[Epidemiological study of clinical backgrounds of influenza patients in an open hospital of Yokohama City in the last ten years].

The Ministry of Health, Labour and Welfare announced in March, 2011 that it shifts to the usual measure against influenza about the pandemic influenza which occurred in 2009. Since epidemic finished, I thought that the surveillance about the measure against infection control was required. In this study we performed an epidemiological investigation of the clinical backgrounds of influenza patients over the last ten years. The number of patients with influenza in the 2009-2010 season was 751 (455 children: under sixteen years old and 296 adults). In seasons covering the last ten years, the majority of patients were children, while the number of adult patients counted fell in second place. Over the last ten years the average ages of the patients were 8.20 +/- 4.00 years for the children and 31.11 +/- 13.46 for the adults. Furthermore, in the investigation of the methods for using the anti-influenza medications (oseltamivir or Zanamivir), the number of patients who used anti-influenza medications in the 2009-2010 season amounted to 517 children and 345 adults. Among these, 87 children (16.8%) and 37 adults (10.7%), i.e., a total of 124 patients (14.3%), took the anti-flu medications although their antigen test results were negative. In the 2007-2008 and 2008-2009 seasons, almost no anti-influenza medications had been used in those cases in which the antigen test results came out negative. The epidemic of the new type of influenza was a special epidemic condition; its effects extended to reviewing the method of using anti-influenza medications. Highly accurate surveillance is needed to solve the problem, and the responsibility of laboratories, the main source of information, is important.

[Susceptibility surveillance of clinical isolates to fluoroquinolone antimicrobial agents from 2003 to 2008: post-marketing study of prulifloxacin].

Yearly changes in the susceptibility of clinical isolates to ulifloxacin (UFX) and other fluoroquinolones were examined through surveys over 3 periods. In the first survey, 534 strains derived from 19 species were collected from clinical specimens during 6 months from December 2003 to May 2004. In the same way, 805 strains were collected from December 2005 to May 2006 in the second survey, and 863 strains were from December 2007 to May 2008 in the third survey. Over these 3 study periods, the susceptibilities of fluoroquinolones against methicillin-susceptible Staphylococcus aureus and Escherichia coli were decreased. The isolation frequency of levofloxacin-nonsusceptible strain was increased from 0% to 11.8% and from 14.6% to 20.8%, respectively. MIC90s of UFX against these pathogens were also increased, but its MIC90 for E. coli was 2 to 4 times lower than that of levofloxacin. On the other hand, the susceptibility of strains of Klebsiella pneumoniae to UFX was increased. Among the fluoroquinolones tested, UFX showed the most potent activity against Pseudomonas aeruginosa, and no changes in the MIC90s occurred during the surveillance. Although one strain of Streptococcus pneumoniae isolated in the third study period showed levofloxacin-resistance (MIC, 8 microg/mL), there were nearly no changes in the MIC90s of any agents tested including UFX against S. pneumoniae during the surveillance. As for other bacterial species, a tendency to increase in resistance to UFX was not observed. The activity of UFX against Salmonella spp. and Shigella spp. was superior/equal to those of fluoroquinolones tested.

[Clinical evaluation of a norovirus antigen detection test in pediatric patients and study targeting application to combat infection].

Typical causative viruses of viral gastroenteritis in childhood are Norovirus(NV), Rotavirus(RV), and Adenovirus (AV). It is difficult to specify the type of virus based on the clinical symptoms, necessitating a search for the causative virus. Antigen testing is the mainstay for the definitive diagnosis of RV and AV. Molecular biology testing, however, is the mainstay for NV, and problems related to the rapidity and simplicity of the test have been a pending issue for many years. In this study, the clinical performance of an NV antigen detection test was investigated in children, and its application to combating infection was considered. Among 181 children with gastroenteritis tested by RT-PCR, there were 87 children (48.0%) showing positive NV findings in stool samples. Taking RT-PCR as the gold standard, the correlation with the antigen detection test showed a sensitivity of 76.0%, specificity of 100%, and a concordance rate of 89.5%. Results obtained in the basic study showed that the antigen detection test could be useful in everyday practice. As a result of studying how long the virus is shed in the feces of children infected by NV, however, the percentage of positive findings on RT-PCR testing was 16 of 17 (94.1%) on day 7 of illness and similarly 6 of 7 (85.7%) on day 14. However, only one case was positive using the antigen detection test on day 7 of the illness, and all were negative on day 14. The viral load of NV is assumed to drop below the sensitivity of the antigen detection test within 7 days. The appropriate method of use remains to be established, but the antigen detection test for NV appears to be able to make a contribution in everyday practice.