Microbial aerosol liberation from soiled textiles isolated during routine residuals handling in a modern health care setting

A Molecular Approach for Detecting Bacteria and Fungi in Healthcare Environment Aerosols: A Systematic Review

Molecular methods have become integral to microbiological research for microbial identification. This literature review focuses on the application of molecular methods in examining airborne bacteria and fungi in healthcare facilities. In January 2024, a comprehensive electronic search was carried out in esteemed databases including PubMed, Web of Science, and Scopus, employing carefully selected keywords such as ((bacteria) OR (virus) OR (fungi)) AND (aerosol) AND ((hospital) OR (healthcare) OR (dental office)) AND ((molecular) OR (PCR) OR (NGS) OR (RNA) OR (DNA) OR (metagenomic) OR (microarray)), following the PRISMA protocol. The review specifically targets healthcare environments with elevated concentrations of pathogenic bacteria. A total of 487 articles were initially identified, but only 13 met the inclusion criteria and were included in the review. The study disclosed that the prevalent molecular methodology for appraising aerosol quality encompassed the utilization of the PCR method, incorporating either 16S rRNA (bacteria) or 18S rRNA (fungi) amplification techniques. Notably, five diverse molecular techniques, specifically PFGE, DGGE, SBT, LAMP, and DNA hybridization methods, were implemented in five distinct studies. These molecular tests exhibited superior capabilities compared to traditional bacterial and fungal cultures, providing precise strain identification. Additionally, the molecular methods allowed the detection of gene sequences associated with antibiotic resistance. In conclusion, molecular testing offers significant advantages over classical microbiological culture, providing more comprehensive information.

Potential airborne human pathogens: A relevant inhabitant in built environments but not considered in indoor air quality standards

Potential airborne human pathogens (PAHPs) may be a relevant component of the air microbiome in built environments. Despite that PAHPs can cause infections, particularly in immunosuppressed patients at medical centers, they are scarcely considered in standards of indoor air quality (IAQ) worldwide. Here, we reviewed the current information on microbial aerosols (bacteria, fungal and viruses) and PAHPs in different types of built environments (e.g., medical center, industrial and non-industrial), including the main factors involved in their dispersion, the methodologies used in their study and their associated biological risks. Our analysis identified the human occupancy and ventilation systems as the primary sources of dispersal of microbial aerosols indoors. We also observed temperature and relative humidity as relevant physicochemical factors regulating the dispersion and viability of some PAHPs. Our analysis revealed that some PAHPs can survive and coexist in different environments while other PAHPs are limited or specific for an environment. In relation to the methodologies (conventional or molecular) the nature of PAHPs and sampling type are pivotal. In this context, indoors air-borne viruses are the less studies because their small size, environmental lability, and absence of efficient sampling techniques and universal molecular markers for their study. Finally, it is noteworthy that PAHPs are not commonly considered and included in IAQ standards worldwide, and when they are included, the total abundance is the single parameter considered and biological risks is excluded. Therefore, we propose a revision, design and establishment of public health policies, regulations and IAQ standards, considering the interactions of diverse factors, such as nature of PAHPs, human occupancy and type of built environments where they develop.

Assessment of indoor bioaerosol exposure using direct-reading versus traditional methods-potential application to home health care

