Relación genética entre cepas productoras y no productoras de carbapenemasas del complejo Enterobacter cloacae, aisladas en hospitales de Chile.
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Date
2025
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Universidad de Concepción
Abstract
El complejo Enterobacter cloacae (ECC) posee genes de resistencia intrínsecos y puede adquirir determinantes que confieren resistencia a antibióticos de última línea, como los carbapenémicos. Esto ha favorecido su prevalencia en países como Estados Unidos y China fomentando su incorporación como patógeno de prioridad crítica por la OMS. En Chile, no existen datos actualizados ni estudios exhaustivos sobre ECC productor de carbapenemasas. Este estudio analizó la relación genética entre cepas productoras y no productoras de carbapenemasas en aislados chilenos obtenidos entre 1998 y 2023.
Se estudiaron 187 cepas mediante antibiograma, Blue-Carba y PCR, identificándose 15 cepas portadoras de genes de carbapenemasa. Mediante rep-PCR y herramientas bioinformáticas, se compararon genéticamente con cepas no productoras de carbapenemasa. Se concluyó que estas cepas están genéticamente relacionadas, que el gen de carbapenemasa pudo ser adquirido mediante conjugación y, además, se determinó que la sinergia entre ceftazdima/avibactam y aztreonam puede ser una alternativa para tratar infecciones por estos microorganismos.
En resumen, estos resultados constituyen el primer análisis integral de ECC productores de carbapenemasa en Chile, aportando datos esenciales para la vigilancia epidemiológica y terapéutica.
The Enterobacter cloacae complex (ECC) possesses intrinsic resistance genes and can acquire determinants that confer resistance to last-line antibiotics, such as carbapenems. This has contributed to its high prevalence in countries like the United States and China and has led to its classification as a critical-priority pathogen by the World Health Organization. In Chile, there are no updated data or comprehensive studies on carbapenemase-producing ECC. This study analyzes the genetic relationship between carbapenemase-producing and non-producing ECC strains isolated in Chile between 1998 and 2023. A total of 187 ECC isolates were analyzed using antibiotic susceptibility testing, Blue-Carba, and PCR, identifying 15 strains harboring carbapenemase genes. These were genetically compared with non-carbapenemase-producing strains using rep-PCR, whole-genome sequencing, and bioinformatics tools. The results revealed a genetic relationship between carbapenem-producing and non-producing isolates, suggesting that the carbapenemase gene was acquired through conjugation. Furthermore, synergy between ceftazidime/avibactam and aztreonam was observed, indicating a potential therapeutic strategy against infections caused by these multidrug-resistant pathogens. In summary, these results constitute the first comprehensive analysis of carbapenemase-producing ECCs in Chile, providing essential data for epidemiological and therapeutic surveillance.
The Enterobacter cloacae complex (ECC) possesses intrinsic resistance genes and can acquire determinants that confer resistance to last-line antibiotics, such as carbapenems. This has contributed to its high prevalence in countries like the United States and China and has led to its classification as a critical-priority pathogen by the World Health Organization. In Chile, there are no updated data or comprehensive studies on carbapenemase-producing ECC. This study analyzes the genetic relationship between carbapenemase-producing and non-producing ECC strains isolated in Chile between 1998 and 2023. A total of 187 ECC isolates were analyzed using antibiotic susceptibility testing, Blue-Carba, and PCR, identifying 15 strains harboring carbapenemase genes. These were genetically compared with non-carbapenemase-producing strains using rep-PCR, whole-genome sequencing, and bioinformatics tools. The results revealed a genetic relationship between carbapenem-producing and non-producing isolates, suggesting that the carbapenemase gene was acquired through conjugation. Furthermore, synergy between ceftazidime/avibactam and aztreonam was observed, indicating a potential therapeutic strategy against infections caused by these multidrug-resistant pathogens. In summary, these results constitute the first comprehensive analysis of carbapenemase-producing ECCs in Chile, providing essential data for epidemiological and therapeutic surveillance.
Description
Tesis presentada para optar al grado de Magíster en Ciencias con mención en Microbiología.
Keywords
Enterobacteriaceae, Antibióticos, Genética bacteriana, Hospitales Chile