Fungal Infections: The Silent Epidemic Threatening Global Health

Candida auris and other fungal infections

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Fungal infections are a growing global health crisis, with rising resistance making treatment difficult. Recently, Infection Control Today^® (ICT^®) spoke with Cornelius (Neil) J. Clancy, MD, professor of medicine at the University of Pittsburgh School of Medicine and chief of the Infectious Diseases Section at the VA Pittsburgh Healthcare System in Pittsburgh, Pennsylvania, highlights the urgent need for research, improved diagnostics, and stronger infection prevention strategies.

Introduction

Fungal infections have become a critical public health concern, affecting millions yearly. Clancy emphasized the growing impact of these infections, ranging from common skin conditions to severe systemic diseases. He explained that antifungal resistance is increasingly complicating treatment, particularly with pathogens such as Candida auris and Aspergillus fumigatus. Addressing this crisis requires a deeper understanding of fungal biology, improved diagnostic tools, and strategic public health policies.

The Nature of Fungal Infections

During the interview, Clancy highlighted the fundamental differences between fungi, bacteria, and viruses, stressing that fungi require entirely different treatments. While antibiotics target bacteria, antifungal drugs are necessary for fungal infections. He pointed out that the widespread use of antibiotics has inadvertently increased fungal infections by disrupting the microbiome, creating an opportunity for fungal overgrowth.

Fungal infections can be categorized into:

• Superficial Infections: Affecting the skin, nails, and mucosal surfaces, including conditions such as athlete’s foot, ringworm, and vaginal candidiasis.
• Invasive Infections: Penetrating deep into organs and tissues, often affecting immunocompromised individuals, including cancer patients and organ transplant recipients.

When ICT asked about the societal impact of fungal infections, Clancy said, “I think the societal impact is widespread. On the one hand, fungi are causes of very common diseases that occur even among otherwise healthy people. So yeast like Candida are major causes of urinary tract infections, vaginal infections in healthy young women. Yeast like Candida [and] fungi like dermatophytes are very common causes of skin infections [and] nail infections, so things like athlete's foot or ringworm [are] very common infections. Generally speaking, they're not going to kill people, but they can be, in some cases, recurrent problems that have an impact on quality of life and diseases that impact millions of people a year.”

Clancy continued, “On the other end of the spectrum, you have more deeply invasive infections by fungi that…penetrate into deeper sites of the body, the bloodstream, the lungs, other organ systems and these are quite common in hospitals, in particular among patients who have suppressed immune systems. In those populations, transplant recipients, cancer chemotherapy recipients, [and] people who are severely ill in critical care units [intensive care units], oftentimes, those types of fungal infections are resistant to at least some of the anti-fungal drugs and increasingly difficult to treat. We're seeing anti-fungal resistance increasingly in both those areas, in sort of the outpatient setting, with skin and soft tissue infections, urinary tract infections, vaginal infections, and then also among more severely ill patients with more severe infections in the hospital.”

The Growing Threat of Antifungal Resistance

Discussing the rise of antifungal resistance, Clancy identified 3 major categories of concern:

1. Candida auris and Other Candida Species

Candida auris has emerged as a significant threat in health care settings. According to Clancy, this fungus is highly resistant to multiple antifungal drug classes and can persist in hospital environments, facilitating rapid transmission.

“So the capacity for [C auris] to survive in the environment, to get passed within the hospital, within a nursing home, from person to person, and then on top of that, to carry this antifungal resistance, is what makes it so unique and why it's become such a public health concern,” Clancy said.

He also noted that other Candida species, such as Candida glabrata and Candida parapsilosis, show increased resistance, making treatment more challenging.

2. Resistant Molds: Aspergillus and Beyond

Aspergillus fumigatus poses a growing threat, particularly to immunocompromised patients. Clancy explained that environmental fungicide use drives resistance in these pathogens, creating cross-resistance to antifungals used in human medicine.

