Hospitals, sanitation linked to spread of antibiotic resistance in Guatemala

In Guatemalan communities, a recent visit to a health clinic or hospital—not antibiotic use—is the strongest predictor of carrying bacteria resistant to critical antibiotics, according to a new study led by Washington State University.

Previous research in Guatemala’s Western Highlands found nearly 46% of residents were colonized in the gastrointestinal tract with bacteria known as extended-spectrum cephalosporin-resistant Enterobacterales (ESCrE). These bacteria, often E. coli, can render the commonly used and important antibiotic ceftriaxone ineffective, complicating care for infections such as pneumonia or urinary tract infections.

The new study, published in Scientific Reports, examined 951 residents from the same region to identify factors linked to ESCrE colonization.

“By identifying the most important risk factors for carrying these resistant bacteria, we can begin to target interventions where they will have the most impact,” said Dr. Brooke Ramay, the study’s lead author and an assistant research professor in the WSU College of Veterinary Medicine’s Paul G. Allen School for Global Health. “This knowledge is critical not only for protecting communities in Guatemala but also for addressing the global threat posed by antibiotic resistance.”

While most studies on antimicrobial resistance have focused on infection and mortality, this research examined colonization—when bacteria live in or on a person without causing illness.

“We’re colonized with all types of bacteria, including antibiotic-resistant bacteria,” Ramay said. “Being colonized isn’t necessarily harmful, but it means you can carry and spread these bacteria to others in the community or in health care facilities. And when these bacteria get into the wrong place—your bloodstream, urinary tract or other vulnerable sites, for example—they can cause serious infections.”

While the study doesn’t prove that health care visits cause colonization, it’s likely that exposure to hospitals and clinics increases the chance of picking up resistant bacteria through contact with surfaces, medical equipment, water or staff. It’s also possible that people who need medical care already have health conditions like chronic illness, diarrhea or malnutrition that make them more vulnerable to colonization.

“People who had reported going to a health care facility or a hospital for treatment for any type of illness had a much higher risk of being colonized in the gastrointestinal tract with these bacteria,” Ramay said.

“This could be due to exposure to the health care environment facilitating transmission. Alternatively, this might be because inflammatory processes occurring in the gut of sick individuals make it easier for these bacteria to colonize. We are exploring this further in ongoing studies.”

The study also found urban residents and households without trash pickup were roughly twice as likely to carry the bacteria compared to rural residents or those with waste services. People using piped or well water were about 1.5 times more likely to be colonized than those using bottled water, possibly due to bacterial biofilms in water infrastructure or contamination during storage.

Contrary to common assumptions, the study found no significant link between colonization and self-reported antibiotic use.

“We’ve seen this in other projects as well,” she said. “In Guatemala, we observe significant effects of antibiotic use on antibiotic resistance in environments with improved hygiene. In households with poor hygiene, transmission factors play a much greater role in colonization risk.”

The research was completed in collaboration with the Centers for Disease Control and Prevention and University del Valle de Guatemala as part of the broader Antimicrobial Resistance in Communities and Hospitals (ARCH) study partnership, which has research projects in six countries. ARCH studies have shown a wide range of ESCrE prevalence, ranging from 34% to 52% in Kenya, 29% in Chile, 72% in India, 24% to 26% in Botswana, 78% in Bangladesh and 46% in Guatemala. WSU is leading the ARCH efforts in both Guatemala and Kenya.

While resistant bacteria remain rare in the U.S., global travel and trade could mean they are just a flight away.

“These bacteria and the resistance genes they carry do not respect borders,” Ramay said. “By understanding and addressing colonization risk factors abroad, we can help slow their spread everywhere.”