New Papers on microbiology of the built environment, November 20, 2015

Lots of cool new papers to share. Unfortunately, many are behind paywalls.

Humans in hospitals

Towards an antimicrobial ‘microglove’ – Ewoud Reilman – Scientific Reports (OA)

Healthcare workers frequently experience difficulties in complying strictly to hand disinfection protocols. This study was therefore aimed at the development of a hand rub with antimicrobial activity that forms a protective film on the hand, a so-called microglove, in order to enhance hand hygiene. (…) a formulation of 80% PVP and 20% M20 co-polymer with 0.9% BKC fulfils the elementary requirements for an antimicrobial microglove.

Pets licking humans

DNA fingerprinting approaches to trace E. coli sharing between dogs and owners – Zahra Naziri – Journal of Applied Microbiology ($$) (no graphs, just a table)

Two fecal E. coli isolates from 25 healthy dog-owner pairs and 16 healthy control humans were tested using three fingerprinting methods. The prevalence of within-household sharing of E. coli was 4%, 8% and 8% using PFGE, RAPD and ERIC-PCR analyses, respectively. Within-household bacterial sharing was more prevalent than across-household sharing (P< 0.05). According to questionnaire analyses avoiding the dog-owner behaviors such as allowing a dog to kiss or lick the owner’s face, sharing people food with dog and feeding it raw meat may decrease the chance of cross-species E. coli sharing.

Microbes at home

Fungal compositions and diversities on indoor surfaces with visible mold growths in residential buildings in the Seoul Capital Area of South Korea – C. An and N. Yamamoto – Indoor Air ($$) (lots of pictures!)

Using swab sampling and high-throughput DNA sequencing, this study analyzed taxonomic compositions and diversities of fungi on indoor surfaces laden with visible mold growths in residential apartments in South Korea. Several allergy-related genera were detected on the same surface (…) Î² diversity analyses showed significant differences in the fungal communities between enclosed balconies and other indoor areas.

Characterization of Microbial Communities in Household Washing Machines – Ilka D. Nix – Tenside Surfactants Detergents ($$, no access even through Stanford)

Although microbial contaminations of domestic appliances are believed to gain importance, especially due to the trend towards lower cleaning temperatures, little is known about the existing microbial communities inside household washing machines. This study aimed to improve the knowledge of microbial composition of biofilms within household washing machines using a cultural-independent technology. Biofilms inside the detergent drawer and the rubber door seal of household washing machines were analysed using the 454-pyrosequencing method. The microbial community inside washing machines appeared to be highly diverse with Proteobacteria as the main prokaryotic and Basidiomycota and Ascomycota as the main fungal colonizers.

Men and Women Alter a Home’s Bacteria Differently – Mark Fischetti – Scientific American (OA)

Men shed more bacteria into their surroundings than women do, studies have shown. Now scientists have found that men and women have different effects on the variety of bacteria inside a home, too. The variation comes down to skin biology and “perhaps to body size and hygiene practices,” note researchers who sequenced the genes in dust that had settled on the tops of doors in 1,200 homes across the U.S. Dogs apparently alter indoor bacteria more extensively than humans or cats. The bacterial signatures of each of these living beings are unique enough that by simply testing dust in a home, investigators can accurately predict if more women or men live there and if dogs or cats do as well.

Microbiota formed on attached stainless steel coupons correlate with the natural biofilm of the sink surface in domestic kitchens – Birgitte Moen – Canadian Journal of Microbiology ($$, no access even through Stanford)

The microbiota of new stainless steel coupons attached to the sink wall for three months and sink wall surfaces in eight domestic kitchen sinks was investigated by next generation sequencing (MiSeq) of the 16S rRNA gene derived from DNA and RNA (cDNA), and by plating/identification of colonies. (…) The microbiota in the majority of biofilms was dominated by Moraxellaceae (genus Moraxella/Enhydrobacter) and Micrococcaceae (genus Kocuria). Results demonstrated that the variation in the microbiota was mainly due to differences between kitchens (38.2%) followed by the different nucleic acid template (DNA vs RNA) (10.8%), and that only 5.1% of the variation was a result of differences between coupons and sink surfaces.

Humans and soils

Glyphosate effects on soil rhizosphere-associated bacterial communities – Molli M. Newman – Science of the Total Environment (OA)

In this study, rhizosphere soil was sampled from rhizoboxes following 4 growth periods, and bacterial community composition was compared between glyphosate treated and untreated rhizospheres using next-generation barcoded sequencing. In the presence or absence of glyphosate, corn and soybean rhizospheres were dominated by members of the phyla Proteobacteria, Acidobacteria, and Actinobacteria. Proteobacteria (particularly gammaproteobacteria) increased in relative abundance for both crops following glyphosate exposure, and the relative abundance of Acidobacteria decreased in response to glyphosate exposure.

Coal mining practices reduce the microbial biomass, richness and diversity of soil – Patricia Dorr de Quadros – Applied Soil Ecology ($$)

The objectives of this study were to evaluate how the soil microbial community changes over time after mining and soil reconstruction at the largest coal mine in Latin America. (…) 42 samples were collected from the seven sites and the V4 region of the 16S rRNA gene was sequenced on the Illumina HiSeq platform. Reads were classified to identify 525 genera from Bacteria and Archaea domains. The composition of the microbial community of post-mined sites was significantly different from the undisturbed sites.

Effects of long-term radionuclide and heavy metal contamination on the activity of microbial communities, inhabiting uranium mining impacted soils – Silvena Boteva – Environmental Science and Pollution Research ($$)

The soil environments of two abandoned uranium mines were chosen to analyze the effects of long-term uranium and heavy metal contamination on soil microbial communities using dehydrogenase and phosphatase activities as indicators of metal stress. (…) The results showed an evidence of microbial tolerance and adaptation to the soil contamination established during the long-term metal exposure and the key role of soil organic matter in maintaining high microbial enzyme activities and mitigating the metal toxicity. Additionally, the results suggested that the soil microbial communities are able to reduce the metal stress by intensive phosphatase synthesis, benefiting a passive environmental remediation and provision of vital ecosystem services.

Down the drain

Seasonal Changes in Bacterial Communities Cause Foaming in a Wastewater Treatment Plant – Ping Wang – Microbial Ecology ($$)

Bio-foaming is a major problem in solid separation in activated sludge (AS) wastewater treatment systems. Understanding the changes in bacterial communities during sludge foaming is vital for explaining foam formation. Changes in bacterial communities in the foam, corresponding foaming AS, and non-foaming AS in a seasonal foaming wastewater treatment plant (WWTP) in Northern China were investigated by high-throughput pyrosequencing and molecular quantification-based approaches.