Correspondence (letter to the editor): The Crucial Role of Molecular Diagnostics

The diagnostic evaluation of patients with nosocomial pneumonia or hospital-acquired pneumonia (HAP) has traditionally focused on bacteriology (1). In the past, one of the reasons was the lack of sensitive tests and diagnostic methods in virus detection. In the light of increasing scientific evidence and our own clinical experiences we wish to stress the critical role of modern molecular diagnostic testing methods for respiratory viruses, and in particular for influenza, in HAP, to ensure that state of the art detection, prevention, and management of such pathogens are given their proper place in future guidelines.

Currently, virological diagnostic work-up is not routinely done in HAP and is often conducted only in individual cases or in certain groups of patients. Comprehensive virological data for HAP are therefore lacking. It can be assumed, however, that the prevalence or viral pathogens in HAP is substantially underestimated.

Giannella and colleagues have recently reported that during the winter months, influenza was confirmed in about a third of patients with respiratory symptoms requiring intensive care (2). In about half of the cases, influenza was not suspected. In 42% of patients, the infection was acquired nosocomially. A recently published intervention study from the Netherlands has confirmed the critical role of hospital staff in the prevalence of influenza in adult inpatients at university medical centers, as well as the preventive effect of vaccinating the healthcare workers against influenza (3). For emerging infections, such as the Middle East respiratory syndrome coronavirus or respiratory syncytial virus, nosocomial transmission is also well documented.

For the purposes of preventing infections and the rational use of antibiotics it seems important to us to consider virological etiologies of HAP and to systematically initiate appropriate diagnostic evaluation thereof. Furthermore, influenza vaccination rates among healthcare staff need to be improved, in accordance with the recommendations of Germany’s Standing Vaccination Committee (STIKO, Ständige Impfkommission).