NCT05020574 · University of California, San Francisco
Microbiome and Association With Implant Infections
What this study is about
The most common tissue expander-related infections are from Staphylococcus and Pseudomonas species. In addition, from breast tissue microbiome studies, Staphylococcus and Pseudomonas show variable abundance across samples.
View original scientific description
The most common tissue expander-related infections are from Staphylococcus and Pseudomonas species. In addition, from breast tissue microbiome studies, Staphylococcus and Pseudomonas show variable abundance across samples. The investigator hypothesizes that participants undergoing mastectomy with high initial abundance of Staphylococcus and/or Pseudomonas are more likely to develop subsequent tissue expander-related infections from these respective organisms.
Interventions
DRUG
Cephalexin
Given orally (PO)
Primary outcome measures
Proportion of tissue samples obtained successfully over time
Time frame: 90 days
The feasibility of success in obtaining samples from breast tissue will be measured as a binary outcome (successful or not successful) over time (intra-operatively, week 1, week 2, week 3, and week 4). The investigators will assess and document success in obtaining a tissue sample immediately at the time of sampling of each participant.
Proportion of aspirate samples obtained successfully overall
Time frame: 90 days
The feasibility of success in obtaining samples from the tissue expander aspiration ports will be measured as a binary outcome (successful or not successful) over time (intra-operatively, week 1, week 2, week 3, and week 4). The investigators will assess and document success in obtaining a aspirate sample immediately at the time of sampling of each participant.
Proportion of tissue samples successfully producing microbiome data
Time frame: 90 days
Feasibility based off of the success rates in producing microbiome data from tissue samples in each patient will be measured as a binary outcome (successful or not successful) and will be reported.
Proportion of aspirate samples successfully producing microbiome data
Time frame: 90 days
Feasibility based off of the success rates in producing microbiome data from tissue samples in each patient will be measured as a binary outcome (successful or not successful) and will be reported.
Proportion of any samples successfully producing microbiome data
Time frame: 90 days
Feasibility based off of the success rates in producing microbiome data from tissue or aspirate samples in each patient will be measured as a binary outcome (successful or not successful) and will be reported.
Correlation of the change in breast microbiome over time with total duration of antibiotics (Cohort A only)
Time frame: 90 days
The investigators will analyze the microbiomes between groups, between microbiome environments (gut v. breast, inter-individual). The correlate of change in breast microbiome over time will be compared to the total duration of antibiotics for Cohort A only. The measure of association ranges from +1 to -1, with a value of zero equal to no association.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Patients must have histologically confirmed breast malignancy OR genetic predisposition to breast cancer.
- Age \>= 18 years
- Scheduled to undergo mastectomy with the immediate placement of tissue expanders or implant placement
- Ability to understand a written informed consent document, and the willingness to sign it
- At least 4 weeks post-completion of chemotherapy or radiation therapy.
Exclusion criteria
- Any significant medical condition or laboratory abnormalities, which places the subject at unacceptable risk if he/she were to participate in the study
- Pregnant or breastfeeding
- Patients who have taken antibiotics within 90 days of the consent date
- Patients who have taken probiotics within 90 days of the consent date
- Patients who have a documented or reported allergic reaction to the outlined antibiotics to be used in this study
- Male patients
Where
- San Francisco, California
Collaborators
The Plastic Surgery Foundation
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Mar 18, 2026 · Source of record for eligibility and locations