RESUMEN
Carba-NP original report for blood cultures described the need of subculture and mechanical lysis before testing, reaching the turnaround time of approximately 4 hours for sample preparation. We tested 100 consecutive blood cultures positive for Gram-negative bacilli on the Gram stain from a large clinical laboratory. Bacterial pellets were prepared by centrifugation and submitted to Carba-NP and Blue-Carba tests and used further to prepare smears for Vitek MS. Results obtained with colonies grown on sheep blood agar using the same methodologies were used as the gold standard. Carbapenemase genes were confirmed by PCR and DNA sequencing. Vitek MS identified correctly 86% of the samples. Of note, 7% of the samples were incorrectly reported by the instrument as containing a single isolate. KPC-2 was the predominant carbapenemase detected. There was 100% concordance for both negative and positive results for Carba-NP. In contrast, for Blue-Carba the concordance for positive results was 92.8%, and 41% of strains negative for carbapenemases presented a yellowish color on control well turning the test non-interpretable. The turnaround time for sample preparation for preparing the pellet was 13 min, and no subculture or mechanical lysis is needed when detecting KPC production in Enterobacterales.
Asunto(s)
Proteínas Bacterianas/metabolismo , Cultivo de Sangre/métodos , Infecciones por Enterobacteriaceae/sangre , Enterobacteriaceae/aislamiento & purificación , Proteínas Bacterianas/genética , Enterobacteriaceae/clasificación , Enterobacteriaceae/genética , Infecciones por Enterobacteriaceae/diagnóstico , Infecciones por Enterobacteriaceae/microbiología , Humanos , Reacción en Cadena de la Polimerasa , Sensibilidad y Especificidad , Flujo de Trabajo , beta-Lactamasas/genética , beta-Lactamasas/metabolismoAsunto(s)
Antibacterianos/farmacología , Carbapenémicos/farmacología , Farmacorresistencia Bacteriana , Infecciones por Klebsiella/epidemiología , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/efectos de los fármacos , Polimixina B/farmacología , Brasil/epidemiología , Humanos , Klebsiella pneumoniae/clasificación , Klebsiella pneumoniae/genética , Pruebas de Sensibilidad Microbiana , Tipificación de Secuencias Multilocus , Vigilancia de la PoblaciónRESUMEN
In this work, we demonstrate that the fosI gene encodes a predicted small protein with 134 amino acids and determines reduced susceptibility to fosfomycin. It raised the MIC from 0.125 to 6 µg/ml when the pBRA100 plasmid was introduced into Escherichia coli TOP10 and to 16 µg/ml when the gene was cloned into the pBC_SK(-) vector and expressed in E. coli TOP10.
Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana/genética , Escherichia coli/genética , Fosfomicina/farmacología , Integrones , Secuencia de Aminoácidos , Escherichia coli/efectos de los fármacos , Escherichia coli/metabolismo , Expresión Génica , Pruebas de Sensibilidad Microbiana , Datos de Secuencia Molecular , Plásmidos/química , Plásmidos/metabolismo , Alineación de Secuencia , Transformación BacterianaRESUMEN
In Enterobacteriaceae, the blaNDM genes have been found in many different genetic contexts, and a wide diversity of plasmid scaffolds bearing those genes has been found. In August 2013, we identified NDM-1-producing Escherichia coli and Enterobacter hormaechei strains from a single rectal swab sample from a patient hospitalized in Rio de Janeiro, Brazil, who had no history of travel abroad. Complete DNA sequencing using the Illumina platform and annotation of the two plasmids harboring the blaNDM-1 gene, one from each strain, showed that they belonged to incompatibility groups IncFIIK and IncX3 and harbored a novel transposon named Tn3000. Similar genetic structures have been identified among other isolates in Brazil but also on plasmids from other continents. Our findings suggest that the blaNDM-1 gene may be transmitted by Tn3000 in different parts of the world.