Comparison of viral infection in healthcare-associated pneumonia (HCAP) and community-acquired pneumonia (CAP)

Abstract

Background: Although viruses are known to be the second most common etiological factor in community-acquired pneumonia (CAP), the respiratory viral profile of the patients with healthcare-associated pneumonia (HCAP) has not yet been elucidated. We investigated the prevalence and the clinical impact of respiratory virus infection in adult patients with HCAP.

Methods: Patients admitted with HCAP or CAP, between January and December 2016, to a tertiary referral hospital in Korea, were prospectively enrolled, and virus identification was performed using reverse-transcription polymerase chain reaction (RT-PCR).

Results: Among 452 enrolled patients (224 with HCAP, 228 with CAP), samples for respiratory viruses were collected from sputum or endotracheal aspirate in 430 (95.1%) patients and from nasopharyngeal specimens in 22 (4.9%) patients. Eighty-seven (19.2%) patients had a viral infection, and the proportion of those with viral infection was significantly lower in the HCAP than in the CAP group (13.8% vs 24.6%, p = 0.004). In both the HCAP and CAP groups, influenza A was the most common respiratory virus, followed by entero-rhinovirus. The seasonal distributions of respiratory viruses were also similar in both groups. In the HCAP group, the viral infection resulted in a similar length of hospital stay and in-hospital mortality as viral-bacterial coinfection and bacterial infection, and the CAP group showed similar results.

Conclusions: The prevalence of viral infection in patients with HCAP was lower than that in patients with CAP, and resulted in a similar prognosis as viral-bacterial coinfection or bacterial infection.

Fig 1. Flow chart of patient enrollment into the study.

Abbreviations: CAP, community-acquired pneumonia; HAP, hospital-acquired pneumonia; HCAP, healthcare-associated pneumonia; VAP, ventilator-associated pneumonia; RT-PCR, reverse-transcription polymerase chain reaction.

Fig 2. Monthly distribution of respiratory viral or bacterial pneumonia.

The x-axis shows each month and the y-axis shows the number of observed pneumonia events. The number of viral and bacterial pneumonia events in each month. (upper panel: all CAP and HCAP patients, middle panel: CAP patients only; and lower panel: HCAP patients only).

Fig 3. Monthly distribution of each respiratory virus.

The x-axis shows each month and the y-axis shows the number of observed pneumonia events. (upper panel: all CAP and HCAP patients, middle panel: CAP patients only; and lower panel: HCAP patients only).