Showing papers on "Bioaerosol published in 2006"

Variability of airborne microflora in a hospital ward within a period of one year.

Abstract: The aim of the study was to determine the seasonal variability of the airborne microflora in a hospital ward of the pneumonological department, with regard to potential impact on respiratory status of asthmatic patients hospitalized in the ward. Microbiological air sampling was carried out for a period of 1 year from June-May, during work-days, 16-21 days per month. Each day, the air samples were collected twice: in the morning at 09:00 and in the afternoon at 13:00. Air samples were taken with a custom-designed particle-sizing slit sampler enabling estimations of both total and respirable fractions of the microbial aerosol. Air samples for determination of bacteria were taken on blood agar and air samples for determination of fungi were taken on Sabouraud agar. Mean monthly concentrations of total microorganisms (bacteria + fungi) in the air of the examined hospital ward were between 296.1-529.9 cfu/m3. Mean monthly concentrations of airborne bacteria ranged from 257.1-436.3 cfu/m3, with peak values in November and May and the lowest values from December to February. Mean monthly concentrations of airborne fungi showed much greater variation than bacteria and ranged from 9.9-96.1 cfu/m3 with the very distinct peak in November and the lowest value in May. The variations in monthly concentrations of total microorganisms, bacteria and fungi in the air of hospital ward were statistically significant (p < 0.001). The concentrations of total airborne microorganisms, bacteria and fungi recorded in the hospital in the morning were significantly greater compared to those recorded in the afternoon (p < 0.01). The mean monthly values of respirable fraction for total microorganisms were within a range of 17.3-44.4%, for bacteria within a range of 17.2-44.8%, and for fungi within a range of 2.2-39.1%. The most common microorganisms in the air of the examined ward were Gram-positive cocci which accounted for 31.4-46.4% of the total count. Gram-negative bacteria and corynebacteria were less numerous, forming respectively 11.8-27.5% and 9.6-20.0% of the total count. Endospore-forming bacilli and actinomycetes occurred in small proportions, respectively 0.3-3.2% and 0-2.0% of the total count. Fungi formed 7.6-42.5% of the total count. The prevailing species was Aspergillus fumigatus which constituted on average 77.0% of total fungal strains isolated from the air of the hospital ward. A significant decrease of spirographic indices (VC, FEV1) in asthmatic patients hospitalized in the ward, at increase of the concentration of airborne bacteria and/or fungi, was found in 9 out of 24 examined patients (37.5%) and in 19 out of 192 analysed single relationships (9.9%). In conclusion, although bacteria and fungi occurred in the air of the examined hospital ward in relatively low numbers (of the order 10(2) cfu/m3 and 10(1) cfu/m3 respectively), they should be considered as a possible cause of asthma exacerbations in some patients because of the presence of Aspergillus fumigatus and other potentially pathogenic species.

Relationship between indoor and outdoor bioaerosols collected with a button inhalable aerosol sampler in urban homes

Abstract: This field study investigated the relationship between indoor and outdoor concentrations of airborne actinomycetes, fungal spores, and pollen. Air samples were collected for 24 h with a button inhalable aerosol sampler inside and outside of six single-family homes located in the Cincinnati area (overall, 15 pairs of samples were taken in each home). The measurements were conducted during three seasons - spring and fall 2004, and winter 2005. The concentration of culturable actinomycetes was mostly below the detection limit. The median indoor/outdoor ratio (I/O) for actinomycetes was the highest: 2.857. The indoor of fungal and pollen concentrations followed the outdoor concentrations while indoor levels were mostly lower than the outdoor ones. The I/O ratio of total fungal spores (median=0.345) in six homes was greater than that of pollen grains (median=0.025). The low I/O ratios obtained for pollen during the peak ambient pollination season (spring) suggest that only a small fraction penetrated from outdoor to indoor environment. This is attributed to the larger size of pollen grains. Higher indoor concentration levels and variability in the I/O ratio observed for airborne fungi may be associated with indoor sources and/or higher outdoor-to-indoor penetration of fungal spores compared to pollen grains. Practical Implication This study addresses the relationship between indoor and outdoor concentrations of three different types of bio-aerosols, namely actinomycetes, fungal spores, and pollen grains. The results show that actinomycetes are rare in indoor and outdoor air in Midwest, USA. Exposure to pollen occurs mainly in the outdoor air even during peak pollen season. Unexpectedly high fungal spore concentrations were measured outdoors during winter. The presented pilot database on the inhalable levels of indoor and outdoor bio-aerosols can help apportion and better characterize the inhalation exposure to these bio-aerosols. Furthermore, the data can be incorporated into existing models to quantify the penetration of biological particles into indoor environments from outdoors.

