Hospital-acquired Fungal Infections: What You Need to Know to Protect Your Patients

  |   February 26, 2020

Over the past year, several reported instances of patient infections related to mold have escalated concerns within the healthcare community. Understanding how these infections can occur, and what your hospital can do to prevent them, is essential for patient safety and hospital reputation.

What are hospital-acquired fungal infections?

True to their name, hospital-acquired fungal (mold) infections are caused by opportunistic fungi that are dangerous to patients who are immunocompromised — whether from surgery, disease or immunosuppressant medications such as chemotherapy. While exposure to these opportunistic fungi (which proliferate at temperature conditions found within the human body) wouldn’t normally cause health problems for the average person, they can be extremely dangerous and even deadly to hospital patients with weakened immune systems or who have undergone invasive procedures.

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There are four general types of fungal infections that pose a risk to patients:

  1. Respiratory infections: Lung infections are most common in stem cell or solid organ transplant recipients and patients receiving immunosuppressant medications.
  2. Invasive Aspergillus infection: This dangerous infection often starts in the lungs, but can then spread to the brain, kidney, liver and other crucial organs. This form of fungal infection often is of concern for patients who receive immunosuppressant medications or have undergone stem cell or solid organ transplants. This is the deadliest type of fungal infection and a study determined that the mortality of Aspergillus-related pneumonia for a bone marrow transplant patient is estimated to be a staggering 85%.1
  3. Surgical site infections: Often caused by an exposure to mold in the operating room (or other recovery environment, such as the ICU), this infection occurs at the site of the incision.
  4. Cutaneous (skin) infection: A fungal infection of the skin.

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It’s important to note that mold is ubiquitous to our environment – both indoors and outdoors. In fact, it’s almost impossible to create a space where there are absolutely no mold spores, especially in an environment where people are present. However, cleanrooms, similar to those used for hospital-based sterile pharmaceutical compounding, are specially designed and maintained to have extremely low levels of airborne particles including mold. With vigilant filtration practices and systems in place to mitigate risks, hospitals can work to keep these sensitive spaces as “clean” as possible. Some ORs and ICUs may have similar airborne molds levels as pharmacy compounding areas where a high level of filtration is provided. But clinicians and infection control personnel are often surprised to discover that filtration for ORs, under the code requirements, are not as protective as pharmacy cleanrooms in prevention of airborne particles including mold spores.

How to know if your hospital has a fungal infection issue

With all hospitals, there is a low incidence of fungal infections that is considered typical or at least “expected”, based on the inherent risk of clinical practice, certain procedures and immunosuppressant medications. When there is an elevated incidence rate of fungal infections or a trend emerges, it’s time to take action.

The first step in determining if the hospital has an increased risk of fungal infections due to mold sources is to assess whether potential mold sources exist in the indoor environment. An industrial hygienist or environmental health scientist with hospital expertise can investigate likely locations for mold growth and identify pathways that may impact the target population. As part of the investigation, they can collect information related to timeframe and locations of the infections to assist in identifying potential sources and abnormalities. Physical environment inspections, interviews with clinical and support services personnel, and/or air sampling and occasionally surface sampling can also be conducted as tools to assess risk retroactively.

Common sources of mold that cause fungal infections in hospitals include:

  1. Construction and renovation, where the demolition processes disturb or release contaminated building materials or soil that harbor mold spores.
  2. Mold within buildings caused by water damage or high humidity conditions.
  3. The HVAC systems, both mold growth from within the system or mold spores from outdoor air that flow through or around the filtration system.
  4. People on their clothes/scrubs.
  5. Equipment or supplies from less clean or contaminated areas.

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The hospital HVAC system—which is crucial to reducing mold risk in highly filtered environments such as pharmacy cleanrooms, ORs and ICUs—can also be a culprit if not maintained properly. Since HVAC systems bring in outside air, the filtration system needs to have highly efficient filtration, be properly fit/sealed, and operate at a high level to remove as much of the naturally occurring mold spores in the air as possible. Similarly, the humidity levels in operating rooms—which are, again, crucial for maintaining a safe environment—can actually provide an ideal environment for mold to grow if too much moisture is added to the air.

Once a probable source(s) is identified, the next step is remediation of the potential source(s) of the outbreak and implementation of enhanced procedures to prevent any future occurrences.

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How to mitigate and prevent future fungal infection risks

Whether the mold issue is visible and easily identifiable or hidden, it’s important to ensure that your hospital’s next steps don’t only solve the problem in the short-term. Instead, aim for identification of root-causes so long-term, continuous prevention is possible. Here are a few recommendations to mitigate and prevent hospital-acquired fungal infections:

  • Know the risk of construction and renovation. If your hospital is planning construction or a renovation, either inside or outside and in close proximity to your hospital, take proper precautions and consult with environmental infection control experts to avoid a potential risk of mold exposure to your patients.
  • Assess your filtration system and “right-size” filter efficiency, as needed. Filters need to be appropriately selected, well-sealed and properly in place in order to do their job. Scheduling periodic preventive maintenance checks and filter changes of your filtration system is critical.
  • Review your humidification process. As any hospital facility director preparing for an accreditation survey knows, reaching the proper levels of humidity can be very challenging when outside dew point temperatures are either high or low. Architects and engineers often slightly oversize humidifiers to ensure future needs are met. The problem is that this could have the adverse effect of putting too much moisture in the air. Checking humidity levels regularly and ensuring your system is properly calibrated is an important part of minimizing the potential for mold growth. Hospitals should also investigate “fail-safe” procedures, where the humidifier is shutdown, rather than over-humidify the space.
  • Include proactive surveillance methods in your environmental infection control program. Today, most hospitals only know they have an increased risk of fungal infections after patients are already sick. Ensure that environmental surveillance rounds include an assessment of evidence of water damage, an interview with staff of high-risk areas about “local” mold or water intrusion issues, and a review of HVAC preventative maintenance procedures.
  • Conduct proactive assessments such periodic air sampling. Consider taking proactive air samples to assess risk in your highest risk locations. By doing so, you can potentially identify an issue before it results in an infection. Though, professional judgment may be needed to support the interpretation of results, you will be able to, at a minimum, characterize a “baseline” of indoor mold spores so any aberrant results are identified before fungal infections occur.

Patients come to your hospital expecting top-notch care and to go home healthier than when they come in. By remaining aware of the risks of hospital-acquired fungal infections and taking proactive steps to prevent the spread of dangerous opportunistic fungi, you can better ensure that expectation becomes a reality. However, you may not be able to do it alone — consult an environmental health expert to fully analyze the safety of your hospital building environment.

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If you are seeking expert guidance with mitigating fungal infections – or determining if your hospital is at risk for fungal infections – contact us today to speak with an expert on environmental infection control.
1. Krueger, KP and Nelson, AC. Economic considerations in the treatment of invasive aspergillosis: a review of voriconazole pharmacoeconomic studies. ClinicoEconomics and Outcomes Research. Aug. 2009; Vol. 2009:1