Genomic and phylogenomic characterization of carbapenem-resistant Pseudomonas aeruginosa 'high-risk' clone O4/ExoS+/ST654 circulating in Chilean hospitals.

INTRODUCTION: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a serious threat to public health. Globally, carbapenemases-producing CRPA isolates mainly belong to 'high-risk' clones; however, the molecular epidemiology of CRPA isolates circulating in Chile are scarce, where this pathogen is the main aetiological agent of ventilator-associated pneumonia. OBJECTIVES: To characterize the phylogenomics and molecular features of ST654 CRPA isolates collected in Chile between 2016 - 2022. METHODS: 89 CRPA isolates collected in different Chilean hospitals from clinical specimens between 2005 and 2022 were analyzed. Antibiotic susceptibility tests and carbapenemases production were carried out on the CRPA ST654 isolates. Also, they were subjected to whole-genome sequencing (WGS) from which in silico analyses were performed. RESULTS: Thirty-four strains (38.2%) belonged to the ST654 'high risk' clone, being the most predominant lineage of the collection. Most of these isolates belonged to a sub-clade including KPC-producers that also clustered with strains from Argentina and the USA, whereas few VIM and NDM co-producers clustered in two different smaller sub-clades. The isolates exhibited a broad resistome encompassing genes mediating resistance to several other clinically relevant drugs. Additionally, all the 34 ST654 isolates were ExoS+ as a virulence factor and associated to the O4-serotype. CONCLUSIONS: Our report represents the most comprehensive phylogenomic study of CRPA 'high risk' clone ST654 to date. Our analyses suggest that this lineage is undergoing a divergent evolutionary path in Chile, since most of the isolates were KPC-producers and were O4-serotype, differing from previous descriptions, which underline the relevance of performing molecular surveillance on this pathogen.

Primer aislamiento de Candida auris en Chile / First isolation de Candida auris in Chile

Resumen Candida auris es una levadura multi-resistente emergente con rápida diseminación mundial. Desde el primer reporte el 2009, varios aislados a través de los cinco continentes han sido identificados como agentes de infecciones asociadas a la atención en salud. Brotes independientes y simultáneos por C. auris se han vuelto prioridad para la comunidad hospitalaria y científica. Además, los errores en identificación y los perfiles de multi-resistencia, raramente observados para otras especies de Candida, resultan en una difícil erradicación y fallas terapéuticas frecuentes en infecciones por C. auris. Presentamos el primer aislamiento de una cepa de C. auris en un hospital en Santiago, en un paciente proveniente de la India, que fue admitido para tratamiento de su pie diabético. La cepa fue recuperada de un cultivo de tejido e identificada por VITEK® 2 Compact. La identificación de C. auris fue confirmada por MALDI-TOF MS y secuenciación. El aislado fue resistente a fluconazol y susceptible a anfotericina y caspofungina, según puntos de corte recomendados por el CDC. La emergencia de C. auris es alarmante debido a que el modo de transmisión dentro del ambiente hospitalario no es claro y probablemente es multifactorial.

Candida auris is an emerging multi-drug-resistant fungus that is rapidly spreading worldwide. Since the first reports in 2009, many isolates across five continents have been identified as agents of hospital-associated infections. Independent and simultaneous outbreaks of C. auris are becoming a major concern for healthcare and scientific community. Moreover, laboratory misidentification and multi-drug-resistant profiles, rarely observed for other non-albicans Candida species, result in difficult eradication and frequent therapeutic failures of C. auris infections. In this article we present the first case of isolation of a strain of C. auris at a hospital in Santiago, in a patient coming from India, who was admitted for treatment of diabetic foot complications. The strain was recovered from a tissue culture and identified by VITEK® 2 Compact. The accurate identification of C. auris was confirmed by means of MALDI-TOF MS and DNA sequence analysis. The isolate was resistant to fluconazole, retaining only susceptibility to amphotericin and caspofungin with MIC breakpoints recommended by CDC. The emergence of C. auris is alarming because the mode of transmission within the healthcare environment is not clear and is likely to be multifactorial.

[First isolation de Candida auris in Chile]. / Primer aislamiento de Candida auris en Chile.

Candida auris is an emerging multi-drug-resistant fungus that is rapidly spreading worldwide. Since the first reports in 2009, many isolates across five continents have been identified as agents of hospital-associated infections. Independent and simultaneous outbreaks of C. auris are becoming a major concern for healthcare and scientific community. Moreover, laboratory misidentification and multi-drug-resistant profiles, rarely observed for other non-albicans Candida species, result in difficult eradication and frequent therapeutic failures of C. auris infections. In this article we present the first case of isolation of a strain of C. auris at a hospital in Santiago, in a patient coming from India, who was admitted for treatment of diabetic foot complications. The strain was recovered from a tissue culture and identified by VITEK® 2 Compact. The accurate identification of C. auris was confirmed by means of MALDI-TOF MS and DNA sequence analysis. The isolate was resistant to fluconazole, retaining only susceptibility to amphotericin and caspofungin with MIC breakpoints recommended by CDC. The emergence of C. auris is alarming because the mode of transmission within the healthcare environment is not clear and is likely to be multifactorial.