Strains of pink-pigmented facultative methylotrophs which were isolated previously from various environments and assigned tentatively to the genus Methylobacterium were characterized in comparison with authentic strains of previously known species of this genus. Most of the isolates derived from chlorinated water supplies exhibited resistance to chlorine, whereas 29 to 40% of the isolates from air, natural aquatic environments, and clinical materials were chlorine resistant. None of the tested authentic strains of Methylobacterium species obtained from culture collections exhibited chlorine resistance. Numerical analysis of phenotypic profiles showed that the test organisms could be divided into 19 clusters at a similarity level of 80%, at which all established Methylobacterium species tested were separated from each other except M. organophilum and M. rhodesianum. The chlorine-resistant isolates were randomly distributed among all clusters. The 16S ribosomal DNA (rDNA) sequence-based phylogenetic analyses showed that representatives of the isolates together with known Methylobacterium species formed a line of descent distinct from that of members of related genera in the alpha-2 subclass of the Proteobacteria and were divided into three subclusters within the Methylobacterium group. These results demonstrate that there is phenotypic and genetic diversity among chlorine-resistant Methylobacterium strains within the genus.

ABSTRACTLegionella pneumophilaserogroup (SG) 1 is the most frequent cause of legionellosis. This study analyzed environmental isolates ofL. pneumophilaSG 1 in Japan using monoclonal antibody (MAb) typing and sequence-based typing (SBT). Samples were analyzed from bathwater (BW;n= 50), cooling tower water (CT;n= 50), and soil (SO;n= 35). The distribution of MAb types varied by source, with the most prevalent types being Bellingham (42%), Oxford (72%), and OLDA (51%) in BW, CT, and SO, respectively. The ratios of MAb 3/1 positive isolates were 26, 2, and 14% from BW, CT, and SO, respectively. The environmental isolates from BW, CT, and SO were divided into 34 sequence types (STs; index of discrimination [IOD] = 0.973), 8 STs (IOD = 0.448), and 11 STs (IOD = 0.879), respectively. Genetic variation among CT isolates was smaller than seen in BW and SO. ST1 accounted for 74% of the CT isolates. The only common STs between (i) BW and CT, (ii) BW and SO, and (iii) CT and SO were ST1, ST129, and ST48, respectively, suggesting that each environment constitutes an independent habitat.

Methicillin-resistant Staphylococcus aureus MRSA is one of the major pathogens responsible for nosocomial infections. The presence of MRSA in a hospital is detrimental to patients and to hospital management. Thus, rapid identification of MRSA is needed. Here, we report on a prospective method to rapidly discriminate of MSSA from MRSA using matrix-assisted laser desorption ionization-time of flight mass spectrometry MALDI-TOF MS and support vector machine SVM analysis in 160 clinical isolates of S. aureus. The predictive model was tested using 100 S. aureus isolates 50 MSSA and 50 MRSA . The identification rates were 90.0% for MSSA and 87.5% for MRSA in a 10-fold cross-validation SVM. In blind test sets, 60 S. aureus isolates 30 MSSA and 30 MRSA were correctly classified, with identification rates of 93.3% for MSSA and 86.7% for MRSA. The method proposed in this study using the predictive model enables detection of one colony in 5 minutes, and thus is useful at clinical sites at which rapid discrimination of MRSA from MSSA is required.Key words Rapid discrimination / MSSA / MRSA / MALDI-TOF MS / MALDI BioTyper software.

Aims:  To investigate the occurrence and distribution of thermo‐acidophilic bacteria (TAB) associated with various commercial fruit crop soils in Japan and to assess their ability to produce the odorous phenolic compound, guaiacol. Methods and Results:  Phylogenetic analysis based on the 5′ end of the 16S rRNA gene (approximately 500 bp), was performed on 62 TAB isolated from the soil of several Japanese fruit orchards. The results suggested that 60 of the bacterial strains analysed belonged to the genus Alicyclobacillus, while the remaining two belonged to the genus Bacillus. The majority of strains (58%) were identified as Alicyclobacillus acidoterrestris. This group partitioned into three phylogenetically distinct subgroups (A–C). Isolates identified as A. acidiphilus (two strains), A. acidoterrestris (36 strains), and A. hesperidum subsp. aigle (one strain), produced guaiacol from vanillic acid. Levels of guaiacol production varied significantly among strains. The guaiacol producing phenotype was conserved among certain species, however no correlation was observed between levels of guaiacol production and 16S rRNA gene‐based phylogenetic relatedness. Conclusions:  Alicyclobacillus acidoterrestris and Alicyclobacillus contaminans were widely distributed among various fruit orchards in Japan. Guaiacol production was common at the species/subspecies level; however the amount of guaiacol produced by each strain varied significantly. Significance and Impact of the Study:  This study provides a comprehensive phylogenetic survey of Alicyclobacillus species in Japanese fruit orchards. Quality control standards for guaiacol producing Alicyclobacillus have also been described.

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