According to AOP

CDC Investigation Links Outbreak to Environmental Contamination

A fungal keratitis outbreak involving three patients at a New York ophthalmology clinic has been linked to environmental contamination and deficiencies in infection prevention and control practices, according to a report published by the U.S. Centers for Disease Control and Prevention (CDC).

The outbreak occurred after three patients underwent laser eye surgery at the same clinic and subsequently developed corneal infections caused by Purpureocillium lilacinum, a fungal pathogen known for its resistance to multiple antifungal treatments.

All three patients experienced significant vision loss as a result of the infections, and one patient ultimately required a corneal transplant to restore vision.

Public Health Investigation Began in December 2024

The cases were first reported in December 2024, prompting an investigation by the New York City Health Department in collaboration with public health authorities.

The investigation sought to identify the source of the infections and determine whether environmental or procedural factors within the clinic contributed to the outbreak.

According to the findings, investigators identified multiple deficiencies in the clinic’s infection prevention and control (IPC) practices.

These deficiencies raised concerns regarding the sterilization and maintenance of medical equipment, medication management, and environmental hygiene within the surgical setting.

Among the issues documented were incomplete instrument sterilization records, which limited the ability to verify that surgical equipment had undergone appropriate decontamination procedures.

Investigators also discovered the use of expired topical ocular medications, which may have increased the risk of contamination or reduced treatment effectiveness.

Cool-Mist Humidifiers Identified as a Potential Risk Factor

Another significant concern involved the presence of cool-mist humidifiers within the procedure room.

Public health authorities noted that such devices can create opportunities for exposure to non-sterile water and airborne microbial contamination.

The CDC currently advises against the use of cool-mist humidifiers in healthcare environments because they may facilitate the dissemination of microorganisms into clinical spaces.

Laboratory testing provided further evidence linking the outbreak to environmental contamination within the facility.

Molecular analysis detected Purpureocillium lilacinum DNA within the tubing of a surgical device used during ophthalmic procedures.

The discovery suggested that environmental contamination may have played a direct role in exposing patients to the fungal pathogen during surgery.

Understanding Fungal Keratitis

Fungal keratitis is an infection of the cornea, the transparent outer layer of the eye.

The condition can lead to pain, redness, inflammation, corneal ulceration, impaired vision, and permanent blindness if not diagnosed and treated promptly.

Although fungal keratitis is more commonly associated with eye trauma, contact lens use, and agricultural exposure, healthcare-associated outbreaks remain relatively rare.

The pathogen identified in this outbreak, Purpureocillium lilacinum, has emerged as an increasingly recognized cause of ocular infections.

Historically known as an environmental fungus found in soil, decaying vegetation, and indoor environments, the organism has demonstrated the ability to infect both healthy and immunocompromised individuals under certain circumstances.

Drug Resistance Complicates Treatment

One of the major clinical concerns surrounding P. lilacinum is its resistance to several commonly used antifungal medications.

Drug-resistant infections can complicate treatment decisions, prolong recovery, and increase the likelihood of permanent visual damage.

Because of these characteristics, early identification of the pathogen is critical for selecting appropriate therapy.

The CDC report noted that Purpureocillium lilacinum infections have previously been associated with soft contact lens use, ocular trauma, eye surgery, and immunosuppression.

However, the organism’s role in healthcare-associated outbreaks remains relatively uncommon, making the New York cases particularly noteworthy.

Researchers emphasized that rates of detection for P. lilacinum appear to be increasing.

As awareness of the pathogen grows, clinicians are being encouraged to consider it as a potential cause of postoperative eye infections, especially when patients fail to respond to standard treatments.

Corrective Actions Halted the Outbreak

The investigation resulted in the temporary suspension of surgical procedures at the clinic.

Surgeries were halted following notification of the outbreak while corrective measures were implemented.

These measures focused on strengthening infection prevention protocols, improving equipment sterilization practices, reviewing medication management procedures, and addressing environmental contamination risks.

Following the implementation of recommended infection prevention and control measures, the clinic resumed surgical operations in January 2025.

According to the CDC, no additional cases were identified after the corrective actions were introduced, suggesting that the interventions were successful in eliminating the source of transmission.

Environmental Fungi Are Emerging Healthcare Threats

The outbreak highlights the critical importance of strict infection control practices within ophthalmology clinics and surgical facilities.

Even minor lapses in sterilization procedures, environmental management, or equipment maintenance can create opportunities for microbial contamination and patient exposure.

The findings also underscore the growing significance of environmental fungi as healthcare-associated pathogens.

While bacterial infections traditionally receive greater attention in clinical settings, fungal organisms are increasingly recognized as important causes of serious healthcare-associated infections, particularly when invasive procedures are involved.

Experts note that healthcare facilities must maintain rigorous environmental controls and continuously monitor compliance with infection prevention standards.

Regular auditing of sterilization procedures, equipment maintenance, medication management, and environmental hygiene remains essential for reducing patient risk.

The CDC’s investigation serves as a reminder that environmental fungi can pose significant threats when introduced into surgical environments.

Early detection, rapid public health response, and comprehensive infection control measures remain vital tools for preventing similar outbreaks in the future.

As awareness of drug-resistant fungal pathogens continues to increase, healthcare providers are likely to place greater emphasis on fungal surveillance, environmental monitoring, and targeted diagnostic testing.

These efforts may help improve patient outcomes and reduce the likelihood of future healthcare-associated fungal infections affecting vulnerable populations.