508. Prevalence of nasopharyngeal colonization by Staphylococcus aureus in adults with chronic diseases in Colombia.

Abstract

Abstract Background Staphylococcus aureus is a significant cause of morbidity and mortality worldwide. It is responsible for many infections, especially soft tissues, and bacteremia. S. aureus is also a commensal microorganism in humans, usually found in the nasopharynx. Colonized subjects, especially adults with comorbidities, have a higher risk of developing clinical infections such as community-acquired pneumonia (CAP). Some researchers have hypothesized that nasopharyngeal colonization is the etiology that could predict the etiology of CAP. Therefore, the objective of this study was to establish the prevalence of nasopharyngeal colonization by S. aureus in adults with comorbidities in a Colombian cohort. Methods This was a multicenter prospective cohort study in 3 centers in Colombia, conducted between December 2020 and March 2021. Patients older than 18 years with a diagnosis of chronic disease were included. Subjects with evidence or diagnosis of CAP before 90 days and subjects admitted to hospitalization during the last seven days were excluded. Nasopharyngeal aspirate (NPA) sampling in each participant according to WHO guidelines. A seeding of 100 ¼L of NPA by counting method on blood agar. The colonies in these cultures were identified by MALDI-TOF. Results NPAs were obtained in 810 subjects. S. aureus was isolated in 16.9% [137/810] of participants, with an average concentration of 148 CFU/100 µL [IQR 1 – 5500]. All the obtained colonies were confirmed by MALDI-TOFF. Patients had a mean age of 61.4 years [IQR 26 – 98], and 48.7% [67/137] were women. All of the subjects presented at least one comorbidity (51,1% [70/137] Arterial hypertension, 21,9% [30/137] chronic kidney disease, 16,8% [23/137] Diabetes and Heart failure). Notably, only 5.8% [8/137] developed pneumonia during the first six months of follow-up. Conclusion Our results confirm that S. aureus is a prevalent microorganism that colonizes the nasopharynx in adults with comorbidities. We will follow up with the patients for two years to determine if the nasopharyngeal colonization due to S. aureus is a risk factor for developing CAP. Disclosures All Authors: No reported disclosures.