Background
Acute upper respiratory tract infections (URIs) that are caused by a
diverse range of viral and bacterial pathogens are one of the most
common illnesses observed in humans.1, The morbidity,
mortality and economic burden associated with all types of URIs have
been demonstrated significant, with influenza virus being the focus of
identification as a causative pathogen for URIs in ambulatory clinical
settings.1,2 Traditional diagnostic testing methods
for URIs including antigenic methods, cell culture, and serology have
limitations with regard to sensitivity, specificity, and/or
turn-around-times, rendering them relatively limited for routine use in
ambulatory care settings.3-5
Recent technological advances have led to the development of multiplexed
molecular amplification assays that are capable of detecting multiple
common causes of URI pathogens from a single nasopharyngeal swab (NP).
Although these methods have been shown to be rapid, highly sensitive,
and specific,6-9 uptake for routine practice remains
relatively limited to research studies, due in part to lack of available
treatment options for non-influenza respiratory viruses and added
expense of employing multiplex molecular methods.6 On
the other hand, these assays afford new opportunities to better
understand the etiologic distribution, prevalence, and rates of
co-infections associated with URIs. Several recent studies employing
multiplex technologies have been conducted with specific select
populations, including patients with community-associated pneumonia
(CAP),10-12 hospitalized
patients,10-14 military
personnel,15-17 relatively healthy outpatients7, 18-20 and selected pediatrics
cohorts.21-23
To date, there is limited data regarding the etiology of non-influenza,
non-RSV, URI viral and bacterial pathogens in unselected ambulatory
populations considered at high risk for respiratory virus related
complications. Such research could be helpful not only for understanding
the epidemiology and etiology of acute URIs, but also could help inform
future research to address antibiotic stewardship.7,
22, 23
Our aim was to contribute to the existing knowledge regarding the
epidemiology and etiology of acute URIs in a broad ambulatory population
of patients considered to be at high-risk of influenza
complications,24, 25 who were tested for influenza,
but were not tested for other respiratory pathogens. We collected
residual waste samples from patients who presented to 4 geographically
disparate EDs, who had already been tested for influenza with a single
target influenza assay24 and subsequently tested them
utilizing the multiplex Genmark ePlex respiratory panel (RP) research
use only (RUO) platform.