Home healthcare workers (HHCWs) can be occupationally exposed to bioaerosols in their clients' homes. However, choosing the appropriate method to measure bioaerosol exposures remains a challenge. Therefore, a systematic comparison of existing measurement approaches is essential. Bioaerosol measurements with a real-time, fluorescence-based Wideband Integrated Bioaerosol Sensor (WIBS) were compared to measurements with four traditional off-line methods (TOLMs). The TOLMS included optical microscopic counting of spore trap samples, microbial cultivation of impactor samples, qPCR, and next-generation sequencing (NGS) of filter samples. Measurements were conducted in an occupied apartment simulating the environments that HHCWs could encounter in their patients' homes. Descriptive statistics and Spearman's correlation test were computed to compare the real-time measurement with those of each TOLM. The results showed that the geometric mean number concentrations of the total fluorescent aerosol particles (TFAPs) detected with the WIBS were several orders of magnitude higher than those of total fungi or bacteria measured with the TOLMs. Among the TOLMs, concentrations obtained with qPCR and NGS were the closest to the WIBS detections. Correlations between the results obtained with the WIBS and TOLMs were not consistent. No correlation was found between the concentrations of fungi detected using microscopic counting and any of the WIBS fluorescent aerosol particle (FAP) types, either indoors or outdoors. In contrast, the total concentrations detected with microbial cultivation correlated with the WIBS TFAP results, both indoors and outdoors. Outdoors, the total concentration of culturable bacteria correlated with FAP-type AC. In addition, fungal and bacterial concentrations obtained with qPCR correlated with FAP types AB and AC. For a continuous, high-time resolution but broad scope, the real-time WIBS could be considered, whereas a TOLM would be the best choice for specific and more accurate microbial characterization. HHCWs' activities tend to re-aerosolize bioaerosols causing wide temporal variation in bioparticle concentrations. Thus, the advantage of using the real-time instrument is to capture those variations. This study lays a foundation for future exposure assessment studies targeting HHCWs.

Impact of antibacterial detergent on used-towel microbiomes at species-level and its effect on malodor control

The impact of antibacterial detergent on microbial exchanges and its subsequent effect on malodor in used towels were examined. Homogenization of microbiome among postwashed and indoor dried towels that was dominated by known malodor-producing bacteria. The microbial exchange was attenuated, and the abundance of malodor-producing bacteria was reduced in towels laundered with antibacterial detergent. Reduction of malodorous volatile organic compounds produced from towels laundered with antibacterial detergent.

Potential sources of contamination on textiles and hard surfaces identified as high-touch sites near the patient environment

The hospital environment represents an important mediator for the transmission of healthcare-associated infections through direct and indirect hand contact with hard surfaces and textiles. In this study, bacteria on high-touch sites, including textiles and hard surfaces in two care wards in Sweden, were identified using microbiological culture methods and 16S rDNA sequencing. During a cross-sectional study, 176 high-touch hard surfaces and textiles were identified and further analysed using microbiological culture for quantification of total aerobic bacteria, Staphylococcus aureus, Clostridium difficile and Enterobacteriacae. The bacterial population structures were further analysed in 26 samples using 16S rDNA sequencing. The study showed a higher frequency of unique direct hand-textile contacts (36 per hour), compared to hard surfaces (2.2 per hour). Hard surfaces met the recommended standard of ≤ 5 CFU/cm2 for aerobic bacteria and ≤ 1 CFU/cm2 for S. aureus (53% and 35%, respectively) to a higher extent compared to textiles (19% and 30%, respectively) (P = 0.0488). The number of bacterial genera was higher on textiles than on the hard surfaces. Staphylococcus (30.4%) and Corynebacterium (10.9%) were the most representative genera for textiles and Streptococcus (13.3%) for hard surfaces. The fact that a big percentage of the textiles did not fulfil the criteria for cleanliness, combined with the higher bacterial diversity, compared to hard surfaces, are indicators that textiles were bacterial reservoirs and potential risk vectors for bacterial transmission. However, since most of the bacteria found in the study belonged to the normal flora, it was not possible to draw conclusions of textiles and hard surfaces as sources of healthcare associated infections.

Fluorescence Methods for the Detection of Bioaerosols in Their Civil and Military Applications

The article presents the history of the development and the current state of the apparatus for the detection of interferents and biological warfare simulants in the air with the laser-induced fluorescence (LIF) method. The LIF method is the most sensitive spectroscopic method and also enables the measurement of single particles of biological aerosols and their concentration in the air. The overview covers both the on-site measuring instruments and remote methods. The spectral characteristics of the biological agents, steady-state spectra, excitation-emission matrices, and their fluorescence lifetimes are presented. In addition to the literature, we also present our own detection systems for military applications.

