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result(s) for
"Higashi, Yoshitsugu"
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Potency of gastrointestinal colonization and virulence of Candida auris in a murine endogenous candidiasis
2020
Candida auris infections have recently emerged worldwide, and this species is highly capable of colonization and is associated with high levels of mortality. However, strain-dependent differences in colonization capabilities and virulence have not yet been reported.
In the present study, we aimed to clarify the differences between clinically isolated invasive and non-invasive strains of C. auris.
We evaluated colonization, dissemination, and survival rates in wild C57BL/6J mice inoculated with invasive or non-invasive strains of C. auris under cortisone acetate immunosuppression, comparing with those of Candida albicans and Candida glabrata infections. We also evaluated the potency of biofilm formation.
Stool fungal burdens were significantly higher in mice inoculated with the invasive strains than in those infected with the non-invasive strain. Along with intestinal colonization, liver and kidney fungal burdens were also significantly higher in mice inoculated with the invasive strains. In addition, histopathological findings revealed greater dissemination and colonization of the invasive strains. Regarding biofilm-forming capability, the invasive strain of C. auris exhibited a significantly higher capacity of producing biofilms. Moreover, inoculation with the invasive strains resulted in significantly greater loss of body weight than that noted following infection with the non-invasive strain.
Invasive strains showed higher colonization capability and rates of dissemination from gastrointestinal tracts under cortisone acetate immunosuppression than non-invasive strains, although the mortality rates caused by C. auris were lower than those caused by C. albicans.
Journal Article
Rapid Identification of Candida Species in Candidemia Directly from Blood Samples Using Imperfect Match Probes
by
Yamamoto, Yoshihiro
,
Kitajima, Isao
,
Sakamaki, Ippei
in
45/77
,
692/699/255/1672
,
692/700/139/1420
2020
Candidemia is associated with a high mortality rate, and initial adequate antifungal therapy results in a significant decrease in the crude mortality. We herein report a rapid method that can identify eight
Candida
species in candidemia using imperfect match quenching probes (IM Q-probes) within three and a half hours of whole blood sample collection. Furthermore, employing the D value, which reflects the difference between the Tm signature from a clinical isolate and that registered in the database, it is possible to quickly identify samples suitable for IM Q-probe identification. We first evaluated the method using 34
Candida
colonies collected from different patients, and 100% (34/34) of the identification results matched the preidentified
Candida
species. We then performed blind tests using eight whole blood samples artificially mixed with eight different
Candida
species respectively, and all identification results correctly matched the preidentified
Candida
species. Finally, using 16 whole blood samples collected from candidemia patients, we compared the IM Q-probe method with the culture/sequencing method. Of a total of 16 patient samples, 100% (16/16) matched the culture and sequencing results. The IM Q-probe method is expected to contribute not only to the life expectancy of candidemia patients but also to antifungal stewardship.
Journal Article
Novel rapid method for identifying and quantifying pathogenic bacteria within four hours of blood collection
by
Niimi, Hideki
,
Ueno, Tomohiro
,
Wakasugi, Masahiro
in
631/1647/1513/2216
,
692/53/2421
,
692/699/255/1318
2024
Sepsis is life-threatening organ dysfunction and is considered a major cause of health loss. However, since the current biomarkers of sepsis reflect the host’s immune response to microorganisms, they would inevitably cause a time-lag. This means that there is still no truly reliable biomarker of sepsis. In the present study, we developed a novel method for identifying and quantifying unknown pathogenic bacteria within four hours of sample collection. The most important point of this study is that the novel method can be used to determine the number of bacteria in a sample as a novel biomarker of infectious diseases. Indeed, based on the number of bacteria, we were able to accurately estimate the severity of microbial infection. Furthermore, using the time-dependent changes in the number of bacteria, we were able to monitor the therapeutic effect accurately. The rapid identification and quantification of bacteria may change our approach to medical care.
Journal Article
Spondylodiscitis due to Parvimonas micra diagnosed by the melting temperature mapping method: a case report
by
Yamamoto, Yoshihiro
,
Sakamaki, Ippei
,
Nakamura, Shigeki
in
Aged
,
Antimicrobial agents
,
Back pain
2017
Background
It has been suggested that more than 100 bacterial species can be identified using only seven universal bacterial primer sets in the melting temperature (Tm) mapping method and that these findings can be obtained within 3 h of sterile site collection.
Case presentation
A 67-year-old Japanese man with type 2 diabetes visited our hospital complaining of progressive lower back pain for 2 months. The patient was suspected to have spondylodiscitis on magnetic resonance imaging of the spine. Blood culture and transcutaneous vertebral biopsy were subsequently performed. Using the Tm mapping method,
Parvimonas micra
was detected from a transcutaneous vertebral biopsy specimen in 3 h. Gram-positive cocci were also detected by Gram staining and
P. micra
was identified directly from the anaerobic blood culture by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Four days after admission, the biopsy specimen culture isolate was identified as
P. micra
.
Conclusions
The Tm mapping method may be useful for the diagnosis of bacterial infections where diagnosis is challenging because of the difficulty of culturing.
