Active Surveillance for Invasive Mold Disease - Four Hospitals, Atlanta, Georgia, 2020-2024

Invasive mold diseases (IMDs) are rare, life-threatening infections that primarily affect persons with immunocompromising conditions. The most common molds associated with IMDs are Aspergillus spp., Mucorales (e.g., Mucor spp., Rhizomucor spp., and Rhizopus spp.), Fusarium spp., and Scedosporium spp. IMDs can affect the lungs, sinuses, skin, central nervous system, or multiple body sites.

2020-2024.

IMD is not a nationally notifiable condition. CDC conducts active, laboratory-based IMD surveillance through the Georgia Emerging Infections Program at three laboratories that serve four Atlanta, Georgia, hospitals: two academic hospitals and their associated outpatient clinics, one federal hospital, and one community hospital. Identifying and classifying IMD cases is challenging because 1) symptoms often are nonspecific and 2) the presence of mold growth in clinical cultures might indicate infection, colonization, or laboratory contamination.Potential IMD cases were identified through a review of records from laboratories serving the hospitals included in this surveillance system to identify patients who received positive results from mold cultures or Aspergillus galactomannan tests, which detect the presence of galactomannan, a compound found in Aspergillus fungi, in serum or bronchoalveolar lavage fluid specimens. Potential cases in these patients were classified as proven or probable cases using established National Institute of Allergy and Infectious Diseases Mycoses Study Group (MSG) criteria that consider laboratory findings (e.g., histopathologic evidence of angioinvasive mold infection or a fungal culture from a normally sterile body site), clinical or radiologic features supporting IMD classification (e.g., chest computed tomography or bronchoscopy results suggestive of fungal disease, sinonasal signs, or central nervous system imaging results), and host factors that predispose patients to IMD (e.g., recent history of neutropenia, hematologic malignancy, transplantation receipt, and use of certain immunosuppressive medications). Potential cases that did not meet the laboratory, clinical, and host-factor criteria for MSG-proven or MSG-probable cases could be categorized as surveillance cases if treating clinicians diagnosed IMD in a patient and initiated treatment with antifungal therapy effective against mold or if the patient died within 3 days of specimen collection.

During 2020-2024, a total of 968 unique patients with potential IMD were identified across four Atlanta hospitals and their associated outpatient clinics. Of those, 449 (46%) were classified as having IMD, including 89 (20%) MSG-proven, 142 (32%) MSG-probable, and 218 (49%) surveillance cases. Among patients with IMD, 58 (13%) had a current or recent COVID-19 diagnosis. Information on bed count was available for three of the four hospitals. At the two academic hospitals, the pooled average annual IMD incidence was 4.8 inpatient cases per 100 inpatient beds and 14.0 intensive care unit (ICU) cases per 100 ICU beds. At the community hospital, the average annual incidence was 2.8 inpatient cases per 100 inpatient beds and 10.2 ICU cases per 100 ICU beds.Among 449 patients with IMD, the largest percentage were aged 45-64 years (43%), followed by ≥65 years (39%), 19-44 years (18%). Patients aged 1-18 years and <1 year each accounted for <1% of IMD cases. Pulmonary infections were most common (68%), followed by cutaneous or deep tissue (nonfacial) infections (11%), sinus or nasal infections (10%), and central nervous system infections (excluding eyes) (9%); less frequent sites of infection included soft tissue (2%), blood (1%), bone (1%), and eye (1%). The most common fungal species identified among IMD cases were Aspergillus spp. (n = 319 [71%]), most commonly Aspergillus fumigatus (n = 94 [21%]). Fusarium spp. were the second most common (n = 20 [4%]), followed by Mucorales (n = 17 [4%]), and Scedosporium spp. (n = 12 [3%]). Aspergillus spp., Scedosporium spp., and Curvularia spp. were most commonly associated with pulmonary infections. Mucorales genera were more commonly associated with sinus, nasal, or facial infections and Fusarium spp. with cutaneous or deep tissue infections. Among patients with IMD, 65% (n = 292) had at least one MSG host factor that predisposes patients to IMD, and 53% (n = 238) had at least one MSG clinical criterion supporting IMD classification, suggesting that surveillance based only on classic host risk factors or typical clinical findings might miss a substantial proportion of IMD cases.A total of 363 (81%) of 449 patients with IMD received antifungal treatment effective against molds, most commonly isavuconazole (n = 178 [40%]), followed by voriconazole (n = 142 [32%]) and amphotericin B (n = 93 [21%]). Overall, 43% of patients with IMD were admitted to an ICU during the 2 weeks preceding specimen collection, and 50% of patients with IMD required intubation and mechanical ventilation; the 90-day all-cause mortality rate, excluding 2024 cases, was 45% (157 of 349). Indicators of severe illness were more common among IMD patients with a current or recent COVID-19 diagnosis than among those without COVID-19, including higher frequency of ICU admission during the 2 weeks preceding specimen collection (66% [38 of 58] versus 39% [154 of 391]; p<0.001) and increased 90-day all-cause mortality (66% [35 of 53] versus 41% [122 of 296]; p<0.001).

IMDs are severe infections associated with frequent ICU admission and high mortality rates, especially among patients with a current or recent COVID-19 diagnosis. The findings from this report could serve as benchmark data in establishing baseline IMD rates for future surveillance to detect outbreaks in health care settings. More than one third of IMD cases (35%) occurred in patients without MSG host factors, underscoring the need for clinicians and surveillance efforts to consider the possibility of IMDs among patients without classic host risk factors for infection.

Health care providers should be vigilant for IMDs as a life-threatening complication among persons with immunocompromising conditions or critical illness. Continued surveillance could help identify emerging populations at risk for IMD, facilitate earlier recognition and treatment, and support detection of health care-associated outbreaks.