Quantitative filter forensics with residential HVAC filters to assess indoor concentrations.

Analysis of the dust from heating, ventilation, and air conditioning (HVAC) filters is a promising long-term sampling method to characterize airborne particle-bound contaminants. This filter forensics (FF) approach provides valuable insights about differences between buildings, but does not allow for an estimation of indoor concentrations. In this investigation, FF is extended to quantitative filter forensics (QFF) by using measurements of the volume of air that passes through the filter and the filter efficiency, to assess the integrated average airborne concentrations of total fungal and bacterial DNA, 36 fungal species, endotoxins, phthalates, and organophosphate esters (OPEs) based on dust extracted from HVAC filters. Filters were collected from 59 homes located in central Texas, USA, after 1 month of deployment in each summer and winter. Results showed considerable differences in the concentrations of airborne particle-bound contaminants in studied homes. The airborne concentrations for most of the analytes are comparable with those reported in the literature. In this sample of homes, the HVAC characterization measurements varied much less between homes than the variation in the filter dust concentration of each analyte, suggesting that even in the absence of HVAC data, FF can provide insight about concentration differences for homes with similar HVAC systems.

Study of the Relation between the Resonance Behavior of Thickness Shear Mode (TSM) Sensors and the Mechanical Characteristics of Biofilms.

This work analyzes some key aspects of the behavior of sensors based on piezoelectric Thickness Shear Mode (TSM) resonators to study and monitor microbial biofilms. The operation of these sensors is based on the analysis of their resonance properties (both resonance frequency and dissipation factor) that vary in contact with the analyzed sample. This work shows that different variations during the microorganism growth can be detected by the sensors and highlights which of these changes are indicative of biofilm formation. TSM sensors have been used to monitor in real time the development of Staphylococcus epidermidis and Escherichia coli biofilms, formed on the gold electrode of the quartz crystal resonators, without any coating. Strains with different ability to produce biofilm have been tested. It was shown that, once a first homogeneous adhesion of bacteria was produced on the substrate, the biofilm can be considered as a semi-infinite layer and the quartz sensor reflects only the viscoelastic properties of the region immediately adjacent to the resonator, not being sensitive to upper layers of the biofilm. The experiments allow the microrheological evaluation of the complex shear modulus (G* = G' + jG″) of the biofilm at 5 MHz and at 15 MHz, showing that the characteristic parameter that indicates the adhesion of a biofilm for the case of S. epidermidis and E. coli, is an increase in the resonance frequency shift of the quartz crystal sensor, which is connected with an increase of the real shear modulus, related to the elasticity or stiffness of the layer. In addition both the real and the imaginary shear modulus are frequency dependent at these high frequencies in biofilms.

Use of natural user interfaces for image navigation during laparoscopic surgery: initial experience.

BACKGROUND: Surgical environments require special aseptic conditions for direct interaction with the preoperative images. We aim to test the feasibility of using a set of gesture control sensors combined with voice control to interact in a sterile manner with preoperative information and an integrated operating room (OR) during laparoscopic surgery. MATERIAL AND METHODS: Two hepatectomies and two partial nephrectomies were performed by three experienced surgeons in a porcine model. The Kinect, Leap Motion, and MYO armband in combination with voice control were used as natural user interfaces (NUIs). After surgery, surgeons completed a questionnaire about their experience. RESULTS: Surgeons required <10 min training with each NUI. They stated that NUIs improved the access to preoperative patient information and kept them more focused on the surgical site. The Kinect system was reported as the most physically demanding NUI and the MYO armband in combination with voice commands as the most intuitive and accurate. The need to release one of the laparoscopic instruments in order to use the NUIs was identified as the main limitation. CONCLUSIONS: The presented NUIs are feasible to directly interact in a more intuitive and sterile manner with the preoperative images and the integrated OR functionalities during laparoscopic surgery.

Monochloramine Cometabolism by Mixed-Culture Nitrifiers under Drinking Water Conditions.

