Over half of ICU patients acquire drug-resistant bacteria in hospital: icddr,b 

Difficult-to-treat drug-resistant bacteria are spreading within Bangladesh's intensive care units (ICUs), with more than half of critically ill patients initially free of the bacteria acquiring them during hospitalisation, according to two new icddr,b studies.

Published in Microbiology Spectrum and Antimicrobial Resistance & Infection Control, the studies found alarmingly high mortality among infected patients but also showed that strengthening infection prevention and control (IPC) measures can dramatically reduce bloodstream infections and deaths.

Led by icddr,b researchers, the studies analysed data from 373 critically ill adults admitted to the ICU of a tertiary government hospital in Dhaka between July 2023 and February 2024, and 363 newborns admitted to its neonatal intensive care unit (NICU) between December 2023 and September 2024, according to a press release.

More than half acquired bacteria in ICU 

The ICU study, funded by the US Centers for Disease Control and Prevention (CDC), focused on difficult-to-treat resistant Gram-negative bacteria resistant to commonly used antibiotics that can cause pneumonia, bloodstream, urinary tract and wound infections.

Researchers examined four major hospital-associated pathogens: Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa.

Nearly half (48.5%) of ICU patients were already colonised with these bacteria in their gut. Although colonisation does not cause illness, it puts patients at risk of developing infection and transmitting the organisms within healthcare settings.

Among 198 patients initially free of the bacteria, 105 (53%) acquired colonisation during their ICU stay, indicating substantial in-hospital transmission.

Using laboratory testing and whole-genome sequencing, researchers found that, in some patients, the same bacterial strain detected during colonisation later caused life-threatening infection.

Mortality exceeded 90% among patients with culture-confirmed infections. Researchers said the exceptionally high death rate likely reflects resource-constrained critical care, limited treatment options and nosocomial infections in overcrowded ICUs.

Hospitals must strengthen infection control

"We followed ICU patients throughout their stay and used laboratory testing and whole-genome sequencing to understand how resistant bacteria spread within the hospital and how colonisation later progressed to infection," said Gazi Md Salahuddin Mamun, assistant scientist at icddr,b and lead author of the study.

Fahmida Chowdhury, lead of icddr,b's AMR Research Unit and principal investigator, said hospitals should be places of healing, not where patients acquire life-threatening infections. She said the finding that more than half of initially uncolonised patients acquired the bacteria underscores the need for stronger infection prevention, hospital hygiene and responsible antibiotic use.

The findings build on an earlier icddr,b study documenting widespread colonisation with drug-resistant bacteria in hospitals and communities, including among newborns.

NICU programme cut infections, deaths

The second study evaluated an IPC programme in a Dhaka NICU, providing baseline and monthly training for healthcare workers and cleaning staff on hand hygiene, environmental cleaning, waste management and infection prevention. Researchers also monitored compliance, bloodstream infections, mortality and colonisation with carbapenem-resistant organisms.

After seven months, bloodstream infections fell from 28 to four per 100 admissions – an 86% reduction – while mortality dropped from 26 to four deaths per 100 admissions, showing that stronger IPC measures can prevent life-threatening infections even where resistant bacteria are widespread.

icddr,b Executive Director Tahmeed Ahmed said the findings show patients are acquiring difficult-to-treat drug-resistant bacteria while receiving hospital care, but stronger infection prevention, hospital hygiene, surveillance and responsible antibiotic use can substantially reduce infections and deaths. 

He urged hospital authorities and policymakers to treat these as core patient safety priorities in combating antimicrobial resistance.