Drug-resistant bacteria spreading rapidly in Bangladesh ICUs: icddr,b

Difficult-to-treat drug-resistant bacteria are spreading within Bangladesh's intensive care units (ICUs), with more than half of ICU patients who were initially free from these drug-resistant bacteria, acquiring them while receiving hospital care, according to two new studies of icddr,b.

The studies found alarmingly high mortality among patients who developed these infections, but also showed that strengthening infection prevention and control practices can dramatically reduce severe infections and deaths, said an icddr,b press release issued today.

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These studies, led by researchers from icddr,b and published in Microbiology Spectrum and Antimicrobial Resistance & Infection Control journals, analysed data from 373 critically ill adult patients admitted to the ICU between July 2023 and February 2024 and 363 neonates admitted in neonatal intensive care unit (NICU) between December 2023 and September 2024 of a tertiary care government hospital in Dhaka.

Gazi Md Salahuddin Mamun, assistant scientist at icddr,b and the lead author of 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 colonisation later progressed to infection. This allowed us to identify links between bacteria carried by patients and those causing subsequent deadly infections.”

The study, funded by US Centers for Disease Control and Prevention (CDC), focussed on difficult-to-treat resistant Gram-negative bacteria, a group of bacteria that are resistant to commonly used antibiotics, making infections extremely difficult to treat. Gram-negative bacteria can cause serious infections such as pneumonia, bloodstream infections, urinary tract infections, and wound infections, especially among critically ill patients.

An earlier icddr,b study documented widespread colonisation with drug-resistant bacteria in hospitals and communities, including among newborns. The current studies add new evidence on how these bacteria spread within ICUs and how improved infection prevention can reduce infections and deaths.

Researchers examined four major Gram-negative bacteria commonly linked to hospital-acquired infections: Escherichia coli (e coli), Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa.

The study found that nearly half of the ICU patients (48.5 percent) were colonised with difficult-to-treat resistant Gram-negative bacteria in their gut.

Colonisation refers to the presence of bacteria in the body without causing infection, although colonised patients remain at risk of developing disease and transmitting the organisms within healthcare settings.

Importantly, 105 out of 198 patients (53 percent), who were initially free from these resistant bacteria, acquired colonisation with them during their ICU stay, suggesting substantial in-hospital transmission.

Among patients who developed culture-confirmed infections with these difficult-to-treat bacteria, mortality was alarmingly high. More than 90 percent of patients with these infections died in ICU.

Researchers note that the exceptionally high mortality observed in this study may reflect challenges in resource-constrained critical care settings, including limited treatment options and nosocomial infections among others in overcrowded ICU settings.

Using whole-genome sequencing, researchers also found evidence that in some patients, the same bacterial strain present in the body during colonisation later caused infection, indicating possible progression from silent carriage to life-threatening disease.

Dr Fahmida Chowdhury, lead, AMR Research Unit at icddr,b and the principal investigator of this study, said a hospital should be a place of healing, not a place where patients acquire another potentially life-threatening infection while seeking treatment.

“In our study, more than half of the patients who were initially free from these difficult-to-treat resistant bacteria acquired them during their ICU stay, which is deeply concerning,” she said.

Strengthening infection prevention and control practices, hospital hygiene, and responsible antibiotic use is essential to better protect critically ill patients, she added.

After seven months of continued intervention, bloodstream infections fell from 28 to 4 per 100 admissions, representing an 86 percent reduction.

Besides, mortality decreased from 26 to 4 deaths per 100 admissions, suggesting that even in settings where resistant bacteria are widespread, stronger infection prevention and control measures can prevent these organisms from causing life-threatening infections.

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 hospitals, and the consequences can be devastating.

At the same time, they show that strengthening basic infection prevention and control measures can dramatically reduce infections and deaths, he said.

“Hospital authorities and policymakers must treat infection prevention, hospital hygiene, surveillance, and responsible antibiotic use as core patient safety priorities if we are to protect patients and combat antimicrobial resistance,” he added.