Chloramines are the second most used secondary disinfectant by United States water utilities. However, chloramination may promote nitrifying bacteria. Recently, monochloramine cometabolism by the pure culture ammonia-oxidizing bacteria, Nitrosomonas europaea, was shown to increase monochloramine demand. The current research investigated monochloramine cometabolism by nitrifying mixed cultures grown under more relevant drinking water conditions and harvested from sand-packed reactors before conducting suspended growth batch kinetic experiments. Four types of batch kinetic experiments were conducted: (1) positive controls to estimate ammonia kinetic parameters, (2) negative controls to account for biomass reactivity, (3) utilization associated product (UAP) controls to account for UAP reactivity, and (4) cometabolism experiments to estimate cometabolism kinetic parameters. Kinetic parameters were estimated in AQUASIM with a simultaneous fit to the experimental data. Cometabolism kinetics were best described by a first-order model. Monochloramine cometabolism kinetics were similar to those of ammonia metabolism, and monochloramine cometabolism accounted for 30% of the observed monochloramine loss. These results demonstrated that monochloramine cometabolism occurred in mixed cultures similar to those found in drinking water distribution systems; therefore, monochloramine cometabolism may be a significant contribution to monochloramine loss during nitrification episodes in drinking water distribution systems.

Delayed administration of allogeneic cardiac stem cell therapy for acute myocardial infarction could ameliorate adverse remodeling: experimental study in swine.

BACKGROUND: The optimal timing of cardiac stem cells administration is still unclear. We assessed the safety of same-day and delayed (one week) delivery and the possible influence of the timing on the therapeutic outcomes of allogeneic porcine cardiac stem cells administration after acute myocardial infarction in a closed-chest ischemia-reperfusion model. METHODS: Female swine surviving 90 min occlusion of the mid left anterior descending coronary artery received an intracoronary injection of 25x10(6) porcine cardiac stem cells either two hours (n = 5, D0) or 7 days (n = 6, D7) after reperfusion. Controls received intracoronary injection of vehicle on day 7 (n = 6, CON). Safety was defined in terms of absence of major cardiac events, changes to the ECG during injection, post-administration coronary flow assessed using the TIMI scale and cardiac troponin I determination after the intervention. Cardiac Magnetic Resonance was performed for morphological and functional assessment prior to infarction, before injection (D7 and CON groups only), at one and 10 weeks. Samples were taken from the infarct and transition areas for pathological examination. RESULTS: No major adverse cardiac events were seen during injection in any group. Animals receiving the therapy on the same day of infarction (D0 group) showed mild transient ST changes during injection (n = 4) and, in one case, slightly compromised coronary flow (TIMI 2). Cardiac function parameters and infarct sizes were not significantly different between groups, with a trend towards higher ejection fraction in the treated groups. Ventricular volumes indexed to body surface area increased over time in control animals, and decreased by the end of the study in animals receiving the therapy, significantly so when comparing End Diastolic Volume between CON and D7 groups (CON: 121.70 ml/m(2) ± 26.09 ml/m(2), D7: 98.71 ml/m(2) ± 8.30 ml/m(2), p = 0.037). The treated groups showed less organization of the collagenous scar, and a significantly (p = 0.019) higher amount of larger, more mature vessels at the infarct border. CONCLUSIONS: The intracoronary injection of 25x10(6) allogeneic cardiac stem cells is generally safe, both early and 7 days after experimental infarction, and alleviates myocardial dysfunction, with a greater limitation of left ventricular remodeling when performed at one week.

In vitro interference of tigecycline at subinhibitory concentrations on biofilm development by Enterococcus faecalis.