Diurnal trends of indoor and outdoor fluorescent biological aerosol particles in a tropical urban area

We evaluated diurnal trends of size-resolved indoor and outdoor fluorescent biological airborne particles (FBAPs) and their contributions to particulate matter (PM) within 0.5-20 μm. After a ten-week continuous sampling via two identical wideband integrated bioaerosol sensors, we found that both indoor and outdoor diurnal trends of PM were driven by its bioaerosol component. Outdoors, the median [interquartile range] FBAP mass concentration peaked at 8.2 [5.8-9.9] μg/m³ around sunrise and showed a downtrend from 6:00 to 18:00 during the daytime and an uptrend during the night. The nighttime FBAP level was 1.8 [1.4-2.2] times higher than that during the daytime, and FBAPs accounted for 45 % and 56 % of PM during daytime and nighttime, respectively. Indoors, the rise in concentrations of FBAPs smaller than 1 μm coincided with the starting operation of the heating, ventilation, and air conditioning (HVAC) system at 6:00, and the concentration peaked at 8:00 and dropped to the daily average by noontime. This indicated that the starting operation of the HVAC system dislodged the overnight settled and accumulated fine bioaerosols into the indoor environment. For particles larger than 1 μm, the variation of mass concentration was driven by occupancy. Based on regression modeling, the contributions of indoor PM, non-FBAP, and FBAP sources to indoor mass concentrations were estimated to be 93 %, 67 %, and 97 % during the occupied period.

Assessing residential indoor and outdoor bioaerosol characteristics using the ultraviolet light-induced fluorescence-based wideband integrated bioaerosol sensor

We assessed and compared indoor and outdoor residential aerosol particles in a third-floor apartment from August through September 2020. The measurements were conducted using a direct-reading ultraviolet light-induced fluorescence (UV-LIF) wideband integrated bioaerosol spectrometer (WIBS). It measures individual particle light scattering and fluorescence from which particle properties can be derived. The number concentrations of total aerosol particles (TAP) and total fluorescent aerosol particles (TFAP) were significantly higher indoors. Daily and hourly TFAP mean concentrations followed the same trends as the TAP, both indoors and outdoors. The daily mean rank of the TFAP fraction (TFAP/TAP) was significantly higher indoors (23%) than outdoors (19%). Particles representing bacteria dominated indoors while particles representing fungi and pollen dominated outdoors. The mean volume-weighted median diameters for TFAP were 1.67 μm indoors and 2.09 μm outdoors. Higher TFAP fraction indoors was likely due to occupants' activities that generated or resuspended particles. This study contributes to understanding the characteristics of residential aerosol particles in situations when occupants spend most of their time indoors. Based on our findings, a large portion of all indoor aerosol particles could be biological (15-20%) and of respirable particle size (≥95%). Using a novel direct reading UV-LIF-based sensor can help quickly assess aerosol exposures relevant to human health.

Direct-Read Fluorescence-Based Measurements of Bioaerosol Exposure in Home Healthcare

Home healthcare workers (HHCWs) are subjected to variable working environments which increase their risk of being exposed to numerous occupational hazards. One of the potential occupational hazards within the industry includes exposure to bioaerosols. This study aimed to characterize concentrations of three types of bioaerosols utilizing a novel fluorescence-based direct-reading instrument during seven activities that HHCWs typically encounter in patients’ homes. Bioaerosols were measured in an indoor residence throughout all seasons in Cincinnati, OH, USA. A fluorescence-based direct-reading instrument (InstaScope, DetectionTek, Boulder, CO, USA) was utilized for all data collection. Total particle counts and concentrations for each particle type, including fluorescent and non-fluorescent particles, were utilized to form the response variable, a normalized concentration calculated as a ratio of concentration during activity to the background concentration. Walking experiments produced a median concentration ratio of 52.45 and 2.77 for pollen and fungi, respectively. Fungi and bacteria produced the highest and lowest median concentration ratios of 17.81 and 1.90 for showering, respectively. Lastly, our current study showed that sleeping activity did not increase bioaerosol concentrations. We further conclude that utilizing direct-reading methods may save time and effort in bioaerosol-exposure assessment.

