Volcano at the molecular level: The unprecedented rise of multidrug-resistant Enterobacterales in Latin America
– by Paula Samper Escobar and María Virginia Villegas

The views and opinions expressed in this article are solely those of the original author(s) and do not necessarily represent those of GARDP, their donors and partners, or other collaborators and contributors. GARDP is not responsible for the content of external sites.

Latin America and the Caribbean (LAC) finds itself situated over one of the most active volcanic belts on the planet, a territory where the pressure accumulated beneath the surface can trigger eruptions capable of transforming entire geographies. In the last two decades, the appearance and expansion of multidrug-resistant (MDR) Enterobacterales – especially Klebsiella pneumoniae and Escherichia coli – has converted LAC into a global epicenter of antimicrobial resistance (AMR). This “molecular volcanic activity” threatens therapeutics, hospital containment, and the resilience of health systems. Just as volcanoes emerge at points where tectonic plates exert opposing forces, AMR arises where fragmented healthcare systems, irregular antibiotic availability, diagnostic limitations, and intense regional circulation converge. Addressing the AMR crisis in the region requires abandoning the traditional view and adopting a “seismic engineering” approach: proactive surveillance, prevention of infections at the structural level, and environmental containment.

A volcanic belt of resistance: recent evidence

The most recent data collected from 2018-2022 in the global antimicrobial surveillance program ATLAS (Antimicrobial Testing Leadership and Surveillance) points out that LAC is repeatedly reported as one of the global resistance epicenters of K. pneumoniae, with carbapenem resistance rates reaching up to 30% in multiple countries of the region; but in our experience, we have seen total carbapenem resistance rates reach almost 50% in some hospitals in Colombia (unpublished data). Klebsiella pneumoniae carbapenemase (KPC) remains predominant, but the region faces a more complex phenomenon: the increasing coexistence of metallo-β-lactamases (MBLs), OXA-48-like and emerging variants, often in different clones or species within the same hospital environment.¹ In Colombia, the coproduction rates are reaching up to 50% of the total percentage of carbapenemases detected in Enterobacterales.² Moreover, we are seeing K. pneumoniae resistance rates to ceftazidime/avibactam of nearly 30%, which suggests the widespread coexistence of MBLs, but also possibly the emergence of KPC mutants that are now developing resistance to ceftazidime/avibactam. Furthermore, there are some reports in the region of these KPC mutants that are reverting their phenotype to extended-spectrum β-lactamase (ESBL)/carbapenem-sensitive.^3-7

Beyond the coexistence of carbapenemases, the regional epidemiology is increasingly determined by the convergence of high-risk clones and highly mobile genetic elements that facilitate horizontal gene transfer between species. Clones such as ST258, ST11, ST307 and ST147 act as efficient genetic platforms for the dissemination of carbapenemase genes, which in turn favors both interspecies dissemination and the emergence of parallel micro-epidemics within the same institution.^8,9 This not only accelerates diversification but also hides the true resistance architecture in the clinical setting, which, for its part, imposes a particularly difficult diagnostic gap in LAC as we have seen in our experience in Colombia, where access to rapid genotypic methods is limited.

In our own experience, it can be disheartening to see AMR become a daily tragedy. Vulnerable patients who are admitted due to treatable diseases or routine surgeries are ending up in critical conditions after acquiring untreatable nosocomial infections by MDR bacteria, with limited therapeutic options.

The hospital environment as the epicenter of the AMR crisis

The core of this crisis is often the hospital environment itself and systemic challenges in infection prevention and control (IPC). The Guatemalan study, ARCH, clearly showed how hospitalization can drastically increase the risk of acquiring MDR organisms.¹⁰ Furthermore, due to limited access to resources and infrastructure, the development and implementation of effective methods for decontaminating the environment in low- and middle-income countries (LMICs) is constrained.¹¹ Other factors, such as inadequate environmental sanitation, wastewater management, and the continued agricultural misuse of antibiotics, may contribute to the amplification of resistance genes before pathogens are identified in patients when they arrive in the emergency rooms.¹²

Clinical severity: Beyond the statistics

The cumulative antibiotic selective pressure due to inappropriate antibiotic use manifests clinically in severe hospital-acquired infections (HAI) with limited treatment options, as well as increases the mortality rate due to the delay in appropriate treatment caused by carbapenemase-producing Enterobacterales. In our own experience, it can be disheartening to see AMR become a daily tragedy. Vulnerable patients who are admitted due to treatable diseases or routine surgeries are ending up in critical conditions after acquiring untreatable nosocomial infections by MDR bacteria with limited therapeutic options. The cohort study EMBARCAR in Argentina details the high mortality impact of bacteremia due to carbapenem-resistant Gram-negative bacilli reaching up to 40%.¹³

The clinical impact of this dissemination is often devastating and drastically limits treatment agents. Even though recent therapeutic options like aztreonam-avibactam have demonstrated high efficiency against MBLs (up to 99.1% of CREs, including MBL-positive ones),¹⁴ its availability in LAC is practically nonexistent. This forces the use of more toxic drugs, such as polymyxins, or worse, elevates the rates of mortality due to therapeutic failure.

Containing antimicrobial resistance in LAC no longer depends solely on discovering new drugs, but on new strategies for redesigning the environments outside and inside the hospitals as well as understanding the complexity of human behavior where we care for our patients.

