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Denissen J, Reyneke B, Barnard T, Khan S, Khan W. Risk assessment of Enterococcus faecium, Klebsiella pneumoniae, and Pseudomonas aeruginosa in environmental water sources: Development of surrogate models for antibiotic resistance genes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 901:166217. [PMID: 37604372 DOI: 10.1016/j.scitotenv.2023.166217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 08/08/2023] [Accepted: 08/08/2023] [Indexed: 08/23/2023]
Abstract
The presence of Enterococcus faecium (E. faecium), Klebsiella pneumoniae (K. pneumoniae), Pseudomonas aeruginosa (P. aeruginosa), and the aminoglycoside resistance genes, aac(6')-Ib and aac(6')-aph(2″), was investigated in environmental water sources obtained from informal settlements in the Western Cape (South Africa). Using ethidium monoazide bromide quantitative polymerase chain reaction (EMA-qPCR) analysis, E. faecium, K. pneumoniae, and P. aeruginosa were detected in 88.9 %, 100 %, and 93.3 % of the samples (n = 45), respectively, with a significantly higher mean concentration recorded for K. pneumoniae (7.83 × 104 cells/100 mL) over the sampling period. The aac(6')-Ib gene was detected in 95.6 % (43/45) of the environmental water samples [mean concentration of 7.07 × 106 gene copies (GC)/100 mL], while the aac(6')-aph(2″) gene was detected in 100 % (n = 45) of the samples [mean concentration of 6.68 × 105 GC/100 mL]. Quantitative microbial risk assessment (QMRA) subsequently indicated that the risks posed by K. pneumoniae and P. aeruginosa were linked to intentional drinking, washing/bathing, cleaning of the home, and swimming, in the samples collected from the various sampling sites. Surrogate risk assessment models were then designed and applied for Gram-positive [aac(6')-aph(2″) gene] and Gram-negative [aac(6')-Ib gene] pathogens that may exhibit aminoglycoside resistance. The results indicated that only the Gram-negative pathogens posed a risk (>10-4) in all the samples for cleaning of the home and intentional drinking, as well as for washing laundry by hand, garden hosing, garden work, washing/bathing, accidental consumption, and swimming at the stream and marsh sites. Thus, while environmental waters may pose a health risk of exposure to pathogenic bacteria, the results obtained indicate that screening for antibiotic resistant genes, associated with multiple genera/species, could serve as a surrogate model for estimating risks with the target group under investigation.
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Affiliation(s)
- Julia Denissen
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa
| | - Brandon Reyneke
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa
| | - Tobias Barnard
- Water and Health Research Centre, Faculty of Health Sciences, University of Johannesburg, PO Box 17011, Doornfontein 7305, South Africa
| | - Sehaam Khan
- Water and Health Research Centre, Faculty of Health Sciences, University of Johannesburg, PO Box 17011, Doornfontein 7305, South Africa
| | - Wesaal Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa.
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Wang J, Wei B, Chen Z, Chen Y, Liu S, Zhang B, Zhu B, Ye D. A rapid and reliable method for the determination of Lactiplantibacillus plantarum during wine fermentation based on PMA-CELL-qPCR. Front Microbiol 2023; 14:1154768. [PMID: 37529324 PMCID: PMC10389660 DOI: 10.3389/fmicb.2023.1154768] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 06/26/2023] [Indexed: 08/03/2023] Open
Abstract
Real-time monitoring of microbial dynamics during fermentation is essential for wine quality control. This study developed a method that combines the fluorescent dye propidium monoazide (PMA) with CELL-qPCR, which can distinguish between dead and live microbes for Lactiplantibacillus plantarum. This method could detect the quantity of microbes efficiently and rapidly without DNA extraction during wine fermentation. The results showed that (1) the PMA-CELL-qPCR enumeration method developed for L. plantarum was optimized for PMA treatment concentration, PMA detection sensitivity and multiple conditions of sample pretreatment in wine environment, and the optimized method can accurately quantify 104-108 CFU/mL of the target strain (L. plantarum) in multiple matrices; (2) when the concentration of dead bacteria in the system is 104 times higher than the concentration of live bacteria, there is an error of 0.5-1 lg CFU/mL in the detection results. The optimized sample pretreatment method in wine can effectively reduce the inhibitory components in the qPCR reaction system; (3) the optimized PMA-CELL-qPCR method was used to monitor the dynamic changes of L. plantarum during the fermentation of Cabernet Sauvignon wine, and the results were consistent with the plate counting method. In conclusion, the live bacteria quantification method developed in this study for PMA-CELL-qPCR in L. plantarum wines is accurate in quantification and simple in operation, and can be used as a means to accurately monitor microbial dynamics in wine and other fruit wines.
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Affiliation(s)
- Jie Wang
- Beijing Key Laboratory of Forestry Food Processing and Safety, School of Biological Science and Technology, Beijing Forestry University, Beijing, China
| | - Bo Wei
- Beijing Key Laboratory of Forestry Food Processing and Safety, School of Biological Science and Technology, Beijing Forestry University, Beijing, China
| | - Zhuojun Chen
- Beijing Key Laboratory of Forestry Food Processing and Safety, School of Biological Science and Technology, Beijing Forestry University, Beijing, China
| | - Yixin Chen
- Beijing Key Laboratory of Forestry Food Processing and Safety, School of Biological Science and Technology, Beijing Forestry University, Beijing, China
| | - Songyu Liu
- Beijing Key Laboratory of Forestry Food Processing and Safety, School of Biological Science and Technology, Beijing Forestry University, Beijing, China
| | - Bolin Zhang
- Beijing Key Laboratory of Forestry Food Processing and Safety, School of Biological Science and Technology, Beijing Forestry University, Beijing, China
| | - Baoqing Zhu
- Beijing Key Laboratory of Forestry Food Processing and Safety, School of Biological Science and Technology, Beijing Forestry University, Beijing, China
| | - Dongqing Ye
- Guangxi Key Laboratory of Fruits and Vegetables Storage-Processing Technology, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
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Steffen HC, Smith K, van Deventer C, Weiskerger C, Bosch C, Brandão J, Wolfaardt G, Botha A. Health risk posed by direct ingestion of yeasts from polluted river water. WATER RESEARCH 2023; 231:119599. [PMID: 36645944 DOI: 10.1016/j.watres.2023.119599] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 01/07/2023] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
River water is an essential human resource that may be contaminated with hazardous microorganisms. However, the risk of yeast infection through river water exposure is unclear because it is highly dependant on individual susceptibility and has therefore not been well-studied, to date. To evaluate this undefined risk, we analysed the fungal communities in less polluted (LP) and highly polluted (HP) river water, as determined using principal coordinate analysis of pollution indicators. We enumerated culturable yeasts using a thermally selective isolation procedure (37 °C) and thus promoted the growth of potentially opportunistic species. Yeast species identified as clinically relevant were then tested for antifungal resistance. In addition, we propose a quantitative microbial risk assessment (QMRA) framework to quantitatively assess the potential risk of yeast infection. Our results indicated that pollution levels significantly altered fungal communities (p = 0.007) and that genera representing opportunistic and pathogenic members were significantly more abundant in HP waters (p = 0.038). Additionally, the yeast species Candida glabrata and Clavispora lusitaniae positively correlated with other pollution indicators, demonstrating the species' indicator potential. Our QMRA results further indicate that higher risk of infection is associated with increased water pollution levels (considering both physicochemical and bacterial indicators). Furthermore, yeast species with higher pathogenic potential present an increased risk of infection despite lower observed concentrations in the river water. Interestingly, the bloom of Meyerozyma guilliermondii during the wet season suggests that other environmental factors, such as dissolved oxygen levels and water turbulence, might affect growth characteristics of yeasts in river water, which consequently affects the distribution of annual infection risks. The presence of antifungal resistant yeasts, observed in this study, could further contribute to variation in risk distribution. Research on the ecophysiology of yeasts in these environments is therefore necessary to ameliorate the uncertainty and sensitivity of the proposed QMRA model. In addition to the vital knowledge on opportunistic and pathogenic yeast occurrence in river water and their observed association with pollution, this study provides valuable methods and insights to initiate future QMRAs of yeast infections.
