Tulips may help spread drug resistance

Brightening up the hospital campus by planting tulip bulbs could become taboo after researchers found that bulbs imported from the Netherlands may be helping spread resistance to vital antifungal medicines.

A laboratory analysis of swabs taken from tulip and narcissus bulbs imported from the Netherlands and purchased from a garden centre in Dublin found that the majority were cultured resistant to Voriconazole, the leading antifungal therapy in treating aspergillosis fumigatus. A.fumigatus is a fungus that can kill immunocompromised patients, by causing fatal pneumonia.

The analysis also showed some evidence of cross-resistance to other antifungal medicines — known as triazoles — the go-to drugs for doctors treating infections caused by A.fumigatus.

The findings have prompted the researchers, led by Professor of Clinical Microbiology at Trinity College Dublin, Tom Rogers, to advise against planting tulip or narcissus bulbs “in or near healthcare facilities or in the gardens or living quarters of patients who are in any way immunocompromised” — until the potential role of the bulbs in spreading drug resistance has been clarified.

Patients most at risk from this potentially deadly “flower power” include those with haematological malignancies — cancers that affect the blood and lymph system. Patients with chronic obstructive pulmonary disorder (COPD) are also at risk.

Prof Rogers said while prior work confirmed that resistant fungi can be found in the environment, they hadn’t considered that they may have been shipped here from the Netherlands, where the tulip industry is big business, with about 2.5bn bulbs exported in 2014:

“We were aware of reports from the Netherlands of this type of resistance and its possible link to the widespread use of triazole antifungal drugs as fungicides in agriculture and floriculture. What we didn’t think about until now is that they could be arriving here via tulip bulbs shipped from the Netherlands.”

The research, entitled ‘Intercounty Transfer of Triazole-Resistant Aspergillus fumigatus on Plant Bulbs’, published in the journal Clinical Infectious Diseases, was conducted against the backdrop of the first documented cases of invasive aspergillosis due to antifungal drug resistance in two stem cell transplant recipients in a Dublin hospital.

Prof Rogers said the next step is to provide “new insights into the way that environmental triazole resistance is evolving and to prompt more debate on the implications of using medically vital triazole antifungals as fungicides in agriculture and floriculture”.

Prof Rogers chaired the Health Protection Surveillance Centre (HPSC) subcommittee that devised updated National Guidelines for the Prevention of Nosocomial (hospital-acquired) Aspergillosis, yet to be published.