Miyuki Hasegawa
Mitsubishi
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Publication
Featured researches published by Miyuki Hasegawa.
Antimicrobial Agents and Chemotherapy | 2009
Kazunari Murakami; Tadayoshi Okimoto; Masaaki Kodama; Jin Tanahashi; Toshio Fujioka; Fumiaki Ikeda; Hiroe Muraoka; Motoko Takigawa; Takeshi Saika; Miyuki Hasegawa; Intetsu Kobayashi
ABSTRACT Sitafloxacin showed MICs of less than or equal to 0.5 μg/ml against 105 isolates of Helicobacter pylori, including 44 isolates with mutations in the gyrA gene. The highest MICs for garenoxacin and levofloxacin were 8 and 64 times, respectively, higher than the highest MICs observed for sitafloxacin.
Medical Mycology | 2009
Fumiaki Ikeda; Takeshi Saika; Y. Sato; Makoto Suzuki; Miyuki Hasegawa; Takashi Mikawa; Intetsu Kobayashi; Akiyoshi Tsuji
The in vitro antifungal activities of micafungin in comparison to caspofungin, fluconazole, itraconazole, voriconazole, and amphotericin B were evaluated against 93 Candida and 23 Aspergillus isolates recovered from pediatric patients with fungal infections. MICs were determined by the CLSI M27-A2 and M38-A for Candida and Aspergillus species, respectively. Micafungin showed potent activity against Candida albicans, Candida tropicalis, and Candida glabrata with a MIC range of <= 0.002 to 0.015mug/ml. In contrast, micafungin demonstrated higher MIC levels against Candida parapsilosis with a MIC range of 0.12 to 2 mug/ml. Micafungin showed potent antifungal activity against Aspergillus species tested with a MIC range of 0.004 to 0.015 mug/ml. Overall, micafungin had excellent in vitro antifungal activities against Candida and Aspergillus species recovered from pediatric patients with fungal infections.
Antimicrobial Agents and Chemotherapy | 2009
Yoichi Hirakata; Kaori Ohmori; Miwako Mikuriya; Takeshi Saika; Kaoru Matsuzaki; Miyuki Hasegawa; Masumitsu Hatta; Natsuo Yamamoto; Hiroyuki Kunishima; Hisakazu Yano; Miho Kitagawa; Kazuaki Arai; Kazuyoshi Kawakami; Intetsu Kobayashi; Ronald N. Jones; Shigeru Kohno; Keizo Yamaguchi; Mitsuo Kaku
ABSTRACT β-Lactamase-negative ampicillin-resistant (BLNAR) isolates of Haemophilus influenzae have been emerging in some countries, including Japan. The Clinical and Laboratory Standards Institute has only a susceptible MIC breakpoint (≤1 μg/ml) for piperacillin-tazobactam and a disclaimer comment that BLNAR H. influenzae should be considered resistant, which was adapted without presentation of data. In addition, fluoroquinolone-resistant H. influenzae isolates have recently been occasionally reported worldwide. To address these problems, we examined susceptibilities to β-lactams, including piperacillin-tazobactam, and ciprofloxacin by microdilution and disk diffusion (only for piperacillin-tazobactam) methods, against a total of 400 recent H. influenzae clinical isolates, including 100 β-lactamase-negative ampicillin-susceptible, β-lactamase-positive ampicillin-resistant, BLNAR, and β-lactamase-positive amoxicillin-clavulanate-resistant (BLPACR) isolates each. BLNAR and BLPACR isolates were tested by PCR using primers that amplify specific regions of the ftsI gene. We also detected mutations in quinolone resistance-determining regions (QRDRs) by direct sequencing of the PCR products of DNA fragments. Among β-lactams, piperacillin-tazobactam exhibited potent activity against all isolates of H. influenzae, with all MICs at ≤0.5 μg/ml (susceptible). A disk diffusion breakpoint for piperacillin-tazobactam of ≥21 mm is proposed. We confirmed that all BLNAR and BLPACR isolates had amino acid substitutions in the ftsI gene and that the major pattern was group III-like (87.5%). One ciprofloxacin-resistant isolate (MIC, 16 μg/ml) and 31 ciprofloxacin-susceptible isolates (MICs, 0.06 to 0.5 μg/ml) had amino acid changes in their QRDRs. Piperacillin-tazobactam was the most potent β-lactam tested against all classes of H. influenzae isolates. It is possible that fluoroquinolone-resistant H. influenzae will emerge since several clinical isolates carried mutations in their QRDRs.
