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PubMed | University of Miyazaki, Japan National Institute of Infectious Diseases, Kyushu University, Osaka Prefectural Institute of Public Health Osaka and University of MiyazakiMiyazaki
Type: | Journal: Frontiers in microbiology | Year: 2016

Serotyping is one of the typing techniques used to classify strains within the same species. O-serogroup diversification shows a strong association with the genetic diversity of O-antigen biosynthesis genes. In a previous study, based on the O-antigen biosynthesis gene cluster (O-AGC) sequences of 184 known Escherichia coli O serogroups (from O1 to O187), we developed a comprehensive and practical molecular O serogrouping (O genotyping) platform using a polymerase chain reaction (PCR) method, named E. coli O-genotyping PCR. Although, the validation assay using the PCR system showed that most of the tested strains were successfully classified into one of the O genotypes, it was impossible to classify 6.1% (35/575) of the strains, suggesting the presence of novel O genotypes. In this study, we conducted sequence analysis of O-AGCs from O-genotype untypeable Shiga toxin-producing E. coli (STEC) strains and identified six novel O genotypes; OgN1, OgN8, OgN9, OgN10, OgN12 and OgN31, with unique wzx and/or wzy O-antigen processing gene sequences. Additionally, to identify these novel O-genotypes, we designed specific PCR primers. A screen of O genotypes using O-genotype untypeable strains showed 13 STEC strains were classified into five novel O genotypes. The O genotyping at the molecular level of the O-AGC would aid in the characterization of E. coli isolates and will assist future studies in STEC epidemiology and phylogeny.

Furuhata K.,Azabu University | Edagawa A.,Osaka Prefectural Institute of Public Health Osaka | Edagawa A.,Saga University | Ishizaki N.,Azabu University | Fukuyama M.,Azabu University
Biocontrol Science | Year: 2013

In order to understand the habitation conditions of the bacteria of the genus Legionella in Noyu( unattended natural hot springs in mountains and fields) in Japan, isolation of Legionella spp. was attempted in the Noyu samples from 11 prefectures nationwide between May and September 2012, and the following results were obtained. Overall, Legionella spp. was isolated from 16 of 43 samples (37.2%). The species was isolated from the Hokkaido region to the Chugoku region but not from the Shikoku region to the Kyushu region. The number of bacteria detected was usually small, less than 5.0×101 CFU/100 ml, as found in 11 samples (68.8%), while counts of 102 or more to 103 or less CFU/100 ml were found in two samples (12.5%). Legionella pneumophila was the most commonly found strain, with 19 strains (90.5%) found, and was the dominant species. Regarding the serogrouping, four strains (21.1%) fell under group 1, the most common grouping, followed by three strains( 15.8%) in group 3, two strains (10.5%) in group 5, etc. Moreover, the detected bacterial strains other than L. pneumophila included two strains( 9.5%) of L. londiniensis. The temperature of the Noyu from which Legionella spp. was isolated was between 33.1°C and 41.5°C with a pH ranging from 5.2 to 8.1. The present report is the first report to clarify the habitation conditions of strains of Legionella spp. isolated from Noyu in Japan.

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