Plant Found to Harbor Drug-Resistant Fungal Pathogen

Results showed that 5 of the 6 bulb packages tested positive for triazole-resistant A. fumigatus.

The spread of antifungal drug resistance is potentially being aided by an unlikely source: flower imports. Researchers from Trinity College Dublin, Ireland, found that tulips imported to Ireland from Holland carried a strain of Aspergillus fumigatus that is resistant to triazole antifungal drugs. Triazoles are used in the treatment of Aspergillosis infections, which are particularly concerning for immunocompromised patients.

Reports of antifungal resistance in Holland prompted the researchers to investigate the importation of plants to Ireland from Holland. Researchers swabbed and screened sealed packages of tulips and narcissus bulbs purchased in a Dublin garden center which were imported from Holland, for the presence of Aspergillus fumigatus and triazole resistance. The soil from the garden center was also sampled, as well as the soil and air from a hospital campus in Dublin, where these flowers are present.

Results showed that 5 of the 6 bulb packages tested positive for triazole-resistant A. fumigatus. “We have an ongoing surveillance program, which has shown that these resistant fungi are sometimes present in air and soil samples but what we didn’t think about until now is that they could be arriving here via tulip bulbs shipped from the Netherlands,” said Professor Thomas R. Rogers, lead author of the study. 

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The clinical and local environmental air and soil isolates had distinct genotypes from each other and also from triazole-resistant isolates from Holland. Some isolates showed cross-resistance to multiple triazoles including itraconazole, voriconazole and posaconazole. A previous study recovered identical isolates from a deceased patient and from in-house cultures 4 months after the patient’s death. 

“Given that these fungi can persist for a long time, we are advising people not to plant tulip or narcissus bulbs in or near healthcare facilities or in the gardens of living quarters of patients who are in any way immunocompromised,” said Professor Rogers. 

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