A two-stage cyclone using microcentrifuge tubes for personal bioaerosol sampling

Abstract: Personal aerosol samplers are widely used to monitor human exposure to airborne materials. For bioaerosols, interest is growing in analyzing samples using molecular and immunological techniques. This paper presents a personal sampler that uses a two-stage cyclone to collect bioaerosols into disposable 1.5 ml Eppendorf-type microcentrifuge tubes. Samples can be processed in the tubes for polymerase chain reaction (PCR) or immunoassays, and the use of multiple stages fractionates aerosol particles by aerodynamic diameter. The sampler was tested using fluorescent microspheres and aerosolized fungal spores. The sampler had first and second stage cut-off diameters of 2.6 μm and 1.6 μm at 2 l min−1 (geometric standard deviation, GSD = 1.45 and 1.75), and 1.8 μm and 1 μm at 3.5 l min−1 (GSD = 1.42 and 1.55). The sampler aspiration efficiency was ≥98% at both flow rates for particles with aerodynamic diameters of 3.1 μm or less. For 6.2 μm particles, the aspiration efficiency was 89% at 2 l min−1 and 96% at 3.5 l min−1. At 3.5 l min−1, the sampler collected 92% of aerosolized Aspergillus versicolor and Penicillium chrysogenum spores inside the two microcentrifuge tubes, with less than 0.4% of the spores collecting on the back-up filter. The design and techniques given here are suitable for personal bioaerosol sampling, and could also be adapted to design larger aerosol samplers for longer-term atmospheric and indoor air quality sampling.

Application of Gaseous Ozone for Inactivation of Bacillus subtilis Spores

Abstract: The effectiveness of gaseous ozone (O3) as a disinfectant was tested on Bacillus subtilis spores, which share the same physiological characteristics as Bacillus anthracis spores that cause the anthrax disease. Spores dried on surfaces of different carrier material were exposed to O3 gas in the range of 500-5000 ppm and at relative humidity (RH) of 70-95%. Gaseous O3 was found to be very effective against the B. subtilis spores, and at O3 concentrations as low as 3 mg/L (1500 ppm), approximately 3-log inactivation was obtained within 4 hr of exposure. The inactivation curves consisted of a short lag phase followed by an exponential decrease in the number of surviving spores. Prehydration of the bacterial spores has eliminated the initial lag phase. The inactivation rate increased with increasing O3 concentration but not >3 mg/L. The inactivation rate also increased with increase in RH. Different survival curves were obtained for various surfaces used to carry spores. Inactivation rates of spores on glass, a vinyl floor tile, and office paper were nearly the same. Whereas cut pile carpet and hardwood flooring surfaces resulted in much lower inactivation rates, another type of carpet (loop pile) showed significant enhancement in the inactivation of the spores.

Bioaerosol sampling by a personal rotating cup sampler CIP 10-M.

Abstract: High concentrations of bioaerosols containing bacterial, fungal and biotoxinic matter are encountered in many workplaces, e.g. solid waste treatment plants, waste water treatment plants and sewage networks. A personal bioaerosol sampler, the CIP 10-M (M-microbiologic), has been developed to measure worker exposure to airborne biological agents. This sampler is battery operated; it is light and easy to wear and offers full work shift autonomy. It can sample much higher concentrations than biological impactors and limits the mechanical stress on the microorganisms. Biological particles are collected in 2 ml of liquid medium inside a rotating cup fitted with radial vanes to maintain an air flow rate of 10 l min−1 at a rotational speed of approximately 7000 rpm. The rotating cup is made of sterilisable material. The sampled particles follow a helicoidal trajectory as they are pushed to the surface of the liquid by centrifugal force, which creates a thin vertical liquid layer. Sterile water or another collecting liquid can be used. Three particle size selectors allow health-related aerosol fractions to be sampled according to international conventions. The sampled microbiological particles can be easily recovered for counting, incubation or further biochemical analysis, e.g., for airborne endotoxins. Its physical sampling efficiency was laboratory tested and field trials were carried out in industrial waste management conditions. The results indicate satisfactory collection efficiency, whilst experimental application has demonstrated the usefulness of the CIP 10-M personal sampler for individual bioaerosol exposure monitoring.

