More than half of intensive care unit (ICU) patients who were initially free from difficult-to-treat drug-resistant bacteria acquired them during hospital care, according to 2 studies by the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b).
Published in Microbiology Spectrum and Antimicrobial Resistance & Infection Control, the studies analyzed data from 373 critically ill adults admitted to an ICU between July 2023 and February 2024 and 363 neonates admitted to a neonatal intensive care unit (NICU) between December 2023 and September 2024 at a tertiary government hospital in Dhaka.
Gazi Md Salahuddin Mamun, assistant scientist at icddr,b and lead author of the difficult-to-treat resistant burden paper, said: “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 colonization later progressed to infection. This allowed us to identify links between bacteria carried by patients and those causing subsequent deadly infections.”
Funded by the US Centers for Disease Control and Prevention (CDC), the study focused on difficult-to-treat resistant Gram-negative bacteria, which are resistant to commonly used antibiotics and can cause pneumonia, bloodstream, urinary tract, and wound infections, particularly among critically ill patients.
An earlier icddr,b study documented widespread colonization with drug-resistant bacteria in hospitals and communities, including among newborns. The new studies examined how these bacteria spread within ICUs and whether improved IPC measures could reduce infections and deaths.
Researchers examined 4 major Gram-negative bacteria associated with hospital-acquired infections: Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa.
The study found that 48.5% of ICU patients were colonized with difficult-to-treat resistant Gram-negative bacteria. Among the 198 patients who were initially free from these bacteria, 105 (53%) acquired colonization during their ICU stay, indicating substantial in-hospital transmission.
More than 90% of patients who developed culture-confirmed infections with these bacteria died in the ICU. Researchers said the high mortality may reflect limited treatment options, nosocomial infections, and overcrowded ICUs in resource-constrained settings.
Whole-genome sequencing also found that, in some patients, the same bacterial strain detected during colonization later caused infection, indicating progression from silent carriage to life-threatening disease.
Fahmida Chowdhury, lead of the Antimicrobial Resistance (AMR) Research Unit at icddr,b and principal investigator of the study, said: “A hospital should be a place of healing, not a place where patients acquire another potentially life-threatening infection while seeking treatment.” She added that strengthening IPC practices, hospital hygiene, and responsible antibiotic use is essential to protect critically ill patients.
A second study by the same research team, published in Antimicrobial Resistance & Infection Control, evaluated a targeted IPC program in a NICU in Dhaka. Healthcare workers and cleaning staff received baseline and monthly training on hand hygiene, environmental cleaning, waste management, and infection prevention practices, while researchers monitored compliance, bloodstream infections, mortality, and colonization with carbapenem-resistant organisms.
After 7 months of intervention, bloodstream infections fell from 28 to 4 per 100 admissions—an 86% reduction—while mortality declined from 26 to 4 deaths per 100 admissions.
Tahmeed Ahmed, executive director of icddr,b, said: “These studies reveal a troubling reality: patients are acquiring difficult-to-treat drug-resistant bacteria while receiving care in our hospitals.” He said infection prevention, hospital hygiene, surveillance, and responsible antibiotic use should be treated as core patient safety priorities to combat antimicrobial resistance.
The researchers said the findings show that strengthening IPC measures—including hand hygiene, environmental cleaning, antimicrobial stewardship, surveillance, and safe patient care practices—can significantly reduce infections and improve patient outcomes in Bangladesh and other resource-constrained settings.