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Affiliation(s)
- Heidi Christa Steffen
- Department of Microbiology, University of Stellenbosch, Stellenbosch, Western Cape 7600, South Africa
| | - Katrin Smith
- Department of Microbiology, University of Stellenbosch, Stellenbosch, Western Cape 7600, South Africa
| | - Corné van Deventer
- Department of Microbiology, University of Stellenbosch, Stellenbosch, Western Cape 7600, South Africa
| | - Chelsea Weiskerger
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, United States
| | - Caylin Bosch
- Department of Microbiology, University of Stellenbosch, Stellenbosch, Western Cape 7600, South Africa
| | - João Brandão
- Department of Environmental Health, National Institute of Health Doctor Ricardo Jorge, Av. Padre Cruz, Lisbon 1649-016, Portugal; Centre for Environmental and Marine Studies (CESAM), Department of Animal Biology, University of Lisbon, Campo Grande, Lisbon 1749-016, Portugal
| | - Gideon Wolfaardt
- Department of Microbiology, University of Stellenbosch, Stellenbosch, Western Cape 7600, South Africa
| | - Alfred Botha
- Department of Microbiology, University of Stellenbosch, Stellenbosch, Western Cape 7600, South Africa.
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Kim SA, Lee DH, Ryu BH, Han NS. Strain-specific barcode PCR and quantitative PCR assay for identification and enumeration of kimchi starter, Leuconostoc mesenteroides DRC1506. Lebensm Wiss Technol 2023. [DOI: 10.1016/j.lwt.2023.114460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Dual-mode visual detection strategies of viable pathogens for point-of-care testing. Biosens Bioelectron 2022; 221:114904. [DOI: 10.1016/j.bios.2022.114904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/31/2022] [Accepted: 11/08/2022] [Indexed: 11/13/2022]
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Evaluation of a Most Probable Number Method for Detection and Quantification of Legionella pneumophila. Pathogens 2022; 11:pathogens11070789. [PMID: 35890033 PMCID: PMC9324539 DOI: 10.3390/pathogens11070789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/02/2022] [Accepted: 07/07/2022] [Indexed: 11/17/2022] Open
Abstract
The detection and enumeration of Legionella pneumophila (L. pneumophila) in water is crucial for water quality management, human health and has been a research hotspot worldwide. Due to the time-consuming and complicated operation of the plate culture method, it is necessary to adopt a fast and effective method for application. The present study aimed to comprehensively evaluate the performance and applicability of the MPN method by comparing its qualitative and quantitative results with the GB/T 18204.5-2013 and ISO methods, respectively. The qualitative results showed that 372 samples (53%) were negative for both methods; 315 samples (45%) were positively determined by the MPN method, compared with 211 samples (30%) using GB/T 18204.5-2013. The difference in the detection rate between the two methods was statistically significant. In addition, the quantitative results showed that the concentration of L. pneumophila by the MPN method was greater than ISO 11731 and the difference was statistically significant. However, the two methods were different but highly correlated (r = 0.965, p < 0.001). The specificity and sensitivity of the MPN method were 89.85% and 95.73%, respectively. Overall, the results demonstrated that the MPN method has higher sensitivity, a simple operation process and good application prospects in the routine monitoring of L. pneumophila from water samples.
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Interaction of Bdellovibrio bacteriovorus with Gram-Negative and Gram-Positive Bacteria in Dual Species and Polymicrobial Communities. Microorganisms 2022; 10:microorganisms10040793. [PMID: 35456843 PMCID: PMC9025206 DOI: 10.3390/microorganisms10040793] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/16/2022] [Accepted: 03/21/2022] [Indexed: 12/10/2022] Open
Abstract
The interaction of Bdellovibrio bacteriovorus PF13 with mixed bacterial communities, consisting of Gram-negative (Pseudomonas fluorescens and Klebsiella pneumoniae) and Gram-positive (Staphylococcus aureus and Enterococcus faecium) bacteria, was investigated to determine if this wild-type predator preferentially preys on certain bacteria and whether the presence of Gram-positive organisms influences its predation efficiency. In co-culture with P. fluorescens and K. pneumoniae, the cell counts (PFU/mL) of PF13 increased by 5.79 and 5.17 logs (48 h), respectively, while in the dual species assay (P. fluorescens, K. pneumoniae and PF13), the cell counts of PF13 increased by 1.95 logs (24 h). Using ethidium monoazide bromide quantitative polymerase chain reaction (EMA-qPCR), the concentration of PF13 increased by 1.25 to 3.62 logs in the co-culture experiments, by 1.41 to 5.05 logs in dual species cultures and by 2.65 logs in a polymicrobial culture. However, PF13 preferentially preyed on K. pneumoniae in the dual species and polymicrobial cultures, highlighting that the presence of Gram-positive bacteria did not affect the predation efficiency of PF13. This is significant as it implies that the predator can be applied in mixed microbial communities to target Gram-negative pathogens which may pose a health risk to patients, consumers or for the treatment of contaminated water.
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Optimization of Propidium Monoazide qPCR (Viability-qPCR) to Quantify the Killing by the Gardnerella-Specific Endolysin PM-477, Directly in Vaginal Samples from Women with Bacterial Vaginosis. Antibiotics (Basel) 2022; 11:antibiotics11010111. [PMID: 35052988 PMCID: PMC8773202 DOI: 10.3390/antibiotics11010111] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 02/07/2023] Open
Abstract
Quantification of the number of living cells in biofilm or after eradication treatments of biofilm, is problematic for different reasons. We assessed the performance of pre-treatment of DNA, planktonic cells and ex vivo vaginal biofilms of Gardnerella with propidium monoazide (PMAxx) to prevent qPCR-based amplification of DNA from killed cells (viability-qPCR). Standard PMAxx treatment did not completely inactivate free DNA and did not affect living cells. While culture indicated that killing of planktonic cells by heat or by endolysin was complete, viability-qPCR assessed only log reductions of 1.73 and 0.32, respectively. Therefore, we improved the standard protocol by comparing different (combinations of) parameters, such as concentration of PMAxx, and repetition, duration and incubation conditions of treatment. The optimized PMAxx treatment condition for further experiments consisted of three cycles, each of: 15 min incubation on ice with 50 µM PMAxx, followed by 15 min-long light exposure. This protocol was validated for use in vaginal samples from women with bacterial vaginosis. Up to log2.2 reduction of Gardnerella cells after treatment with PM-477 was documented, despite the complex composition of the samples, which might have hampered the activity of PM-477 as well as the quantification of low loads by viability-qPCR.
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Consonni M, Grassi A, Scuri S, Gori M, Tanzi E, Tesauro M. Assessing the viability of Legionella pneumophila in environmental samples: regarding the filter application of Ethidium Monoazide Bromide. ANN MICROBIOL 2021. [DOI: 10.1186/s13213-021-01653-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Purpose
Analyses of 34 water samples from 13 healthcare structures revealed how culture method and quantitative PCR (qPCR) often differ in the detection of Legionella pneumophila (Lp). With these considerations in hand, culture method, PCR and Ethidium Monoazide Bromide (EMA) qPCR have all been compared in order to detect Lp in water samples, identify a method able to speed up the procedures, detect the “viable but not cultivable” bacteria (VBNC) and exclude non-viable bacteria using a commercial kit for extraction and amplification as well as modification of the protocol.
Methods
Pure water samples artificially spiked with viable, non-viable and VBNC Lp ATCC 33152 were analyzed using a commercial kit for both qPCR and EMA-qPCR, while ISO 11731-2-2004 was used for culture method.
Results
Only 35% (12/34) of the environmental samples were positive in both culture and qPCR methods. With regard to EMA-qPCR, results showed the absence of dye toxicity on viable and VBNC strains and an incomplete effectiveness on the non-viable ones. In both viable and VBNC strains, a decrease of bacterial DNA amplification was recorded as a function of sample dilution but not of EMA concentration.
Conclusions
Discrepancies between culture method and EMA-qPCR were observed and may be due to different causes such as membrane-dye interactions, presence of interfering compounds and the sensitivity of the kit used.
Study significance and impact
In the presence of one or more suspected cases of nosocomial legionellosis, the application of a rapid molecular method able to identify only the viable and VBNC Lp would be useful in order to quickly identify the source of infection and to intervene with sanitation treatments. However, seeing that in our experience EMA pretreatment on the filter membrane did not come up with the expected results, it would be necessary to proceed with other experiments and/or different dyes.
