Inclusion Criteria:

• Each individual must meet all of the following criteria at Screening to be eligible for enrollment as a study participant:
• 1. Must be able to understand and provide informed consent.
• 2. Male or female participant 12 years of age or older.
• 3. Meet ADRN Standard Diagnostic Criteria for active AD.
• Each individual must meet all of the following criteria at Baseline to be eligible for enrollment as a study participant:
• 4. Have at least 7 cm2 of lesional skin within the upper extremities, lower extremities, and/or trunk. Lesions on the face, neck, palms, soles, and intertriginous areas do not count toward the required area, as samples may not be taken from these areas. The required area may be one contiguous area or may be comprised of multiple areas with a compliant total area.
• 5. Have at least 3% body surface area of AD involvement within the upper extremities, lower extremities, and/or trunk. Lesions on the face, neck, palms, soles, and intertriginous areas do not count toward the required area.
• 6. Have an IGA score of two or greater.
• 7. Have obtained skin swab test results prior to randomization indicating the presence of one positive S. aureus colonized lesion within the upper extremities, lower extremities, and/or trunk.
• 8. Each potential participant who can become pregnant must meet either of the following criteria prior to randomization to be eligible for enrollment as a study participant.
• 1. Willing to remain abstinent from intercourse that may result in a pregnancy.
• 2. Willing to use an FDA-approved method of contraception for the duration of study participation. Acceptable methods include the following:
• * Permanent sterilization of partner
• * Long-acting reversible contraceptives (e.g., intrauterine devices or systems, implantable rods, contraceptive injections) when used as directed for at least 7 days prior to Baseline.
• * Short-acting hormonal contraceptives (e.g., oral contraceptive pills, patch, vaginal ring) when used as directed for at least 30 days prior to Baseline
• * Barrier methods (e.g., condoms; diaphragm, sponge, or cervical cap with spermicide)

Exclusion Criteria:

• Individuals who meet any of the following criteria at Screening or Baseline are not eligible for enrollment as study participants:
• 1. Inability or unwillingness to give written informed consent or comply with study protocol.
• 2. Pregnant or lactating.
• 3. Sensitivity to or difficulty tolerating Dove fragrance-free bar soap, Cetaphil® lotion, alcohol-based cleaners, clobetasol and fluocinonide ointments, triamcinolone ointment, hydrocortisone ointment, glycerol, hydroxyethylcellulose or soy products.
• 4. Known recalcitrance to topical steroids, including class 1 steroids, within 6 months of the Screening Visit.
• 5. History of serious life-threatening reaction to tape or adhesives.
• 6. Known allergy to all antibiotics to which S. hominis A9 is sensitive. These include ampicillin-sulbactam, cefazolin, cefoxitin, clindamycin, daptomycin, doxycycline, levofloxacin, linezolid, minocycline, moxifloxacin, mupirocin, nitrofurantoin, oxacillin, rifampin, trimethoprim-sulfamethoxazole, and vancomycin.
• 7. Has a major defect in the epidermal barrier such as open wounds or genodermatoses (e.g., Netherton's syndrome).
• 8. Is immunocompromised (e.g., Human Immunodeficiency Virus (HIV)/Acquired Immunodeficiency Syndrome (AIDS), Wiskott-Aldrich Syndrome) or has an immune system disorder (e.g., autoimmune disease).
• 9. Has current malignant disease (except non-melanoma skin cancer in an area not affected by treatment).
• 10. Has a history of psychiatric disease or history of alcohol or drug abuse that, in the opinion of the study investigator, would interfere with the ability to comply with the study protocol.
• 11. Past or current medical problems or findings from physical examination or laboratory testing that are not listed above, which, in the opinion of the investigator, may pose additional risks from participation in the study, may interfere with the participant's ability to comply with study requirements or that may impact the quality or interpretation of the data obtained from the study.
• 12. Ongoing participation in another investigational trial or use of investigational drugs within 8 weeks, or five half-lives (if known), whichever is longer, of the Screening Visit.
• 13. Treatment with non-steroid systemic immunosuppressant within 6 months of the Screening Visit.
• 14. Treatment with any biologic, including dupilumab, within 16 weeks of the Screening Visit.
• 15. Treatment with oral or injectable therapy for AD (excluding oral steroids) within five half-lives (if known) or 16 weeks before the Screening Visit, whichever is longer.
• 16. Treatment with allergen immunotherapy within 30 days of Screening Visit.
• 17. Has close contacts (e.g., spouse, children, or members in the same household) who have severe barrier defects or are immunocompromised.
• 18. May, in the opinion of the investigator, have difficulty tolerating the medication washout requirements for topical AD treatments, prescription moisturizers, antibiotics, oral steroid therapies, and phototherapy ahead of Baseline.
• Individuals who meet any of the following criteria at Baseline are not eligible for enrollment as study participants:
• 19. Have more than 30% body surface area of AD involvement.
• 20. Active bacterial, viral, or fungal skin infections.
• 21. Any noticeable breaks or cracks in the skin on the target areas of investigational product application, including severely excoriated skin or skin with open or weeping wounds suggestive of an active infection.
• 22. Use of topical AD treatments - including steroids and calcineurin inhibitors - on the upper extremities, lower extremities, or trunk within seven days of the Baseline Visit.
• 23. Treatment with prescription moisturizers classified as medical device (e.g., Atopiclair®, MimyX®, Epiceram®, etc.) on the upper extremities, lower extremities, or trunk within seven days of the Baseline Visit.
• 24. Use of any oral or topical antibiotic within fourteen days of the Baseline Visit.
• 25. Use of systemic corticosteroid therapies for any indication within 28 days of the Baseline Visit.
• 26. Use of systemic corticosteroid therapies for treatment of an asthma exacerbation within 3 months of the Baseline Visit.
• 27. Require a dose greater than 880 mcg/day of fluticasone propionate or equivalent inhaled corticosteroid to maintain asthma control, at the time of the Baseline Visit.
• 28. Any phototherapy for skin disease (such as narrow band ultraviolet B \[NBUVB\], ultraviolet B \[UVB\], ultraviolet A1 \[UVA1\], psoralen + UVA \[PUVA\]) or regular use (more than 2 visits per week) of a tanning bed within 28 days of the Baseline Visit.