Journal Article
Predictive value of cell population data with Sysmex XN-series hematology analyzer for culture-proven bacteremia
by
Matsui, Atsushi
,
Iwasaki, Yosuke
,
Yamamoto, Yoshihiro
in
bacteremia
,
Bacteria
,
Bacterial infections
2023
Cell population data (CPD) parameters related to neutrophils, such as fluorescent light intensity (NE-SFL) and fluorescent light distribution width index (NE-WY), have emerged as potential biomarkers for sepsis. However, the diagnostic implication in acute bacterial infection remains unclear. This study assessed the diagnostic value of NE-WY and NE-SFL for bacteremia in patients with acute bacterial infections, and those associations with other sepsis biomarkers.
Patients with acute bacterial infections were enrolled in this prospective observational cohort study. For all patients, a blood sample, with at least two sets of blood cultures, were collected at the onset of infection. Microbiological evaluation included examination of the blood bacterial load using PCR. CPD was assessed using Automated Hematology analyzer Sysmex series XN-2000. Serum levels of procalcitonin (PCT), interleukin-6 (IL-6), presepsin, and CRP were also assessed.
Of 93 patients with acute bacterial infection, 24 developed culture-proven bacteremia and 69 did not. NE-SFL and NE-WY were significantly higher in patients with bacteremia than in those without bacteremia (
< 0.005, respectively), and were significantly correlated with the bacterial load determined by PCR (
= 0.384 and
= 0.374,
< 0.005, respectively). To assess the diagnostic value for bacteremia, receiver operating characteristic curve analysis was used. NE-SFL and NE-WY showed an area under the curve of 0.685 and 0.708, respectively, while those of PCT, IL-6, presepsin, and CRP were 0.744, 0.778, 0.685, and 0.528, respectively. Correlation analysis showed that the levels of NE-WY and NE-SFL were strongly correlated with PCT and IL-6 levels.
This study demonstrated that NE-WY and NE-SFL could predict bacteremia in a manner that may be different from that of other indicators. These findings suggest there are potential benefits of NE-WY/NE-SFL in predicting severe bacterial infections.
Journal Article
Potency of gastrointestinal colonization and virulence of Candida auris in a murine endogenous candidiasis
2020
Candida auris infections have recently emerged worldwide, and this species is highly capable of colonization and is associated with high levels of mortality. However, strain-dependent differences in colonization capabilities and virulence have not yet been reported. In the present study, we aimed to clarify the differences between clinically isolated invasive and non-invasive strains of C. auris. We evaluated colonization, dissemination, and survival rates in wild C57BL/6J mice inoculated with invasive or non-invasive strains of C. auris under cortisone acetate immunosuppression, comparing with those of Candida albicans and Candida glabrata infections. We also evaluated the potency of biofilm formation. Stool fungal burdens were significantly higher in mice inoculated with the invasive strains than in those infected with the non-invasive strain. Along with intestinal colonization, liver and kidney fungal burdens were also significantly higher in mice inoculated with the invasive strains. In addition, histopathological findings revealed greater dissemination and colonization of the invasive strains. Regarding biofilm-forming capability, the invasive strain of C. auris exhibited a significantly higher capacity of producing biofilms. Moreover, inoculation with the invasive strains resulted in significantly greater loss of body weight than that noted following infection with the non-invasive strain. Invasive strains showed higher colonization capability and rates of dissemination from gastrointestinal tracts under cortisone acetate immunosuppression than non-invasive strains, although the mortality rates caused by C. auris were lower than those caused by C. albicans.
Journal Article
Potency of gastrointestinal colonization and virulence of Candida auris in a murine endogenous candidiasis
2020
Candida auris infections have recently emerged worldwide, and this species is highly capable of colonization and is associated with high levels of mortality. However, strain-dependent differences in colonization capabilities and virulence have not yet been reported. In the present study, we aimed to clarify the differences between clinically isolated invasive and non-invasive strains of C. auris. We evaluated colonization, dissemination, and survival rates in wild C57BL/6J mice inoculated with invasive or non-invasive strains of C. auris under cortisone acetate immunosuppression, comparing with those of Candida albicans and Candida glabrata infections. We also evaluated the potency of biofilm formation. Stool fungal burdens were significantly higher in mice inoculated with the invasive strains than in those infected with the non-invasive strain. Along with intestinal colonization, liver and kidney fungal burdens were also significantly higher in mice inoculated with the invasive strains. In addition, histopathological findings revealed greater dissemination and colonization of the invasive strains. Regarding biofilm-forming capability, the invasive strain of C. auris exhibited a significantly higher capacity of producing biofilms. Moreover, inoculation with the invasive strains resulted in significantly greater loss of body weight than that noted following infection with the non-invasive strain. Invasive strains showed higher colonization capability and rates of dissemination from gastrointestinal tracts under cortisone acetate immunosuppression than non-invasive strains, although the mortality rates caused by C. auris were lower than those caused by C. albicans.
Journal Article