OBJECTIVES: Since biofilm formation is the hallmark of Enterococcus faecalis isolates, the aim of this study was to quantify biofilm formation in the presence of subinhibitory concentrations of tigecycline. METHODS: Interference of tigecycline on biofilm formation was spectrophotometrically quantified using 20 biofilm-producing E. faecalis isolates with tigecycline MICs of 0.12 (8 strains) or 0.25 mg/L (12 strains). Biofilm production was measured in antibiotic-free tryptic soy broth supplemented with 1% glucose and compared with biofilm production in the same medium with tigecycline at subinhibitory concentrations (0.25× or 0.5× MIC, similar to trough concentrations in serum or concentrations in the colon after a standard dose) by reading the optical density at 450 nm (OD(450)) after staining with Crystal Violet. RESULTS: In the presence of subinhibitory tigecycline concentrations, pooled OD(450) values for the 20 strains [median (IQR)] were significantly lower than those for controls: 0.468 (0.379-0.516) for antibiotic-free controls versus 0.295 (0.200-0.395) for 0.25× MIC tigecycline (P < 0.001) and 0.287 (0.245-0.479) for 0.5× MIC tigecycline (P < 0.001), with significant differences between pooled OD(450) values obtained with each concentration of tigecycline (P = 0.022). In 17 out of 20 (85%) strains the OD(450) obtained with 0.25× MIC tigecycline was significantly (P < 0.05) lower than the basal OD(450), while this occurred in 12 out of 20 (60%) strains with 0.5× MIC. CONCLUSIONS: In vitro tigecycline subinhibitory concentrations were able to interfere with biofilm formation by E. faecalis.

Correlation between clinical parameters characterising peri-implant and periodontal health: a practice-based research in Spain in a series of patients with implants installed 4-5 years ago.

OBJECTIVES: To explore peri-implant health (and relation with periodontal status) 4-5 years after implant insertion. STUDY DESIGN: A practice-based dental research network multicentre study was performed in 11 Spanish centres. The first patient/month with implant insertion in 2004 was considered. Per patient four teeth (one per quadrant) showing the highest bone loss in the 2004 panoramic X-ray were selected for periodontal status assessment. Bone losses in implants were calculated as the differences between 2004 and 2009 bone levels in radiographs. RESULTS: A total of 117 patients were included. Of the 408 teeth considered, 73 (17.9%) were lost in 2009 (losing risk: >50% for bone losses ≥7 mm). A total of 295 implants were reviewed. Eight of 117 (6.8%) patients had lost implants (13 of 295 implants installed; 4.4%). Implant loss rate (quadrant status) was 1.4% (edentulous), 3.6% (preserved teeth), and 11.1% (lost teeth) (p=0.037). The percentage of implant loss significantly (p<0.001) increased when the medial/distal bone loss was ≥3 mm. The highest (p≤0.001) pocket depths were found in teeth with ≥5 mm and implants with ≥3 mm bone losses, with similar mean values (≥4 mm), associated with higher rates of plaque index and bleeding by probing. CONCLUSIONS: The significant bi-directional relation between plaque and bone loss, and between each of these two parameters/signs and pocket depths or bleeding (both in teeth and implants, and between them) together with the higher percentage of implants lost when the bone loss of the associated teeth was ≥3 mm suggest that the patient's periodontal status is a critical issue in predicting implant health/lesion.

Monitoring COVID-19 through SARS-CoV-2 quantification in wastewater: progress, challenges and prospects.

Wastewater-Based Epidemiology (WBE) is widely used to monitor the progression of the current SARS-CoV-2 pandemic at local levels. In this review, we address the different approaches to the steps needed for this surveillance: sampling wastewaters (WWs), concentrating the virus from the samples and quantifying them by qPCR, focusing on the main limitations of the methodologies used. Factors that can influence SARS-CoV-2 monitoring in WWs include: (i) physical parameters as temperature that can hamper the detection in warm seasons and tropical regions, (ii) sampling methodologies and timetables, being composite samples and Moore swabs the less variable and more sensitive approaches, (iii) virus concentration methodologies that need to be feasible and practicable in simpler laboratories and (iv) detection methodologies that should tend to use faster and cost-effective procedures. The efficiency of WW treatments and the use of WWs for SARS-CoV-2 variants detection are also addressed. Furthermore, we discuss the need for the development of common standardized protocols, although these must be versatile enough to comprise variations among target communities. WBE screening of risk populations will allow for the prediction of future outbreaks, thus alerting authorities to implement early action measurements.

Hurricane María drives increased indoor proliferation of filamentous fungi in San Juan, Puerto Rico: a two-year culture-based approach.

