Drug-resistant fungal 'superbug' found spreading in intensive care units: icddr,b study

A hard-to-treat drug-resistant fungus known as Candida auris is spreading within intensive care units (ICUs) in Dhaka, according to a study conducted by icddr,b.

The findings show that this so-called “superbug” is not limited to newborn units, but is also affecting other critically ill patients, raising concerns about hospital-acquired infections.

Earlier research had shown the fungus spreading among newborns in intensive care unit (NICU), and the new findings suggest the problem is broader and affects other ICU settings as well.

The study, published in the journal Microbiology Spectrum, was carried out in one public and one private tertiary-level hospital in Dhaka, in collaboration with the Institute of Epidemiology, Disease Control and Research (IEDCR), with technical support from the United States Centers for Disease Control and Prevention (CDC).

In total, 372 ICU patients were included in the study between August 2021 and September 2022.

Researchers tested patients soon after admission and again during their ICU stay to see whether they were carrying Candida auris on their skin or had developed a bloodstream infection. Skin swabs and blood samples were analysed in the laboratory, and suspected samples were confirmed using VITEK-2.

Candida auris can colonize and live on the skin without causing symptoms. However, in some patients, it can enter the bloodstream and cause severe and life-threatening infection. The fungus is especially alarmingfor people who are critically ill or have weak immune systems. It is also difficult to treat because almost all strains are resistant to commonly used antifungal medicines. For these reasons, health authorities around the world consider C. auris a serious healthcare-associated threat.

In this study, about 7.0 per cent of patients were found to be carrying C. auris at some point during their ICU stay. Importantly, more than one-third of the patients who were found to be carrying the fungus picked it up during their stay in the ICU, showing that the fungus is spreading mostly inside hospital settings.

The researchers also found that this happened more often in the public hospital than in the private hospital, with about 13 per cent of patients picking up the fungus during their ICU stay in the public hospital compared to about 4.0 per cent in the private hospital, pointing to possible differences in infection prevention and control practices.

By international standards, the levels seen in these Dhaka ICUs are high. Studies from high-income countries such as Canada and the United Arab Emirates have reported much lower rates, often well below 0.5 per cent.

Patients who were carrying C. auris were more likely to be very ill, to stay longer in the ICU, and to need invasive procedures such as mechanical ventilation and the use of central or urinary catheters. These procedures are often life-saving, but they can also increase the risk of infection if strict hygiene and cleaning standards are not followed.

Laboratory testing showed that all C. auris samples were resistant to fluconazole and all but one to voriconazole, the commonly used first- and second-line antifungal medicines, and some were resistant to multiple drugs. This highlights the growing difficulty of treating these infections and the need for better guidance on the use of antifungal medicines.

“This study shows that Candida auris is not just a problem among critically ill neonates, but a wider threat in all intensive care settings,” said Dr Fahmida Chowdhury, Lead of the AMR Research Unit of the Infectious Diseases Division at icddr,b and principal investigator of this research project.

She said, “We are seeing clear signs of spread within hospitals and high levels of resistance to commonly used antifungal drugs. This underlines the urgent need to strengthen infection prevention, improve surveillance, and guide treatment more carefully.”

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