Human Emissions of Size-Resolved Fluorescent Aerosol Particles: Influence of Personal and Environmental Factors

Human emissions of fluorescent aerosol particles (FAPs) can influence the biological burden of indoor air. Yet, quantification of FAP emissions from human beings remains limited, along with a poor understanding of the underlying emission mechanisms. To reduce the knowledge gap, we characterized human emissions of size-segregated FAPs (1-10 μm) and total particles in a climate chamber with low-background particle levels. We probed the influence of several personal factors (clothing coverage and age) and environmental parameters (level of ozone, air temperature, and relative humidity) on particle emissions from human volunteers. A material-balance model showed that the mean emission rate ranged 5.3-16 × 10⁶ fluorescent particles per person-h (0.30-1.2 mg per person-h), with a dominant size mode within 3-5 μm. Volunteers wearing long-sleeve shirts and pants produced 40% more FAPs relative to those wearing t-shirts and shorts. Particle emissions varied across the age groups: seniors (average age 70.5 years) generated 50% fewer FAPs compared to young adults (25.0 years) and teenagers (13.8 years). While we did not observe a measurable influence of ozone (0 vs 40 ppb) on human FAP emissions, there was a strong influence of relative humidity (34 vs 62%), with FAP emissions decreasing by 30-60% at higher humidity.

Detection of Airborne Biological Particles in Indoor Air Using a Real-Time Advanced Morphological Parameter UV-LIF Spectrometer and Gradient Boosting Ensemble Decision Tree Classifiers

We present results from a study evaluating the utility of supervised machine learning to classify single particle ultraviolet laser-induced fluorescence (UV-LIF) signatures to investigate airborne primary biological aerosol particle (PBAP) concentrations in a busy, multifunctional building using a Multiparameter Bioaerosol Spectrometer. First we introduce and demonstrate a gradient boosting ensemble decision tree algorithm’s ability to accurately classify laboratory generated PBAP samples into broad taxonomic classes with a high level of accuracy. We then develop a framework to appraise the classification accuracy and performance using the Hellinger distance metric to compare product parameter probability density function similarity; this framework showed that key training classes were sufficiently different in terms of particle fluorescence and morphology to facilitate classification. We also demonstrate the utility of including advanced morphological parameters to minimise inter-class conflation and improve classification confidence, where relying on the fluorescent spectra alone would likely result in misattribution. Finally, we apply these methods to ambient data collected within a large multi-functional building where ambient bacterial- and fungal-like classes were identified to display trends corresponding to human activity; fungal-like classes displayed a consistent diurnal trend with a maximum at midday and hourly peaks correlating to movements within the building; bacteria-like aerosol displayed complex, episodic events during opening hours. All PBAP classes fell to low baseline concentrations when the building was unoccupied overnight and at weekends.

The role of textiles as fomites in the healthcare environment: a review of the infection control risk

BACKGROUND

Infectious diseases are a significant threat in both healthcare and community settings. Healthcare associated infections (HCAIs) in particular are a leading cause of complications during hospitalisation. Contamination of the healthcare environment is recognised as a source of infectious disease yet the significance of porous surfaces including healthcare textiles as fomites is not well understood. It is currently assumed there is little infection risk from textiles due to a lack of direct epidemiological evidence. Decontamination of healthcare textiles is achieved with heat and/or detergents by commercial or in-house laundering with the exception of healthcare worker uniforms which are laundered domestically in some countries. The emergence of the COVID-19 pandemic has increased the need for rigorous infection control including effective decontamination of potential fomites in the healthcare environment. This article aims to review the evidence for the role of textiles in the transmission of infection, outline current procedures for laundering healthcare textiles and review studies evaluating the decontamination efficacy of domestic and industrial laundering.

METHODOLOGY

Pubmed, Google Scholar and Web of Science were searched for publications pertaining to the survival and transmission of microorganisms on textiles with a particular focus on the healthcare environment.

RESULTS

A number of studies indicate that microorganisms survive on textiles for extended periods of time and can transfer on to skin and other surfaces suggesting it is biologically plausible that HCAIs and other infectious diseases can be transmitted directly through contact with contaminated textiles. Accordingly, there are a number of case studies that link small outbreaks with inadequate laundering or infection control processes surrounding healthcare laundry. Studies have also demonstrated the survival of potential pathogens during laundering of healthcare textiles, which may increase the risk of infection supporting the data published on specific outbreak case studies.