Extensive flooding caused by Hurricane María in Puerto Rico (PR) created favorable conditions for indoor growth of filamentous fungi. These conditions represent a public health concern as contamination by environmental fungi is associated with a higher prevalence of inflammatory respiratory conditions. This work compares culturable fungal spore communities present in homes that sustained water damage after Hurricane María to those present in dry, non-flooded homes. We collected air samples from 50 houses in a neighborhood in San Juan, PR, 12 and 22 months after Hurricane María. Self-reported data was used to classify the homes as flooded, water-damage or dry non-flooded. Fungi abundances, composition and diversity were analyzed by culturing on two media. Our results showed no significant differences in indoor fungal concentrations (CFU/m3) one year after the Hurricane in both culture media studied (MEA and G25N). During the second sampling period fungal levels were 2.7 times higher in previously flooded homes (Median = 758) when compared to dry homes (Median = 283), (p-value < 0.005). Fungal profiles showed enrichment of Aspergillus species inside flooded homes compared to outdoor samples during the first sampling period (FDR-adjusted p-value = 0.05). In contrast, 22 months after the storm, indoor fungal composition consisted primarily of non-sporulated fungi, most likely basidiospores, which are characteristic of the outdoor air in PR. Together, this data highlights that homes that suffered water damage not only have higher indoor proliferation of filamentous fungi, but their indoor fungal populations change over time following the Hurricane. Ultimately, after nearly two years, indoor and outdoor fungal communities converged in this sample of naturally ventilated homes.

Novel strategy for microsphere-mediated DNA transfection.

A new approach for microsphere-mediated delivery of plasmid DNA has been developed and successfully evaluated. Basic molecular biology techniques were used to linearize and functionalize plasmid DNA by aminomodification, enabling efficient conjugation to carboxy-functionalized microspheres. A T cell hybridoma line was successfully transfected as determined by the efficient expression of a biologically relevant YFP fusion protein. Moreover, our data identified microsphere-mediated delivery of plasmid DNA as a noninvasive, nontoxic, and efficient gene delivery method with the potential to be applied to transfection-resistant, nondividing primary cells, including naïve T cells.

Efficient solid phase strategy for preparation of modified xanthene dyes for biolabelling.

An efficient solid phase strategy for the versatile functionalisation of xanthene dyes for conjugation and labelling of biomolecules is presented. The low cost, high purity and excellent spectral properties of the obtained materials provide an attractive alternative for the labelling of a wide range of molecules.

Development of a reproducible method for monitoring SARS-CoV-2 in wastewater.

Monitoring the genetic signal of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through RNA titers in wastewater has emerged as a promising strategy for tracking community-scale prevalence of coronavirus disease 2019 (COVID-19). Although many studies of SARS-CoV-2 in wastewater have been conducted around the world, a uniform procedure for concentrating the virus in wastewater is lacking. The goal of this study was to comprehensively evaluate how different methods for concentrating the suspended solids in wastewater affect the associated SARS-CoV-2 RNA signal and the time required for processing samples for wastewater-based epidemiology efforts. We additionally consider the effects of sampling location in the wastewater treatment train (i.e., following preliminary or primary treatment), pasteurization, and RNA extraction method. Comparison of the liquid phase to suspended solids obtained via centrifugation or vacuum filtration suggests that the RNA signal of SARS-CoV-2 preferentially occurs in the solids. Therefore, we assert that the recovery of SARS-CoV-2 from wastewater should focus on suspended solids. Our data indicate that the measured SARS-CoV-2 signal is higher among samples taken from the primary clarifier effluent, as opposed to those taken after preliminary treatment. Additionally, we provide evidence that sample pasteurization at 60 °C for 90 min reduces the SARS-CoV-2 signal by approximately 50-55%. Finally, the results indicate that a magnetic bead approach to RNA extraction leads to a higher SARS-CoV-2 signal than does a silica membrane approach.

Distribution of SARS-CoV-2 RNA signal in a home with COVID-19 positive occupants.