Graphical Abstract
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Fu J, Chiang ELC, Medriano CAD, Li L, Bae S. Rapid quantification of fecal indicator bacteria in water using the most probable number - loop-mediated isothermal amplification (MPN-LAMP) approach on a polymethyl methacrylate (PMMA) microchip. WATER RESEARCH 2021; 199:117172. [PMID: 33991777 DOI: 10.1016/j.watres.2021.117172] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 04/13/2021] [Accepted: 04/15/2021] [Indexed: 05/22/2023]
Abstract
Fecal contamination of water and its associated pathogens are a major public health concern in both developing and industrialized areas. Fecal indicator bacteria (FIB) are commonly used to assess microbial water quality, but they require a relatively long period of incubation time. Currently, molecular techniques have been applied to rapidly detect FIB. However, these molecular techniques require expensive and sophisticated equipment. In this study, we developed a rapid on-chip gene quantification method based on loop-mediated isothermal amplification (LAMP) PCR. The LAMP assays can measure the target genes of the fecal indicator bacteria (FIB), including E. coli and Enterococcus spp, using the most probable number (MPN) approach. The colorimetric LAMP assay allows for naked-eye observation of the PCR reaction as few as 4 gene copies / well. When the reaction ends, MPN measurement of positive outcomes on the white-based PMMA (polymethacrylic acid) microchips provides the concentrations of the target genes of FIB with a confidence interval. We validated the feasibility of the MPN-LAMP approach by obtaining a strong correlation between the results of the MPN estimations and the qPCR analysis. Moreover, the MPN-LAMP approach was used to quantify the FIB in different environmental water collected from the freshwater reservoirs, beach, agriculture farm, and sewage. Our research demonstrates that the MPN- LAMP method enables us to easily and quickly quantifying FIB genes isolated from the environment without expensive qPCR instruments.
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Affiliation(s)
- Jing Fu
- Department of Civil and Environmental Engineering, National University of Singapore, Block E2-04-07, No.1 Engineering Drive 2, Singapore 117576, Singapore
| | - Elaine Li Ching Chiang
- Department of Civil and Environmental Engineering, National University of Singapore, Block E2-04-07, No.1 Engineering Drive 2, Singapore 117576, Singapore
| | - Carl Angelo Dulatre Medriano
- Department of Civil and Environmental Engineering, National University of Singapore, Block E2-04-07, No.1 Engineering Drive 2, Singapore 117576, Singapore
| | - Liyan Li
- Department of Civil and Environmental Engineering, National University of Singapore, Block E2-04-07, No.1 Engineering Drive 2, Singapore 117576, Singapore
| | - Sungwoo Bae
- Department of Civil and Environmental Engineering, National University of Singapore, Block E2-04-07, No.1 Engineering Drive 2, Singapore 117576, Singapore.
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Denissen JK, Reyneke B, Waso M, Khan S, Khan W. Human Pathogenic Bacteria Detected in Rainwater: Risk Assessment and Correlation to Microbial Source Tracking Markers and Traditional Indicators. Front Microbiol 2021; 12:659784. [PMID: 34025613 PMCID: PMC8138566 DOI: 10.3389/fmicb.2021.659784] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/09/2021] [Indexed: 11/22/2022] Open
Abstract
Roof-harvested rainwater (RHRW) was investigated for the presence of the human pathogenic bacteria Mycobacterium tuberculosis (M. tuberculosis), Yersinia spp. and Listeria monocytogenes (L. monocytogenes). While Yersinia spp. were detected in 92% (n = 25) of the RHRW samples, and L. monocytogenes and M. tuberculosis were detected in 100% (n = 25) of the samples, a significantly higher mean concentration (1.4 × 103 cells/100 mL) was recorded for L. monocytogenes over the sampling period. As the identification of appropriate water quality indicators is crucial to ensure access to safe water sources, correlation of the pathogens to traditional indicator organisms [Escherichia coli (E. coli) and Enterococcus spp.] and microbial source tracking (MST) markers (Bacteroides HF183, adenovirus and Lachnospiraceae) was conducted. A significant positive correlation was then recorded for E. coli versus L. monocytogenes (r = 0.6738; p = 0.000), and Enterococcus spp. versus the Bacteroides HF183 marker (r = 0.4071; p = 0.043), while a significant negative correlation was observed for M. tuberculosis versus the Bacteroides HF183 marker (r = −0.4558; p = 0.022). Quantitative microbial risk assessment indicated that the mean annual risk of infection posed by L. monocytogenes in the RHRW samples exceeded the annual infection risk benchmark limit (1 × 10–4 infections per person per year) for intentional drinking (∼10–4). In comparison, the mean annual risk of infection posed by E. coli was exceeded for intentional drinking (∼10–1), accidental consumption (∼10–3) and cleaning of the home (∼10–3). However, while the risk posed by M. tuberculosis for the two relevant exposure scenarios [garden hosing (∼10–5) and washing laundry by hand (∼10–5)] was below the benchmark limit, the risk posed by adenovirus for garden hosing (∼10–3) and washing laundry by hand (∼10–3) exceeded the benchmark limit. Thus, while the correlation analysis confirms that traditional indicators and MST markers should be used in combination to accurately monitor the pathogen-associated risk linked to the utilisation of RHRW, the integration of QMRA offers a more site-specific approach to monitor and estimate the human health risks associated with the use of RHRW.
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Affiliation(s)
- Julia K Denissen
- Department of Microbiology, Faculty of Science, Stellenbosch University, Stellenbosch, South Africa
| | - Brandon Reyneke
- Department of Microbiology, Faculty of Science, Stellenbosch University, Stellenbosch, South Africa
| | - Monique Waso
- Faculty of Health Sciences, University of Johannesburg, Doornfontein, South Africa
| | - Sehaam Khan
- Faculty of Health Sciences, University of Johannesburg, Doornfontein, South Africa
| | - Wesaal Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Stellenbosch, South Africa
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Solcova M, Demnerova K, Purkrtova S. Application of Nanopore Sequencing (MinION) for the Analysis of Bacteriome and Resistome of Bean Sprouts. Microorganisms 2021; 9:microorganisms9050937. [PMID: 33925711 PMCID: PMC8146283 DOI: 10.3390/microorganisms9050937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/22/2021] [Accepted: 04/25/2021] [Indexed: 01/11/2023] Open
Abstract
The aspiration these days is to apply rapid methods for parallel analysis of bacteriome and resistome of food samples to increase food safety and prevent antibiotic resistance genes (ARGs) spreading. In this work, we used nanopore sequencing (NS) to determine the diversity and dynamics of the microbiome and resistome in two types of bean sprouts. We proved that NS provided an easy, quick, and reliable way to identify the microbiome and resistome of a food sample also. The species diversity obtained by NS and by cultivation methods with MALDI-TOF MS identification was comparable. In both samples, before and after cultivation (30 °C, 48 h), the dominant part of bacteriome formed Gammaproteobacteria (Enterobacteriaceae, Erwiniaceae, Pseudomonadaceae, Moraxellaceae) and then Firmicutes (Streptococcaceae). The diversity and abundance of single ARGs groups were comparable for both samples despite bacteriome differences. More than 50% of the detected ARGs alignments were mutations conferring resistance to aminoglycosides (16S rRNA), resistance to fluoroquinolones (gyrA, gyrB, parC, parD) and elfamycin (EF-Tu). ARGs encoding efflux pumps formed more than 30% of the detected alignments. Beta-lactamases were represented by many variants, but were less abundant.
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Affiliation(s)
- Milada Solcova
- Correspondence: (M.S.); (S.P.); Tel.: +420-220-44-5196 (M.S. & S.P.)
| | | | - Sabina Purkrtova
- Correspondence: (M.S.); (S.P.); Tel.: +420-220-44-5196 (M.S. & S.P.)