Changing the conversation: Structural strategies

It’s likely that the molecular epidemiology of Enterobacterales in LAC will continue to evolve rapidly, with greater carbapenemase diversity, regional spread of high-risk clones, and a greater impact of the environment on transmission. Decreasing the activity of this molecular ‘volcano’ demands a bold, coordinated and realistic strategy, anchored in collaborative frameworks. Our research group has established a national network along Colombia with whom we work collaboratively to analyze their resistance patterns, confirm their resistance mechanisms, identify outbreaks, participate in IPC and educative sessions. We have also created an international symposium focused on AMR as well as antimicrobial stewardship programs (ASP) that takes place yearly.

This is a call to action for us: we must scale these collaborative models into a unified LAC front. We already know what to do and how to do it in terms of IPC in hospitals. However, we are now studying what drives and changes people’s behavior, coming from countries with limited resources, so we must know how to be efficient with it. Another strategy that could work would be the creation of a regional revolving fund for reserve antibiotics. This strategy, inspired by the Pan American Health Organization (PAHO) Revolving Fund for vaccines and complemented by the subscription-based reimbursement models already piloted for antibiotics in the United Kingdom, aims to centralize and subsidize access to last-resort drugs, conditioned on hospitals that demonstrate objective improvement in their IPC metrics and ASP. By linking access to life-saving treatments with the objective improvement of basic hospital ecology, we can create a realistic economic incentive that drives microbiological resilience across the region.

Containing antimicrobial resistance in LAC no longer depends solely on discovering new drugs, but on new strategies for redesigning the environments outside and inside the hospitals as well as understanding the complexity of human behavior where we care for our patients.

References

1. Wise MG, Karlowsky JA, Mohamed N, Hermsen ED, Kamat S, Townsend A, et al. (2024) Global trends in carbapenem- and difficult-to-treat-resistance among World Health Organization priority bacterial pathogens: ATLAS surveillance program 2018–2022. J Glob Antimicrob Resist. 37:168–175.
2. Saavedra Rojas SY (2024) Vigilancia por laboratorio de resistencia antimicrobiana en IAAS en Colombia, 2012–2024. [Accessed 30 Apr 2026]
3. Sanz MB, Pasteran F, de Mendieta JM, Brunetti F, Albornoz E, Rapoport M, et al. (2024) KPC-2 allelic variants in Klebsiella pneumoniae isolates resistant to ceftazidime-avibactam from Argentina: blaKPC‑80, blaKPC‑81, blaKPC‑96 and blaKPC‑97. Microbiol Spectr. 12(3).
4. Gu D, Yan Z, Cai C, Li J, Zhang Y, Wu Y, et al. (2023) Comparison of the NG-Test Carba 5, colloidal gold immunoassay test, and Xpert Carba‑R for the rapid detection of carbapenemases in carbapenemase-producing organisms. 12(2):300.
5. Shi Q, Yin D, Han R, Guo Y, Zheng Y, Wu S, et al. (2020) Emergence and recovery of ceftazidime-avibactam resistance in blaKPC‑33–harboring Klebsiella pneumoniae sequence type 11 isolates in China. Clin Infect Dis. 71(Suppl 4):S436–S439.
6. Antonelli A, Giani T, Di Pilato V, Riccobono E, Perriello G, Mencacci A, et al. (2019) KPC‑31 expressed in a ceftazidime-avibactam–resistant Klebsiella pneumoniae is associated with relevant detection issues. J Antimicrob Chemother. 74(8):2464–2466.
7. De la Cadena E, Mojica MF, Rojas LJ, Castro BE, García‑Betancur JC, Marshall SH, et al. (2024) First report of KPC variants conferring ceftazidime-avibactam resistance in Colombia: introducing KPC‑197. Microbiol Spectr. 12(6).
8. Reyes JA, Melano R, Cárdenas PA, Trueba G (2020) Mobile genetic elements associated with carbapenemase genes in South American Enterobacterales. Braz J Infect Dis. 24(3):231–238.
9. Krapp F, Cuicapuza D, Salvatierra G, Buteau JP, Amaro C, Astocondor L, et al. (2025) Emerging carbapenem-resistant Klebsiella pneumoniae in a tertiary care hospital in Lima, Peru. Microbiol Spectr. 13(2).
10. Ramay BM, Castillo C, Grajeda L, Santos LF, Romero JC, Lopez MR, et al. (2023) Colonization with antibiotic-resistant bacteria in a hospital and associated communities in Guatemala: an ARCH study. Clin Infect Dis. 77(Suppl 1):S82–S88.
11. Ogunsola FT, Mehtar S (2020) Challenges regarding the control of environmental sources of contamination in healthcare settings in low- and middle-income countries: a narrative review. Antimicrob Resist Infect Control. 9(1):81.
12. McEwen SA, Collignon PJ (2018) Antimicrobial resistance: a One Health perspective. Microbiol Spectr. 6(2).
13. Balbuena JP, Cordova E, Mykietiuk A, Farina J, Gañete M, Scapellato P, et al. (2025) Carbapenem-resistant Gram-negative bacilli bacteremia in Argentina (EMBARCAR): findings from a prospective, multicenter cohort study. Clin Infect Dis. 81(5):879–888.
14. Villegas MV, Pallares CJ, Escandón‑Vargas K, Hernández‑Gómez C, Correa A, Álvarez C, et al. (2016) Characterization and clinical impact of bloodstream infection caused by carbapenemase-producing Enterobacteriaceae in seven Latin American countries. PLoS One. 11(4):e0154092.