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Biomedical subjects

Masato Touyama

Publications and source records attributed to Masato Touyama.

5 recordsLinked to original sources
PubMed2006

In vitro activity of sitafloxacin against clinical strains of Streptococcus pneumoniae with defined amino acid substitutions in QRDRs of gyrase A and topoisomerase IV.

OBJECTIVES: Fluoroquinolone-resistant Streptococcus pneumoniae are increasing worldwide rapidly. In vitro activities of sitafloxacin were evaluated against clinical isolates of S. pneumoniae resistant to levofloxacin (MIC of levofloxacin > or = 4 mg/L), which were characterized genetically. METHODS: The quinolone resistance determining regions (QRDRs) of gyrA, gyrB, parC and parE of these strains were analysed by PCR-based sequencing. MICs of sitafloxacin and other quinolones were determined by a microdilution broth method. RESULTS: All 18 strains had at least one amino acid substitution in the QRDRs of GyrA and ParC, which included Ser-81-->Tyr/Phe and Glu-85-->Lys in GyrA and Ser-79-->Phe/Ile/Tyr, Asp-83-->Tyr, Asn-91-->Asp, Ser-107-->Phe, Lys-137-->Asn and Ala-142-->Ser in ParC. Most isolates had Asp-435-->Asn/Ile-460-->Val/Ala-596-->Thr substitutions in ParE, while no amino acid substitution in GyrB was noted in all isolates. Ten isolates for which levofloxacin MICs were 16 or 32 mg/L had multiple mutations in both GyrA and ParC. The MIC80 value of sitafloxacin for levofloxacin-resistant isolates was 0.25 mg/L. The range of MICs of sitafloxacin for isolates resistant to levofloxacin (MIC 4-32 mg/L) was 0.016-0.5 mg/L. CONCLUSIONS: These findings warrant further studies to evaluate the usefulness of sitafloxacin in the treatment of levofloxacin-resistant S. pneumoniae infection.

Amino Acid Substitution↗
PubMed2005

[Two cases of pulmonary aspergillosis successfully treated with combinated micafungin and itraconazole therapy].

We report 2 cases of pulmonary aspergillosis treated successfully by combining micafungin and traconazole. Case 1: A 51-year-old man with hemoptysis and dyspnea on effort treated for pulmonary tuberculosis and aspergillosis was found on chest CT on admission to have a fungus ball in the left upper lobe and increasing consolidation around the cavity of both lung fields. Bronchoscopy proved positive for aspergillus PCR in bronchial lavage. He was diagnosed with chronic necrotizing pulmonary aspergillosis, based on clinical and radiological findings and the positive reaction for aspergillus PCR. He was treated with micafungin alone at first, this proved ineffective, so itraconazole was added, resulting in improvement. Case 2: A 24-year-old woman with stabilized Hodgkin's disease (mixed). She had suffered from a cough and back pain, and chest CT showed increasing consolidation inside and around a giant bulla. She was diagnosed with chronic necrotizing pulmonary aspergillosis, based on isolation for Aspergillus sp. in sputum culture and a positive reaction for Aspergillus antigen in bronchial lavage and Aspergillus antibody in serum. She was treated with the combined micafungin and itraconazole, which rapidly improved symptoms and radiological findings. Pulmonary aspergillosis therapy is often difficult, because delivery of the drug to the infection site is limited and drug tolerance is poor. We found that combination micafungin and itraconazole therapy is tolerable and effective in these cases.

Adult↗
PubMed2002

[A case of cat scratch disease with encephalopathy].

We report an atypical case of cat scratch disease (CSD), accompanied with encephalopathy that is a rare complication of CSD. A 17-year old man consulted a doctor for his right axillary lymphadenopathy. The history of his contact with cats and the sign of lymphnode swelling and fever suggested a suspect of cat scratch disease. Administration of ampicillin improved his clinical symptoms, but a few days later he suddenly fell into coma after an episode of convulsion. The CT scan of the brain and laboratory tests showed no significant findings except the slightly elevated cell counts and concentration of protein in his cerebrospinal fluid. He was referred to our hospital on the next day for further examinations and treatments for his coma of unknown cause. The physical examination on admission revealed slight neck stiffening and hypertonicity of his right lower limb, but radiological and laboratory tests showed no significant findings. He gradually recovered from his coma without apparent sequelae in three weeks. Indirect fluorescence antibody titers for CSD in his serum showed a significant elevation to 1:160 of IgM and 1:512 of IgG, and his clinical features were compatible to these of CSD with complications of the central nervous system.

Adolescent↗
PubMed2002

[Bloodstream infection].

Bloodstream infection is the most serious disease and the third mortality rate among nosocomial infections. Recently, catheter-related bloodstream infection(CRBSI) is the major cause of the bloodstream infection, related to serious complication, leading to increase in morbidity and mortality. Coagulase-negative staphylococci, Staphylococcus aureus, enterococci and Candida spp. are most commonly causes of CRBSI. A variety of methods such as aseptic insertion techniques and appropriate catheter care have proved effective, which are also preferable to prevent CRBSI. If CRBSI occurs, empirical antimicrobial therapy should be immediately started after appropriate cultures of blood and catheter sample are performed.

Anti-Bacterial Agents↗