Diversity | In Milk Collected with Mother's Own Pump Set-Up | 3.93 Shannon Diversity Index | Standard Deviation 1.26 |
p-value: 0.3Mixed Models Analysis
Primary
Bacterial Community Richness
Richness is the total number of different bacterial taxa detected in the sample. This metric will be assessed on data collected via high-throughput sequencing of the bacterial 16S rRNA gene present in milk.
Time frame: 0 days after pumping
Population: Data analyzed for all participants
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Sterile Pump Set-up First | Bacterial Community Richness | In Milk Collected with Sterile Pump Set-Up | 64.2 Observed taxa | Standard Deviation 38.3 |
| Sterile Pump Set-up First | Bacterial Community Richness | In Milk Collected with Mother's Own Pump Set-Up | 64.0 Observed taxa | Standard Deviation 30.7 |
| Mother's Own Pump Set-up First | Bacterial Community Richness | In Milk Collected with Sterile Pump Set-Up | 58.9 Observed taxa | Standard Deviation 26.9 |
| Mother's Own Pump Set-up First | Bacterial Community Richness | In Milk Collected with Mother's Own Pump Set-Up | 60.8 Observed taxa | Standard Deviation 32.8 |
p-value: 0.9Mixed Models Analysis
Primary
Total Live Aerobic Bacterial Counts
Number of live total aerobic bacteria in milk assessed by aerobic culturing of milk on plate count agar. Reported as colony-forming units (CFU)/mL.
Time frame: 0 days after pumping
Population: Data for all participants analyzed.
| Arm | Measure | Group | Value (GEOMETRIC_MEAN) | Dispersion |
|---|---|---|---|---|
| Sterile Pump Set-up First | Total Live Aerobic Bacterial Counts | In Milk Collected with Sterile Pump Set-Up | 1848 Colony-forming units (CFU)/mL | Standard Deviation 734 |
| Sterile Pump Set-up First | Total Live Aerobic Bacterial Counts | In Milk Collected with Mother's Own Pump Set-Up | 9157 Colony-forming units (CFU)/mL | Standard Deviation 3638 |
| Mother's Own Pump Set-up First | Total Live Aerobic Bacterial Counts | In Milk Collected with Sterile Pump Set-Up | 1233 Colony-forming units (CFU)/mL | Standard Deviation 490 |
| Mother's Own Pump Set-up First | Total Live Aerobic Bacterial Counts | In Milk Collected with Mother's Own Pump Set-Up | 6109 Colony-forming units (CFU)/mL | Standard Deviation 2427 |
p-value: 0.0003Mixed Models Analysis