Drug-resistant ‘superbug’ spreading in Dhaka ICUs: icddr,b study

A hard-to-treat drug-resistant fungus, Candida auris, is spreading within intensive care units (ICUs) in Dhaka, raising concerns about hospital-acquired infections, according to a new study by icddr,b.

The study reveals that the so-called “superbug” is no longer limited to neonatal intensive care units (NICUs), where previous research had documented its spread among newborns. It is now affecting a wider range of critically ill patients in both public and private tertiary hospitals in the capital.

The study, published in the journal Microbiology Spectrum, was carried out in one public and one private tertiary-level hospital in Dhaka between August 2021 and September 2022.

It was conducted in collaboration with the Institute of Epidemiology, Disease Control, and Research and received technical support from the Centers for Disease Control and Prevention, where a total of 372 ICU patients were included in the study.

Rapid spread within hospitals

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

Although the fungus can live on the skin without causing symptoms, it can enter the bloodstream and trigger severe, life-threatening infections, particularly in critically ill or immunocompromised patients. C. auris is considered a serious healthcare-associated threat worldwide because of its high resistance to commonly used antifungal drugs.

The study found about 7% of ICU patients carried C. auris at some point during their stay. More than a third of these patients picked up the fungus while in the ICU, indicating that transmission is occurring mainly within hospital settings.

The rate of in-hospital acquisition was significantly higher in the public hospital. Around 13% of ICU patients in the public facility contracted the fungus during their stay, compared to about 4% in the private hospital, pointing to possible differences in infection prevention and control practices.

By international standards, the rates reported in Dhaka are high. Studies from high-income countries, including Canada and the United Arab Emirates, have recorded much lower rates, often under 0.5%.

Critically ill patients are at greater risk

Patients with C. auris were more likely to be critically ill, stay longer in the ICU, and need invasive procedures like mechanical ventilation or central and urinary catheters. While life-saving, these interventions raise infection risk if hygiene and cleaning standards are not strictly maintained.

Laboratory testing revealed that all C. auris samples were resistant to fluconazole and all but one were resistant to voriconazole — the most commonly used first- and second-line antifungal drugs. Some strains were resistant to multiple medications, underscoring the growing difficulty in treating these infections.

Laboratory tests showed that all C. auris samples were resistant to fluconazole, and all but one were resistant to voriconazole, the most commonly used first- and second-line antifungal drugs. Some strains were resistant to multiple medications, highlighting the growing difficulty in treating these infections.

“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 Antimicrobial Resistance (AMR) Research Unit of the Infectious Diseases Division at icddr,b and principal investigator of the project.

“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,” she added.

Genetic testing of selected samples showed the strains belong to a South Asian clade of C. auris, indicating that the fungus is now established in the region rather than being an occasional imported threat.

Urgent measures for clinical safety

The researchers recommend regular, thorough cleaning with effective chlorine-based disinfectants, strict hand hygiene for healthcare workers, and routine screening in high-risk units to identify carriers early.

They also emphasise the careful use of antifungal drugs to preserve the effectiveness of the limited treatment options currently available.

The researchers say larger studies across more hospitals are needed to assess the full extent of the problem in Dhaka and nationwide.