Chemotherapy | 1997
Miyuki Hasegawa; Intetsu Kobayashi; Takeshi Saika; Minoru Nishida
Fifty-nine strains of Pseudomonas aeruginosa, isolated from blood, urine, pus, sputum and feces, were divided into three groups on the basis of differences in their LPS composition, in long- and short-LPS strains and in LPS-deficient strains. The long-LPS strains were far more frequently isolated among blood, urine and fecal specimens than in the remainder, and the frequency of LPS-deficient strains was higher in sputum specimens than in the remainder. The drug resistance patterns of the three LPS-type strains to six different kinds of anti-pseudomonal drugs, including gentamicin, differed significantly.
Chemotherapy | 1999
Takeshi Saika; Miyuki Hasegawa; Intetsu Kobayashi; Minoru Nishida
The clinical isolates of Pseudomonas aeruginosa can be roughly classified into long- and short-LPS strains and LPS-deficient strains. Ionic binding of 3H-gentamicin was the highest in the long-LPS strains followed in descending order by short-LPS and LPS-deficient strains. However, PAC605 strain, completely lacking in the repeated units of O-polysaccharide and also lacking in some of the neutral sugar residues of the core oligosaccharide region, highly bound to 3H-gentamicin and it is suggested that the negatively charged sites on the deep-core oligosaccharide region and/or on lipid A participated in the binding to 3H-gentamicin. This manner of binding may be also applied to P. aeruginosa No. 45 (LPS-deficient), a clinical isolate.
Microbiology and Immunology | 1992
Intetsu Kobayashi; Miyuki Hasegawa; Minoru Nishida; Sachiko Goto
The biological characteristics of individual colonies of Pseudomonas aeruginosa from 138 specimens were investigated. Of these isolates, 90 (65.2%) formed colonies of similar appearance and morphology, and 48 (34.8%) formed colonies which differed either in appearance or morphology. The individual colonies of 138 isolates were tested for serotype. The former 90 isolates formed only the colonies with one kind of serotype, whereas 17 of the latter 48 isolates formed the colonies with more than one kind of serotype. All the 9 isolates tested also differed in other biochemical characteristics: acid productions from xylose, mannitol and maltose, urease production and gelatin liquefaction. β‐Lactamase activity was investigated in 7 isolates forming colonies with more than one serotype. There were no marked differences in β‐lactamase activity among the different colonies in 5 isolates but marked differences among those in the other 2 isolates.
Journal of Antimicrobial Chemotherapy | 2002
Intetsu Kobayashi; Hiroe Muraoka; Miyuki Hasegawa; Takeshi Saika; Minoru Nishida; Makoto Kawamura; Ryoichi Ando
The Journal of Antibiotics | 1994
Intetsu Kobayashi; Miyuki Hasegawa; Shuichi Miyazaki; Minoru Nismda; Sachiko Goto
The Journal of Antibiotics | 1999
Kaoru Matsuzaki; Koyama H; Chiba A; Omika K; Harada S; Y. Sato; Miyuki Hasegawa; Intetsu Kobayashi; Kaneko A; Sasaki J
Journal of Infection and Chemotherapy | 2002
Takeshi Saika; Intetsu Kobayashi; Miyuki Hasegawa; Minoru Nishida