Molecular epidemiology of carbapenem-resistant gram-negative bacilli in Ecuador

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2024年4月6日

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Claudia Soria-Segarra,
Carmen Soria-Segarra,
Marcos Molina-Matute,
Ivanna Agreda-Orellana,
Tamara Núñez-Quezada,
Kerly Cevallos-Apolo,
Marcela Miranda-Ayala,
Grace Salazar-Tamayo,
Margarita Galarza-Herrera,
Victor Vega-Hall,
José E. Villacis,
José Gutiérrez-Fernández

摘要

Introduction

Carbapenem-resistant gram-negative bacilli are a worldwide concern because of high morbidity and mortality rates. Additionally, the increasing prevalence of these bacteria is dangerous. To investigate the extent of antimicrobial resistance and prioritize the utility of novel drugs, we evaluated the molecular characteristics and antimicrobial susceptibility profiles of carbapenem-resistant Enterobacterales, Pseudomonas aeruginosa and Acinetobacter baumannii in Ecuador in 2022.

Methods

Ninety-five clinical isolates of carbapenem non-susceptible gram-negative bacilli were collected from six hospitals in Ecuador. Carbapenem resistance was confirmed with meropenem disk diffusion assays following Clinical Laboratory Standard Institute guidelines. Carbapenemase production was tested using a modified carbapenemase inactivation method. Antimicrobial susceptibility was tested with a disk diffusion assay, the Vitek 2 System, and gradient diffusion strips. Broth microdilution assays were used to assess colistin susceptibility. All the isolates were screened for the bla_KPC, bla_NDM, bla_OXA-48, bla_VIM and bla_IMP genes_. In addition, A. baumannii isolates were screened for the bla_OXA-23, bla_OXA-58 and bla_OXA-24/40 genes.

Results

Carbapenemase production was observed in 96.84% of the isolates. The bla_KPC, bla_NDM and bla_OXA-48 genes were detected in Enterobacterales, with bla_KPC being predominant. The bla_VIM gene was detected in P. aeruginosa, and bla_OXA-24/40 predominated in A. baumannii. Most of the isolates showed co-resistance to aminoglycosides, fluoroquinolones, and trimethoprim/sulfamethoxazole. Both ceftazidime/avibactam and meropenem/vaborbactam were active against carbapenem-resistant gram-negative bacilli that produce serin-carbapenemases.

Conclusion

The epidemiology of carbapenem resistance in Ecuador is dominated by carbapenemase-producing K. pneumoniae harbouring bla_KPC. Extensively drug resistant (XDR) P. aeruginosa and A. baumannii were identified, and their identification revealed the urgent need to implement strategies to reduce the dissemination of these strains.