Preliminary survey of indoor and outdoor airborne microfungi at coastal buildings in Egypt

Abstract: Forty six species and two sterile fungi and yeast species were isolated from samples collected both indoors and outdoors of coastal buildings located in an Egyptian coastal city. Twenty flats from ten buildings were investigated; children living in these buildings have been reported to suffer from respiratory illnesses. Samples were taken using a New Brunswick sampler (model STA-101) operating for 3.0 min at a flow rate of 6.0 l/min. Most of the species isolated have been associated with symptoms of respiratory allergies. Indoors the total culturable fungal count was 1548 CFU/m3; outdoors, it was 1452 CFU/m3. Indoor values of culturable fungal count, total spores count and ergosterol content ranged from 52 to 124 CFU/m3, 100 to 400 spore/m3 and 5 to 27.7 mg/m3, respectively, whereas outdoor levels typically varied between 25 and 222 CFU/m3, 110 and 900 spore/m3 and 3.3 and 67.2 mg/m3, respectively. The maxima for these parameters were detected indoors in house no. 6 and outdoors, outside of house no. 7. The most abundant species were primarily mitosporic (2832 CFU/m3). The most frequent species in both the indoor and outdoor samples were Cladosporium cladosporioides followed by Alternaria alternata and Penicillium chrysogenum,with inside:outside ratios of 1.4, 1.8 and 1.9, respectively. The patterns of fungal abundance were influenced to some extent by changes in the relative humidity and temperature. Other factors, such as type of culture media, rate of sedimentation, size, survival rates of spore and species competition,also affected fungal counts and should be taken into consideration during any analysis of bioaerosol data.

Fluorescence preselection of bioaerosol for single-particle mass spectrometry

Abstract: We have designed, constructed, and tested a system that preselects the biological fraction of airborne particles from the overall aerosol. The preselection is based on fluorescence emission excited by a continuous 266 nm laser beam. This beam is one of two cw beams used to measure the aerodynamic particle size of sampled particles. The intention in our system is that single particles, based on size and fluorescence emission, can be selected and further examined for chemical composition by mass spectrometry.

Effect of spraying biological additives for reduction of dust and bioaerosol in a confinement swine house.

Abstract: The aim of this on-site experiment is to evaluate and compare efficiencies of currently utilized biological additives to reduce emissions of dust and bioaerosol in a confinement swine house. The mean reduction rate of total dust only after spray ranged was approximately 30% for all the treatments, compared to initial level before spraying additives which was found to reduce the initial level of total dust significantly (p 0.05). The fluctuations of total airborne bacteria and fungi, which were similar to total dust, were observed for all the treatments 3 hr after spray.

Analysis of Bioaerosols from Chicken Houses by Culture and Non-Culture Method

Abstract: In livestock breeding, high bioaerosol concentrations in environments such as chicken houses are an occupational health concern. Two sampling methods (impinger and filter) and three non-culture methods [epifluoresence microscopy with fluorochrome (EFM/FL), flow cytometry with the fluorochrome (FCM/FL), and fluorescent in situ hybridization (FISH)] were used to monitor the total concentration, viability, and culturability of bioaerosols in chicken houses. These results were compared to the commonly used culture method. Total microbial cell concentrations measured by the non-culture methods averaged about 5 × 10 7 cells/m 3 . However, culture method underestimated bioaerosol concentrations by a factor of 10. For sampler comparison, viability determined following impinger collection was higher than that following filter method. In conclusion, impinger was considered an appropriate sampler, and EFM/FL, FCM/FL, and FISH approaches could adequately assess total microbial cell concentration and viability of bioa...

Spectral detection of ultraviolet laser induced fluorescence from individual bioaerosol particles

Abstract: We present results of a measurement system designed for detecting the fluorescence spectrum of individual aerosol particles of biological warfare agents excited with laser pulses at wavelengths around 290 or 340 nm. The biological aerosol is prepared and directed into a narrow air beam. A red laser is focused on the aerosol beam and a trigger photomultiplier tube monitor the presence of individual particles by measuring the scattered light. When a particle is present in the detection volume, a laser pulse is triggered from an ultraviolet laser and the fluorescence spectrum is acquired with a spectrometer based on a diffraction grating and a 32 channels photomultiplier tube array with single-photon sensitivity. The spectrometer measures the fluorescence spectra in the wavelength region from 300 to 800 nm. In the experiment we used different simulants of biological warfare agents. These bioaerosol particles were excited by a commercial available gas laser (337 nm), or a laser (290 nm) that we have developed based on an optical parametric oscillator with intracavity sum-frequency mixing. In the analysis of the experiments we compare the measured signals (fluorescence spectra, total fluorescence energy and the scattered energy) from the individual bioaerosol particles excited with the two different ultraviolet wavelengths.

