Genetic diversity of the Helicobacter pylori sialic acid-binding adhesin (sabA) gene.

A putative virulence factor, SabA, a sialic acid-binding adhesin, has recently been characterized in Helicobacter pylori from European isolates. However, little genetic information is available for sabA genes in strains isolated from Japanese patients. Here, we investigated the presence of the sabA gene in 23 H. pylori clinical isolates using polymerase chain reaction detection. It was found that 91.3% of H. pylori isolates examined contain the sabA gene. Sequence comparison and phylogenetic analysis based on the deduced amino acid sequence of sabA in nine H. pylori isolates from Japanese patients and three H. pylori strains from Western individuals suggested that sabA is genetically diverse and the clustering of the strains based on SabA is related to their geographical origin. It needs to be further assessed whether the genetic diversity of sabA is associated with the clinical outcomes of H. pylori infection.

Analysis of monthly isolation of respiratory viruses from children by cell culture using a microplate method: a two-year study from 2004 to 2005 in yamagata, Japan.

Although well over 200 viral agents have been implicated in acute respiratory infections (ARIs) among children, no system able to detect such a wide range of viruses has been established. Between January 2004 and December 2005, a modified microplate method, including HEF, HEp-2, Vero E6, MDCK, RD-18S, and GMK cell lines (HHVe6MRG plate), was adopted to isolate viruses. A total of 1,551 viruses were isolated, representing both outbreaks and sporadic cases, from 4,107 nasopharyngeal specimens, at monthly isolation rates of 22.3 to 52.6%. Influenza, parainfluenza, respiratory syncytial (RS), and mumps viruses, and human metapneumovirus, enterovirus, parechovirus, rhinovirus, adenovirus, herpesvirus, and cytomegalovirus were all isolated. The use of multiple cell lines increased the isolation rates of most of these viruses. The findings showed that ARIs due to a number of respiratory viruses occurred across all seasons in succession and/or concurrently in children in the community. These data will help clinicians determine in which seasons and for which age groups they should use the rapid diagnostic test kits available for influenza virus, RS virus, and adenovirus. In conclusion, we verified that the modified microplate method was able to clarify the etiology and epidemiology of numerous viruses isolated from children with ARI.

A slow spread of adenovirus type 7 infection after its re-emergence in Yamagata, Japan, in 1995.

We have continued the epidemiological study on adenovirus type 7 (Ad7), which re-emerged in 1995 in Yamagata, Japan. Between 1999 and 2004, we isolated only four strains from 10,778 throat swab specimens among children with acute respiratory infections. A serological survey of 303 specimens revealed the antibody-positive rate against Ad7 to be 0-7.4% in children under 10 years of age in 2005, although it was 3.3-16.7% in 1997 and 0% in 1993. Our results suggest that a re-emergence does not always provoke a sudden major outbreak, even if the antibody-positive rate against Ad7 is low in the local community.

[Isolation of Neisseria meningitidis from healthy persons in Japan].

Between September 2000 and March 2003 healthy subjects in 10 prefectures of Japan were investigated to identify carriers of Neisseria meningitidis. Twenty-five N. meningitidis strains were isolated from 5886 throat swab specimens collected from healthy persons, such as students, elderly, and foreigners. Of the 25 carriers, 9 were teenagers, 15 were in their twenties, and only one was in the fifties. The male-female ratio of the carriers was 17 to 8, showing male dominance. The serogroups of the 25 strains were B (9 strains), Y (4 strains) and non-groupable (12 strains). One of the strains was found to be deficient in gamma-glutamyl aminopeptidase activity, which is an identification marker for N. meningitidis.

Re-emergence of echovirus type 13 infections in 2002 in Yamagata, Japan.

OBJECTIVES: To analyze the prevalence of echovirus type 13 (Echo13) in Yamagata, Japan. METHODS: Virus isolation was performed from 6514 clinical specimens using six cell lines between January 1999 and December 2002. We also carried out a seroepidemiological study against Echo13, using 234 serum samples collected in 2001. RESULTS: In 2002, we isolated a total of 50 Echo13 strains, which had not been detected from 1981 until 2001 in Japan. The antibody positive rate was higher (57.2-62.0%) in subjects 50 years or over than in those under 50 years (0-14.4%). CONCLUSIONS: Serological study suggested that Echo13 had been present in Yamagata until around 1960, at which time the antibody positive persons were exposed to Echo13 in their childhood. Furthermore, results of virus isolation demonstrated that Echo13 re-emerged in around 2002 after a hiatus of several decades.