Background: In Japan, the inoculation dosage of inactivated influenza vaccine for hildren under 1 year old is 0.1mL per dose. The dosage is not half as much as that in Europe and the U.S.A. Weconsidered that low efficacy fate of influenza vaccine in children under 1 year old results from its lessdosage. So we designed this study to verify this hypothesis.
Materials and Methods: This study was prospective in design. Subjects were dividedinto twogroups by age: 8 to 11 months old (n=26) and 12 to 16 months old (n=22). Infantsreceived 0.1mLof inactivated influenza vaccine and over 1 year, 0.2mL. Forty-eight children wereinoculated twice atintervals of over 4 weeks. Serum samples were drawn before the first inoculation and 1 month afterthe second vaccination. Pre and post immunization antibody titers were measured. The titers ofhemaglutinatinin inhibiting antibodies to the 3 viral strains were assayed. Antibody titers were de-termined using HAI.
Results: The post-vaccination proportions of children with protective HAI antibodytiters weresignificantly smaller in infants than those in children over 1 year old (A/H1N1; 23%vs. 77%, A/H3N2; 39%vs. 73%, B; 0%vs. 32%). The number of children with>four-fold increasedantibodieswere significantly smaller in infants than that in 1 year old (A/H1N1; 74%vs. 91%, B; 0%vs. 39%).In the mean antibody titer, there were signficant differences between infants and hildren over 1year old (A/H1N1; 19 times vs. 56 times, B; 8 times vs. 14 times).
Conclusion: We consider that significant differences in antibody titers between infants and chil-dren over 1 year old were caused by the difference of dosage in influenza vaccines. To obtain protec-tive levels of antibodies by influenza vaccines in infants, they must be inoculated with enough dosage.

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Measurement of blood (1→3)-β-D-glucan is useful for early diagnosis and follow-up of the therapeutic process of deep seated mycoses. The Fungitec G test MK (Seikagaku Corp., Tokyo) kit usingalkaline-pretreatment followed by chromogenic kinetic assay has been widely used in Japan becauseof its high sensitivity and easy handling of a large number of samples. Discrepancy in the levels of (1→3)-β-D-glucan and/or in the quantitative judgement, however, has been pointed out between this kit and other commercial kits. One of the reasons for this discrepancy has been reported to be nonpecific reactions caused by substances other than β-glucan.In this study, we have improved the alkaline pretreatment reagent by changing the concentration of KOH and salts, resulting in a marked reduction of the non-specific reaction. Recovery of standard β-glucan added to plasma or serum after the improved pretreatment was 80 to 120%, and no amidolytic activity was detected either in plasmaor in serum. By the improved pretreatment, the incidence of non-specific reactions, i.e., those that ex-ceed the quantitation limit (3.9 pg/mL), were markedly decreased from 139 to 16 out of 200 plasmasamples and from 106 to 22 out of 170 serum samples. The incidence of strong non-specific reactions, i.e., those that exceed the cut-off level (20pg/mL), were also decreased from seven to one with plasma and seven to zero with serum samples. Correlation between corrected β-glucan measurements by the current pretreatment and non-corrected ones by the improved pretreatment was quite good.The improved method is thus expected to decrease the frequency of non-specific false-positive reac-tions, with the high sensitivity of Fungitec G test MK.

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Group A Streptococci (GAS) from patients with pharyngitis and skin infections were examinedfor Tserotypes, emm types, and streptococcal pyrogenic exotoxin gene types.
The results were summarized as follaws:
1) T and emm types were determined in 130 GAa isolates obtained between 2000 and 2004.Among 85 throat isolates, predominant T/emm types were T12/emm12 (25%), T4/emm4 (19%), andT1/emm1 (14%).Among 45 skin iso1Btes, predominant T/emm types were T28/emm28 (13%), TB3264/emm89 (13%), Tnontypeable/emm58 (13%), T1/emm 1 (11%), and T12/emm (11%).Pre-dominant T/emm types of skin isolates in 2000-2004 slightly differed from those during 1990s in ourprevious report.
2) The presence of streptococcal pyrogenic exotoxin, genes in 292 GAS isolates obtained between1990 and 2004 was examined.Significantly lower proportion of skin isolates, compared with throatisolates, was found to harbar the speA gene (12 versus 26%, respectively;p<0.01), or the speC gene (40 versus 65%, respectively; P< 0.01).All but one of tested isolates carried the speB gene. ThespeB-negative isolate was identified as S. dysgalactiae subsp. equisimilis with the group A antigen.
3) Types of the speA alleles were determined in 59 speA-positive GAS isolates.Among 44 throatisolates, 37 (84%) were speA lineage I (speA1-speA2-speA3-speA6), and 7 (16%) were lineage II (speA4-speA5).Among 15 skin isolates, 11 (73%) were lineage I and 4 (27%) were lineage IL The pair-wise associations were observed between emm type and speA allele: emm1 and speA2, emm3 and speA3, emmd and speA4, emm11 and speA2, emm18 and speA1.

