ABSTRACT

1. The Importance of Viral Etiology in Hospitalized Patients with Community Acquired Pneumonia in Jefferson County Martin Gnoni MD, SwethaKadali, MD, Jorge Perez, MD, Rehab Abdelfattah, MD, MPH, Daniel Curran, MD, MuraliKolikonda, MD, SrinivasUppatla, MD, SridivyaPeddapalli, MD, Robert Kelley, PhD, Paula Peyrani, MD ABSTRACT RESULTS RESULTS (con’t) CONCLUSIONS (con’t) Background: Community Acquired Pneumonia (CAP) is a leading cause of infectious disease-related death in the world. Traditionally CAP has been considered primarily a bacterial infection. A few studies have addressed the role of viruses as etiologic agents of CAP. The pathogenic role of rhinovirus isolated from clinical samples in hospitalized patients with lower respiratory tract infections (LRTIs) is not clear in the literature. The objective of this study is to determine the incidence of respiratory viruses in hospitalized adult patients with CAP and the possible role of rhinovirus as a pathogen. Methods: Hospitalized patients with CAP from the Rapid Empiric Treatment with Oseltamivir Study (RETOS) database were included in the study. A sub analysis was made of the patients with a viral organism identified by PCR. Incidence of organism isolation calculated. Results: A total of 262 viral CAP patients were identified in the RETOS database. Influenza was the most common virus isolated overall (n=112, 43%). The second most common virus was rhinovirus(n=67, 26%) . In 55(21%) of the viral CAP patients, rhinovirus was the only organism isolated. Discussion: We conclude that because rhinovirus was the sole isolate in a high percentage of viral-CAP patients, rhinovirus may be considered a real pathogen in hospitalized adult patients with CAP. This study supports the need for an extensive microbiologic work up in patients with CAP for both bacterial and viral etiologies. • There are some limitations of this study. In a considerable number of our patients rhinovirus was the only organism isolated. However we cannot ignore the fact that we utilized nasopharyngeal swabs in most of our patients for diagnosis so we were unable to distinguish if the viral etiology was a real pathogen or a predisposing condition for a superimposed viral/bacterial infection that was not detected. • We also identified a significant number of viral CAP in our cohort that has risk factors for HCAP. The significance of the association between risk factors for HCAP and viral CAP remains unknown. • A strength of this study is that it is one of the few multicenter studies addressing the viral etiology of CAP. • Another strength is the use of molecular techniques for diagnosis of viral respiratory infections. • We conclude that one third of adult hospitalized patients with CAP are infected with a respiratory virus, with influenza and rhinovirus being the two most common. • The patients with more severe disease that are admitted to the ICU are more likely to have a dual infection. • Because rhinovirus was the sole isolate in a high percentage of viral-CAP patients, rhinovirus may be considered a real pathogen in hospitalized adult patients with CAP. • From a total of 800 hospitalized patients with CAP identified in the RETOS database 262 (32%) were identified as viral CAP (v-CAP) (Table 1, Figure 1). • 29 (11%) v-CAP were admitted to ICU (ICU-v-CAP) • 233 (89%) v-CAP were admitted to the ward (W-v-CAP) • 11(38%) ICU-v-CAP were associated with coinfections • 35 (15%) W-v- CAP were associated with coinfections • Influenza was the most common virus isolated (10 out of 29 -34%- ICU-v-CAP , and 101 out of 233 - 43% - W-v-CAP). • The second most common virus was rhinovirus (9 out of 29 -31%- ICU-v-CAP and 58 out of 233 -25%- W–v-CAP). • In 55 (21%) of the v-CAP patients, rhinovirus was the only organism isolated. Figure 1: Overall percentage of virus isolated in patients with CAP INTRODUCTION CONCLUSIONS Table 1: Characteristics and outcomes of hospitalized patients with LRTI and HRV detection Community Acquired Pneumonia (CAP) is a leading cause of infectious disease-related death in the world [1] despite improvements in antibiotic and supportive treatment. Traditionally CAP has been considered primarily a bacterial infection. Until recently few studies have addressed the role of viruses as etiologic agents of CAP probably due to the poor sensitivity and specificity of diagnostic assays along with the lack of available biomolecular tests (PCR) [2]. The pathogenic role of rhinovirus isolated from clinical samples in hospitalized patients with lower respiratory tract infections (LRTIs) including CAP is controversial in the literature [3-5]. The objective of this study is to determine the incidence of respiratory viruses in hospitalized adult patients with CAP and the possible role of rhinovirus as a pathogen. • Viruses are a common etiology of CAP either in the ward or ICU. • Influenza and Rhinovirus were the two most common viruses isolated in our cohort. • The severity of the ICU-v-CAP patients can be explained by the fact that one third of the ICU-v-CAP are associated with coinfections. • Since most of the respiratory viruses can be transmitted from patient to patient, our study suggests that one out of three adult hospitalized patients with CAP may need some sort of respiratory and/or contact isolation in Jefferson County. • This study also supports the need for an extensive microbiologic work up in patients with CAP (ICU-CAP and W-CAP) for both bacterial and viral etiologies in order to target therapy and improve clinical outcomes. • Even when the significance of the isolation of rhinovirus in adult patients with CAP is controversial, in a significant proportion of our CAP patients it was the only organism isolated. • It is unknown if rhinovirus should be considered a primary pathogen or a predisposing condition associated with a secondary viral or bacterial infection [1]. REFERENCES 1. WiemkenT, Peyrani P, Bryant K, Kelley RR, Summersgill J, Arnold F, et al. Incidence of respiratory viruses in patients with community-acquired pneumonia admitted to the intensive care unit: results from the Severe Influenza Pneumonia Surveillance (SIPS) project. European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology. 2013;32(5):705-10. 2. KhawajaA, Zubairi AB, Durrani FK, Zafar A. Etiology and outcome of severe community acquired pneumonia in immunocompetent adults. BMC infectious diseases. 2013;13:94. 3. Pavia AT. What is the role of respiratory viruses in community-acquired pneumonia?: What is the best therapy for influenza and other viral causes of community-acquired pneumonia? Infectious disease clinics of North America. 2013;27(1):157-75. 4. Esposito S, Daleno C, Tagliabue C, Scala A, Tenconi R, Borzani I, et al. Impact of rhinoviruses on pediatric community-acquired pneumonia. European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology. 2012;31(7):1637-45. 5. CillonizC, Ewig S, Ferrer M, Polverino E, Gabarrus A, Puig de la Bellacasa J, et al. Community-acquired polymicrobial pneumonia in the intensive care unit: aetiology and prognosis. Critical care. 2011;15(5):R209. MATERIALS AND METHODS • Hospitalized patients with CAP from the Rapid Empiric Treatment with Oseltamivir Study (RETOS) database were included in the study. A sub analysis was made of the patients with a viral organism identified by PCR. Incidence of organism isolation was calculated. • Definitions: • CAP: The presence of criteria A plus at least one of the following criteria : • X-ray evidence of new pulmonary infiltrate (at time of hospitalization ) • New or increased cough with/without sputum production • Fever > 37.8 oC (100.0oF) or hypothermia    <35.6oC (96.0oF) • Changes in WBC (leukocytosis, left shift or leukopenia) • Viral CAP(v-CAP):The presence of CAP plus a positive PCR for one of the viruses included in the viral panel (multiplex PCR)