Identification of yellow-pigmented bacteria isolated from hospital tap water in Japan and their chlorine resistance.

Twenty-five yellow chromogenic strains isolated from hospital tap water samples collected nationwide were identified by partial 16S rDNA sequencing. In addition, the chlorine resistance of the isolates was experimentally investigated. The results showed that of the strains tested, 12 strains (48.0%) were Sphingomonas ursincola/natatoria, which was most frequently identified, followed by 2 strains (8.0%) of Mycobacterium frederiksbergense and 1 strain (4.0%) each of Sphingomonas adhaesiva, Sphingopyxis witflariensis and Porphyrobacter donghaensis. The other strains were not identified clearly but they belonged to the order of Alphaproteobacteria. On the other hand, the identification results by sequencing and biochemical property testing were not consistent in any of the strains, showing that it was difficult to accurately identify the yellow chromogenic bacteria in tap water based on only their biochemical properties. When the 25 isolates were exposed to 0.1 mg/l residual free chlorine for 1 minute, 22 isolates (88.0%) survived. When the CT (Concentration Time) value killing 99.99% of the bacteria was investigated in 6 of these survivors, M. frederiksbergense (Y-1 strain) was most resistant to chlorine with the CT value of 32 mg x min/l, followed by S. ursincola/natatoria (Y-7 strain) with the CT value of 3.3 mg x min/l. The CT values of Y-5 (Sphingomonas sp.), Y-27 (S. ursincola/natatoria) and Y-21 (Asticacaulis sp.) were within the range of 0.9-0.1 mg x min /l. Of the 6 strains, S. adhaesiva (Y-10) showed the weakest resistance with the CT value of 0.03 mg x min/l. It was clarified that most yellow chromogenic bacteria isolated from hospital tap water were Sphingomonas spp., and these bacteria were experimentally resistant to chlorine.

[1]  古畑 勝則,et al.  Isolation of Oligotrophic Bacteria from Hospital Tap Water , 2007 .

[2]  S. Oie,et al.  Microbial contamination of nebulization solution and its measures. , 2006, Biological & pharmaceutical bulletin.

[3]  S. Yoshida,et al.  Isolation and Identification of Methylobacterium Species from the Tap Water in Hospitals in Japan and Their Antibiotic Susceptibility , 2006, Microbiology and immunology.

[4]  Largus T. Angenent,et al.  Molecular Analysis of Shower Curtain Biofilm Microbes , 2004, Applied and Environmental Microbiology.

[5]  Kazuo Kobayashi,et al.  Emendation of the genus Sphingomonas Yabuuchi et al. 1990 and junior objective synonymy of the species of three genera, Sphingobium, Novosphingobium and Sphingopyxis, in conjunction with Blastomonas ursincola. , 2002, International journal of systematic and evolutionary microbiology.

[6]  Shiao-ping Huang,et al.  Identification of Nontuberculous Mycobacteria Existing in Tap Water by PCR-Restriction Fragment Length Polymorphism , 2002, Applied and Environmental Microbiology.

[7]  E. Stackebrandt,et al.  Mycobacterium frederiksbergense sp. nov., a novel polycyclic aromatic hydrocarbon-degrading Mycobacterium species. , 2001, International journal of systematic and evolutionary microbiology.

[8]  M. Sasatsu,et al.  Distribution of Legionella and Nontuberculous Mycobacteria in Environment , 2000 .

[9]  Steven G. Buchberger,et al.  Relationships between levels of heterotrophic bacteria and water quality parameters in a drinking water distribution system , 2000 .

[10]  I. Yano,et al.  Proposal of Sphingomonas suberifaciens (van Bruggen, Jochimsen and Brown 1990) Comb. Nov., Sphingomonas natatoria (Sly 1985) Comb. Nov., Sphingomonas ursincola (Yurkov et al. 1997) Comb. Nov., and Emendation of the Genus Sphingomonas , 1999, Microbiology and immunology.

[11]  J. Morató,et al.  Resistance to chlorine of freshwater bacterial strains , 1997, Journal of applied microbiology.

[12]  A. Hiraishi,et al.  Phenotypic and genetic diversity of chlorine-resistant Methylobacterium strains isolated from various environments , 1995, Applied and environmental microbiology.

[13]  P. Loudon,et al.  Inactivation of Hepatitis a Virus , 1995 .

[14]  J. R. O'brien.  An unusual yellow pigmented Pseudomonas species isolated from chlorinated municipal town water supply. , 1992, Microbios.

[15]  E. Geldreich,et al.  Nonphotosynthetic pigmented bacteria in a potable water treatment and distribution system , 1989, Applied and environmental microbiology.

[16]  N. Saitou,et al.  The neighbor-joining method: a new method for reconstructing phylogenetic trees. , 1987, Molecular biology and evolution.

[17]  W. Grabow,et al.  Inactivation of Hepatitis A Virus, Other Enteric Viruses and Indicator Organisms in Water by Chlorination , 1985 .

[18]  O. Prozesky,et al.  Inactivation of hepatitis A virus and indicator organisms in water by free chlorine residuals , 1983, Applied and environmental microbiology.

[19]  R. Owen,et al.  Pseudomonas paucimobilis, a New Species Isolated from Human Clinical Specimens, the Hospital Environment, and Other Sources , 1977 .