The ability of virulence factor expression by Pseudomonas aeruginosa to predict clinical disease in hospitalized patients.

Michel Ledizet,Martin D Slade,Sailaja Puttagunta,Vincent J Quagliarello,Barbara I Kazmierczak,Thomas S Murray,Gunnar F Kaufmann

doi:10.1371/journal.pone.0049578

Abstract

Background Pseudomonas aeruginosa is an opportunistic pathogen that frequently causes hospital acquired colonization and infection. Accurate identification of host and bacterial factors associated with infection could aid treatment decisions for patients with P. aeruginosa cultured from clinical sites.MethodsWe identified a prospective cohort of 248 hospitalized patients with positive P. aeruginosa cultures. Clinical data were analyzed to determine whether an individual met predefined criteria for infection versus colonization. P. aeruginosa isolates were tested for the expression of multiple phenotypes previously associated with virulence in animal models and humans. Logistic regression models were constructed to determine the degree of association between host and bacterial factors with P. aeruginosa infection of the bloodstream, lung, soft tissue and urinary tract.ResultsOne host factor (i.e. diabetes mellitus), and one bacterial factor, a Type 3 secretion system positive phenotype, were significantly associated with P. aeruginosa infection in our cohort. Subgroup analysis of patients with P. aeruginosa isolated from the urinary tract revealed that the presence of a urinary tract catheter or stent was an additional factor for P. aeruginosa infection.ConclusionsAmong hospitalized patients with culture-documented P. aeruginosa, infection is more likely to be present in those with diabetes mellitus and those harboring a Type 3 secretion positive bacterial strain.

Highlights

Hospital acquired infections (HAI) are estimated to complicate 5–10% of hospitalizations in the United States annually, leading to increased health care costs and prolonged hospitalizations [1]
The most robust virulence factor in animal models and human studies is the Type 3 secretion system (T3SS), a specialized protein secretion apparatus that allows Gram-negative bacteria such as P. aeruginosa to translocate a specific subset of bacterial effector proteins into the host cell cytosol [8]
All pediatric and adult patients hospitalized at Yale New Haven Hospital (New Haven, computed tomography (CT)) with a positive culture for P. aeruginosa from the respiratory tract, urinary tract, blood, or deep tissue were eligible for study enrollment if they, or designated proxies, provided written consent

Summary

Introduction

Hospital acquired infections (HAI) are estimated to complicate 5–10% of hospitalizations in the United States annually, leading to increased health care costs and prolonged hospitalizations [1]. Prospective studies have shown that a subgroup of colonized patients develop clinically significant disease, such as ventilator-associated pneumonia. The most robust virulence factor in animal models and human studies is the Type 3 secretion system (T3SS), a specialized protein secretion apparatus that allows Gram-negative bacteria such as P. aeruginosa to translocate a specific subset of bacterial effector proteins into the host cell cytosol [8]. Pseudomonas aeruginosa is an opportunistic pathogen that frequently causes hospital acquired colonization and infection. Accurate identification of host and bacterial factors associated with infection could aid treatment decisions for patients with P. aeruginosa cultured from clinical sites

Methods

Results

Conclusion