Cohorts 1 and 2: Healthy Volunteers Males and females aged 18-50 years. - Subjects must participate fully and be willing to comply with the procedures of the protocol - Subjects must be co-enrolled in NIH protocol 08-HG-0059 - Ability of subject to understand and provide written informed consent. - Access to bathing facilities - Ability to swallow capsules or tablets Cohort 3: Atopic Dermatitis Patients - Subjects must be aged 2-50 years. - Subjects must be co-enrolled in NIH protocol 08-HG-0059 - Subjects must have a diagnosis of atopic dermatitis on the basis of the criteria defined by UK Working Party s Diagnostic Criteria for Atopic Dermatitis - Subjects must have a primary care provider - Subjects must have an Objective SCORAD (SCORing Atopic Dermatitis) of greater than or equal to 15 indicating AD severity of moderate to severe - Prior to initiation of randomized treatment, subjects must have signs of bacterial skin infections (skin weeping, crusting, and/or pustules) - Access to bathing facilities - All subjects and/or their Legally Authorized Representative (LAR) must have the ability and agree to participate fully and comply with the procedures of the protocol and provide informed consent. Pediatric patients will be included in age appropriate discussions and age appropriate assent will be obtained in accordance with NIH guidelines.

Cohorts 1 and 2: Healthy Volunteers - Does not meet inclusion criteria - Any female with symptoms and/or serum hormone levels consistent with perimenopause - Use of systemic antibiotics in 12 months preceding baseline sampling - Use of swimming pools, hot tubs, or whirlpools in 7 days preceding baseline sampling - Use of topical or oral complementary/alternative medicine (CAM) agents within 4 weeks of initiation of treatment - Known allergic reaction to sulfa, beta-lactam, or tetracycline class drugs; or lidocaine or epinephrine - Family history of toxic epidermal necrolysis - Known allergy or sensitivity to sodium hypochlorite (NaOCl) - History of AD and asthma - Inability to comply with the requirements of the protocol - Pregnant or lactating - Subjects with a primary or acquired immunodeficiency, including HIV seropositiviy - Any chronic past or present medical illness, including chronic skin diseases like psoriasis - Subjects receiving or planning to receive an IND agent, ultraviolet light therapy, monoclonal antibodies, or systemic immunosuppressants - Subjects who provide direct healthcare or reside in healthcare facilities or in non-hospital settings such as clinics, assisted living facilities, homeless shelters, jails and prisons as well as subjects with frequent exposure to laboratory animals Cohort 3: Atopic Dermatitis Patients - Does not meet inclusion criteria - Any female with symptoms and/or serum hormone levels consistent with perimenopause - Known allergic reaction to beta-lactam class drugs, lidocaine, or epinephrine - Family history of toxic epidermal necrolysis - Known allergic reaction to sodium hypochlorite (NaOCl) - Use of systemic antibiotics within 8 weeks, or topical antibiotics on intended sampling sites within 3 weeks, prior to baseline sampling - Use of topical corticosteroids on all intended sampling sites within 7 days, prior to baseline sampling - Use of topical or oral CAM agents within 4 weeks of initiation of treatment - Subjects with known primary or acquired immunodeficiency - Subjects with unstable or uncontrolled medical conditions that could require hospitalization during the initial month of the study or who have been hospitalized for treatment of these conditions in the one month prior to baseline sampling - Subjects receiving or planning to receive an IND agent, ultraviolet light therapy, monoclonal antibodies, or systemic immunosuppressants within 7 days or 5 half-lives (whichever is the longer time period) of initiating treatment on this protocol - Subjects who are currently receiving or have received chemotherapy or radiation for treatment of malignancies within the previous 6 months - Pregnancy or lactating - Pregnant or lactating females in all cohorts are excluded from participating due to the potential effects of the above listed antimicrobials on the developing human fetus or nursing infant; listed in Sections 11.1 through 11.5. Females of childbearing potential must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while she is participating in this study, she should inform her treating physician immediately. Lactating mothers will discontinue breastfeeding prior to study enrollment. - Smokers and subjects who use smokeless tobacco products are excluded in all cohorts due to tobacco s unknown impact on human oral mucosa and microflora.