Purpose: It is necessity of new rapid method for detecting microorganisms in bloodstream infection. Especially, patients with febrile-neutropenia tends to be poor prognosis. We focused on the new sequencing system, MinION. The new third-generation sequencing platform MinION is an attractive maintenance-free and disposable portable tool that can perform long reads 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 collected from the patients of bloodstream infection, among which 18 isolates of Gram-negative (GN) bacteria and 19 isolates of Grampositive (GP) bacteria were identified using16S rRNA sequencing, were enrolled in this study. One case detected fungus from blood culture bottles. 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 identified on the basis of the most frequent classified reads by MinION sequencing for 30 min using WIMP via EPI2ME were consistent with those identified by 16S rRNA sequencing. On the other hand, the results of identification by 16S rRNA sequencing and those by MinION agreed in 12 of 19 GP bacteria specimens. The ARMA analysis was able to detect extended spectrum β-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 its confirmation of an ESBL phenotype. This innovative sequence technology and application could be a breakthrough technology for the diagnosis of infectious diseases.

In June 2015, febrile neutropenia was approved as an additional indication for tazobactam/piperacillin (ZOSYN^®). A special drug use-results survey was performed between August 2015 and July 2018 to investigate the clinical safety and efficacy of this drug in children with febrile neutropenia. A total of 142 patients from 48 institutions were enrolled in the study; safety and efficacy assessments were performed on 136 and 117 patients, respectively.

Among the 136 patients, adverse drug reactions (ADRs) were found in 23 patients (30 cases), with an incidence rate of ADRs being 16.9% (23/136 patients). None of the ADRs were serious. ADRs occurring in two or more patients included diarrhea (20 patients) and hepatic function abnormal (three patients). ADRs not expected from the “Precautions” section of the package insert included hyponatremia (one patient) and anal erosion (one patient). With the exception of one case of diarrhea in which the outcome was unclear, all cases recovered or improved.

The occurrence of ADRs did not differ greatly between this study and the previous clinical studies including a pre-approval clinical study of ZOSYN^® in children with febrile neutropenia; a special drug use-results survey in children after the approval of sepsis, pneumonia, pyelonephritis, and complicated cystitis as indications; and a special drug use-results survey in children after the approval of peritonitis, intra-abdominal abscess, cholecystitis, and cholangitis as indications.

The efficacy assessment showed a response rate of 88.0% in 117 patients, which was consistent with those of previous clinical studies and special drug use-results surveys.

This study revealed no clinically significant problems related to the safety and efficacy of ZOSYN^® in children with febrile neutropenia, indicating that the drug remains a useful empiric treatment for infectious diseases, as is currently recommended by various guidelines.

Antimicrobial susceptibilities of 12 bacterial species isolated at Toyama University Hospital between 2018 and 2019 were measured. We calculated the target attainment rates for several dosing regimens of piperacillin (PIPC) against 12 bacterial species using monte carlo simulation with a view to examining the effect by increase in dose of PIPC.

Antimicrobial susceptibilities of methicillin-susceptible Staphylococcus aureus (MSSA), Streptococcus pneumoniae, Enterococcus faecalis, Klebsiella pneumoniae, Enterobacter cloacae, Moraxella catarrhalis and Pseudomonas aeruginosa of 12 bacterial species to PIPC were similar levels to those in nationwide surveillance in 2016 or 2018. On the other hand, antimicrobial susceptibilities of Escherichia coli and Serratia marcescens to PIPC were superior to those in nationwide surveillance.

In analysis using monte carlo simulation, the regimens of 2g four times daily, 4g three times daily and 4 g four times daily of PIPC were expected to show more excellent clinical efficacy than those of 2 g twice daily and 4 g twice daily of PIPC in terms of bacteriostatic effect and maximum bactericidal effect.