We examined 402 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from clinical specimens in our hospital between November 19, 2010 and December 27, 2011 to evaluate the similarity between cluster analysis of drug susceptibility tests and pulsed-field gel electrophoresis (PFGE). The results showed that the 402 strains tested were classified into 27 PFGE patterns (151 subtypes of patterns). Cluster analyses of drug susceptibility tests with the cut-off distance yielding a similar classification capability showed favorable results—when the MIC method was used, and minimum inhibitory concentration (MIC) values were used directly in the method, the level of agreement with PFGE was 74.2% when 15 drugs were tested. The Unweighted Pair Group Method with Arithmetic mean (UPGMA) method was effective when the cut-off distance was 16. Using the SIR method in which susceptible (S), intermediate (I), and resistant (R) were coded as 0, 2, and 3, respectively, according to the Clinical and Laboratory Standards Institute (CLSI) criteria, the level of agreement with PFGE was 75.9% when the number of drugs tested was 17, the method used for clustering was the UPGMA, and the cut-off distance was 3.6. In addition, to assess the reproducibility of the results, 10 strains were randomly sampled from the overall test and subjected to cluster analysis. This was repeated 100 times under the same conditions. The results indicated good reproducibility of the results, with the level of agreement with PFGE showing a mean of 82.0%, standard deviation of 12.1%, and mode of 90.0% for the MIC method and a mean of 80.0%, standard deviation of 13.4%, and mode of 90.0% for the SIR method. In summary, cluster analysis for drug susceptibility tests is useful for the epidemiological analysis of MRSA.

We investigated the clinical symptoms of 206 pediatric patients with influenza virus infection and compared them among oseltamivir-treated, zanamivir-treated, and laninamivirtreated groups in 2013/2014 influenza season. The drug compliance of each neuraminidase inhibitor was good in all three groups. Although the duration of fever after administration of the first dose of each neuraminidase inhibitor were significantly prolonged in the patient with influenza B infection than in the patient with influenza A infection, no statistically significant difference in the clinical efficacy and the side effect among three groups were found. The number of biphasic fever episodes in patients treated with neuraminidase inhibitor was rare(two episodes of oseltamivir-treated group and one episode of zanamivir-treated group). In conclusion, under the good drug compliance, the efficacy of all three neuraminidase inhibitor was the same for the treatment of influenza virus infection in children.

Clostridium difficile(C. difficile) is a major pathogen for diarrhea in hospitalized patients and because of outbreak of highly virulent strain in EU and US, increased length of hospital stay and increased numbers of severe patients and deaths have become major challenges. In recent years, transmissions through community-acquired or food-borne infections are reported. National surveillance has been already performed overseas. Guidelines for preventing C. difficile infection (CDI) is available, and education activities are promoted for preventing the infection spread.

Meanwhile, in Japan, medical hospitals are reporting individual CDI incidence, however, a large-scale research has not been conducted up to the present date and therefore the entire status of CDI including infection of the highly virulent strain has yet to be revealed.

This time, we performed a questionnaire-based survey at 2,537 hospitals nationwide between April 15, 2013 and May 31, 2013 to investigate CDI incidence, diagnosis and treatment. Valid responses were obtained from 321 hospitals.

Regarding the annual number of CDI patients at all the hospitals, the highest group of hospitals responding “1 to 5 patients a year” was 17.8%, and the second highest group of hospitals responding “no patients a year” was 13.1%. In contrast, there was a group of hospitals with “more than 101 patients a year”, which was 3.1%. This indicates that there was the difference in the CDI incidences among hospitals.

According to the questionnaire results, a highest group of hospitals responding “0–20%” for CDI patients with serious complication such as toxic megacolon, gastrointestinal perforation, ileus paralytic, bacteremia, sepsis, crohn’s disease, and ulcerative colitis was 62.6%, and for CDI patients with recurrence more than one, a group of hospitals answering “0 to 20%” was 56.4%, which was the highest. This suggested that there was only a small number of serious CDI patients and recurrence CDI patients in Japan.

For rapid toxin detection kit used in CDI diagnosis, a group of hospitals using “C. DIFF QUIK CHEK COMPLETE” was over 40%, which showed that the kit was a major product used in Japan. And a group of institutions responding that they will start antibacterial medication such as vancomycin (VCM) and metronidazole (MNZ) as soon...

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