Pathogens and Data in Healthcare Laundry Environments

In the medical laundry environment, the washing of medical textiles is a critical component of hospital infection control. However, due to shortcomings in equipment design, operational procedures, and disinfection effectiveness, medical laundries still face a high risk of bacterial contamination. The following is an analysis of common types of bacteria found in medical laundry environments and their associated contamination levels, along with a discussion on their relationship to China’s WS/T 508 standard.
I. Common Types of Pathogenic Bacteria and Their Contamination Status
(1) Bacterial species
• Escherichia coli
Escherichia coli is a common component of the intestinal microbiota and often contaminates medical textiles through patient excreta. Studies have shown that even clean textiles that haven't been rigorously disinfected may still harbor this bacterium, with higher detection rates observed particularly in infectious textiles.
• Staphylococcus aureus
This includes drug-resistant strains (such as MRSA), which are transmitted through skin contact and thrive in warm, humid environments. If the washing temperature is insufficient, these bacteria may remain on the surface of fabrics.
• Pseudomonas aeruginosa
This bacterium is commonly found in moist environments, such as washing equipment where scale accumulates, and can easily cause hospital-acquired infections, particularly among patients with burns or weakened immune systems.
• Enterococcus and Klebsiella
These multidrug-resistant bacteria often remain on equipment surfaces due to improper washing procedures or inadequate disinfection.
(2) Fungi
• Candida albicans
This fungus thrives in humid environments and can spread to a patient’s skin or mucous membranes via contaminated fabrics, causing infection.
• Zygomycetes (such as Mucor)
A hospital in Hong Kong once experienced an outbreak of mucormycosis caused by fabric contamination, resulting in patient deaths. This type of fungus exhibits strong resistance to conventional disinfectants and can only be inactivated through high temperatures or specialized chemical disinfection.
(3) Viruses and Other Pathogens
• Hepatitis B virus (HBV) and Human Immunodeficiency Virus (HIV)
Although these viruses have a relatively short survival time in dry environments, if fabrics are contaminated with blood or bodily fluids and not promptly disinfected, they can still spread through routes such as needlestick injuries.
• Enteroviruses (such as norovirus)
The virus can contaminate fabrics through vomit or feces. If washing procedures are not strictly segregated, cross-contamination may occur.
II. Analysis of Pollution Levels and Causes
(1) Pollution Rate Data
Studies show that the average rate of microbial contamination on surfaces in hospital laundry rooms can exceed the standard by as much as 98.14%. The contamination rate on staff hands is 94.12%, and the rate of airborne colony counts exceeding the standard is 48%. Furthermore, a French study found that 58% of “clean” bed sheets were already contaminated before coming into contact with patients.
(2) Pollution Pathways and Risk Factors
• Defects in washing equipment
The spiral discharge channel of the tunnel-type washing unit has become a breeding ground for bacteria due to insufficient temperature and accumulated scale.
• Process management vulnerabilities
Failure to strictly segregate areas—such as the absence of complete isolation barriers between contaminated and clean zones, especially internal isolation—and the mixing of waste between hospitals, as well as failure to disinfect transport vehicles, can all lead to cross-contamination.
III. Relationship with WS/T 508 Standard
According to the standard WS/T 508-2016, the microbiological requirements for clean textiles are as follows: the total bacterial count shall be ≤200 CFU/100 cm², and no pathogenic bacteria such as coliforms or Staphylococcus aureus shall be detected. However, in actual testing, some medical institutions find it difficult to meet these standards due to equipment or operational issues. To reduce risks, the following measures should be taken:
• High-temperature disinfection (all areas in contact with fabric);
• Strict zoning management (internal is more important than external);
• Regularly remove scale and monitor it periodically.
IV. Recommendations
As shown by the analysis above, the types of pathogens detected in medical laundry environments closely overlap with the common pathogens responsible for hospital-acquired infections. The contamination levels are closely related to equipment design, operational procedures, and disinfection effectiveness. Currently, the spiral discharge channels of tunnel-type washing machines pose a high risk of pathogen contamination due to issues such as insufficient temperature and accumulation of scale. However, the WS/T508 standard has yet to introduce mandatory disinfection measures specifically addressing these problems, making it difficult for some medical laundry facilities to meet the standard requirements in actual operations.
To safeguard patient health, it is recommended that the relevant authorities refine the WS/T508 standard by clearly specifying the disinfection requirements for tunnel-type washing machines, ensuring that they meet the microbiological standards. Furthermore, medical staff’s personal items should be treated on an equal footing with patient supplies—for example, including medical staff’s items within the scope of mandatory use of tunnel-type washing machines would rapidly accelerate the upgrading and improvement of such equipment. By refining the standards, we can effectively cut off cross-infection pathways at the source and reduce the incidence of infections caused by medical textiles.