CONCLUSIONS

There are no large-scale epidemiological studies demonstrating a direct link between HCAIs and contaminated textiles yet evidence of outbreaks from published case studies should not be disregarded. Adequate microbial decontamination of linen and infection control procedures during laundering are required to minimise the risk of infection from healthcare textiles. Domestic laundering of healthcare worker uniforms is a particular concern due to the lack of control and monitoring of decontamination, offering a route for potential pathogens to enter the clinical environment. Industrial laundering of healthcare worker uniforms provides greater assurances of adequate decontamination compared to domestic laundering, due to the ability to monitor laundering parameters; this is of particular importance during the COVID-19 pandemic to minimise any risk of SARS-CoV-2 transmission.

Characterization of Bacteria and Inducible Phages in an Intensive Care Unit

Intensive care units (ICUs) are critical locations for the transmission of pathogenic and opportunistic microorganisms. Bacteria may develop a synergistic relationship with bacteriophages and more effectively resist various stresses, enabling them to persist despite disinfection and antimicrobial treatment. We collected 77 environmental samples from the surroundings of 12 patients with infection/colonizations by Escherichia coli, Staphylococcus aureus or Klebsiella spp in an ICU in Austria. Surface swabs were tested for lytic phages and bacterial isolates for mitomycin C-inducible prophages. No lytic bacteriophages were detected, but S. aureus was isolated from the surroundings of all patients. About 85% of the colonies isolated from surface samples were resistant to antimicrobials, with 94% of them multidrug resistant. Two inducible temperate bacteriophages-myovirus vB_EcoM_P5 and siphovirus vB_SauS_P9-were recovered from two clinical isolates. Staphylococci phage vB_SauS_P9 lysed S. aureus isolates from the surface swabs collected from the surroundings of three patients. No transductants were obtained on propagation in phage-sensitive antimicrobial-resistant isolates. The two phages were sensitive to 0.25% (v/v) of the disinfectant TPH Protect, which eliminated viable phages after 15 min. Coliphage vB_EcoM_P5 was inactivated at 70 °C and staphylococci phage vB_SauS_P9 at 60 °C after 60 min.

Microbial Community Profiling in Intensive Care Units Expose Limitations in Current Sanitary Standards

Hospital-associated infections (HAIs) are a leading cause of morbidity and mortality in intensive care units (ICUs) and neonatal intensive care units (NICUs). Organisms causing these infections are often present on surfaces around the patient. Given that microbiota may vary across different ICUs, the HAI-related microbial signatures within these units remain underexplored. In this study, we use deep-sequencing analyses to explore and compare the structure of bacterial communities at inanimate surfaces of the ICU and NICU wards of The Medical School Clinics Hospital (Brazil). The data revealed that NICU presents higher biodiversity than ICU and surfaces closest to the patient showed a peculiar microbiota, distinguishing one unit from the other. Several facultative anaerobes or obligate anaerobes HAI-related genera were classified as biomarkers for the NICU, whereas Pseudomonas was the main biomarker for ICU. Correlation analyses revealed a distinct pattern of microbe-microbe interactions for each unit, including bacteria able to form multi-genera biofilms. Furthermore, we evaluated the effect of concurrent cleaning over the ICU bacterial community. The results showed that, although some bacterial populations decreased after cleaning, various HAI-related genera were quite stable following sanitization, suggesting being well-adapted to the ICU environment. Overall, these results enabled identification of discrete ICU and NICU reservoirs of potentially pathogenic bacteria and provided evidence for the presence of a set of biomarkers genera that distinguish these units. Moreover, the study exposed the inconsistencies of the routine cleaning to minimize HAI-related genera contamination.

