Qualitative and quantitative methodologies for determination of airborne microorganisms at concentrated animal-feeding operations

Dungan, Robert S.; Leytem, April B.

doi:10.1007/s11274-009-0043-1

Cited by 33 publications

(23 citation statements)

References 130 publications

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“…qPCR values were about 3 logs greater than those determined by the MPN technique (a statistically significant difference; P Ͻ 0.0001), which indicated that the majority of enterococci might have gone into a VBNC state such as was seen in earlier studies involving bovine feces and manure (28,30). However, since the DNA could also have been extracted from damaged or dead cells, qPCR analysis may have resulted in overestimation of actual titer values in the samples (7,31,37).…”

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confidence: 77%

“…qPCR is often used as a convenient alternative to culture-dependent techniques that has the added advantage of being able to detect viable but nonculturable (VBNC) cells of potential pathogens (7,27,59). While there are documented advantages and disadvantages with both molecular method-and culture-dependent approaches, it was our intent to provide the first quantitative survey of selected bacterial indicators and putative pathogens in dairy wastewaters.…”

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confidence: 99%

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Quantification of Bacterial Indicators and Zoonotic Pathogens in Dairy Wastewater Ponds

Dungan

Klein

Leytem

2012

Appl Environ Microbiol

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bZoonotic pathogens in land-applied dairy wastewaters are a potential health risk. The occurrence and abundance of 10 pathogens and 3 fecal indicators were determined by quantitative real-time PCR (qPCR) in samples from 30 dairy wastewaters from southern Idaho. Samples tested positive for Campylobacter jejuni, stx 1 -and eaeA-positive Escherichia coli, Listeria monocytogenes, Mycobacterium avium subsp. paratuberculosis, and Salmonella enterica, with mean recoveries of genomic DNA corresponding to 10 2 to 10 4 cells ml ؊1 wastewater. The most predominant organisms were C. jejuni and M. avium, being detected in samples from up to 21 and 29 of 30 wastewater ponds, respectively. The qPCR detection limits for the putative pathogens in the wastewaters ranged from 16 cells ml ؊1 for M. avium to 1,689 oocysts ml ؊1 for Cryptosporidium. Cryptosporidium and Giardia spp., Yersinia pseudotuberculosis, and pathogenic Leptospira spp. were not detected by qPCR. In the United States, there are 9.3 million milk cows (33) producing an estimated 200 million metric tons of manure annually. Because cattle can be reservoirs of zoonotic pathogens, there is concern over the contamination of soil, water, air, and crops when the manure solids and liquids are land applied (6,9,44). At dairies, the solids are often removed from the manure slurries and the liquid fraction (i.e., urine, wash water) is then sent to a pond for storage or can be anaerobically digested first to produce biogas (43). During the crop-growing season, the pond wastewater is diluted with irrigation water and land applied through pressurized irrigation systems to improve the soil nutrient status. It is during spray irrigation that zoonotic pathogens could be aerosolized, increasing the risk of exposure to downwind receptors via inhalation or ingestion after deposition on fomites or food crops (8,23). Once in the soil after manure addition, pathogens can be internalized by plants (49) and also reach recreational waters by overland flow transport during rainfall events (36,53,54), causing significant contamination.Zoonotic pathogens of potential interest in cattle are Campylobacter jejuni, Escherichia coli, Leptospira spp., Listeria monocytogenes, Mycobacterium avium subsp. paratuberculosis, Salmonella spp., Yersinia spp., Giardia lamblia, and Cryptosporidium parvum (38,39,40). While numerous studies have measured the occurrence of these zoonotic pathogens in cattle manures and assessed their fate and transport in the environment (41,48,55), to our knowledge, no comprehensive studies have been conducted to quantify pathogens in dairy wastewaters. In addition, only a few studies to date have quantified a wide range of pathogens within cattle manures (20,21,26). Understanding the number of pathogens in any land-applied waste is particularly important when developing a quantitative microbial risk assessment (12,17,56). Estimation of the risk represented by pathogens in animal manures, however, has largely been based on the cultivation and enumeration of fecal indicator orga...