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Gao R, Liao X, Zhao X, Liu D, Ding T. The diagnostic tools for viable but nonculturable pathogens in the food industry: Current status and future prospects. Compr Rev Food Sci Food Saf 2021; 20:2146-2175. [PMID: 33484068 DOI: 10.1111/1541-4337.12695] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/21/2020] [Accepted: 12/28/2020] [Indexed: 12/21/2022]
Abstract
Viable but nonculturable (VBNC) microorganisms have been recognized as pathogenic contaminants in foods and environments. The failure of VBNC cells to form the visible colonies hinders the ability to use conventional media for their detection. Efficient and rapid detection of pathogens in the VBNC state is a prerequisite to ensure the food safety and public health. Despite their nonculturability, VBNC cells have distinct characteristics, such as morphology, metabolism, chemical composition, and gene and protein expression, that have been used as the basis for the development of abundant diagnostic tools. This review covers the current status and advances in various approaches for examining microorganisms in the VBNC state, including but not limited to the methodological aspects, advantages, and drawbacks of each technique. Existing methods, such as direct viable count, SYTO/PI dual staining, and propidium monoazide quantitative polymerase chain reaction (PCR), as well as some techniques with potential to be applied in the future, such as digital PCR, enhanced-surface Raman spectroscopy, and impedance-based techniques, are summarized in depth. Finally, future prospects for the one-step detection of VBNC bacteria are proposed and discussed. We believe that this review can provide more optional methods for researchers and promote the development of rapid, accurate detecting methods, and for inspectors, the diagnostic tools can provide data to undertake risk analysis of VBNC cells.
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Affiliation(s)
- Rui Gao
- Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xinyu Liao
- Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xihong Zhao
- Research Center for Environmental Ecology and Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan, China
| | - Donghong Liu
- Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Tian Ding
- Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
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Reyneke B, Hamilton KA, Fernández-Ibáñez P, Polo-López MI, McGuigan KG, Khan S, Khan W. EMA-amplicon-based sequencing informs risk assessment analysis of water treatment systems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 743:140717. [PMID: 32679496 DOI: 10.1016/j.scitotenv.2020.140717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/29/2020] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
Illumina amplicon-based sequencing was coupled with ethidium monoazide bromide (EMA) pre-treatment to monitor the total viable bacterial community and subsequently identify and prioritise the target organisms for the health risk assessment of the untreated rainwater and rainwater treated using large-volume batch solar reactor prototypes installed in an informal settlement and rural farming community. Taxonomic assignments indicated that Legionella and Pseudomonas were the most frequently detected genera containing opportunistic bacterial pathogens in the untreated and treated rainwater at both sites. Additionally, Mycobacterium, Clostridium sensu stricto and Escherichia/Shigella displayed high (≥80%) detection frequencies in the untreated and/or treated rainwater samples at one or both sites. Numerous exposure scenarios (e.g. drinking, cleaning) were subsequently investigated and the health risk of using untreated and solar reactor treated rainwater in developing countries was quantified based on the presence of L. pneumophila, P. aeruginosa and E. coli. The solar reactor prototypes were able to reduce the health risk associated with E. coli and P. aeruginosa to below the 1 × 10-4 annual benchmark limit for all the non-potable uses of rainwater within the target communities (exception of showering for E. coli). However, the risk associated with intentional drinking of untreated or treated rainwater exceeded the benchmark limit (E. coli and P. aeruginosa). Additionally, while the solar reactor treatment reduced the risk associated with garden hosing and showering based on the presence of L. pneumophila, the risk estimates for both activities still exceeded the annual benchmark limit. The large-volume batch solar reactor prototypes were thus able to reduce the risk posed by the target bacteria for non-potable activities rainwater is commonly used for in water scarce regions of sub-Saharan Africa. This study highlights the need to assess water treatment systems in field trials using QMRA.
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Affiliation(s)
- B Reyneke
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa
| | - K A Hamilton
- School for Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ 85281, United States; The Biodesign Institute Center for Environmental Health Engineering, Arizona State University, Tempe, AZ 85281, United States
| | - P Fernández-Ibáñez
- Plataforma Solar de Almeria-CIEMAT, P.O. Box 22, Tabernas, Almería, Spain; Nanotechnology and Integrated BioEngineering Centre, School of Engineering, University of Ulster, Newtownabbey, Northern Ireland, United Kingdom
| | - M I Polo-López
- Plataforma Solar de Almeria-CIEMAT, P.O. Box 22, Tabernas, Almería, Spain
| | - K G McGuigan
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - S Khan
- Faculty of Health Sciences, University of Johannesburg, PO Box 17011, Doornfontein 2028, South Africa
| | - W Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa.
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15
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Copin S, Mougin J, Raguenet V, Robert-Pillot A, Midelet G, Grard T, Bonnin-Jusserand M. Ethidium and propidium monoazide: comparison of potential toxicity on Vibrio sp. viability. Lett Appl Microbiol 2020; 72:245-250. [PMID: 33058219 DOI: 10.1111/lam.13412] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 10/07/2020] [Accepted: 10/07/2020] [Indexed: 11/29/2022]
Abstract
Vibrio sp., ubiquitous in the aquatic ecosystem, are bacteria of interest because of their involvement in human health, causing gastroenteritis after ingestion of seafood, as well as their role in vibriosis leading to severe losses in aquaculture production. Their ability to enter a viable but non-culturable (VBNC) state under stressful environmental conditions may lead to underestimation of the Vibrio population by traditional microbiological enumeration methods. As a result, using molecular methods in combination with EMA or PMA allows the detection of viable (VBNC and culturable viable) cells. In this study, the impact of the EMA and PMA was tested at different concentrations on the viability of several Vibrio species. We compared the toxicity of these two DNA-binding dyes to determine the best pretreatment to use with qPCR to discriminate between viable and dead Vibrio cells. Our results showed that EMA displayed lethal effects for each strain of V. cholerae and V. vulnificus tested. In contrast, the concentrations of PMA tested had no toxic effect on the viability of Vibrio cells studied. These results may help to achieve optimal PMA-qPCR methods to detect viable Vibrio sp. cells in food and environmental samples.
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Affiliation(s)
- S Copin
- Agence Nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES), Laboratoire de sécurité des aliments, Boulogne-sur-Mer, France
| | - J Mougin
- Institut Charles Viollette, Univ. Littoral Côte d'Opale, UMR 1158 BioEcoAgro, USC ANSES, INRAE, Univ. Lille, Univ. Artois, Univ. Picardie Jules Verne, Univ. Liège, Yncréa, Boulogne-sur-Mer, France
| | - V Raguenet
- Agence Nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES), Laboratoire de sécurité des aliments, Boulogne-sur-Mer, France
| | - A Robert-Pillot
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Vibrions et du Choléra, Paris, France
| | - G Midelet
- Agence Nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES), Laboratoire de sécurité des aliments, Boulogne-sur-Mer, France
| | - T Grard
- Institut Charles Viollette, Univ. Littoral Côte d'Opale, UMR 1158 BioEcoAgro, USC ANSES, INRAE, Univ. Lille, Univ. Artois, Univ. Picardie Jules Verne, Univ. Liège, Yncréa, Boulogne-sur-Mer, France
| | - M Bonnin-Jusserand
- Institut Charles Viollette, Univ. Littoral Côte d'Opale, UMR 1158 BioEcoAgro, USC ANSES, INRAE, Univ. Lille, Univ. Artois, Univ. Picardie Jules Verne, Univ. Liège, Yncréa, Boulogne-sur-Mer, France
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16
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Lv X, Wang L, Zhang J, Zeng H, Chen X, Shi L, Cui H, He X, Zhao L. Rapid and sensitive detection of VBNC Escherichia coli O157: H7 in beef by PMAxx and real-time LAMP. Food Control 2020. [DOI: 10.1016/j.foodcont.2020.107292] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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17
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Qin H, Shi X, Yu L, Li K, Wang J, Chen J, Yang F, Xu H, Xu H. Multiplex real-time PCR coupled with sodium dodecyl sulphate and propidium monoazide for the simultaneous detection of viable Listeria monocytogenes, Cronobacter sakazakii, Staphylococcus aureus and Salmonella spp. in milk. Int Dairy J 2020. [DOI: 10.1016/j.idairyj.2020.104739] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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18
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Mangiaterra G, Cedraro N, Vaiasicca S, Citterio B, Galeazzi R, Laudadio E, Mobbili G, Minnelli C, Bizzaro D, Biavasco F. Role of Tobramycin in the Induction and Maintenance of Viable but Non-Culturable Pseudomonas aeruginosa in an In Vitro Biofilm Model. Antibiotics (Basel) 2020; 9:antibiotics9070399. [PMID: 32664334 PMCID: PMC7400124 DOI: 10.3390/antibiotics9070399] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/12/2020] [Accepted: 07/08/2020] [Indexed: 01/25/2023] Open
Abstract
The recurrence of Pseudomonas aeruginosa (PA) biofilm infections is a major issue in cystic fibrosis (CF) patients. A pivotal role is played by the presence of antibiotic-unresponsive persisters and/or viable but non-culturable (VBNC) forms, whose development might be favored by subinhibitory antibiotic concentrations. The involvement of tobramycin and ciprofloxacin, widely used to treat CF PA lung infections, in the abundance of VBNC cells was investigated in PA biofilms models. In vitro biofilms of the laboratory strain PAO1-N and the clinical strain C24 were developed and starved by subculture for 170 days in a non-nutrient (NN) broth, unsupplemented or supplemented with one-quarter minimal inhibitory concentration (MIC) of tobramycin or ciprofloxacin. VBNC cells abundance, estimated as the difference between total live (detected by qPCR and flow cytometry) and colony forming unit (CFU) counts, showed a strain- and drug-specific pattern. A greater and earlier abundance of VBNC PAO1-N cells was detected in all conditions. Exposure of the C24 strain to NN and NN + ciprofloxacin induced only a transient VBNC subpopulation, which was more abundant and stable until the end of the experiment in tobramycin-exposed biofilms. The same response to tobramycin was observed in the PAO1-N strain. These findings suggest that low tobramycin concentrations might contribute to PA infection recurrence by favoring the development of VBNC forms.