On the interpretation of bioaerosol exposure measurements and impacts on health

Bioaerosols are recognized as one of the main transmission routes for infectious diseases and are responsible for other various types of health effects through inhalation and potential ingestion. Associating exposure with bioaerosol and health problems is challenging, and adequate exposure monitoring is a top priority for aerosol scientists. The multiple factors affecting bioaerosol content, the variability in the focus of each bioaerosol exposure study, and the variations in experimental design and the standardization of methods make bioaerosol exposure studies very difficult. Therefore, the health impacts of bioaerosol exposure are still poorly understood. This paper presents a brief description of a state-of-the-art development in bioaerosol exposure studies supported by studies on several related subjects. The main objective of this paper is to propose new considerations for bioaerosol exposure guidelines and the development of tools and study designs to better interpret bioaerosol data. The principal observations and findings are the discrepancy of the applicable methods in bioaerosol studies that makes result comparison impossible. Furthermore, the silo mentality helps in creating a bigger gap in the knowledge accumulated about bioaerosol exposure. Innovative and original ideas are presented for aerosol scientists and health scientists to consider and discuss. Although many examples cited herein are from occupational exposure, the discussion has relevance to any human environment. This work gives concrete suggestions for how to design a full bioaerosol study that includes all of the key elements necessary to help understand the real impacts of bioaerosol exposure in the short term. The creation of the proposed bioaerosol public database could give crucial information to control the public health. Implications: How can we move toward a bioaerosol exposure guidelines? The creation of the bioaerosol public database will help accumulate information for long-term association studies and help determine specific exposure biomarkers to bioaerosols. The implementation of such work will lead to a deeper understanding and more efficient utilization of bioaerosol studies to prevent public health hazards.

Clothing-Mediated Exposures to Chemicals and Particles

A growing body of evidence identifies clothing as an important mediator of human exposure to chemicals and particles, which may have public health significance. This paper reviews and critically assesses the state of knowledge regarding how clothing, during wear, influences exposure to molecular chemicals, abiotic particles, and biotic particles, including microbes and allergens. The underlying processes that govern the acquisition, retention, and transmission of clothing-associated contaminants and the consequences of these for subsequent exposures are explored. Chemicals of concern have been identified in clothing, including byproducts of their manufacture and chemicals that adhere to clothing during use and care. Analogously, clothing acts as a reservoir for biotic and abiotic particles acquired from occupational and environmental sources. Evidence suggests that while clothing can be protective by acting as a physical or chemical barrier, clothing-mediated exposures can be substantial in certain circumstances and may have adverse health consequences. This complex process is influenced by the type and history of the clothing; the nature of the contaminant; and by wear, care, and storage practices. Future research efforts are warranted to better quantify, predict, and control clothing-related exposures.

Precision public health to inhibit the contagion of disease and move toward a future in which microbes spread health

Antimicrobial resistance continues to outpace the development of new chemotherapeutics. Novel pathogens continue to evolve and emerge. Public health innovation has the potential to open a new front in the war of "our wits against their genes" (Joshua Lederberg). Dense sampling coupled to next generation sequencing can increase the spatial and temporal resolution of microbial characterization while sensor technologies precisely map physical parameters relevant to microbial survival and spread. Microbial, physical, and epidemiological big data could be combined to improve prospective risk identification. However, applied in the wrong way, these approaches may not realize their maximum potential benefits and could even do harm. Minimizing microbial-human interactions would be a mistake. There is evidence that microbes previously thought of at best "benign" may actually enhance human health. Benign and health-promoting microbiomes may, or may not, spread via mechanisms similar to pathogens. Infectious vaccines are approaching readiness to make enhanced contributions to herd immunity. The rigorously defined nature of infectious vaccines contrasts with indigenous "benign or health-promoting microbiomes" but they may converge. A "microbial Neolithic revolution" is a possible future in which human microbial-associations are understood and managed analogously to the macro-agriculture of plants and animals. Tradeoffs need to be framed in order to understand health-promoting potentials of benign, and/or health-promoting microbiomes and infectious vaccines while also discouraging pathogens. Super-spreaders are currently defined as individuals who play an outsized role in the contagion of infectious disease. A key unanswered question is whether the super-spreader concept may apply similarly to health-promoting microbes. The complex interactions of individual rights, community health, pathogen contagion, the spread of benign, and of health-promoting microbiomes including infectious vaccines require study. Advancing the detailed understanding of heterogeneity in microbial spread is very likely to yield important insights relevant to public health.