A new sub-sampling method for analysis of air samples collected with the Andersen single-stage sampler

Abstract: A protocol for bioaerosol collection was developed that provides not only accurate predictions of fungal concentration, but also improves species recovery. Random transfer of a subset of 50 of the 400 impaction points from Andersen single-stage bioaerosol sampling plates results in subcultures that are accurate predictors of fungal concentration (CFU/m3), when compared to duplicate untouched Andersen plates. A linear regression model was developed to estimate CFU/m3 from the colonies counted on the Random-50 plates. The random transfer to five plates (“Random-50” plates), allows large numbers of fungi to be recovered and identified, including slow-growing fungi that otherwise would be masked by fast-growing fungi.

The distribution of Staphylococci in bioaerosols from red-meat abattoirs.

Abstract: The quality and shelf-life of perishable foodstuffs can be reduced by high concentrations in the processing environment of bioaerosols consisting of spoilage microbiota. A lack of documented literature on the distribution of such bioaerosols has, however, led to the underestimation of their impact. In the study reported here, the deboning rooms of selected South African red-meat abattoirs were investigated for airborne concentrations of staphylococci; the authors studied the distribution of Staphylococcus species in general, as well as the coagulase types of Staphylococcus aureus in particular. Average staphylococci bioaerosol concentrations varied considerably among the abattoirs investigated, with Abattoir B having the highest counts (3 x 10(2) CFUs/m3) and Abattoir A having the lowest (7.6 CFUs/m3). There was a significant link between bioaerosols and microbial loads from red meat in the same environment. The recorded levels were, however, well below the recommended maximum limits for bioaerosols suggested by various international and governmental authorities. Staphylococcus xylosus and S. saprophyticus were found to be the most abundant species in the air of the deboning rooms, while among S. aureus coagulase types, Type III and Type VIII were predominant. On the basis of the ecology of the bacterial groups, the authors suggest probable sources of staphylococcal bioaerosols and propose strategies that could be developed for red-meat abattoirs to reduce the levels of airborne pathogens.

An improved wetted-wall bioaerosol sampling cyclone

Abstract: An Improved Wetted-Wall Bioaerosol Sampling Cyclone. (August 2005) Manpreet Singh Phull, B.Tech., IIT Madras, India Chair of Advisory Committee: Dr. Andrew R. McFarland A modified wetted-wall cyclone using different methods of water injection techniques upstream of the inlet was designed as an improvement to a wetted-wall cyclone developed by White, which uses liquid injection through a port on the wall of the cyclone inlet. The new cyclone has a high aerosol sampling flow rate (1250 L/min) and maintains constant cut-point with the modified White-type cyclone along with greater collection efficiency, lower time response, and reduced pressure drop. The final air-blast atomizer cyclone (AAC2.1a) design considered has an aerosol-tohydrosol collection efficiency cut-point of 1.3 μm with collection efficiencies at 1 and 2 μm of 39.9% and 86%, respectively. The efficiency reported for the modified White-type cyclone for particle sizes of 1 and 2 μm was 40.5% and 76.3%, respectively, under no water bypass conditions. The aerosol-to-aerosol transmission efficiency for the AAC2.1a configuration was found to be approximately 53.7% for 1 μm diameter particles as compared with 67.2% for the modified White-type cyclone. Dry and wet time response tests were performed in which the modified White-type cyclone had an initial response of 2.5 minutes for a wet start and 1 minute for a dry start for a condition where there was no liquid carryover through the cyclone outlet. The rise time for AAC2.1a cyclone under dry and wet start conditions was 0.5 minutes and 1.3 minutes, respectively. The decay response of the modified White-type cyclone was 1.1 minutes for a

Poultry slaughtering plants: concentrations of microbial aerosols in poultry slaughtering and processing plants.

Abstract: Concentrations of airborne microorganisms were measured at four poultry slaughtering plants during four one-day visits using Anderson single- and six-stage viable particle (bioaerosol) samplers. Nonselective bioaerosols including total aerobic mesophilic bacteria, psychrotrophic bacteria, and yeasts and molds were measured at approximately 40 sites in and around each plant. Bioaerosol concentrations were highest in shackling and defeathering areas and decreased with product flow through the plant until they approached outside levels in packaging areas. Bioaerosols exhibited a lognormal particle size distribution, with a count median diameter of 4.26 ± 0.19 m (n = 59) for total aerobic mesophilic bacteria, and 4.17 ± 0.33 m (n = 33) for yeasts and molds. Selected bacteria were speciated from some samples taken during each visit. Listeria monocytogenes, Staphylococcus aureas spp., Escherichia coli, Salmonella spp., and Lactobacilli were detected on 47% (n = 188), 54% (n = 92), 18% (n = 208), 31% (n = 206), and 89% (n = 100) of the samples, respectively. Some of the detections occurred in areas of the plant where meat was exposed following the chilling process.