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Affiliation(s)
- Gianmarco Mangiaterra
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
- Correspondence: ; Tel.: +39-071-220-4622; Fax: +39-071-220-4316
| | - Nicholas Cedraro
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
| | - Salvatore Vaiasicca
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
| | - Barbara Citterio
- Department of Biomolecular Science, Biotechnology Section, University of Urbino “Carlo Bo”, via Arco d’Augusto 2, 61032 Fano, Italy;
| | - Roberta Galeazzi
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
| | - Emiliano Laudadio
- Department of Materials, Environmental Sciences and Urban Planning, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy;
| | - Giovanna Mobbili
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
| | - Cristina Minnelli
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
| | - Davide Bizzaro
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
| | - Francesca Biavasco
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
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19
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Bindari YR, Walkden-Brown SW, Gerber PF. Methods to prevent PCR amplification of DNA from non-viable virus were not successful for infectious laryngotracheitis virus. PLoS One 2020; 15:e0232571. [PMID: 32442180 PMCID: PMC7244108 DOI: 10.1371/journal.pone.0232571] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 04/16/2020] [Indexed: 11/23/2022] Open
Abstract
Molecular-based testing of poultry dust has been used as a fast, sensitive and specific way to monitor viruses in chicken flocks but it provides no information on viral viability. Differentiation of viable and nonviable virus would expand the usefulness of PCR-based detection. This study tested three treatments (1. DNAse, 2. propidium monoazide [PMA], 3. immunomagnetic separation [IMS]) applied to dust or virus stock prior to nucleic acid extraction for their ability to exclude nonviable virus from PCR amplification. Infectious laryngotracheitis virus (ILTV) was used as a model. These treatments assume loss of viral viability due to damage to the capsid or to denaturation of epitope proteins. DNAse and PMA assess the integrity of the capsid to penetration by enzyme or intercalating dye, while IMS assesses the integrity of epitope proteins. Treatments were evaluated for their ability to reduce PCR signal, measured as ILTV log10 genomic copies (ILTV GC), of heat and chemically inactivated ILTV in poultry dust and virus stock. Compared to untreated dust samples, there was an overall reduction of 1.7 ILTV GC after IMS treatment (p<0.01), and a reduction of 2.0 ILTV GC after PMA treatment (p<0.0001). DNAse treatment did not reduce ILTV GC in dust (p = 0.68). Compared to untreated virus stocks, there was an overall reduction of 0.5 ILTV GC after DNAse treatment (p = 0.04), a reduction of 1.8 ILTV GC after IMS treatment (p<0.001) and a reduction of 1.4 ILTV GC after PMA treatment (p<0.0001). None of the treatments completely suppressed the detection of inactivated ILTV GC. In conclusion, treatments that use capsid integrity or protein epitope denaturation as markers to assess ILTV infectivity are unsuitable to accurately estimate proportions of viable virus in poultry dust and virus stocks.
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Affiliation(s)
- Yugal Raj Bindari
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Stephen W. Walkden-Brown
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Priscilla F. Gerber
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
- * E-mail:
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20
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Reyneke B, Ndlovu T, Vincent MB, Martínez-García A, Polo-López MI, Fernández-Ibáñez P, Ferrero G, Khan S, McGuigan KG, Khan W. Validation of large-volume batch solar reactors for the treatment of rainwater in field trials in sub-Saharan Africa. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 717:137223. [PMID: 32062239 DOI: 10.1016/j.scitotenv.2020.137223] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/24/2020] [Accepted: 02/07/2020] [Indexed: 06/10/2023]
Abstract
The efficiency of two large-volume batch solar reactors [Prototype I (140 L) and II (88 L)] in treating rainwater on-site in a local informal settlement and farming community was assessed. Untreated [Tank 1 and Tank 2-(First-flush)] and treated (Prototype I and II) tank water samples were routinely collected from each site and all the measured physico-chemical parameters (e.g. pH and turbidity, amongst others), anions (e.g. sulphate and chloride, amongst others) and cations (e.g. iron and lead, amongst others) were within national and international drinking water guidelines limits. Culture-based analysis indicated that Escherichia coli, total and faecal coliforms, enterococci and heterotrophic bacteria counts exceeded drinking water guideline limits in 61%, 100%, 45%, 24% and 100% of the untreated tank water samples collected from both sites. However, an 8 hour solar exposure treatment for both solar reactors was sufficient to reduce these indicator organisms to within national and international drinking water standards, with the exception of the heterotrophic bacteria which exceeded the drinking water standard limit in 43% of the samples treated with the Prototype I reactor (1 log reduction). Molecular viability analysis subsequently indicated that mean overall reductions of 75% and 74% were obtained for the analysed indicator organisms (E. coli and enterococci spp.) and opportunistic pathogens (Klebsiella spp., Legionella spp., Pseudomonas spp., Salmonella spp. and Cryptosporidium spp. oocysts) in the Prototype I and II solar reactors, respectively. The large-volume batch solar reactor prototypes could thus effectively provide four (88 L Prototype II) to seven (144 L Prototype I) people on a daily basis with the basic water requirement for human activities (20 L). Additionally, a generic Water Safety Plan was developed to aid practitioners in identifying risks and implement remedial actions in this type of installation in order to ensure the safety of the treated water.
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Affiliation(s)
- B Reyneke
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa
| | - T Ndlovu
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa
| | - M B Vincent
- Ecosystem Environmental Services S.A., Sant Andreu de Llavaneres, Barcelona, Spain
| | - A Martínez-García
- Plataforma Solar de Almeria-CIEMAT, P.O. Box 22, Tabernas, Almería, Spain
| | - M I Polo-López
- Plataforma Solar de Almeria-CIEMAT, P.O. Box 22, Tabernas, Almería, Spain
| | - P Fernández-Ibáñez
- Plataforma Solar de Almeria-CIEMAT, P.O. Box 22, Tabernas, Almería, Spain; Nanotechnology and Integrated BioEngineering Centre, School of Engineering, University of Ulster, Newtownabbey, Northern Ireland, United Kingdom
| | - G Ferrero
- IHE Delft Institute for Water Education, Westvest 7, 2611, AX, Delft, the Netherlands
| | - S Khan
- Faculty of Health Sciences, University of Johannesburg, PO Box 17011, Doornfontein 2028, South Africa
| | - K G McGuigan
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - W Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa.
