In the rural and urban communities of Guatemala, a pressing and complex public health issue has come to light through recent scientific investigation: the widespread colonization of bacteria resistant to critical antibiotics. Extending beyond the traditional focus on antibiotic consumption, a groundbreaking study led by researchers from Washington State University (WSU) reveals that visits to healthcare facilities—rather than antibiotic use per se—constitute the most significant risk factor for carrying extended-spectrum cephalosporin-resistant Enterobacterales (ESCrE). This discovery reshapes how we conceptualize the drivers of antimicrobial resistance in resource-limited settings and challenges prevailing assumptions about the origins of these formidable pathogens.
Enterobacterales are a large order of gram-negative bacteria commonly found within the gastrointestinal tract, with Escherichia coli (E. coli) being among the most prevalent species. These organisms, while typically harmless, can acquire resistance genes that render front-line antibiotics such as ceftriaxone ineffective. Ceftriaxone, a third-generation cephalosporin, is integral to the treatment of serious infections like pneumonia and urinary tract infections worldwide. The study’s context is the Western Highlands of Guatemala, where prior research already identified nearly half of the population harboring these resistant strains asymptomatically, raising alarms about silent reservoirs of antimicrobial resistance in community settings.
Delving into the epidemiology of ESCrE colonization, the WSU-led team analyzed stool samples and health data from 951 residents to pinpoint factors influencing carriage rates. Remarkably, the data indicate that healthcare exposure—specifically recent visits to hospitals and clinics—emerges as the strongest predictor of ESCrE colonization. This association hints at nosocomial transmission pathways that may facilitate the spread of resistant bacteria within clinical environments, which are often hotspots for antimicrobial resistance due to high antibiotic use, vulnerable patients, and potential lapses in infection control.
However, the study cautiously emphasizes that healthcare visits themselves may not directly cause colonization. Instead, these environments could facilitate bacterial acquisition via contaminated surfaces, medical devices, water sources, or healthcare personnel. Furthermore, individuals seeking medical care frequently present with underlying conditions such as chronic illnesses, diarrhea, or malnutrition, which may compromise gut integrity and alter the microbial milieu—factors known to enhance colonization by opportunistic resistant bacteria. This interplay of environmental exposure and host susceptibility underscores the intricate biology underlying bacterial colonization dynamics.
Beyond healthcare exposure, the investigation uncovered additional socio-environmental determinants of ESCrE carriage that illuminate broader transmission mechanisms. Urban dwellers were found to be approximately twice as likely to harbor resistant Enterobacterales compared to rural residents. Similarly, households lacking formal trash collection services experienced elevated colonization risk. These findings underscore the critical role of infrastructure and sanitation in shaping the spread of antimicrobial resistance. Inadequate waste disposal may contaminate communal spaces, while urban density can accelerate interpersonal transmission.
Water source quality also emerged as a non-negligible factor. Individuals consuming piped or well water had approximately 1.5 times higher odds of colonization than those using bottled water. This disparity likely reflects biofilms containing resistant bacteria within water distribution networks, as well as contamination that can occur during water storage at home. These microbial reservoirs within domestic environments represent insidious and underappreciated sources of resistant organisms, emphasizing the urgency of improving water safety and hygiene practices to curb dissemination.
Contradicting widespread assumptions about the direct causal link between antibiotic consumption and resistance carriage, this study revealed no statistically significant association between self-reported antibiotic use and ESCrE colonization in these communities. This finding suggests that in environments burdened by poor sanitation and high transmission potential, the impact of antibiotic pressure may be overshadowed by other factors enabling bacterial spread. It reframes the antimicrobial resistance narrative in such settings, positing that transmission dynamics and environmental reservoirs may govern colonization risk more profoundly than individual drug use history.
Dr. Brooke Ramay, the study’s lead author and an assistant research professor at WSU’s Paul G. Allen School for Global Health, highlights that colonization — while asymptomatic — poses a serious public health threat. Colonized individuals can serve as vectors, silently disseminating resistant bacteria to others in the household, community, or healthcare settings. Importantly, these bacteria can become pathogenic if they invade normally sterile sites such as the bloodstream or urinary tract, causing infections that are difficult to treat and often associated with higher morbidity and mortality.
This research forms part of the broader Antimicrobial Resistance in Communities and Hospitals (ARCH) study, an international collaborative network spanning six countries, including Guatemala, Kenya, Chile, India, Botswana, and Bangladesh. ARCH studies indicate ESCrE prevalence rates ranging from 24 to 78 percent across disparate geographic and socio-economic contexts, underscoring the global scale and variability of this public health challenge. As the lead institution overseeing ARCH activities in Guatemala and Kenya, WSU is at the forefront of elucidating context-specific drivers of antimicrobial resistance to inform tailored interventions.
The implications of these findings extend well beyond Guatemala’s borders. Although resistant bacteria remain relatively rare in the United States, the interconnectedness of the modern world through international travel and commerce elevates the risk of transnational dissemination of resistant strains and resistance genes. This global mobility means that antimicrobial resistance is not contained within geographic boundaries, demanding coordinated international efforts to monitor, understand, and mitigate its spread.
Recognizing the multifaceted origins of ESCrE colonization, the study advocates for a paradigm shift in intervention strategies that extend beyond antimicrobial stewardship alone. Targeted efforts to improve infection prevention and control in healthcare settings—addressing contamination of surfaces, medical equipment, and staff practices—are critical. Simultaneously, enhancing water, sanitation, and waste management infrastructure in both urban and rural communities can reduce environmental reservoirs that perpetuate bacterial transmission.
Moreover, the research team is actively exploring the biological mechanisms by which host inflammation and gut microbiota disruptions influence colonization susceptibility. Understanding these host factors could unlock novel therapeutic and preventive avenues, including microbiome modulation or anti-inflammatory interventions to reduce colonization and subsequent infection risk. These avenues represent exciting frontiers in combating antimicrobial resistance.
Ultimately, the WSU-led study offers a nuanced and comprehensive analysis of antimicrobial resistance drivers in a high-burden setting, challenging the reductionist view that antibiotic use alone propels resistance. By illuminating the pivotal role of healthcare exposure and environmental determinants, this work invites a reconceptualization of public health priorities and resource allocation in the global fight against antibiotic-resistant infections. It also reinforces the critical need for integrated, context-sensitive approaches to safeguard antibiotics’ efficacy for future generations.
As Dr. Ramay poignantly notes, “These bacteria and the resistance genes they carry do not respect borders. By understanding and addressing colonization risk factors abroad, we can help slow their spread everywhere.” This statement encapsulates the imperative for translated scientific insights into policy action and community engagement worldwide, recognizing antimicrobial resistance as a shared global threat requiring collective responsibility.
Subject of Research: Risk factors associated with community colonization of extended-spectrum cephalosporin-resistant Enterobacterales in Guatemala.
Article Title: Risk factors associated with community colonization of extended-spectrum cephalosporin-resistant Enterobacterales from an antibiotic resistance in communities and hospitals (ARCH) study, Guatemala.
News Publication Date: 29-May-2025
Web References:
- Scientific Reports article: https://www.nature.com/articles/s41598-025-03379-9
- DOI: http://dx.doi.org/10.1038/s41598-025-03379-9
References: The study was conducted by Washington State University in collaboration with the Centers for Disease Control and Prevention and University del Valle de Guatemala, as part of the ARCH study partnership.
Keywords: Antimicrobial resistance, extended-spectrum cephalosporin-resistant Enterobacterales, ESCrE, antibiotic resistance, colonization, Guatemala, healthcare exposure, water sanitation, gut microbiota, infectious diseases, public health, epidemiology.