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As a part of studies on the source of infection of Vero toxin-producing Escherichia coli (VTEC), O157: H7 strains isolated from human infectious enteritis between 1986 and 1995 and O157: H7strains isolated from feces of milk cows between 2001 and 2003 were subjected to drug sensitivitytest with drugs widely used as therapeutic drugs for various infectious diseases in humans and ani-mals, and the following results were obtained.
1) Drug sensitivity tests with 20 drugs were performed in 52 strains derived human from diar-rhea and 100 strains derived from milk cows, and resistance was noted in 115 strains (75.7%): 36 ofthe 52 human diarrhea-derived strains (69.2%) and 79 of the 100 milk cow-derived strains (79.0%).
2) The human diarrhea-derived strains and milk cow-derived strains were compared with re-gard to MIC₉₀ of each drug. The antibacterial activity of the drugs was generally higher against thehuman diarrhea-derived strains than against the milk cow-derived strains.
3) In the 115 strains exhibiting resistance, the most frequent pattern of drug resistance was sin-gle drug resistance noted in 80 strains (68.4%), and multidrug resistance was noted in 35 strains (30. 4%) consisting of 17 strains with resistance to 3 drugs, 14 strains with resistance to 2 drugs, and2 strains each with resistance to 4 drugs and 5 drugs. More strains were multidrug-resistant in themilk cow-derived strains.

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A retrospective study was conducted to evaluate the utility of Mycoplasma pneumoniae IgG (quantitative), IgA (quantitative), IgM (qualitative) ELISA kits (Medac Diagnostika, Germany) forthe diagnosis of M. pneumoniae pneumonia in children under 16 years of age. This study included a to-tal of 159 serum samples from 113 patients with acute respiratory diseases such as bronchitis, pneu-monia, which were classified into three groups according to the results of a particle agglutination (PA) test as a reference method, that is, Group I (Mycoplasma-definite cases): Group I-a (paired 52samples from 26 cases); a four-fold or greater rise of antibody from an acute phase PA titer of =/<1: 80, Group I-b (paired 12 samples from 6 cases); a four-fold or greater rise of antibody from aacute phase PA titer of =/ >1: 160, Group I-c (48 samples from 38 cases); a single high PA titerof =/>1: 640 either or both in acute or convalescent serum, Group II (Mycoplasma-probable cases, 18samples from 17 cases): a PA titer of 1: 160 or 320 was observed either or both in acute or conva-lescent serum, but the above serological criteria for Group I were not fulfilled, Group III (non-cases, 29samples from 26 cases): a PA titer of any sample was =/< 1: 80. The ELISA tests were performedaccording to the supplier's recommendations, and the results were classified according to the interpretation provided by the supplier: Early stage of infection (category 1, 2), Acute-(3, 4, 5), Current-(6), Past-(7), and No-infection (8). The day of onset of fever (defined as a body temperature of =/>37.5 degrees Celsius) was denoted as day O. As a result from Group I, the category initially observedfollowing the onset of fever was category 8 (triple negative), and the predominance of category 8 wasreplaced by category 1 (IgM solely positive) after day 4, followed by a shift of predominance to cate-gory 4 (1gM and IgG double positive) or 5 (triple positive) after day 10 or later. Specifically, category1 was rather exclusively observed before day 21 following the onset of fever. These results suggestthat category 1, when observed, is a useful marker of acute infection by Mycoplasma pneumoniae inchildren because it appears early in the acute phase and no longer observed beyond the convalescentphase. On the other hand, significance of detecting IgA antibody, which must be important for adults, was not remarkable in our study. Five samples in group II and 3 samples in group III fell into cate-gory 1. Whether or not such cases, in the absence of significant PA titers, can be taken actually asmycoplasmal infection remains to be clear. This study validated the utility of this ELISA methodol-ogy in terms of the acute phase diagnosis using a single point serum sample for Mycoplasma pneumoniae infection specifically in children.

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