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confidence: 77%

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confidence: 99%

Quantification of Bacterial Indicators and Zoonotic Pathogens in Dairy Wastewater Ponds

Dungan

Klein

Leytem

2012

Appl Environ Microbiol

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“…The conventional PCR assay has been applied to analyse air samples for the presence of airborne mycobacteria [78] and fungi commonly associated with adverse health effects [79]. PCR allows the detection and identification of non-culturable airborne microorganisms; it does not allow distinguishing between non-viable and viable microorganisms [80]. Currently, the real-time PCR (RT-PCR) is evolving into a promising tool capable of reproducible and accurate measurements of total microorganism concentrations in environmental samples.…”

Section: Polymerase Chain Reaction (Pcr) -Pcr Techniquementioning

confidence: 99%

Bioaerosols in Indoor Environment - A Review with Special Reference to Residential and Occupational Locations

Brandl¹

2011

TOEBMJ

177

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Bioaerosols such as bacterial and fungal cells and their spores are -along with non-biological particles -part of indoor airborne particulate matter and have been related since a long time to health issues of human beings as well as flora, and fauna. To identify the different risks and to establish exposure thresholds, microbiology of air samples from a series of indoor environments must be characterized, i.e. the different microorganisms (bacteria and fungi) must be identified and quantified. This review discusses the techniques of air sampling and sample analysis. In addition, a literature study has been performed regarding the levels of these microorganisms in various indoor occupational (e.g., schools, offices, hospitals, museums) and dwelling environments. These results will provide a significant scientific basis for indoor air quality control and help in elaborating risk prevention programs for workers and dwellers. This review shall contribute to the knowledge of identification and quantification of airborne microbial constituents in various indoor environments. Combining the indoor microbial load data with data from studies focusing on health effects caused by inhalation of specific airborne microorganisms will allow the evaluation of various risks to which inhabitants are exposed. Bioaerosols in Indoor Environment -A Review with Special Reference to Residential and Occupational LocationsJyotshna Mandal and Helmut Brandl* Institute of Evolutionary Biology and Environmental Studies, University of Zurich, SwitzerlandAbstract: Bioaerosols such as bacterial and fungal cells and their spores are -along with non-biological particles -part of indoor airborne particulate matter and have been related since a long time to health issues of human beings as well as flora, and fauna. To identify the different risks and to establish exposure thresholds, microbiology of air samples from a series of indoor environments must be characterized, i.e. the different microorganisms (bacteria and fungi) must be identified and quantified. This review discusses the techniques of air sampling and sample analysis. In addition, a literature study has been performed regarding the levels of these microorganisms in various indoor occupational (e.g., schools, offices, hospitals, museums) and dwelling environments. These results will provide a significant scientific basis for indoor air quality control and help in elaborating risk prevention programs for workers and dwellers. This review shall contribute to the knowledge of identification and quantification of airborne microbial constituents in various indoor environments. Combining the indoor microbial load data with data from studies focusing on health effects caused by inhalation of specific airborne microorganisms will allow the evaluation of various risks to which inhabitants are exposed.

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“…While molecular-based methods such as quantitative PCR (qPCR) have increased sensitivity over traditional culture techniques, they cannot distinguish between inactive and infectious organisms. 17 Due to the difficulties in detecting airborne pathogens and deciphering positive results, many researchers instead target indicator organisms in bioaerosol studies. 12,18−20 However, the survival of airborne indicator organisms is likely different from that of pathogens, making them a poor pathogen surrogate.…”

Section: ■ Introductionmentioning

confidence: 99%

Estimation of Infectious Risks in Residential Populations Exposed to Airborne Pathogens During Center Pivot Irrigation of Dairy Wastewaters

Dungan

2014

Environ. Sci. Technol.

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In the western United States where dairy wastewaters are commonly land applied, there are concerns over individuals being exposed to airborne pathogens. In response, a quantitative microbial risk assessment (QMRA) was performed to estimate infectious risks after inhalation exposure of pathogens aerosolized during center pivot irrigation of diluted dairy wastewaters. The dispersion of pathogens (Campylobacter jejuni, Escherichia coli O157:H7, non-O157 E. coli, Listeria monocytogenes, and Salmonella spp.) was modeled using the atmospheric dispersion model, AERMOD. Pathogen concentrations at downwind receptors were used to calculate infectious risks during one-time (1, 8, and 24 h) and multiday (7 d at 1 h d −1 ) exposure events using a β-Poisson dose−response model. This assessment considered risk of infection in residential populations that were 1 to 10 km from a center pivot operation. In the simulations, infectious risks were estimated to be the greatest in individuals closest to the center pivot, as a result of a higher pathogen dose. On the basis of the results from this QMRA, it is recommended that wastewaters only be applied during daylight hours when inactivation and dilution of airborne pathogens is highest. Further refinement of the dispersion and dose−response models should be considered to increase the utility of this QMRA.

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Qualitative and quantitative methodologies for determination of airborne microorganisms at concentrated animal-feeding operations

Cited by 33 publications

References 130 publications

Quantification of Bacterial Indicators and Zoonotic Pathogens in Dairy Wastewater Ponds

Quantification of Bacterial Indicators and Zoonotic Pathogens in Dairy Wastewater Ponds

Bioaerosols in Indoor Environment - A Review with Special Reference to Residential and Occupational Locations

Estimation of Infectious Risks in Residential Populations Exposed to Airborne Pathogens During Center Pivot Irrigation of Dairy Wastewaters

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