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21
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Ni J, Hatori S, Wang Y, Li YY, Kubota K. Uncovering Viable Microbiome in Anaerobic Sludge Digesters by Propidium Monoazide (PMA)-PCR. MICROBIAL ECOLOGY 2020; 79:925-932. [PMID: 31701171 DOI: 10.1007/s00248-019-01449-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 10/09/2019] [Indexed: 06/10/2023]
Abstract
Use of anaerobic sludge digester is a common practice around the world for solids digestion and methane generation from municipal sewage sludge. Understanding microbial community structure is vital to get better insight into the anaerobic digestion process and to gain better process control. However, selective analysis of viable microorganisms is limited by DNA-based assays. In this study, propidium monoazide (PMA)-PCR with 16S rRNA gene sequencing analysis was used to distinguish live and dead microorganisms based on cell membrane integrity. Microbial community structures of PMA-treated and PMA-untreated anaerobic digester sludge samples were compared. Quantitative PCR revealed that 5-30% of the rRNA genes were derived from inactive or dead cells in anaerobic sludge digesters. This caused a significant decrease in the numbers of operational taxonomic units and Chao1 and Shannon indices compared with that of the PMA-untreated sludge. Microbial community analysis showed that majority of the viable microbiome consisted of Euryarchaeota, Bacteroidetes, Deltaproteobacteria, Chloroflexi, Firmicutes, WWE1, Spirochaetes, Synergistetes, and Caldiserica. On the other hand, after the PMA treatment, numbers of Alphaproteobacteria and Betaproteobacteria declined. These were considered residual microbial members. The network analysis also revealed a relationship among the OTUs belonging to WWE1 and Bacteroidales. PMA-PCR-based 16S rRNA gene sequencing analysis is an effective tool for uncovering viable microbiome in complex environmental samples.
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Affiliation(s)
- Jialing Ni
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Shingo Hatori
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Yin Wang
- Institute of Urban Environment, Chinese Academy of Sciences, 1799 JiMei Road, Xiamen, 361021, China
| | - Yu-You Li
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Kengo Kubota
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan.
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22
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Jiang SC, Han M, Chandrasekaran S, Fang Y, Kellogg CA. Assessing the water quality impacts of two Category-5 hurricanes on St. Thomas, Virgin Islands. WATER RESEARCH 2020; 171:115440. [PMID: 31955059 PMCID: PMC7001102 DOI: 10.1016/j.watres.2019.115440] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 12/17/2019] [Accepted: 12/22/2019] [Indexed: 05/12/2023]
Abstract
Managing waterborne and water-related diseases is one of the most critical factors in the aftermath of hurricane-induced natural disasters. The goal of the study was to identify water-quality impairments in order to set the priorities for post-hurricane relief and to guide future decisions on disaster preparation and relief administration. Field investigations were carried out on St. Thomas, U.S. Virgin Islands as soon as the disaster area became accessible after the back-to-back hurricane strikes by Irma and Maria in 2017. Water samples were collected from individual household rain cisterns, the coastal ocean, and street-surface runoffs for microbial concentration. The microbial community structure and the occurrence of potential human pathogens were investigated in samples using next generation sequencing. Loop mediated isothermal amplification was employed to detect fecal indicator bacteria, Enterococcus faecalis. The results showed both fecal indicator bacteria and Legionella genetic markers were prevalent but were low in concentration in the water samples. Among the 22 cistern samples, 86% were positive for Legionella and 82% for Escherichia-Shigella. Enterococcus faecalis was detected in over 68% of the rain cisterns and in 60% of the coastal waters (n = 20). Microbial community composition in coastal water samples was significantly different from cistern water and runoff water. Although identification at bacterial genus level is not direct evidence of human pathogens, our results suggest cistern water quality needs more organized attention for protection of human health, and that preparation and prevention measures should be taken before natural disasters strike.
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Affiliation(s)
- Sunny C Jiang
- Department of Civil and Environmental Engineering, University of California, Irvine, CA, USA.
| | - Muyue Han
- Department of Civil and Environmental Engineering, University of California, Irvine, CA, USA
| | - Srikiran Chandrasekaran
- Department of Civil and Environmental Engineering, University of California, Irvine, CA, USA
| | - Yingcong Fang
- Department of Civil and Environmental Engineering, University of California, Irvine, CA, USA
| | - Christina A Kellogg
- St. Petersburg Coastal and Marine Science Center, U.S. Geological Survey, St. Petersburg, FL, USA
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23
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Baymiev AK, Baymiev AK, Kuluev BR, Shvets KY, Yamidanov RS, Matniyazov RT, Chemeris DA, Zubov VV, Alekseev YI, Mavzyutov AR, Ivanenkov YA, Chemeris AV. Modern Approaches to Differentiation of Live and Dead Bacteria Using Selective Amplification of Nucleic Acids. Microbiology (Reading) 2020. [DOI: 10.1134/s0026261720010038] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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24
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Böllmann J, Martienssen M. Comparison of different media for the detection of denitrifying and nitrate reducing bacteria in mesotrophic aquatic environments by the most probable number method. J Microbiol Methods 2019; 168:105808. [PMID: 31837971 DOI: 10.1016/j.mimet.2019.105808] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/06/2019] [Accepted: 12/10/2019] [Indexed: 10/25/2022]
Abstract
The cultivation based characterization of microbial communities and the quantification of certain functional bacterial groups is still an essential part of microbiology and microbial ecology. For plate count methods meanwhile low strength media are recommended, since they cover a broader range of different species and result in higher counts compared to established high strength media. For liquid media, as they are used for most probable number (MPN) quantifications, comparisons between high and low strength media are rare. In this study we compare the performance of different high and low strength media for the MPN quantification of nitrate reducing and denitrifying bacteria in two different fresh water environments. We also calculated the cell specific turnover rates of several denitrifying cultures previously enriched in high and low strength media from three different fresh water environments and a waste water treatment plant. For fresh water samples, our results indicate that high strength media detect higher MPN of denitrifying bacteria and in equal MPN of nitrate reducing bacteria compared to low strength media, which is in contrary to plate count techniques. For sediment samples, high and low strength media performed equal. The cell specific turnover rate was independent from the enrichment media and the media of the performance test. The cause of the lower denitrifyer MPN in low strength media remains, however, unclear. The results are important for further MPN quantifications of bacteria in nutrient poor environments and for calculations of nitrogen turnover rates by kinetical models using the number of metabolic active cells as one parameter.
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Affiliation(s)
- Jörg Böllmann
- Department of Biotechnology for water treatment, BTU-Cottbus-Senftenberg, Siemens-Halske-Ring 8, 03046 Cottbus, Germany.
| | - Marion Martienssen
- Department of Biotechnology for water treatment, BTU-Cottbus-Senftenberg, Siemens-Halske-Ring 8, 03046 Cottbus, Germany
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25
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Assessment of predatory bacteria and prey interactions using culture-based methods and EMA-qPCR. Microbiol Res 2019; 228:126305. [DOI: 10.1016/j.micres.2019.126305] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/19/2019] [Accepted: 07/20/2019] [Indexed: 10/26/2022]
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26
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Detection of viable but nonculturable Vibrio parahaemolyticus in shrimp samples using improved real-time PCR and real-time LAMP methods. Food Control 2019. [DOI: 10.1016/j.foodcont.2019.04.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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27
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Kumar SS, Ghosh AR. Assessment of bacterial viability: a comprehensive review on recent advances and challenges. Microbiology (Reading) 2019; 165:593-610. [DOI: 10.1099/mic.0.000786] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Shravanthi S. Kumar
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India
| | - Asit Ranjan Ghosh
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India
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Golpayegani A, Douraghi M, Rezaei F, Alimohammadi M, Nodehi RN. Propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR) assay for rapid detection of viable and viable but non-culturable (VBNC) Pseudomonas aeruginosa in swimming pools. JOURNAL OF ENVIRONMENTAL HEALTH SCIENCE & ENGINEERING 2019; 17:407-416. [PMID: 31297217 PMCID: PMC6582174 DOI: 10.1007/s40201-019-00359-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 02/21/2019] [Indexed: 05/17/2023]
Abstract
Lack of culturability in the viable but non-culturable (VBNC) bacteria and the ability to regain infectivity in favourable conditions is one of the new challenges of public health providers for Pseudomonas aeruginosa monitoring in environmental samples. Propidium monoazide quantitative polymerase chain reaction (PMA-qPCR) is one of the promising methods for timely detection of VBNC pathogens in environmental samples. We developed and used a method for the first time to detection of VBNC P. aeruginosa in swimming pool water samples using a membrane filter (MF). Moreover, the dominant model of the distribution of colonies on the MF and the effect of the culture medium and MF type on colony recovery by MF were evaluated. Swimming pool samples were subjected to conventional culture-based, qPCR and PMA-qPCR methods and the results were compared for the presence of VBNC P. aeruginosa in the samples. The positivity rate was 21% and 75% for P. aeruginosa in water samples as confirmed by standard culture-based and qPCR methods, respectively. Furthermore, of 24 samples, 9 (37.5%) were positive for VBNC P. aeruginosa. The developed qPCR/PMA-qPCR assay can detect the VBNC bacteria directly from aquatic samples and may result in better monitoring of recreational waters.
