This week’s research highlights the growing challenge of antifungal resistance, encouraging early experience with a once-weekly antifungal treatment, and progress in diagnosing invasive aspergillosis.
Research published during the past week provides new insights into the diagnosis and treatment of Aspergillus infections. Three studies stand out: a report of azole-resistant invasive aspergillosis in children, early clinical experience using rezafungin for difficult infections, and a study of a more sensitive molecular diagnostic technique.
Other research examines how antifungal resistance develops in the environment and why some people with rare immune disorders are particularly vulnerable to Aspergillus infection.
1. Azole-resistant aspergillosis in children: a serious treatment challenge
Mendoza-Palomar N et al. – Mycoses, 2026
Azole antifungals, including voriconazole and isavuconazole, are important treatments for invasive aspergillosis. However, some Aspergillus strains are resistant to these medicines.
Researchers in Spain reviewed 11 children with azole-resistant invasive aspergillosis treated at four specialist hospitals between 2019 and 2024.
Most had serious underlying conditions, particularly blood cancers requiring stem cell transplantation or heart transplantation.
The 11 resistant cases represented 22% of the 50 proven or probable paediatric invasive aspergillosis cases identified at the participating centres.
Five children had previously received azole antifungals to prevent infection.
Despite treatment, eight of the 11 children died from aspergillosis.
Why is this important?
These findings demonstrate how difficult resistant invasive aspergillosis can be to treat in severely immunocompromised children.
However, this was a small study involving selected high-risk patients. The results do not mean that 22% of all children with aspergillosis have resistant infections.
The researchers emphasise the importance of identifying the Aspergillus species, testing for antifungal resistance and considering alternative antifungal classes when infection develops despite preventive treatment.
What does this mean for patients?
This research reinforces the importance of specialist assessment and laboratory testing when invasive aspergillosis is not responding as expected.
It does not suggest that patients should change or stop their antifungal medicines without medical advice.
2. Rezafungin: encouraging early experience with a once-weekly antifungal
Stone N et al. – Mycoses, 2026
Long-term antifungal treatment can be difficult for people who develop resistance, experience side effects or cannot tolerate existing medicines.
Rezafungin is a newer antifungal belonging to the echinocandin family.
Unlike older intravenous echinocandins, which generally require daily administration, rezafungin has a long duration of action and can be given once a week.
Researchers from the UK, Spain and Italy described eight adults who received rezafungin for challenging Aspergillus infections.
These patients had experienced problems such as resistance to standard medicines, treatment failure or unacceptable side effects.
The infections varied considerably, including pulmonary and other forms of aspergillosis. Rezafungin was sometimes given alongside other antifungal medicines.
Several patients experienced clinical improvement or stabilisation. In some cases, weekly infusions made outpatient treatment possible and reduced the need for prolonged hospital attendance.
Why is this important?
For patients requiring long-term intravenous treatment, once-weekly administration could offer considerable practical benefits.
Rezafungin also has fewer of the drug interactions associated with triazole antifungals.
However, this study involved only eight patients, without a comparison group. Some were receiving additional treatments, making it difficult to determine how much improvement was directly attributable to rezafungin.
It is therefore too early to conclude that rezafungin is an effective replacement for established Aspergillus treatments.
What happens next?
A separate Phase II clinical study is evaluating rezafungin in adults with chronic pulmonary aspergillosis (CPA) who have limited treatment options.
This should provide more systematic information about effectiveness, safety and quality of life.
What does this mean for patients?
Rezafungin is a promising option under investigation, particularly for people who cannot tolerate conventional antifungals.
It is not currently an established routine treatment for aspergillosis. Decisions about its use belong with specialist clinical teams.
Read the original research
Read about the CPA clinical trial
3. A more sensitive PCR test for invasive aspergillosis
Bitterman R et al. – Journal of Clinical Microbiology, 2026
Diagnosing invasive aspergillosis can be difficult, especially in people undergoing treatment for blood cancers.
Researchers investigated whether a laboratory technique called droplet digital PCR (ddPCR) could improve detection of Aspergillus DNA.
Unlike conventional PCR, ddPCR divides a sample into thousands of tiny droplets before testing for genetic material. This can improve the detection and measurement of small quantities of DNA.
