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Medical and microbiological problems arising from airborne infection in hospitals
1Institute for Medical Microbiology and Immunology, University of Bonn, Germany.
Abstract:
The practical importance and frequency of airborne nosocomial infections has been a matter of dispute for many years. This is because most of the pathogens acquired in hospitals are able to use various different routes of infecting the patient's body so that it may be difficult or even impossible to prove an individual infection to be airborne. Only microbes such as Streptococcus pyogenes, Neisseria meningitidis, Corynebacterium diphtheriae, Mycobacterium tuberculosis, or certain respiratory viruses that are known to be predominantly transmitted by droplet infection from infected persons or healthy carriers, have been accepted to the cause of airborne nosocomial infections. Other pathogens such as legionellae, pseudomonads or clostridia may be distributed in the hospital environment via an insufficient or defective air-conditioning system, with or without humidification. The assessment of indirect airborne infections caused by infective particles derived from dust which has settled on furniture or the floor or which has been introduced to the hospital environment by shoes, open windows, building works or potted indoor plants is much more difficult. Many Gram-positive bacteria such as Staphylococcus aureus, mycobacteria, nocardiae, and endospores of clostridia and bacilli, as well as the reproductive elements of fungi do remain viable and infective in dry dust and may therefore infect patients when the dust is disturbed. In contrast to nosocomial infections due to Gram-negative bacteria, against which most preventive measures have been concentrated in the past and which are usually not airborne in origin, it appears that the possibility of direct or indirect transmission of hospital pathogens by air has been underestimated.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Airborne nosocomial infections are often underestimated. While some bacteria and viruses spread via droplets, others like Staphylococcus aureus can survive in dust, posing a significant risk through indirect airborne transmission.
Area of Science:
- Hospital-acquired infections
- Infectious disease transmission
- Environmental microbiology
Background:
- The role of airborne transmission in hospital-acquired infections (nosocomial infections) remains debated.
- Many hospital pathogens can infect patients through various routes, complicating the identification of airborne sources.
- Certain microbes like Streptococcus pyogenes and Mycobacterium tuberculosis are recognized as predominantly droplet-transmitted.
Purpose of the Study:
- To explore the significance and routes of airborne nosocomial infections.
- To investigate the transmission potential of various pathogens in hospital environments.
- To highlight the underestimation of airborne transmission, particularly indirect routes.
Main Methods:
- Review of existing literature on nosocomial infection transmission routes.
- Analysis of pathogen characteristics and their survival in different environmental conditions (e.g., dust).
- Comparison of transmission routes for Gram-positive and Gram-negative bacteria.
Main Results:
- While direct droplet transmission is acknowledged for specific pathogens, indirect airborne transmission is often overlooked.
- Pathogens like Staphylococcus aureus and fungi can remain viable and infectious in settled dust.
- Defective air-conditioning systems can distribute pathogens like Legionellae and Clostridia.
- Gram-positive bacteria and fungal elements in dust pose infection risks when disturbed.
Conclusions:
- The potential for direct and indirect airborne transmission of hospital pathogens has been underestimated.
- Preventive measures have historically focused on non-airborne Gram-negative bacteria, neglecting airborne risks.
- Further attention is needed to address airborne routes in infection control strategies for hospitals.