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Affiliation(s)
- Abdolali Golpayegani
- Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Vice-Chancellor for Health, Bam University of Medical Sciences, Bam, Iran
- Environmental Health Engineering Research Center, Kerman University of Medical Sciences, Kerman, Iran
| | - Masoumeh Douraghi
- Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Farhad Rezaei
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmood Alimohammadi
- Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Center for Water Quality Research (CWQR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, PO Box 14155-6446, Tehran, Iran
| | - Ramin Nabizadeh Nodehi
- Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Center for Water Quality Research (CWQR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, PO Box 14155-6446, Tehran, Iran
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Ge J, Huang G, Sun X, Yin H, Han L. New insights into the kinetics of bacterial growth and decay in pig manure-wheat straw aerobic composting based on an optimized PMA-qPCR method. Microb Biotechnol 2019; 12:502-514. [PMID: 30838800 PMCID: PMC6465228 DOI: 10.1111/1751-7915.13380] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 01/01/2019] [Accepted: 02/04/2019] [Indexed: 02/04/2023] Open
Abstract
Aerobic composting is a bacteria-driven process to degrade and recycle wastes. This study quantified the kinetics of bacterial growth and decay during pig manure-wheat straw composting, which may provide insights into microbial reaction mechanisms and composting operations. First, a propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR) method was developed to quantify the viable bacteria concentration of composting samples. The optimal PMA concentration and light exposure time were 100 μM and 8 min respectively. Subsequently, the concentrations of total and decayed bacteria were quantified. Viable and decayed bacteria coexisted during the entire composting period (experiments A and B), and the proportion of viable bacteria finally fell to only 35.1%. At the beginning, bacteria grew logarithmically and decayed rapidly. Later, the bacterial growth in experiment A remained stable, while that of experiment B was stable at first and then decomposed. The duration of the stable stage was positively related to the soluble sugar content of composting materials. The logarithmic growth and rapid decay of bacteria followed Monod equations with a specific growth (0.0317 ± 0.0033 h-1 ) and decay rate (0.0019 ± 0.0000 h-1 ). The findings better identified the bacterial growth stages and might enable better prediction of composting temperatures and the degree of maturation.
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Affiliation(s)
- Jinyi Ge
- Biomass Resources and Utilization LaboratoryCollege of EngineeringChina Agricultural University (East Campus)Beijing100083China
- Department of Civil and Environmental EngineeringPrinceton UniversityPrincetonNJ08540USA
| | - Guangqun Huang
- Biomass Resources and Utilization LaboratoryCollege of EngineeringChina Agricultural University (East Campus)Beijing100083China
| | - Xiaoxi Sun
- Biomass Resources and Utilization LaboratoryCollege of EngineeringChina Agricultural University (East Campus)Beijing100083China
| | - Hongjie Yin
- Biomass Resources and Utilization LaboratoryCollege of EngineeringChina Agricultural University (East Campus)Beijing100083China
| | - Lujia Han
- Biomass Resources and Utilization LaboratoryCollege of EngineeringChina Agricultural University (East Campus)Beijing100083China
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Rosenberg M, Azevedo NF, Ivask A. Propidium iodide staining underestimates viability of adherent bacterial cells. Sci Rep 2019; 9:6483. [PMID: 31019274 PMCID: PMC6482146 DOI: 10.1038/s41598-019-42906-3] [Citation(s) in RCA: 171] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 04/08/2019] [Indexed: 02/07/2023] Open
Abstract
Combining membrane impermeable DNA-binding stain propidium iodide (PI) with membrane-permeable DNA-binding counterstains is a widely used approach for bacterial viability staining. In this paper we show that PI staining of adherent cells in biofilms may significantly underestimate bacterial viability due to the presence of extracellular nucleic acids (eNA). We demonstrate that gram-positive Staphylococcus epidermidis and gram-negative Escherichia coli 24-hour initial biofilms on glass consist of 76 and 96% PI-positive red cells in situ, respectively, even though 68% the cells of either species in these aggregates are metabolically active. Furthermore, 82% of E. coli and 89% S. epidermidis are cultivable after harvesting. Confocal laser scanning microscopy (CLSM) revealed that this false dead layer of red cells is due to a subpopulation of double-stained cells that have green interiors under red coating layer which hints at eNA being stained outside intact membranes. Therefore, viability staining results of adherent cells should always be validated by an alternative method for estimating viability, preferably by cultivation.
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Affiliation(s)
- Merilin Rosenberg
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia. .,Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia.
| | - Nuno F Azevedo
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy; Department of Chemical Engineering; Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Angela Ivask
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
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Zhai L, Li J, Tao T, Lu Z, Lv F, Bie X. Propidium monoazide real-time PCR amplification for viable Salmonella species and Salmonella Heidelberg in pork. Can J Microbiol 2019; 65:477-485. [PMID: 30865841 DOI: 10.1139/cjm-2018-0547] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Salmonella enterica serovar Heidelberg causes foodborne infections and is a major threat to the food chain and public health. In this study, we aimed to develop a rapid molecular typing approach to identify Salmonella enterica serovar Heidelberg. Using comparative genomics, four serovar-specific gene fragments were identified, and a real-time polymerase chain reaction (PCR) combined with a propidium monoazide (PMA) pretreatment method was developed for simultaneous detection of viable Salmonella sp. (invA) and Salmonella Heidelberg (SeHA_C3258). The assay showed 100% specificity for all strains tested. The assay was able to distinguish effectively viable or dead cells with the PMA. The detection limit was 2.4 CFU/mL following 6 h of incubation in enrichment Luria-Bertani medium, and the assay could detect 1.7 × 102 CFU/mL in the presence of pork background flora. In artificially contaminated pork, real-time PCR detected inoculum levels of 1.15 CFU/25 g of pork after a 6 h enrichment. Thus, our findings indicated that this comparative genomics approach could be used to screen for serovar-specific fragments and that real-time PCR with PMA was a simple and reliable method for detecting viability of Salmonella species and Salmonella Heidelberg.
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Affiliation(s)
- Ligong Zhai
- a College of Food Science and Technology, Nanjing Agricultural University, Key Laboratory of Food Processing and Quality Control, Ministry of Agriculture of China, Nanjing, Jiangsu Province, China.,b College of Food Engineering, Anhui Science and Technology University Chuzhou, Anhui Province, China
| | - Junjie Li
- a College of Food Science and Technology, Nanjing Agricultural University, Key Laboratory of Food Processing and Quality Control, Ministry of Agriculture of China, Nanjing, Jiangsu Province, China
| | - Tingting Tao
- a College of Food Science and Technology, Nanjing Agricultural University, Key Laboratory of Food Processing and Quality Control, Ministry of Agriculture of China, Nanjing, Jiangsu Province, China
| | - Zhaoxin Lu
- a College of Food Science and Technology, Nanjing Agricultural University, Key Laboratory of Food Processing and Quality Control, Ministry of Agriculture of China, Nanjing, Jiangsu Province, China
| | - Fengxia Lv
- a College of Food Science and Technology, Nanjing Agricultural University, Key Laboratory of Food Processing and Quality Control, Ministry of Agriculture of China, Nanjing, Jiangsu Province, China
| | - Xiaomei Bie
- a College of Food Science and Technology, Nanjing Agricultural University, Key Laboratory of Food Processing and Quality Control, Ministry of Agriculture of China, Nanjing, Jiangsu Province, China
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Salas-Massó N, Linh QT, Chin WH, Wolff A, Andree KB, Furones MD, Figueras MJ, Bang DD. The Use of a DNA-Intercalating Dye for Quantitative Detection of Viable Arcobacter spp. Cells (v-qPCR) in Shellfish. Front Microbiol 2019; 10:368. [PMID: 30873146 PMCID: PMC6403187 DOI: 10.3389/fmicb.2019.00368] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 02/12/2019] [Indexed: 11/13/2022] Open
Abstract
The genus Arcobacter (Vandamme et al., 1991), comprised of Campylobacter-related species, are considered zoonotic emergent pathogens. The presence of Arcobacter in food products like shellfish, has an elevated incidence worldwide. In this study, we developed a specific viable quantitative PCR (v-qPCR), using the dye propidium monoazide (PMA), for quantification of the viable Arcobacter spp. cells in raw oysters and mussels. The high selectivity of primers was demonstrated by using purified DNA from 38 different species, 20 of them from the genus Arcobacter. The optimization of PMA concentration showed that 20 μM was considered as an optimal concentration that inhibits the signal from dead cells at different concentrations (OD550 from 0.2 to 0.8) and at different ratios of live: dead cells (50:50 and 90:10). The v-qPCR results from shellfish samples were compared with those obtained in parallel using several culture isolation approaches (i.e., direct plating on marine and blood agar and by post-enrichment culturing in both media). The enrichment was performed in parallel in Arcobacter-CAT broth with and without adding NaCl. Additionally, the v-qPCR results were compared to those obtained with traditional quantitative (qPCR). The v-qPCR and the qPCR resulted in c.a. 94% of positive detection of Arcobacter vs. 41% obtained by culture approaches. When examining the reduction effect resulting from the use of v-qPCR, samples pre-enriched in Arcobacter-CAT broth supplemented with 2.5% NaCl showed a higher reduction (3.27 log copies) than that of samples obtained directly and those pre-enriched in Arcobacter-CAT broth isolation (1.05 and 1.04). When the v-qPCR was applied to detect arcobacter from real shellfish samples, 15/17 samples tested positive for viable Arcobacter with 3.41 to 8.70 log copies 1g-1. This study offers a new tool for Arcobacter surveillance in seafood.
