home Journal club New papers on Microbiology of the Built Environment, September 25, 2016

New papers on Microbiology of the Built Environment, September 25, 2016

Microbes and buildings

The Microbiome of Green Design: Sustainable building practices may have unforeseen consequences for microbial communities and human health – Carolyn Beans – BioScience ($40 for 1 day)

Damp buildings often invite mold
Damp buildings often invite mold

Just as our bodies teem with microbial life, so, too, do the homes, offices, schools, and other indoor spaces where we spend the majority of our lives. Scientists across the globe are now taking a closer look at the bacteria and fungi that live alongside us. They want to better understand whether indoor microbes affect our health and whether we–through the ways we design and live in buildings–shape their communities. Researchers in this emerging field known as the microbiome of the built environment come from varied backgrounds, including architecture; ecology; evolution; and heating, ventilation, and air-conditioning (HVAC) installation. But many of them share the same goal: to design buildings to encourage microbial ecosystems that benefit human health.

Self-healing cementitious materials based on bacteria and nutrients immobilized respectively – Huaicheng Chen – Construction and Building Materials ($39.95)

Schematic diagram for the self-healing cementitious material
Schematic diagram for the self-healing cementitious material

(…) This study presents a bio-restoration method to improve the self-healing effectiveness of the cement-based materials cracks rapidly. Ceramsite carrier was used to immobilize bacteria, while substrate and nutrients mixed evenly were immobilized into other original carrier. (…)  The area repair rate of section surface of the samples with bacteria and nutrients immobilized into ceramsite was run up to 87.5%. The flexural strength of specimens repaired could increase from 56% to 72% than other microbiological methods. SEM/EDS and XRD analysis results show that the precipitation formed in cracks is calcite.

Distribution and Diversity of Bacteria and Fungi Colonization in Stone Monuments Analyzed by High-Throughput Sequencing – Qiang Li – PLOS ONE (OA)

Sampling site locations.
Sampling site locations.

The historical and cultural heritage of Qingxing palace and Lingyin and Kaihua temple, located in Hangzhou of China, include a large number of exquisite Buddhist statues and ancient stone sculptures which date back to the Northern Song (960—1219 A.D.) and Qing dynasties (1636—1912 A.D.) and are considered to be some of the best examples of ancient stone sculpting techniques. (…). However, biodeterioration of the surface of the ancient Buddhist statues and white marble pillars not only severely impairs their aesthetic value but also alters their material structure and thermo-hygric properties. In this study, high-throughput sequencing was utilized to identify the microbial communities colonizing the stone monuments. The diversity and distribution of the microbial communities in six samples collected from three different environmental conditions with signs of deterioration were analyzed by means of bioinformatics software and diversity indices. (…)

Persistence analysis of poliovirus on three different types of fomites – Sushil Tamrakar – Journal of Applied Microbiology

Comparison of attenuation rate on different fomites from poliovirus
Comparison of attenuation rate on different fomites from poliovirus

The persistence of poliovirus over time was studied on three different fomite materials: steel, cotton, and plastic. Known concentrations of poliovirus type 1 were applied to the surface coupons in an indoor environment for various lengths of time. (…) While the preferred model varied by fomite type, the virus showed a rapid initial decay on all of the fomite types, followed by a transition to a more gradual decay after about 4 to 8 days. Estimates of the time for 99% reduction ranged from 81 hours for plastic to 143 hours for cotton. A 6 log reduction of recoverable infectivity of poliovirus did not occur during the 3 week duration of the experiment for any of the fomites. In protected indoor environments poliovirus can remain infective for weeks. The models identified by this study can be used in risk assessments to identify appropriate strategies for managing this risk.

Microbes in (or on their way to) the hospital

Drone Transport of Microbes in Blood and Sputum Laboratory Specimens – Timothy K. Amukele – Journal of Clinical Microbiology ($25 for 1 day)

Timeline and schematic for blood and sputum drone flights.
Timeline and schematic for blood and sputum drone flights.

Unmanned aerial vehicles (UAVs) could potentially be used to transport microbiological specimens. To examine the impact of UAVs on microbiological specimens, blood and sputum culture specimens were seeded with usual pathogens and flown in a UAV for 30 ± 2 min. Times to recovery, colony counts, morphologies, and matrix-assisted laser desorption ionization—time of flight mass spectrometry (MALDI-TOF MS)-based identifications of the flown and stationary specimens were similar for all microbes studied.

Surface Finish Materials: Considerations for the Neonatal Intensive Care Unit (NICU) – Debra Harris – Newborn and Infant Nursing Reviews ($31.50)

Baby at a Neonatal Intensive Care Unit. Source: Wikipedia
Baby at a Neonatal Intensive Care Unit. Source: Wikipedia

NICU surface material finishes require consideration to support the design of a healing environment benefitting the patients, families, and caregivers. The evidence from a growing body of research that focuses on the healthcare facility design influence on occupant outcomes suggests that material finishes for the NICU contribute to the clinical, operational and social dimensions of health outcomes. The main surface finishes in the NICU are the flooring, ceiling, walls, work surfaces, and upholstery. Appropriate specifications assure that materials are durable, cleanable, easy to disinfect, attractive, comfortable, minimize unwanted noise, and addresses safety concerns. (…)

How do antibiotic-resistant bacteria get into the environment? – Suzanne Young and Valerie Harwood – The Conversation

The sampling site, photo by Suzanne Young.
The sampling site, photo by Suzanne Young.

