Biology subjects

Komine, T.

Publications and source records attributed to Komine, T..

3 recordsLinked to original sources

bioRxiv2026

A novel recombinant BCG vaccine using a mycobacteriophage promoter shows improved protection against tuberculosis

The limited efficacy of conventional bacillus Calmette-Guerin (BCG) vaccination against adult pulmonary tuberculosis highlights the need for improved vaccine strategies. Genome integration can overcome the plasmid instability of recombinant BCG, but we hypothesized that this approach would be constrained by reduced transcriptional activity of conventional promoters when present as a single genomic copy. Here we identified P79, a mycobacteriophage-derived promoter that sustains high-level expression from a single genomic locus and used it to construct a genome-integrated recombinant BCG, termed LRC-BCG. LRC-BCG secretes the HSP70-MMPII fusion antigen flanked by the PEST sequences, maintained stable antigen expression over serial passages, and induced strong activation of macrophages and dendritic cells in vitro. In vivo, LRC-BCG inhibited Mycobacterium tuberculosis multiplication more effectively than conventional BCG, even at low doses. These findings demonstrate the feasibility of using P79 for stable genome-integrated recombinant BCG and support LRC-BCG as a promising tuberculosis vaccine candidate.

microbiology↗

bioRxiv2025

Plasmid-mediated macrolide resistance among rapidly growing mycobacteria in Japan

ObjectivesThe spread of a transmissible plasmid carrying the 23S rRNA methylase gene erm(55), which confers inducible macrolide resistance in rapidly growing mycobacteria (RGM), has raised significant clinical concerns. The aim of this study was to investigate the prevalence of erm(55)-carrying plasmids in clinically isolated RGM strains in Japan. MethodsIn total, 607 RGM clinical isolates, representing 32 species or complexes, collected between 2019 and 2023 in Japan were examined. To detect the presence of erm(55)-carrying plasmids, we conducted PCR screening, minimum inhibitory concentration testing for clarithromycin, and whole-plasmid genome sequencing. Comparative genomic analyses were performed to characterise the plasmids. ResultsAmong the 607 RGM isolates, 0.8% (5/607) possessed the plasmid with the erm(55) gene and exhibited inducible macrolide resistance, with ratios of 100% (1/1) in Mycobacterium murale, 50% (3/6) in M. obuense, and 0.8% (1/125) in M. chelonae. The erm(55)-carrying plasmids ranged from 126,187 to 170,220 bp in size. Pairwise BLASTn comparisons of the erm(55)-carrying plasmids showed weighted percent identity values ranging from 99.5% to 99.9%, with query and subject coverage values ranging from 74.2% to 100%. All erm(55) sequences (813 bp) were identical and located within a horizontal gene transfer region. ConclusionsThis study confirmed the presence of macrolide-resistant RGMs related to the erm(55)-carrying plasmid in Japan, although the overall prevalence remains low. These findings emphasise the need to consider plasmid-mediated resistance when treating infections caused by the RGM species.

microbiology↗

bioRxiv2022

A case of mycobacteriosis associated with Mycobacterium pseudoshottsii in aquarium-reared fish in Japan

In 2019, several aquarium-reared fish died at a sea life park in Japan. Necropsy revealed micronodules on the spleen in the dotted gizzard shad (Konosirus punctatus). Seven of 16 fish exhibited microscopic multifocal granulomas associated with acid-fast bacilli in the spleen, kidney, liver, alimentary tract, mesentery, gills, and/or heart. Bacterial cultures yielded isolates from the dotted gizzard shad and a Japanese sardine (Sardinops melanostictus). Microbiological examination, multilocus sequence typing analysis, and variable number of tandem repeats analysis with a newly proposed 6-loci set revealed the isolates as Mycobacterium pseudoshottsii. To our knowledge, this is the first isolation of M. pseudoshottsii from aquarium-reared fish.

microbiology↗