Clothing as a transport vector for airborne particles: Chamber study

Strong evidence suggests that clothing serves as a reservoir of chemical pollutants and particles, including bioaerosols, which may have health significance. However, little is known about the role that clothing may play as a transport vector for inhaled airborne particles. Here, we contribute toward bridging the knowledge gap by conducting experiments to investigate clothing release fraction (CRF), determined as the size-dependent ratio of released to deposited particulate matter in the diameter range 0.5-10 μm. In a fully controlled chamber with low background particle levels, we deployed a programmable robot to reproducibly quantify the size-dependent CRF as a function of motion type and intensity, dust loadings, and activity duration. On average, 0.3%-3% of deposited particles were subsequently released with fabric motion, confirming that clothing can act as a vehicle for transporting airborne particles. The CRF increased with the vigor of movement and with dust loading. Rubbing and shaking the fabric were more effective than fabric stretching in resuspending particles. We also found that most of the release happened quickly after the onset of the resuspension activity. Particle size substantially influenced the CRF, with larger particles exhibiting higher values.

Airway microbiota across age and disease spectrum in cystic fibrosis

Our objectives were to characterise the microbiota in cystic fibrosis (CF) bronchoalveolar lavage fluid (BALF), and determine its relationship to inflammation and disease status.BALF from paediatric and adult CF patients and paediatric disease controls undergoing clinically indicated bronchoscopy was analysed for total bacterial load and for microbiota by 16S rDNA sequencing.We examined 191 BALF samples (146 CF and 45 disease controls) from 13 CF centres. In CF patients aged <2 years, nontraditional taxa (e.gStreptococcus, Prevotella and Veillonella) constituted ∼50% of the microbiota, whereas in CF patients aged ≥6 years, traditional CF taxa (e.gPseudomonas, Staphylococcus and Stenotrophomonas) predominated. Sequencing detected a dominant taxon not traditionally associated with CF (e.gStreptococcus or Prevotella) in 20% of CF BALF and identified bacteria in 24% of culture-negative BALF. Microbial diversity and relative abundance of Streptococcus, Prevotella and Veillonella were inversely associated with airway inflammation. Microbiota communities were distinct in CF compared with disease controls, but did not differ based on pulmonary exacerbation status in CF.The CF microbiota detected in BALF differs with age. In CF patients aged <2 years, Streptococcus predominates, whereas classic CF pathogens predominate in most older children and adults.

Sources and dynamics of fluorescent particles in hospitals

Fluorescent particles can be markers of bioaerosols and are therefore relevant to nosocomial infections. To date, little research has focused on fluorescent particles in occupied indoor environments, particularly hospitals. In this study, we aimed to determine the spatial and temporal variation of fluorescent particles in two large hospitals in Brisbane, Australia (one for adults and one for children). We used an Ultraviolet Aerodynamic Particle Sizer (UVAPS) to identify fluorescent particle sources, as well as their contribution to total particle concentrations. We found that the average concentrations of both fluorescent and non-fluorescent particles were higher in the adults' hospital (0.06×10⁶ and 1.20×10⁶  particles/m³ , respectively) than in the children's hospital (0.03×10⁶ and 0.33×10⁶  particles/m³ , respectively) (P<.01). However, the proportion of fluorescent particles was higher in the children's hospital. Based on the concentration results and using activity diaries, we were able to identify sources of particle production within the two hospitals. We demonstrated that particles can be easily generated by a variety of everyday activities, which are potential sources of exposure to pathogens. Future studies to further investigate their role in nosocomial infection are warranted.

An Ergonomic Assessment of Hospital Linen Bag Handling

The Joint Commission provides accreditation standards for staging hospital waste, but there are no federal lifting safety standards for linen bags. We evaluated hospital laundry bag lifting using the Revised National Institute for Occupational Safety and Health (NIOSH) Lifting Equation. We hypothesized that the permitted 32-gallon linen container capacity might allow filling to weights above our calculated Recommended Weight Limit (RWL) for some lifting positions and contents. We found that 30- and 40-gallon bags filled with loose dry linen had predicted weights within estimated RWLs only for lifts close to the body. Thirty- and 40-gallon bags filled more than halfway with dry compact linen had predicted weights above estimated RWLs for all lifting positions. Thirty- and 40-gallon bags filled with wet compact linen exceeded estimated RWLs for all positions when less than one-quarter full. Bag volume and filling controls may be considered to ensure linen bags are not excessively heavy.