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Affiliation(s)
- Nuria Salas-Massó
- Unitat de Microbiologia, Departament de Ciènces Médiques Bàsiques, Facultat de Medicina i Ciències de la Salut, Institut d’Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus, Spain
- IRTA-Sant Carles de la Ràpita, Sant Carles de la Ràpita, Spain
| | - Quyen Than Linh
- Department of Bioengineering and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | | | - Anders Wolff
- Department of Bioengineering and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Karl B. Andree
- IRTA-Sant Carles de la Ràpita, Sant Carles de la Ràpita, Spain
| | | | - María José Figueras
- Unitat de Microbiologia, Departament de Ciènces Médiques Bàsiques, Facultat de Medicina i Ciències de la Salut, Institut d’Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus, Spain
| | - Dang Duong Bang
- Division of Microbiology, National Food Institute, Technical University of Denmark, Lyngby, Denmark
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Caicedo C, Rosenwinkel KH, Exner M, Verstraete W, Suchenwirth R, Hartemann P, Nogueira R. Legionella occurrence in municipal and industrial wastewater treatment plants and risks of reclaimed wastewater reuse: Review. WATER RESEARCH 2019; 149:21-34. [PMID: 30445393 DOI: 10.1016/j.watres.2018.10.080] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/26/2018] [Accepted: 10/27/2018] [Indexed: 05/22/2023]
Abstract
Wastewater treatment plants (WWTPs) have been identified as confirmed but until today underestimated sources of Legionella, playing an important role in local and community cases and outbreaks of Legionnaires' disease. In general, aerobic biological systems provide an optimum environment for the growth of Legionella due to high organic nitrogen and oxygen concentrations, ideal temperatures and the presence of protozoa. However, few studies have investigated the occurrence of Legionella in WWTPs, and many questions in regards to the interacting factors that promote the proliferation and persistence of Legionella in these treatment systems are still unanswered. This critical review summarizes the current knowledge about Legionella in municipal and industrial WWTPs, the conditions that might support their growth, as well as control strategies that have been applied. Furthermore, an overview of current quantification methods, guidelines and health risks associated with Legionella in reclaimed wastewater is also discussed in depth. A better understanding of the conditions promoting the occurrence of Legionella in WWTPs will contribute to the development of improved wastewater treatment technologies and/or innovative mitigation approaches to minimize future Legionella outbreaks.
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Affiliation(s)
- C Caicedo
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany.
| | - K-H Rosenwinkel
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany
| | - M Exner
- University of Bonn, Institute for Hygiene and Public Health, Bonn, Germany
| | - W Verstraete
- Ghent University, CMET, Ghent, and Avecom, Wondelgem, Belgium
| | - R Suchenwirth
- Public Health Office of Lower Saxony, Hannover, Germany
| | - P Hartemann
- Faculty of Medicine, Department of Environment and Public Health, Nancy University-CHU Nancy, Vandoeuvre Les Nancy, France
| | - R Nogueira
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany.
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Comparison of conventional plating, PMA-qPCR, and flow cytometry for the determination of viable enterotoxigenic Escherichia coli along a gastrointestinal in vitro model. Appl Microbiol Biotechnol 2018; 102:9793-9802. [PMID: 30238141 DOI: 10.1007/s00253-018-9380-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 09/06/2018] [Accepted: 09/06/2018] [Indexed: 12/26/2022]
Abstract
Recent technological advances for bacterial viability assessment using molecular methods or flow cytometry can provide meaningful interest for the demarcation between live and dead microorganisms. Nonetheless, these methods have been scarcely applied to foodborne pathogens and never for directly assessing their viability within the human digestive environment. The purpose of this study was to compare two methods based on membrane integrity (propidium monoazide (PMA) q-PCR and Live/Dead flow cytometry) and the classical plate-count method to determine the viability of a common foodborne pathogen, enterotoxigenic Escherichia coli (ETEC), during its transit trough simulated human gastrointestinal environment. Viable ETEC counts in the gastric and small intestinal compartments of the gastrointestinal TIM model indicated a consensus between the three tested methods (PMA-qPCR, flow cytometry, and plate counts). In a further step, flow cytometry analysis appeared as the preferred method to elucidate ETEC physiological states in the in vitro digestive environment by discriminating four subpopulations, while PMA-qPCR can only distinguish two. The defined viable/altered ETEC population was found during all in vitro digestions, but mainly in the gastric compartment. Being able to discriminate the particular physiological states of pathogenic microorganisms in the digestive environment is of high interest, because if some cells are not observable on culture media, they might keep their ability to express virulence functions.
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Huang Z, Zheng J, Shi C, Chen Q. Flow cytometry-based method facilitates optimization of PMA treatment condition for PMA-qPCR method. Mol Cell Probes 2018; 40:37-39. [PMID: 29792916 DOI: 10.1016/j.mcp.2018.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 05/10/2018] [Accepted: 05/21/2018] [Indexed: 11/18/2022]
Abstract
Coupling propidium monoazide (PMA) with quantitative PCR (PMA-qPCR) has been successfully applied to specific detection and quantification of viable cells in various samples. The optimal PMA treatment condition is usually determined through qPCR. However, it is a tedious, time consuming and costly process including DNA extraction and qPCR. To overcome this problem, a flow cytometry-based (FCM-based) method was first proposed in this study to replace qPCR for screening of the optimal PMA treatment condition for Helicobacter pylori, since the pure culture treated with PMA was actually a single cell suspension with fluorescent dye. Results showed that the optimal PMA treatment condition (30 μM of PMA and 8 min of exposure time) determined by the novel method was the same as that determined by the qPCR-based method, which demonstrate the feasibility of this approach. In addition, with the comparison of the qPCR-based method, the FCM-based method allows screening of the optimal PMA treatment condition become much more simple, rapid and economical.
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Affiliation(s)
- Zhiqing Huang
- Fujian Medical University Union Hospital, Fuzhou, Fujian Province 350001, China
| | - Jianwei Zheng
- Fujian Medical University Union Hospital, Fuzhou, Fujian Province 350001, China
| | - Chunmei Shi
- Fujian Medical University Union Hospital, Fuzhou, Fujian Province 350001, China
| | - Qiang Chen
- Fujian Medical University Union Hospital, Fuzhou, Fujian Province 350001, China; Fujian Medical University Stem Cell Research Institute, Fuzhou, Fujian Province 350004, China.
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36
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Lee S, Bae S. Evaluating the newly developed dye, DyeTox13 Green C-2 Azide, and comparing it with existing EMA and PMA for the differentiation of viable and nonviable bacteria. J Microbiol Methods 2018; 148:33-39. [DOI: 10.1016/j.mimet.2018.03.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 03/10/2018] [Accepted: 03/27/2018] [Indexed: 10/17/2022]
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