At the Harwood Lab at the University of South Florida, we study how resistant bacteria survive in the environment and the impact sewage entering recreational waters might have on human health. In fact, we found vancomycin resistant enterococci (VRE), one of the most common causes of hospital acquired infections, in water and sediment near St. Petersburg, Florida after a domestic sewer line break in September 2014.

Microbes in the stable

Reducing exposure to pathogens in the horse; A preliminary study into the survival of bacteria on a range of equine bedding types – Kelly Yarnell – Journal of Applied Microbiology ($6 to rent, $38 to own)

Mean (±SD) wet weight of each bedding type
Mean (±SD) wet weight of each bedding type

Aims: Compare the rate of growth of four microbial strains that cause disease in the equine, on four commonly used types of bedding. (Note EB: five types of bedding were tested). The moisture holding capacity of each bedding type was also tested. (…) Conclusions: Factors resulting in the inhibition of bacterial growth include the anti-bacterial effects reported in the Pinacea family and the physical properties of the bedding substrate.

Microbes on sensors underwater

Buzz Off! An Evaluation of Ultrasonic Acoustic Vibration for the Disruption of Marine Microorganisms on Sensor Housing Materials – Jonathan S. McQuillan – Letters in Applied Microbiology ($6 to rent, $38 to own)

Photographs of the ultrasonic anti-fouling testing apparatus.
Photographs of the ultrasonic anti-fouling testing apparatus.

Bio-fouling is a process of ecological succession which begins with the attachment and colonisation of microorganisms to a submerged surface. For marine sensors and their housings, bio-fouling can be one of the principle limitations to long-term deployment and reliability. Conventional anti-bio-fouling strategies using biocides can be hazardous to the environment, and therefore alternative chemical-free methods are preferred. In this study, custom made testing assemblies were used to evaluate ultrasonic vibration as an anti-bio-fouling process for marine sensor housing materials over a 28-day time course. (…)

Microbes and food production

The microbiota of marketed processed edible insects as revealed by high-throughput sequencing – Cristiana Garofalo – Food Microbiology ($39.95)

Relative abundance (%) of phyla present in edible insect samples.
Relative abundance (%) of phyla present in edible insect samples.

The aim of this study was to elucidate the microbial species occurring in some processed marketed edible insects, namely powdered small crickets, whole dried small crickets (Acheta domesticus), whole dried locusts (Locusta migratoria), and whole dried mealworm larvae (Tenebrio molitor), through culture-dependent (classical microbiological analyses) and -independent methods (pyrosequencing). A great bacterial diversity and variation among insects was seen. (…) The results of this study contribute to the elucidation of the microbiota associated with edible insects and encourage further studies aimed to evaluate the influence of rearing and processing conditions on that microbiota.

Microbes and pollution

Revealing the relationship between microbial community structure in natural biofilms and the pollution level in urban rivers: a case study in the Qinhuai River basin, Yangtze River Delta – Wei Cai – Water Science & Technology (behind paywall)

The course of the Yangtze River through China. Source: Wikipedia.
The course of the Yangtze River through China. Source: Wikipedia.

River pollution is one of the most challenging environmental issues, but the effect of river pollution levels on the biofilm communities has not been well-studied. Spatial and temporal distribution characteristics of environmental parameters and the biofilm communities were investigated in the Qinhuai River basin, Nanjing, China. Water samples were grouped into three clusters reflecting their varying pollution levels of relatively slight pollution, moderated pollution, and high pollution by hierarchical cluster analysis. In different clusters, the biofilm communities mainly differed in the proportion of Actinobacteria, Firmicutes, and Proteobacteria. (…)

Differential decomposition of bacterial and viral fecal indicators in common human pollution types – Pauline Wanjugi – Water Research

Graphical Abstract
Graphical Abstract

Understanding the decomposition of microorganisms associated with different human fecal pollution types is necessary for proper implementation of many water quality management practices, as well as predicting associated public health risks. Here, the decomposition of select cultivated and molecular indicators of fecal pollution originating from fresh human feces, septage, and primary effluent sewage in a subtropical marine environment was assessed over a six day period with an emphasis on the influence of ambient sunlight and indigenous microbiota. (…) A two-way analysis of variance of log10 reduction values for sewage and feces experiments indicated that treatments differentially impact survival of cultivated bacteria, cultivated phage, and genetic indicators. Findings suggest that sunlight is critical for phage decay, and indigenous microbiota play a lesser role. (…)

Attack of the plastic eaters: Can mushrooms, bacteria and mealworms save the planet from pollution? – Diane Stopyra – Salon

Credit: Getty/kotangens
Credit: Getty/kotangens

So the ocean and the planet are choked with plastic – what are we going to do about it? For students at Yale University in 2012, the “aha!” moment came in the Ecuadorian rainforest, during a study of mushrooms, or the visible flowers of a fungus web. (…) But the Yale study – and the mushroom-growing dome it inspired – created huge Internet buzz largely because “it’s a snazzy headline,” Melissa Duhaime, PhD, Assistant Research Scientist in Ecology and Evolutionary Biology with the University of Michigan, told Salon. “But as it happens right now, the rate is very slow, and it’s not a feasible pathway to answers for plastic pollution.”

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