Environment and climate effect of bioaerosol:A review

Abstract: Bioaerosols are a significant subgroup of atmospheric aerosols and its transport should be related to spread of human,animal and plant disease epidemics.Bioaerosols have indirect effect on the alteration of the global climate and atmospheric process.International bioaerosol research has been developing very rapidly during the last two decades,and the area has received an addi-tional spike of attention.Several types of biological organisms(e.g.,fungi,bacteria,and algae)have been identified as effective cloud condensation nuclei(CCN),being active in cloud.The bioaerosols have potential role in modifying the chemical composition of other organic compounds upon collision or contact,and hence inducing changes in the IN or CCN ability of organics in atmos-phere,and implicating them in the alteration of cloud coverage and hence the global climate.Airborne microorganism also has im-pact on air quality,and most research has focused on the source and monitoring of indoor bioaerosols such as fungi,bacteria and allergens.The sample validity is very important for bioaerosols measurement.Some new and applicable on-line sampling and analy-sis technologies,such as Raman Spectroscopic techniques and Time-of-fight Mass Spectrometer,have been developed to reduce sampling error and improve living efficiency of organisms.The atmospheric bioaerosols can be transported for a long range follow-ing some routines,and the temporal and spatial distribution is dependent on the kind of bioaerosol.The recent studies on environ-ment effect,sampling,analysis,distribution and transportation of bioaerosols are reviewed.

Characterization of ambient aerosols at the San Francisco International Airport using bioaerosol mass spectrometry

Abstract: The BioAerosol Mass Spectrometry (BAMS) system is a rapidly fieldable, fully autonomous instrument that can perform correlated measurements of multiple orthogonal properties of individual aerosol particles. The BAMS front end uses optical techniques to nondestructively measure a particle's aerodynamic diameter and fluorescence properties. Fluorescence can be excited at 266nm or 355nm and is detected in two broad wavelength bands. Individual particles with appropriate size and fluorescence properties can then be analyzed more thoroughly in a dual-polarity time-of-flight mass spectrometer. Over the course of two deployments to the San Francisco International Airport, more than 6.5 million individual aerosol particles were fully analyzed by the system. Analysis of the resulting data has provided a number of important insights relevant to rapid bioaerosol detection, which are described here.

Size-based characteristics of airborne bacteria and fungi distributed in the general hospital

Abstract: The objective of this study is to provide fundamental data for pertinent management of indoor air quality through investigating the size-based characteristics of bioaerosol distributed in the general hospital. Measurement sites are main lobby, ICU, ward and laboratory and total five times were sampled with six-stage cascade impactor. Based on the result of this study, concentrations of airborne bacteria and fungi were the highest in main lobby as followed by an order of ward, ICU and laboratory. Concentrations of airborne bacteria was generally higher than those of airborne fungi and the ratio of indoor and outdoor concentration of both exceeded 1.0 in all the measurement sites of the general hospital. The predominant genera of airborne bacteria identified in the general hospital were Staphylococcus spp.(50%), Micrococcus spp.(15 20%), Corynebacterium spp.(5 20%), and Bacillus spp.(5 15%). On the other hand, the predominant genera of airborne fungi identified in the general hospital were Cladosporium spp.(30%), Penicillium spp.(20 25%), Aspergillus spp.(15 20%), and Alternaria spp.(10 20%). In regard to size distribution of bioaerosol, the detection rate was generally highest on 5 stage(1.1 2.1 ) for airborne bacteria and on 1 stage( 7.0 ) for airborne fungi. Cleanliness of facilities in the general hospital and condition of HVAC system should be monitored regularly to prevent indoor air contamination by airborne microorganisms.

Multi-wavelength fluorescence lidar detection of bioaerosols

Abstract: Multi-wavelength lidar systems are designed to detect and identify biological agents at a distance away from the aerosol/plume or from the detector system,before the agents reach the location of the system.It is an active standoff detection system with both ultraviolet (UV) and infrared (IR) capability.The UV wavelength can provide near real time detection and ranging of bioaerosol cloud with demonstrated discrimination capability,the IR wavelength extends the cloud detection range and acquisition capability.The system and the capability of Laser Induced Fluorescence(LIF) technique for the detection of bioaerosols are described.It shows a numerical simulation of signal-to-noise of the fluorescence of bioaerosol particles as a function of ranges,and for both day and night operational scenarios.