ABSTRACT
PURPOSE: The new third-generation sequencing platform MinION is an attractive maintenance-free and disposable portable tool that can perform long-read and real-time sequencing. In this study, we validated this technology for the identification of pathogens from positive blood culture (BC) bottles. METHODOLOGY: A total of 38 positive BC bottles were collected from patients with bloodstream infections, and 18 isolates of Gram-negative (GN) bacteria and 20 isolates of Gram-positive (GP) bacteria were identified from these using 16S rRNA sequencing and then used in this study. DNA was extracted from each aliquot using an extraction protocol that combined glass bead beating and chemical lysis. Up to 200 ng of each purified DNA sample was processed for library preparation and whole-genome sequencing was performed on up to 12 samples through a single MinION flow cell. RESULTS: All GN bacteria identifications made by MinION sequencing for 30 min using the What's In My Pot? (WIMP) workflow via EPI2ME on the basis of the most frequent classified reads were consistent with those made by 16S rRNA sequencing. On the other hand, for GP bacteria specimens, the identification results for 16S rRNA sequencing and MinION were only in agreement in 12 out of 20 (60.0 %) cases. ARMA analysis was able to detect extended-spectrum ß-lactamase (ESBL)-associated genes among various antimicrobial resistance-related genes. CONCLUSION: We demonstrated the potential of the MinION sequencer for the identification of GN bacteria from positive BC bottles and the confirmation of an ESBL phenotype. This innovative sequence technology and its application could lead to a breakthrough in the diagnosis of infectious diseases.
Subject(s)
Bacteremia/microbiology , Gram-Negative Bacteria/genetics , Gram-Negative Bacteria/isolation & purification , Molecular Diagnostic Techniques/instrumentation , Molecular Diagnostic Techniques/methods , beta-Lactamases/genetics , Anti-Bacterial Agents/pharmacology , DNA, Bacterial/genetics , Genome, Bacterial/genetics , Gram-Negative Bacteria/classification , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/classification , Gram-Positive Bacteria/genetics , Gram-Positive Bacteria/isolation & purification , Humans , Microbial Sensitivity Tests , Nanopores , Polymerase Chain Reaction/standards , RNA, Ribosomal, 16S/genetics , RNA, Ribosomal, 16S/standards , Sequence Analysis, DNA , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/standards , Time FactorsABSTRACT
PURPOSE: Bloodstream infections are major causes of morbidity and mortality that lead to prolonged hospital stays and higher medical costs. In this study, we aimed to evaluate the MinION nanopore sequencer for the identification of the most dominant pathogens in positive blood culture bottles. METHODOLOGY: 16S and ITS1-5.8S-ITS2 rRNA genes were amplified by PCR reactions with barcoded primers using nine clinical isolates obtained from positive blood bottles and 11 type strains, including five types of Candida species. Barcoded amplicons were mixed, and multiplex sequencing with the MinION sequencer was performed. In addition, barcoded PCR amplicons were sequenced by Sanger sequencing to validate the performance of the MinION. RESULTS: The bacterial and Candida spp. identified by MinION sequencing, based on the highest homology of reference sequences from the NCBI gene databases, agreed with the matrix-assisted laser desorption ionization time of flight mass spectrometry results, excepting the closely related species Streptococcusand Escherichia coli. The 'pass' reads obtained within about 10 min of sequencing were sufficient to identify the pathogens. The average values of sequence identities with 1D2 chemistry and the R9.5 flow cell were around 99â%; thus, frequent sequence errors did not affect species identification based on amplicon sequencing. CONCLUSION: We have established a rapid, portable and economical technique for the identification of pathogens in positive blood culture bottles through a novel MinION nanopore sequencer amplicon sequencing scheme, which replaces traditional Sanger sequencing.