Although many COVID-19 patients isolate and recover at home, the dispersal of SARS-CoV-2 onto surfaces and dust within the home environment remains poorly understood. To investigate the distribution and persistence of SARS-CoV-2 in a home with COVID-19 positive occupants, samples were collected from a household with two confirmed COVID-19 cases (one adult and one child). Home surface swab and dust samples were collected two months after symptom onset (and one month after symptom resolution) in the household. The strength of the SARS-CoV-2 molecular signal in fomites varied as a function of sample location, surface material and cleaning practices. Notably, the SARS-CoV-2 RNA signal was detected at several locations throughout the household although cleaning appears to have attenuated the signal on many surfaces. Of the 24 surfaces sampled, 46% were SARS-CoV-2 positive at the time of sampling. The SARS-CoV-2 concentrations in dust recovered from floor and HVAC filter samples ranged from 104 to 105 N2 gene copies/g dust. While detection of viral RNA does not imply infectivity, this study confirms that the SARS-CoV-2 RNA signal can be detected at several locations within a COVID-19 isolation home and can persist after symptoms have resolved. In addition, the concentration of SARS-CoV-2 (normalized per unit mass of dust) recovered in home HVAC filters may prove useful for estimating SARS-CoV-2 airborne levels in homes. In this work, using the quantitative filter forensics methodology, we estimated an average integrated airborne SARS-CoV-2 concentration of 69 ± 43 copies/m3. This approach can be used to help building scientists and engineers develop best practices in homes with COVID-19 positive occupants.

The epicardial delivery of cardiosphere derived cells or their extracellular vesicles is safe but of limited value in experimental infarction.

The epicardial administration of therapeutics via the pericardial sac offers an attractive route, since it is minimally invasive and carries no risks of coronary embolization. The aim of this study was to assess viability, safety and effectiveness of cardiosphere-derived cells (CDCs), their extracellular vesicles (EVs) or placebo administered via a mini-thoracotomy 72 h after experimental infarction in swine. The epicardial administration was completed successfully in all cases in a surgery time (knife-to-skin) below 30 min. No significant differences between groups were found in cardiac function parameters evaluated using magnetic resonance imaging before therapy and at the end of the study, despite a trend towards improved function in CDC-treated animals. Moreover, infarct size at 10 weeks was smaller in treated animals, albeit not significantly. Arrhythmia inducibility did not differ between groups. Pathological examination showed no differences, nor were there any pericardial adhesions evidenced in any case 10 weeks after surgery. These results show that the epicardial delivery of CDCs or their EVs is safe and technically easy 3 days after experimental myocardial infarction in swine, but it does not appear to have any beneficial effect on cardiac function. Our results do not support clinical translation of these therapies as implemented in this work.

Supersaturated-oxygen aeration effects on a high-loaded membrane bioreactor (HL-MBR): Biological performance and microbial population dynamics.

Conventional diffused aeration systems (such as fine-bubble diffusers) exhibit a poor oxygen transfer in wastewater treatment plants (WWTPs), particularly when operating at sludge concentrations higher than 15 g L-1. The supersaturated dissolved oxygen (SDOX) system has been proposed as an alternative for supplying dissolved oxygen (DO) at high mixed liquor suspended solids (MLSS) concentrations. The advantages introduced by such technology include the possibility of operating WWTPs at much higher than usual MLSS concentrations, increasing the treatment capacity of WWTPs. Recent studies have demonstrated that the SDOX system has higher oxygen transfer rates (OTRs) and oxygen transfer efficiencies (OTEs) relative to fine-bubble diffusers. However, it is unknown if the high-pressure conditions introduced by SDOX may possibly impact the biological performance of WWTPs. In this study, the effects of SDOX technology on the biological performance of a membrane bioreactor (MBR) were evaluated. The MBR was operated at an MLSS concentration of approximately 15 g L-1 in four phases as follows: (P1) with bubble diffusers, (P2) with an SDOX unit, (P3) with the bubble diffusers, and (P4) with the SDOX unit. The performance of the MBR was assessed by monitoring the sludge concentration, as well as changes in the particle size distribution (PSD), sludge activity, organic matter removal and nitrification performance, and changes in the microbial community within the MBR. The operational conditions exerted by the SDOX technology did not affect the concentration of active biomass during the study period. The biological performance of the MBR was not affected by the introduction of the SDOX technology. Finally, the microbial community was relatively stable although some variations at the family and genus level were evident during each of the study phases. Therefore, the SDOX system can be proposed as an alternative technology for DO supply in WWTPs increasing the overall treatment capacity.

