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1.
Biocontrol Sci ; 19(4): 173-9, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25744213

RESUMO

We have previously conducted a microflora analysis and examined the biofilm-forming activity of bacteria isolated from toilet bowl biofilms. In the present investigation, to reveal the strain involved in the formation of black dirt in toilet bowls, we performed a microflora analysis of the bacteria and fungi isolated from the black dirt of toilet bowls at ten homes. Among samples from different isolation sites and sampling seasons, although a similar tendency was not seen in bacterial microflora, Exophiala sp. was detected in the fungal microflora from all samples of black dirt except for one, and constituted the major presence. By scanning electron microscope (SEM) analysis of the formed black dirt, SEM image at × 1,000 and × 5,000 magnification showed objects like hyphae and many bacteria adhering to them, respectively. Micro fourier transform infrared spectroscopy (micro FT-IR) and SEM with X-ray microanalysis (SEM-XMA) were used to investigate the components of black dirt. IR spectra of micro-FT-IR showed typical absorptions associated with amide compounds and protein, and the elements such as C, N, O, Na, Mg, Al, Si, P, S, K, and Ba were detected with SEM-XMA. These results showed that black dirt had living body ingredients. Furthermore, Exophiala sp. and Cladosporium sp. strains, which were observed at a high frequency, accumulated 2-hydroxyjuglone (2-HJ) and flaviolin as one of the intermediates in the melanin biosynthetic pathway by the addition of a melanin synthesis inhibitor (tricyclazole) at the time of cultivation. These results suggested strongly that the pigment of black dirt in toilet bowls was melanin produced by Exophiala sp. and Cladosporium sp. strains.


Assuntos
Bactérias/isolamento & purificação , Biota , Misturas Complexas/química , Microbiologia Ambiental , Fungos/isolamento & purificação , Utensílios Domésticos , Bactérias/classificação , Elementos Químicos , Fungos/classificação , Humanos , Microscopia Eletrônica de Varredura , Compostos Orgânicos/análise , Pigmentos Biológicos/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície
2.
Biocontrol Sci ; 18(3): 129-35, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24195153

RESUMO

To evaluate the sanitary conditions of toilets, the bacterial counts of the toilet bowl biofilms in 5 Kansai area and 11 Kansai and Kanto area homes in Japan were measured in winter and summer seasons, respectively. Isolates (128 strains) were identified by analyzing 16S ribosomal RNA sequences. The number of colonies and bacterial species from biofilms sampled in winter tended to be higher and lower, respectively, than those in summer. Moreover, the composition of bacterial communities in summer and winter samples differed considerably. In summer samples, biofilms in Kansai and Kanto areas were dominated by Blastomonas sp. and Mycobacterium sp., respectively. Methylobacterium sp. was detected in all toilet bowl biofilms except for one sample. Methylobacterium sp. constituted the major presence in biofilms along with Brevundimonas sp., Sphingomonas sp., and/or Pseudomonas sp. The composition ratio of the sum of their genera was 88.0 from 42.9% of the total bacterial flora. The biofilm formation abilities of 128 isolates were investigated, and results suggested that Methylobacterium sp. and Sphingomonas sp. were involved in biofilm formation in toilet bowls. The biofilm formation of a mixed bacteria system that included bacteria with the highest biofilm-forming ability in a winter sample was greater than mixture without such bacteria. This result suggests that isolates possessing a high biofilm-forming activity are involved in the biofilm formation in the actual toilet bowl. A bactericidal test against 25 strains indicated that the bactericidal activities of didecyldimethylammonium chloride (DDAC) tended to be higher than those of polyhexamethylene biguanide (PHMB) and N-benzyl-N,N-dimethyldodecylammonium chloride (ADBAC). In particular, DDAC showed high bactericidal activity against approximately 90% of tested strains under the 5 h treatment.


Assuntos
Bactérias/efeitos dos fármacos , Fenômenos Fisiológicos Bacterianos , Biofilmes/crescimento & desenvolvimento , Desinfetantes/farmacologia , Microbiologia Ambiental , Bactérias/isolamento & purificação , Biguanidas/farmacologia , Biota , Japão , Compostos de Amônio Quaternário/farmacologia , Estações do Ano
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