Asunto(s)
Antibacterianos/uso terapéutico , Proteínas Bacterianas/genética , Infecciones por Klebsiella/diagnóstico , Infecciones por Klebsiella/tratamiento farmacológico , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/genética , beta-Lactamasas/genética , Proteínas Bacterianas/metabolismo , Resultado Fatal , Humanos , Italia , Klebsiella pneumoniae/clasificación , Klebsiella pneumoniae/enzimología , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Plásmidos , Virulencia , Secuenciación Completa del Genoma , beta-Lactamasas/metabolismoRESUMEN
Objectives: KPC-producing Klebsiella pneumoniae (KPC-Kp) represent a serious problem worldwide. Herein, we describe the evolution of ceftazidime/avibactam resistance by sequencing longitudinal clinical isolates from a patient with KPC-Kp bloodstream infection undergoing ceftazidime/avibactam treatment. Methods: WGS was performed on one ceftazidime/avibactam-susceptible KPC-Kp (BOT-CA-S) and two phenotypically different ceftazidime/avibactam-resistant KPC-Kp with low (BOT-CA-R) and high (BOT-EMO) carbapenem MICs. The population diversity was assessed by the frequency of allele mutations and population analysis profiles (PAPs). Results: Phylogenetic analysis demonstrated clonal relatedness of the KPC-Kp isolates, all belonging to the clone ST1519. The D179Y mutation in blaKPC-3 was detected in both of the ceftazidime/avibactam-resistant KPC-Kp, whereas it was absent in the ceftazidime/avibactam-susceptible isolate. The mutation emerged independently in the two ceftazidime/avibactam-resistant isolates and was associated with a significant reduction in carbapenem MICs in BOT-CA-R, but not in BOT-EMO. WGS analysis revealed that the frequency of the D179Y mutation was 96.32% and 51.05% in BOT-CA-R and BOT-EMO, respectively. PAP results demonstrated that carbapenem resistance in BOT-EMO was due to the coexistence of mixed subpopulations harbouring WT and mutated blaKPC-3. A bacterial subpopulation with high ceftazidime/avibactam resistance for BOT-EMO KPC-Kp showed low carbapenem MICs, whereas a subpopulation with high meropenem resistance had a low MIC of ceftazidime/avibactam. Conclusions: Our analysis indicates that mixed subpopulations of ceftazidime/avibactam-resistant KPC-Kp emerge after ceftazidime/avibactam treatment. The evolution of different subpopulations that are highly resistant to ceftazidime/avibactam likely contributes to treatment failure, thereby highlighting the need for combination treatment strategies to limit selection of ceftazidime/avibactam-resistant KPC-Kp subpopulations.
Asunto(s)
Compuestos de Azabiciclo/uso terapéutico , Enterobacteriaceae Resistentes a los Carbapenémicos/genética , Ceftazidima/uso terapéutico , Farmacorresistencia Bacteriana Múltiple/genética , Evolución Molecular , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/genética , Antibacterianos/uso terapéutico , Proteínas Bacterianas/genética , Enterobacteriaceae Resistentes a los Carbapenémicos/aislamiento & purificación , Combinación de Medicamentos , Humanos , Infecciones por Klebsiella/sangre , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/enzimología , Pruebas de Sensibilidad Microbiana , Mutación , Filogenia , Porinas/genética , Secuenciación Completa del Genoma , beta-Lactamasas/genéticaRESUMEN
We describe three cases of bloodstream infection caused by colistin-resistant Escherichia coli in patients in a tertiary hospital in Italy, between August 2016 and January 2017. Whole genome sequencing detected the mcr-1 gene in three isolated strains belonging to different sequence types (STs). This occurrence of three cases with mcr-1-positive E. coli belonging to different STs in six months suggests a widespread problem in settings where high multidrug resistance is endemic such as in Italy.
Asunto(s)
Antibacterianos/uso terapéutico , Infecciones por Escherichia coli/tratamiento farmacológico , Proteínas de Escherichia coli/genética , Escherichia coli/efectos de los fármacos , Escherichia coli/genética , Tienamicinas/uso terapéutico , Anciano , Anciano de 80 o más Años , Farmacorresistencia Bacteriana/genética , Escherichia coli/aislamiento & purificación , Infecciones por Escherichia coli/diagnóstico , Infecciones por Escherichia coli/microbiología , Femenino , Humanos , Italia , Meropenem , Pruebas de Sensibilidad Microbiana , Tipificación Molecular , Análisis de Secuencia de ADN , Resultado del TratamientoRESUMEN
Klebsiella pneumoniae is at the forefront of antimicrobial resistance for Gram-negative pathogenic bacteria, as strains resistant to third-generation cephalosporins and carbapenems are widely reported. The worldwide diffusion of these strains is of great concern due to the high morbidity and mortality often associated with K. pneumoniae infections in nosocomial environments. We sequenced the genomes of 89 K. pneumoniae strains isolated in six Italian hospitals. Strains were selected based on antibiotypes, regardless of multilocus sequence type, to obtain a picture of the epidemiology of K. pneumoniae in Italy. Thirty-one strains were carbapenem-resistant K. pneumoniae carbapenemase producers, 29 were resistant to third-generation cephalosporins, and 29 were susceptible to the aforementioned antibiotics. The genomes were compared to all of the sequences available in the databases, obtaining a data set of 319 genomes spanning the known diversity of K. pneumoniae worldwide. Bioinformatic analyses of this global data set allowed us to construct a whole-species phylogeny, to detect patterns of antibiotic resistance distribution, and to date the differentiation between specific clades of interest. Finally, we detected an â¼ 1.3-Mb recombination that characterizes all of the isolates of clonal complex 258, the most widespread carbapenem-resistant group of K. pneumoniae. The evolution of this complex was modeled, dating the newly detected and the previously reported recombination events. The present study contributes to the understanding of K. pneumoniae evolution, providing novel insights into its global genomic characteristics and drawing a dated epidemiological scenario for this pathogen in Italy.