Multi-modal data collection for measuring health, behavior, and living environment of large-scale participant cohorts.

BACKGROUND: As mobile technologies become ever more sensor-rich, portable, and ubiquitous, data captured by smart devices are lending rich insights into users' daily lives with unprecedented comprehensiveness and ecological validity. A number of human-subject studies have been conducted to examine the use of mobile sensing to uncover individual behavioral patterns and health outcomes, yet minimal attention has been placed on measuring living environments together with other human-centered sensing data. Moreover, the participant sample size in most existing studies falls well below a few hundred, leaving questions open about the reliability of findings on the relations between mobile sensing signals and human outcomes. RESULTS: To address these limitations, we developed a home environment sensor kit for continuous indoor air quality tracking and deployed it in conjunction with smartphones, Fitbits, and ecological momentary assessments in a cohort study of up to 1,584 college student participants per data type for 3 weeks. We propose a conceptual framework that systematically organizes human-centric data modalities by their temporal coverage and spatial freedom. Then we report our study procedure, technologies and methods deployed, and descriptive statistics of the collected data that reflect the participants' mood, sleep, behavior, and living environment. CONCLUSIONS: We were able to collect from a large participant cohort satisfactorily complete multi-modal sensing and survey data in terms of both data continuity and participant adherence. Our novel data and conceptual development provide important guidance for data collection and hypothesis generation in future human-centered sensing studies.

Long-term ammonia removal in a coconut fiber-packed biofilter: analysis of N fractionation and reactor performance under steady-state and transient conditions.

A comprehensive study of long-term ammonia removal in a biofilter packed with coconut fiber is presented under both steady-state and transient conditions. Low and high ammonia loads were applied to the reactor by varying the inlet ammonia concentration from 90 to 260 ppm(v) and gas contact times ranging from 20 to 36 s. Gas samples and leachate measurements were periodically analyzed and used for characterizing biofilter performance in terms of removal efficiency (RE) and elimination capacity (EC). Also, N fractions in the leachate were quantified to both identify the experimental rates of nitritation and nitratation and to determine the N leachate distribution. Results showed stratification in the biofilter activity and, thus, most of the NH(3) removal was performed in the lower part of the reactor. An average EC of 0.5 kg N-NH(3)m(-3)d(-1) was obtained for the whole reactor with a maximum local average EC of 1.7 kg N-NH(3)m(-3)d(-1). Leachate analyses showed that a ratio of 1:1 of ammonium and nitrate ions in the leachate was obtained throughout steady-state operation at low ammonia loads with similar values for nitritation and nitratation rates. Low nitratation rates during high ammonia load periods occurred because large amounts of ammonium and nitrite accumulated in the packed bed, thus causing inhibition episodes on nitrite-oxidizing bacteria due to free ammonia accumulation. Mass balances showed that 50% of the ammonia fed to the reactor was oxidized to either nitrite or nitrate and the rest was recovered as ammonium indicating that sorption processes play a fundamental role in the treatment of ammonia by biofiltration.

Characterization of the bacterial community in a biotrickling filter treating high loads of H(2)S by molecular biology tools.

The diversity and spatial distribution of bacteria in a lab-scale biotrickling filter treating high loads of hydrogen sulfide (H(2)S) were investigated. Diversity and community structure were studied by terminal-restriction fragment length polymorphism (T-RFLP). A 16S rRNA gene clone library was established. Near Full-length 16S rRNA gene sequences were obtained, and clones were clustered into 24 operational taxonomic units (OTUs). Nearly 74% and 26% of the clones were affiliated with the phyla Proteobacteria and Bacteroidetes, respectively. Beta-, epsilon- and gamma-proteobacteria accounted for 15, 9 and 48%, respectively. Around 45% of the sequences retrieved were affiliated to bacteria of the sulfur cycle including Thiothrix spp., Thiobacillus spp. and Sulfurimonas denitrificans. Sequences related to Thiothrix lacustris accounted for a 38%. Rarefaction curve demonstrated that clone library constructed can be sufficient to describe the vast majority of the bacterial diversity of this reactor operating under strict conditions (2,000 ppm(v) of H(2)S). A spatial distribution of bacteria was found along the length of the reactor by means of the T-RFLP technique. Although aerobic species were predominant along the reactor, facultative anaerobes had a major relative abundance in the inlet part of the reactor, where the sulfide to oxygen ratio is higher.

