Healthy Patients & Effect of Antibiotics

The objective of this study is to evaluate the impact of antimicrobial (antibiotic) exposures on the microbiome in healthy adults, specifically during and after usual courses of the antimicrobials used to treat community acquired pneumonia (CAP). Pneumonia is a lung infection, and community-acquired pneumonia is pneumonia that develops outside of a healthcare facility (i.e., in the community). A microbiome is a the community of microorganisms living in a particular location, such as the gut or the mouth. Disruptions to a person's microbiome may reduce his/her "colonization resistance" (resistance to colonization with pathogenic microorganisms) and make him/her more susceptible to multidrug resistant organism (MDRO) colonization and infection. To study changes in the microbiome, the investigators will recruit 20 healthy adult volunteers and obtain fecal, salivary, skin, and urine specimens at multiple time points before, during, and after administration of antimicrobials. Participants will be randomized to one of 4 antimicrobial regimens, all of which are FDA-approved for treatment of community-acquired pneumonia. Stool specimens will be analyzed via stool culture and genetic sequencing, and all remaining specimens will be frozen and used to create a biospecimen repository for future analysis. The rationale for using healthy volunteers (instead of patients already prescribed antibiotics by their physicians) is because the human microbiome is very complex and can be affected by a variety of medical conditions and other medications. In addition, the presence or absence of patient-specific factors means people with infections may not be prescribed the specific courses of antibiotics the investigators are trying to study. Studying the effect of antibiotics on healthy volunteers will provide baseline data that are more applicable to the population at large.