The goal of this study is to measure bacterial burden, specifically Staph aureus, and how it spreads between mothers and their infants. Researchers will evaluate if the amount of bacteria on their skin remains the same after mothers use a skin antisepsis treatment prior to delivering their infants. The investigators also aim to assess participant interest in and compliance with skin antisepsis treatments. The hypothesis is that increased maternal interest will align with increased treatment compliance.

Few studies have assessed the clinical epidemiology of bacterial transmission among mother-infant dyads in hospitalized and community settings. In an era of rising antimicrobial resistance, the epidemiology of colonization and infections are also changing. Maternal factors account for infants' early exposure to bacteria. Maternal colonization with multi-drug resistant (MDR) bacteria portends a high likelihood of transmission to the infant.

As methicillin resistant Staph aureus (S. aureus) bacteria remain among the top causes of pediatric infections, the presence of these species among mothers and infants can be used to assess antimicrobial resistance, colonization and transmission in maternal-infant dyads. S. aureus is a uniquely interesting pathogen in the perinatal period. MRSA nasal colonization is a sensitive predictor of bloodstream, genitourinary and respiratory infections. Also, parental colonization with S. aureus is typically concordant with infants' colonizing and infecting S. aureus strains. In tandem, there have been numerous studies assessing the utility and impact of MRSA decolonization for high risk patients. This project creates a unique opportunity for in-depth microbiological analyses of maternal-infant dyads.

Design & Procedures: S. aureus skin decolonization methods have been safely tolerated in adults and children. The investigators propose a combination of intranasal mupirocin and chlorhexidine baths for a 5-day decolonization treatment targeting pregnant women already consented to participate in a longitudinal cohort - Project HOPE cohort. The investigators will aim for maternal participation in their third trimester. The decolonization regimen will include:

1. Intranasal mupirocin - Participants will place a pea-sized amount (or approximately 1cm ribbon) of 2% mupirocin ointment on a cotton swab and gently massage it into the anterior nares twice daily for 5 days.
2. Chlorhexidine baths - Participants will be instructed to use pre-packaged chlorhexidine cloths. Each cloth will be used to wipe designated body areas (i.e., arms, legs, chest and neck, back and perineum) once a day for 5 days. These are inexpensive cloths that are easy to use and have been shown to be effective at eradicating Staph aureus carriage. Ideally, participants will be instructed not to rinse off immediately after using the cloths. Baths should be performed on the same 5 days as they apply the intranasal mupirocin.

Evaluation of decolonization protocol compliance: The investigators will provide verbal and printed instructions in participants' preferred languages (English or Spanish). The research team will conduct two weekly check-ins - one during the treatment week and the other during the subsequent week. The investigators will also conduct online surveys to gauge decolonization tolerance and self-reported completion rates. When plausible, participants will be asked to return the mupirocin tube at their next routinely scheduled visit to confirm appropriate use.

Inclusion Criteria:

• Participants must be enrolled in longitudinal study Project HOPE1000.

Exclusion Criteria:

• Participants not enrolled in Project HOPE1000 will be excluded.