A comprehensive survey of microbial flora within pink biofilms in bathrooms was performed. Pink biofilms develop relatively rapidly in bathrooms, can be difficult to remove, and are quick to recur. Bacterium-sized cells were found to be predominant in 42 pink biofilms in Japan using a scanning electron microscope. Methylobacterium strains were detected from all samples in bathrooms by an isolation method. To explain this predominance, 14 biofilm samples were analyzed by fluorescence in situ hybridization. Methylobacterium was indicated to be the major genus in all biofilms. The isolated Methylobacterium survived after contact with 1.0% cleaning agents, including benzalkonium chloride for 24 h. Their tolerance did not differ under biofilm-like conditions on fiber reinforced plastics (FRP), a general material of bath tubs, floors, and walls. Also, the strains exhibited higher tolerance to desiccation than other isolated species on FRP. Some Methylobacterium survived and exhibited potential to grow after four weeks of desiccation without any nutrients. These specific characteristics could be a cause of their predominance in bathrooms, an environment with rapid flowing water, drying, low nutrients, and occasional exposure to cleaning agents.

bThe genus Methylobacterium tolerates hygiene agents like benzalkonium chloride (BAC), and infection with this organism is an important public health issue. Here, we found that the combination of BAC with particular alcohols at nonlethal concentrations in terms of their solitary uses significantly reduced bacterial viability after only 5 min of exposure. Among the alcohols, Raman spectroscopic analyses showed that pentanol (pentyl alcohol [PeA]) and benzyl alcohol (BzA) accelerated the cellular accumulation of BAC. Fluorescence spectroscopic assays and morphological assays with giant vesicles indicated that PeA rarely attacked membrane structures, while BzA increased the membrane fluidity and destabilized the structures. Other fluorescent spectroscopic assays indicated that PeA and BzA inactivate bacterial membrane proteins, including an efflux pump for BAC transportation. These findings suggested that the inactivation of membrane proteins by PeA and BzA led to the cellular accumulation but that only BzA also enhanced BAC penetration by membrane fluidization at nonlethal concentrations.

Towels differ remarkably from other textile products in their fibre structure and usage, and microbial behaviours on towels remain underexplored. Thus, we evaluated biofilm formation on towels during use for 6 months in daily life and analysed its relationship with odour, dullness, and laundry habits. The towels exhibited odour and dullness after 2 months of use and biofilm structures were observed over the 6 months, especially in the ground warp part. Polysaccharides, proteins, nucleic acids, and viable counts on the towels increased over time. The microbiota was significantly different from that on human skin and clothing. Several species of Alphaproteobacteria were correlated with dullness intensity and the quantity of biofilm components. Therefore, bacterial species that specifically adapt to the towel fibre environment could form biofilms. Our results demonstrate bacterial diversity in textile products and suggest careful consideration of the textile fibre material, structure, and usage pattern to control bacterial communities.

Towels differ remarkably from other textile products in their fibre structure and usage, and microbial behaviours on towels remain underexplored. Thus, we evaluated biofilm formation on towels during use for 6 months in daily life and analysed its relationship with odour, dullness, and laundry habits. The towels exhibited odour and dullness after 2 months of use and biofilm structures were observed over the 6 months, especially in the ground warp part. Polysaccharides, proteins, nucleic acids, and viable counts on the towels increased over time. The microbiota was significantly different from that on human skin and clothing. Several species of Alphaproteobacteria were correlated with dullness intensity and the quantity of biofilm components. Therefore, bacterial species that specifically adapt to the towel fibre environment could form biofilms. Our results demonstrate bacterial diversity in textile products and suggest careful consideration of the textile fibre material, structure, and usage pattern to control bacterial communities.

Correlation betu,een the green (FAM) and red (TMRA) fiuorescence intensities wil] reveal an infiuence of the discreteness on the molecular computing reactions. [1]