“We’re exposed to hundreds of fungal spores every day as we go out and breathe, and they don’t cause any health problems. Some people may have allergic reactions to them, but if you're strongly immunosuppressed, these inhaled spores can cause disease. These are major diseases in transplant recipients, cancer chemotherapy recipients, and people who have high levels of immunosuppression,” Clancy said.

“The leading fungus within this group within the hospital is something called Aspergillus,” Clancy continued. “We're seeing increasing resistance among Aspergillus fumigatus, the most common of the Aspergillus species we encounter, as well as other Aspergillus and other non-Aspergillus molds. And [fungicide use in the environment] has been best documented in Northern Europe, places like Holland. The fungicides themselves are broadly related, not closely related broadly chemically related to the classes of antifungals that would be given to patients. What's been observed is that environmental resistance is emerging in response to fungicide use in agriculture. In Holland, it's been seen with tulip farming, which then develops cross-resistance to the anti-fungal drugs we use in patients. So, there are now examples worldwide of patients infected with an antifungal-resistant Aspergillus that has emerged in the environment because of fungicide use. Now we have a human infection resistant to an antifungal that we normally use in humans.”

3. Dermatophytes and Skin Infections

Resistant dermatophytes, such as Trichophyton species, are becoming more prevalent. While not life-threatening, they significantly impact quality of life, requiring better diagnostic tools and alternative treatments.

Challenges in Diagnosis and Treatment

Clancy emphasized that diagnosing fungal infections is inherently difficult due to their slow growth and nonspecific symptoms. Several barriers hinder early diagnosis:

• Delayed recognition: Many fungal infections are initially misdiagnosed as bacterial infections, leading to treatment delays.
• Limited diagnostic tools: Culture-based methods are slow, and molecular diagnostics are not yet widely available in many health care settings.
• Genetic complexity: Because fungi are more closely related to human cells than bacteria, developing antifungal treatments that do not harm human tissues remains a challenge.

The Role of Infection Prevention and Public Health Policies

Clancy underscored the importance of robust policies to mitigate the impact of fungal infections. Several strategies are key:

• Enhanced surveillance systems: Monitoring fungal infections and resistance trends at national and international levels.
• Hospital infection control measures: Implement stricter disinfection protocols to prevent outbreaks of Candida auris.
• Antifungal stewardship programs: Encouraging judicious antifungal use to prevent the emergence of resistance.
• Regulation of agricultural fungicides: Addressing the link between environmental fungicide overuse and antifungal resistance in clinical settings.

When asked for a direct comment to infection preventionists, Clancy said, “Consider fungi if you encounter unusual cases and are unsure of the cause. Remember that fungi could be behind these infections, and not every issue in a hospital or health care setting is due to bacteria. If you notice clusters of cases, keep in mind that molds are everywhere in our environment, and in a health care setting with vulnerable patients, they might lead to outbreaks. Recent instances of contaminated bed sheets and other hospital surfaces carried spores and molds, exposing immunosuppressed individuals and resulting in mold infections. So, if you observe unusual clusters of cases, both clinically and from an infection prevention standpoint, think about fungi and the hospital environment. Identify these factors and look specifically for fungi sooner rather than later.”

Future Directions and Recommendations

To effectively combat fungal infections, Clancy highlighted the need for a multipronged approach:

1. Investment in research: Increased funding for novel antifungal agents and rapid diagnostic tools.
2. Education and awareness: Training health care professionals to recognize fungal infections early and implement appropriate treatment strategies.
3. Multidisciplinary collaboration: Encouraging partnerships between researchers, clinicians, policymakers, and the agricultural sector to address antifungal resistance comprehensively.

Conclusion

Fungal infections represent a growing yet often overlooked public health challenge. In his discussion with ICT, Clancy emphasized that the rise of resistant fungal pathogens, particularly in hospital settings, demands improved diagnostics, innovative treatments, and comprehensive infection control policies. Addressing these issues proactively can help mitigate the impact of fungal infections and strengthen preparedness against emerging threats.