An examination of the microbial community and occurrence of potential human pathogens in rainwater harvested from different roofing materials.

While harvested rainwater can serve as an alternative water supply, microbial contaminants within the collection system can negatively affect water quality. Here, we investigated the impact of roofing material on the microbial quality of rainwater freshly harvested from pilot-scale roofs (concrete tile, cool, green, Galvalume® metal, and asphalt fiberglass shingle). The microbial quality of freshly harvested rainwater from six rain events over two years was analyzed by high-throughput sequencing and culture-dependent and -independent techniques. The concentrations of total coliform were significantly different among rainwaters harvested from the various roofing materials (p-value >0.05). However, the fecal coliform concentrations and the copy numbers of Enterococcus 23S rRNA genes and total Bacteria 16S rRNA genes did not vary by type of roofing material in a statistically significant way. Potential human pathogens such as Legionella, Escherichia coli O157:H7, Shiga-toxin-producing Escherichia coli, and adenovirus were detected at least once in rainwater harvested from the different roofing materials, even though the lowest occurrence of those potential human pathogens was noted from the metal roof. Also, substantial variation in the microbial communities from the different roofing materials was observed at the family and genus levels. These results demonstrate that the type of roofing material affects the microbial quality of freshly harvested rainwater, indicating that the choice of roofing material could shape the microbial community structure entering a rainwater storage tank. Given that detection of potential pathogens in the freshly harvested rainwater also differed between roofing materials, the type of roofing used to capture rainwater needs to be considered in rainwater harvesting system design, particularly if the water is intended for potable use.

Longitudinal homogenization of the microbiome between both occupants and the built environment in a cohort of United States Air Force Cadets.

BACKGROUND: The microbiome of the built environment has important implications for human health and wellbeing; however, bidirectional exchange of microbes between occupants and surfaces can be confounded by lifestyle, architecture, and external environmental exposures. Here, we present a longitudinal study of United States Air Force Academy cadets (n = 34), which have substantial homogeneity in lifestyle, diet, and age, all factors that influence the human microbiome. We characterized bacterial communities associated with (1) skin and gut samples from roommate pairs, (2) four built environment sample locations inside the pairs' dormitory rooms, (3) four built environment sample locations within shared spaces in the dormitory, and (4) room-matched outdoor samples from the window ledge of their rooms. RESULTS: We analyzed 2,170 samples, which generated 21,866 unique amplicon sequence variants. Linear convergence of microbial composition and structure was observed between an occupants' skin and the dormitory surfaces that were only used by that occupant (i.e., desk). Conversely, bacterial community beta diversity (weighted Unifrac) convergence between the skin of both roommates and the shared dormitory floor between the two cadet's beds was not seen across the entire study population. The sampling period included two semester breaks in which the occupants vacated their rooms; upon their return, the beta diversity similarity between their skin and the surfaces had significantly decreased compared to before the break (p < 0.05). There was no apparent convergence between the gut and building microbiota, with the exception of communal bathroom door-handles, which suggests that neither co-occupancy, diet, or lifestyle homogenization had a significant impact on gut microbiome similarity between these cadets over the observed time frame. As a result, predictive classifier models were able to identify an individual more accurately based on the gut microbiota (74%) compared to skin (51%). CONCLUSIONS: To the best of our knowledge, this is the first study to show an increase in skin microbial similarity of two individuals who start living together for the first time and who are not genetically related or romantically involved. Cohabitation was significantly associated with increased skin microbiota similarity but did not significantly influence the gut microbiota. Following a departure from the occupied space of several weeks, the skin microbiota, but not the gut microbiota, showed a significant reduction in similarity relative to the building. Overall, longitudinal observation of these dynamics enables us to dissect the influence of occupation, diet, and lifestyle factors on occupant and built environment microbial ecology.