Do patients with invasive aspergillosis require isolation precautions?

Isolation Precautions for Patients with Invasive Aspergillosis

Standard precautions are sufficient for patients with invasive aspergillosis; no special isolation precautions are required as Aspergillus is not transmitted person-to-person. 1

Rationale for Standard Precautions

Invasive aspergillosis (IA) is an opportunistic fungal infection that primarily affects immunocompromised patients. Unlike some other infectious diseases, Aspergillus does not spread from person to person through direct contact. The infection is acquired through inhalation of fungal spores that are ubiquitous in the environment.

Key considerations:

1. Mode of transmission:

   • Aspergillus spores are acquired through inhalation from environmental sources
   • There is no documented person-to-person transmission
   • Isolation of infected patients does not reduce risk to others

2. Environmental control measures:

   • The focus should be on environmental control measures rather than patient isolation
   • HEPA filtration and positive pressure rooms are recommended for high-risk patients (to protect them from acquiring infection)
   • Construction activities in hospitals increase environmental fungal contamination 2

Recommended Approach

For the infected patient:

• Standard precautions only
• No need for contact, droplet, or airborne isolation
• Regular hand hygiene and standard infection control practices

For protecting high-risk patients:

• Place high-risk patients (e.g., allogeneic HSCT recipients, patients with severe neutropenia) in protected environments with:
  • HEPA filtration
  • Positive room air pressure relative to corridors
  • Well-sealed rooms
  • High air exchange rates (>12 per hour) 1
  • Directed room airflow 1

Special Considerations

During hospital construction:

• Implement additional protective measures during construction activities
• Monitor airborne fungal spore levels during construction periods 2
• Construction activities, especially demolition and excavation, are associated with higher Aspergillus spore counts and increased incidence of invasive aspergillosis 2

For outpatients at high risk:

• Recommend reasonable precautions to reduce mold exposure
• Advise avoidance of gardening, spreading mulch, or close exposure to construction/renovation 1

Common Pitfalls to Avoid

1. Confusing protective environments with isolation precautions:

   • Protective environments (HEPA filtration, positive pressure) are designed to protect vulnerable patients FROM acquiring Aspergillus
   • These are not isolation precautions to prevent spread FROM infected patients

2. Unnecessary restriction of patient movement:

   • Unlike with diseases requiring isolation precautions, patients with invasive aspergillosis do not need restricted movement
   • No special precautions are needed when transporting these patients

3. Misallocating resources:

   • Focus resources on environmental control measures rather than unnecessary isolation
   • Prioritize HEPA filtration and proper air handling systems in areas housing immunocompromised patients

In summary, patients with invasive aspergillosis do not require isolation precautions beyond standard precautions. The emphasis should be on environmental controls to protect vulnerable patients from acquiring Aspergillus infection, rather than isolating those who already have the infection.