BIOTIC AND ABIOTIC FACTORS ASSOCIATED WITH THE COLONIZATION OF STAPHYLOCOCCUS AUREUS AND ITS SUBTYPES IN HEALTHY HUMAN SUBJECTS Open Access

Joseph, Sandeep Jose (2016)

Permanent URL: https://etd.library.emory.edu/concern/etds/nz806001q?locale=en
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Abstract

Background: Staphylococcus aureus, a human commensal and prevalent human pathogen, affects public health worldwide. It is a common asymptomatic colonizer predominantly in the nares, and also at the oral cavity and skin. Neither the role of carriage in the propagation of S. aureus infections nor the factors associated with the colonization of a particular subtype at a body site are well understood. The purpose of this study was to assess associations between demographic and life history characteristics and the profile of S. aureus subtypes identified at each body site using a metagenome-based subtyping scheme using data generated by the human microbiome project (HMP).

Materials and Methods: The metagenomic samples were collected from various body sites of healthy 18 - 40 years old adults. The exposure variables investigated in relation to the subtype profile of S. aureus in a body site were diet, breastfed, tobacco use, health insurance, history of surgery, age, BMI and ethnicity. Both binary (S. aureus +/-) and multinomial (4 outcomes: 3 subtypes of S. aureus (CC8, CC30, any other subtypes), vs. no detection of S. aureus) logistic regression were performed to identify predictors for S. aureus detection among HMP participants.

Results: In the binary outcome logistic regression model, main body site (p <0.001), health insurance (OR for no health insurance=0.5 (0.2-1.0); p=0.0525) and BMI (OR for high BMI vs. normal BMI=1.7 (1.1-2.5); p=0.0276) were predictors of detection of S. aureus, whereas for the multinomial logistic regression model with 4 outcomes, only main site and BMI were significant (p<0.05) predictors of the presence of S. aureus at significance level of 0.1. Compared to subjects with normal BMI, the odds of detecting CC8 subtype tended to be higher in high BMI subjects (OR=1.4, 95% CI=0.6-3.0) while CC30 subtype detection was higher in those with low BMI (OR=1.6, 95% CI=0.6-3.8).

Conclusions: Results suggest that high BMI and health insurance are risk factors for S. aureus colonization. Larger studies with more heterogeneous subjects are needed to identify predictors of S. aureus subtype colonization in human body sites.

Table of Contents

TABLE OF CONTENTS

BACKGROUND AND LITERATURE REVIEW.........................1

INTRODUCTION............................................................6

MATERIALS AND METHODS............................................8

RESULTS.....................................................................12

DISCUSSION AND CONCLUSIONS..................................15

REFERENCES...............................................................20

TABLES.......................................................................26

FIGURES.....................................................................33

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