The prospective study involved 203 patients with haematological malignancies, of whom 26 were diagnosed with proven or probable invasive aspergillosis.
The researchers tested samples collected during bronchoscopy, known as bronchoalveolar lavage fluid (BALF), as well as moisture collected from exhaled breath.
What did they find?
The best results came from ddPCR testing of the liquid portion of bronchoalveolar lavage samples.
This achieved:
- Sensitivity of approximately 65%.
- Specificity of approximately 96%.
- Better overall diagnostic performance than conventional quantitative PCR in the study.
Among patients who had not recently received mould-active antifungal treatment, diagnostic performance improved further.
However, testing exhaled breath condensate performed poorly and was not reliable enough to diagnose invasive aspergillosis.
Why is this important?
Earlier and more accurate diagnosis can help clinicians begin appropriate treatment promptly.
The results suggest that ddPCR could become a useful additional test, particularly when bronchoscopy samples are already being collected.
However, sensitivity of 65% means that a negative result would still miss some infections. The test cannot replace clinical assessment or other diagnostic investigations.
What does this mean for patients?
This is a promising laboratory development rather than a new test that patients can currently request routinely.
Further studies are needed to establish how ddPCR should be incorporated into diagnostic pathways.
4. Greenhouse environments and antifungal resistance
Duan C et al. – mSystems, 2026
Antifungal resistance can develop not only during medical treatment but also in the environment.
Some agricultural fungicides act on fungal targets similar to those affected by medicines used to treat aspergillosis.
Researchers examined Aspergillus fumigatus collected from greenhouse environments in China and compared their genetic characteristics with strains from other parts of the world.
The study used whole-genome sequencing and other genetic techniques to investigate population structure, resistance and relationships between environmental and clinical isolates.
The researchers identified considerable genetic diversity and distinct groups of Aspergillus, including resistant isolates without the familiar cyp51A resistance mutations.
Why is this important?
These findings support the view that environmental resistance is genetically complex and cannot always be explained by the best-known resistance mutations.
The study also identified genetic relationships between isolates from different environmental and geographical sources.
However, genetic similarity does not by itself establish that a particular patient acquired an infection from a greenhouse or other agricultural environment.
What does this mean for patients?
The findings reinforce the importance of monitoring antifungal resistance in both clinical and environmental settings.
They do not establish that ordinary contact with plants or vegetables causes resistant aspergillosis.
5. A rare immune disorder reveals how the body defends itself against Aspergillus
Mackie J et al. – Science Signaling, 2026
STAT3 is a protein involved in regulating immune responses.
Certain inherited changes in the STAT3 gene cause a rare condition known as hyper-IgE syndrome, which can involve recurrent infections, eczema and lung complications.
Researchers investigated how a particular STAT3 variant disrupts normal immune signalling.
The study described a patient with serious Aspergillus infection affecting the lungs and brain, alongside bronchiectasis and other features of immune dysfunction.
The findings help explain how disruption of STAT3 function can contribute to susceptibility to severe infections.
Why is this important?
Understanding these immune pathways may eventually help researchers identify why some people are unusually vulnerable to fungal disease.
However, this is mechanistic research involving a rare inherited disorder. It does not imply that most people with aspergillosis have a STAT3 abnormality.
What have we learned this week?
Three themes emerge from these studies.
Antifungal resistance remains a major challenge. The paediatric study demonstrates the serious consequences resistant infections can have in highly vulnerable patients, while the environmental research illustrates the complexity of resistance development.
New treatment approaches are being explored. Rezafungin could eventually provide another option for people who cannot tolerate existing antifungal medicines, although controlled clinical evidence is still needed.
Diagnostics continue to improve. Droplet digital PCR offers a potentially useful advance, but no single laboratory test can reliably diagnose or exclude every case of invasive aspergillosis.
Together, these studies underline the importance of specialist expertise, accurate diagnosis, antifungal susceptibility testing and continued clinical research.
For people living with aspergillosis, the most encouraging message is that researchers are actively working on the problems that make these infections difficult to manage: resistance, treatment tolerability and delayed diagnosis.
This weekly update summarises recently published scientific research. Many findings are preliminary and do not necessarily represent changes to current clinical practice. Patients should discuss treatment decisions with their own specialist team.
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