Influence of moisturizer and relative humidity on human emissions of fluorescent biological aerosol particles

Utilizing the ultraviolet light-induced fluorescence (UV-LIF) measurement technique as embodied in the Waveband Integrated Bioaerosol Sensor (WIBS-4A), we evaluated the fluorescent particle emissions associated with human shedding while walking in a chamber. The mean emission rates of supermicron (1-10 μm) fluorescent particles were in the range 6.8-7.5 million particles per person-h (~0.3 mg per person-h) across three participants, for conditions when the relative humidity was 60%-70% and no moisturizer was applied after showering. The fluorescent particles displayed a lognormal distribution with the geometric mean diameter in the range 2.5-4 μm and exhibited asymmetry factors that increased with particle size. Use of moisturizer was associated with changes in number and mass emission rates, size distribution, and particle shape. Emission rates were lower when the relative humidity was reduced, but these differences were not statistically significant.

Microorganisms in Confined Habitats: Microbial Monitoring and Control of Intensive Care Units, Operating Rooms, Cleanrooms and the International Space Station

Indoor environments, where people spend most of their time, are characterized by a specific microbial community, the indoor microbiome. Most indoor environments are connected to the natural environment by high ventilation, but some habitats are more confined: intensive care units, operating rooms, cleanrooms and the international space station (ISS) are extraordinary living and working areas for humans, with a limited exchange with the environment. The purposes for confinement are different: a patient has to be protected from infections (intensive care unit, operating room), product quality has to be assured (cleanrooms), or confinement is necessary due to extreme, health-threatening outer conditions, as on the ISS. The ISS represents the most secluded man-made habitat, constantly inhabited by humans since November 2000 – and, inevitably, also by microorganisms. All of these man-made confined habitats need to be microbiologically monitored and controlled, by e.g., microbial cleaning and disinfection. However, these measures apply constant selective pressures, which support microbes with resistance capacities against antibiotics or chemical and physical stresses and thus facilitate the rise of survival specialists and multi-resistant strains. In this article, we summarize the available data on the microbiome of aforementioned confined habitats. By comparing the different operating, maintenance and monitoring procedures as well as microbial communities therein, we emphasize the importance to properly understand the effects of confinement on the microbial diversity, the possible risks represented by some of these microorganisms and by the evolution of (antibiotic) resistances in such environments – and the need to reassess the current hygiene standards.

The roles of the outdoors and occupants in contributing to a potential pan-microbiome of the built environment: a review

Recent high-throughput sequencing technology has led to an expansion of knowledge regarding the microbial communities (microbiome) across various built environments (BEs). The microbiome of the BE is dependent upon building factors and conditions that govern how outdoor microbes enter and persist in the BE. Additionally, occupants are crucial in shaping the microbiome of the BE by releasing human-associated microorganisms and resuspending microbes on floors and surfaces. Therefore, both the outdoors and occupants act as major sources of microorganisms found in the BE. However, most characterizations of the microbiome of the BE have been conducted in the Western world. Notably, outdoor locations and population groups present geographical variations in outdoor and human microbiomes, respectively. Given the influences of the outdoor and human microbiomes on BE microbiology, and the geographical variations in outdoor and human microbiomes, it is likely that the microbiomes of BEs also vary by location. The summation of microbiomes between BEs contribute to a potential BE pan-microbiome, which will both consist of microbes that are ubiquitous in indoor environments around the world, and microbes that appear to be endemic to particular geographical locations. Importantly, the BE pan-microbiome can potentially question the global application of our current views on indoor microbiology. In this review, we first provide an assessment on the roles of building and occupant properties on shaping the microbiome of the BE. This is then followed by a description of geographical variations in the microbiomes of the outdoors and humans, the two main sources of microbes in BEs. We present evidence of differences in microbiomes of BEs around the world, demonstrating the existence of a global pan-microbiome of the BE that is larger than the microbiome of any single indoor environment. Finally, we discuss the significance of understanding the BE pan-microbiome and identifying universal and location-specific relationships between building and occupant characteristics and indoor microbiology. This review highlights the much needed efforts towards determining the pan-microbiome of the BE, thereby identifying general and location-specific links between the microbial communities of the outdoors, human, and BE ecosystems, ultimately improving the health, comfort, and productivity of occupants around the world.