Clinical implication of the antidiuretic hormone (ADH) receptor antagonist mozavaptan hydrochloride in patients with ectopic ADH syndrome.

Ectopic antidiuretic hormone syndrome is a medical emergency characterized by dilutional hyponatremia. Clinical effectiveness of the vasopressin V2 receptor antagonist mozavaptan was evaluated in 16 patients. In short-term (7-day) treatment with the drug, serum sodium concentration (mean ± standard deviation) significantly (P = 0.002) increased from 122.8 ± 6.7 to 133.3 ± 8.3 mEq/l, and symptoms due to hyponatremia were improved. On the basis of these results, mozavaptan (Physuline(®)) was approved as an orphan drug for the treatment of the syndrome in 2006 in Japan. During the 43 months following its launch, 100 patients have been treated with the drug; overall clinical effects of the drug were found similar to those of this clinical trial. Clinically, mozavaptan may allow hyponatremic patients to be treated by aggressive cancer chemotherapy with platinum-containing drugs. Moreover, the drug may free patients from strict fluid-intake restrictions and thereby improve their quality of life.

Microbiological and clinical study of methicillin-resistant Staphylococcus aureus (MRSA) carrying VraS mutation: changes in susceptibility to glycopeptides and clinical significance.

The VraSR two-component regulatory system is involved in glycopeptide resistance in Staphylococcus aureus. We examined the relationship between VraS mutation and susceptibility to various antimicrobial agents in 400 clinical isolates of methicillin-resistant S. aureus (MRSA) from Cancer Institute Hospital between 1998 and 2004. The prevalence of MRSA isolates with teicoplanin minimum inhibitory concentrations (MICs) of 4-8 microg/mL rose between 2000 and 2002 (52% in 2000). Among the isolates displaying reduced susceptibility to teicoplanin (78 isolates), 99% harboured the Ile5Asn (I5N) mutation in VraS. In addition, MICs of oxacillin and imipenem tended to be higher for I5N mutants compared with those for non-I5N isolates. By contrast, no significant change was noted in susceptibility to arbekacin or vancomycin. In this hospital, I5N mutants emerged at an early stage after the introduction of teicoplanin and thereafter declined in number upon increased usage of arbekacin instead of glycopeptides. Outcomes from 18 patients who were infected with MRSA with reduced susceptibility to teicoplanin were analysed microbiologically in a retrospective manner. Teicoplanin was effective in 50% of the patients treated with this drug. On the other hand, arbekacin and vancomycin were effective in all cases. The results indicate the relationship between antimicrobial susceptibility and therapeutic effect.

[In-vitro susceptibilites to levofloxacin and various antibacterial agents of 18,639 clinical isolates obtained from 77 centers in 2004].

A total of 18,639 clinical isolates in 19 species collected from 77 centers during 2004 in Japan were tested for their susceptibility to fluoroquinolones (FQs) and other selected antibiotics. The common respiratory pathogens, Streptococcus pyogenes, Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae showed a high susceptible rate against FQs. The isolation rate of beta lactamase non-producing ampicillin-resistant H. influenzae was approximately three times as large as those of western countries. Most strains of Enterobacteriaceae were also susceptible to FQs. The resistance rate of Escherichia coli against FQs has however been rapidly increasing so far as we surveyed since 1994. The FQs-resistant rate in methicillin-resistant Staphylococcus aureus (MRSA) showed approximately 90% except for 36%. of sitafloxacin while FQs-resistant rate in methicillin-susceptible S. aureus (MSSA) was around 5%. The FQs-resistant rate of methicillin-resistant coagulase negative Staphylococci (MRCNS) was also higher than that of methicillin-susceptible coagulase negative Staphylococci (MSCNS), however, it was lower than that of MRSA. In Pseudomonas aeruginosa clinical isolates, 32-34% from UTI and 15-19% of from RTI was resistant to FQs. Acinetobacter spp. showed a high susceptibility to FQs. Although FQs-resistant Neisseria gonorrhoeae have not been increased in western countries, it is remarkably high in Japan. In this survey, isolates of approximately 85% was resistant to FQs.