Outbreak of adenovirus type 1 severe pneumonia in a French intensive care unit, September-October 2012

Area of Science:

• Infectious Diseases
• Virology
• Critical Care Medicine

Background:

• Severe pneumonia outbreaks in intensive care units (ICUs) pose significant challenges.
• Human adenovirus type 1 (HAdV-1) is a known respiratory pathogen, but outbreaks of severe pneumonia in ICUs are rare.
• Immunocompetent patients are typically considered at lower risk for severe adenovirus-related pneumonia.

Purpose of the Study:

• To describe and analyze the first reported outbreak of severe pneumonia caused by HAdV-1 in an ICU.
• To identify the source and transmission dynamics of the HAdV-1 outbreak.
• To highlight the potential of HAdV-1 to cause severe illness in immunocompetent individuals and inform prevention strategies.

Main Methods:

• Retrospective analysis of seven successive patients diagnosed with severe pneumonia.
• Real-time polymerase chain reaction (PCR) used for HAdV-specific diagnosis on bronchoalveolar lavage samples.
• Nasopharyngeal swabs collected from healthcare workers to investigate potential transmission sources.

Main Results:

• Seven patients in an ICU were diagnosed with severe pneumonia caused by HAdV-1 between September and October 2012.
• Three nurses tested positive for HAdV-1, with one exhibiting prior respiratory symptoms, suggesting she was the likely source.
• The outbreak occurred despite patients being immunocompetent, challenging typical assumptions about HAdV severity.

Conclusions:

• HAdV-1 should be considered a potential cause of severe pneumonia, even in immunocompetent patients.
• Intensive care units are susceptible to HAdV-1 outbreaks, necessitating prompt identification and typing.
• Enhanced hand hygiene and preventing healthcare workers with respiratory symptoms from patient contact are critical for HAdV transmission control.