Fungal Meningitis Outbreak Traced to Epidurals From Mexico

An outbreak of fungal meningitis cases in the US was traced to a single center in Matamoros, Mexico, where affected individuals received epidural anesthesia, according to a report from the CDC.

“Patients with signs and symptoms of meningitis without any confirmed specific etiology should be tested for fungi, especially patients with history of epidural anesthesia for any reason, whether linked to medical procedures performed in the United States or to international medical tourism,” lead author Dallas J. Smith, PharmD, MAS, epidemiologist in the CDC’s Mycotic Diseases Branch, Atlanta, said in an interview.

In the report, published in Clinical Infectious Diseases, Smith and colleagues investigated fungal meningitis caused by Fusarium solani species complex beginning in May 2023, when two women in Texas developed meningitis after undergoing cosmetic procedures under epidural anesthesia in Mexico. One patient died soon after hospital admission. The other patient’s cerebrospinal fluid (1,3)-beta-D-glucan level was > 500 pg/mL, which led researchers to suspect fungus. The researchers identified a total of 233 potential patients who underwent epidurals for mainly cosmetic surgery at one of two now-closed clinics in Mexico between January 1 and May 13, 2023.

A total of 170 individuals were contacted; 104 reported receiving epidural anesthesia and were deemed at risk for meningitis. Of these, at least 30 individuals received a diagnostic lumbar puncture, and 24 were diagnosed with fungal meningitis. Half of the meningitis patients died, and all identified cases involved epidural anesthesia delivered by the same anesthesiologist in Mexico.

The median age of the 24 confirmed and possible cases was 31 years; all but one were women. The most common symptoms on presentation were headache, nausea, and a stiff neck. The average time from symptom onset to antifungal treatment was 39 days among patients who died and 52 days among those who survived. Of the seven patients treated with fosmanogepix in the wake of updated recommendations, six survived.

The high cost of medical procedures in the US was the most cited reason for the procedure, according to patient questionnaires.

Prior to the Matamoros outbreak in the US, the CDC provided technical support for Mexican investigators responding to a similar outbreak in Durango, Mexico, that did not involve US citizens, Smith told Medscape Medical News.

Durango and Matamoros are far apart, so the researchers were unsure whether the outbreaks were related. Whole-genome sequencing showed isolates from patients in the two locations were genetically distant, but two isolates from patients treated at the Matamoros clinic were closely related, said Smith. “However, this finding cannot rule out a possibility that the outbreaks may be related, as Fusarium species are common in the environment, and contamination with multiple strains or species is possible,” he said.

“The high mortality rate of more than 50% that we saw in the Matamoros outbreak among young, healthy, women was shocking and highlights how deadly fungal infections can be,” Smith added.

The takeaway from the investigation: “Think fungus early and often when evaluating a patient with meningitis without a clear etiology, particularly in the setting of a recent epidural,” Smith told Medscape Medical News. “Early recognition and treatment can save lives and reduce risk of long-term complications,” he said. “Novel nonculture-based diagnostics can be critical tools in helping to determine fungal etiology and pipeline antifungals show promise in treating patients with refractory fungal infections as demonstrated in this outbreak,” he noted.

A Clinician’s Take

“Fungal meningitis acquired in the healthcare setting is very rare; it is important to identify these cases with urgency since they are associated with a high mortality rate and can lead to long-term complications,” Shirin Mazumder, MD, infectious diseases specialist in Memphis, Tennessee, said in an interview.

Since fungal meningitis cases are less common than those caused by bacteria, clinicians may not immediately suspect a fungal etiology, which can delay necessary testing to confirm the diagnosis, said Mazumder. Nonspecific symptoms can make diagnosis of fungal meningitis challenging, as can a lack of access to the advanced diagnostic testing that may be needed in some cases, she said.

“Clinical signs of meningitis can include headache, stiff neck, nausea, vomiting, altered mental status, fever, and photosensitivity,” Mazumder told Medscape Medical News. In addition to contaminated medication or equipment, or a breach in infection control practices, fungal meningitis can be caused by a variety of endemic mycoses that occur in the environment, she noted.

“The recent outbreak of fungal meningitis in Mexico is not the first outbreak associated with a healthcare setting,” Mazumder emphasized. “Patients seeking surgery should be counseled on the specific risks associated with the procedure they are interested in and the potential for healthcare-associated infections,” she said. “Patients who are interested in medical tourism, especially in low-income countries, should be advised to ask plenty of questions, as the potential for poor infection control, substandard surgical care, and use of outdated medications can pose a risk,” she said. Also, patients need to understand that extensive follow-up care closer to home may be necessary should a complication arise, said Mazumder. “An open discussion about the risks and benefits of obtaining medical procedures abroad can help patients make an informed decision,” she added.

The investigation was part of an emergency public health response and was not considered research requiring review by an institutional review board or informed consent from the patients. Smith and Mazumder had no financial conflicts to disclose.