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Kao YT, Calabrese S, Borst N, Lehnert M, Lai YK, Schlenker F, Juelg P, Zengerle R, Garstecki P, von Stetten F. Microfluidic One-Pot Digital Droplet FISH Using LNA/DNA Molecular Beacons for Bacteria Detection and Absolute Quantification. BIOSENSORS 2022; 12:bios12040237. [PMID: 35448297 PMCID: PMC9032532 DOI: 10.3390/bios12040237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/06/2022] [Accepted: 04/10/2022] [Indexed: 02/06/2023]
Abstract
We demonstrate detection and quantification of bacterial load with a novel microfluidic one-pot wash-free fluorescence in situ hybridization (FISH) assay in droplets. The method offers minimal manual workload by only requiring mixing of the sample with reagents and loading it into a microfluidic cartridge. By centrifugal microfluidic step emulsification, our method partitioned the sample into 210 pL (73 µm in diameter) droplets for bacterial encapsulation followed by in situ permeabilization, hybridization, and signal detection. Employing locked nucleic acid (LNA)/DNA molecular beacons (LNA/DNA MBs) and NaCl-urea based hybridization buffer, the assay was characterized with Escherichia coli, Klebsiella pneumonia, and Proteus mirabilis. The assay performed with single-cell sensitivity, a 4-log dynamic range from a lower limit of quantification (LLOQ) at ~3 × 103 bacteria/mL to an upper limit of quantification (ULOQ) at ~3 × 107 bacteria/mL, anda linearity R2 = 0.976. The total time-to-results for detection and quantification was around 1.5 hours.
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Affiliation(s)
- Yu-Ting Kao
- Laboratory for MEMS Applications, IMTEK-Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (Y.-T.K.); (N.B.); (Y.-K.L.); (R.Z.)
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland;
| | - Silvia Calabrese
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (S.C.); (M.L.); (F.S.); (P.J.)
| | - Nadine Borst
- Laboratory for MEMS Applications, IMTEK-Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (Y.-T.K.); (N.B.); (Y.-K.L.); (R.Z.)
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (S.C.); (M.L.); (F.S.); (P.J.)
| | - Michael Lehnert
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (S.C.); (M.L.); (F.S.); (P.J.)
| | - Yu-Kai Lai
- Laboratory for MEMS Applications, IMTEK-Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (Y.-T.K.); (N.B.); (Y.-K.L.); (R.Z.)
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland;
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (S.C.); (M.L.); (F.S.); (P.J.)
| | - Franziska Schlenker
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (S.C.); (M.L.); (F.S.); (P.J.)
| | - Peter Juelg
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (S.C.); (M.L.); (F.S.); (P.J.)
| | - Roland Zengerle
- Laboratory for MEMS Applications, IMTEK-Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (Y.-T.K.); (N.B.); (Y.-K.L.); (R.Z.)
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (S.C.); (M.L.); (F.S.); (P.J.)
| | - Piotr Garstecki
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland;
| | - Felix von Stetten
- Laboratory for MEMS Applications, IMTEK-Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (Y.-T.K.); (N.B.); (Y.-K.L.); (R.Z.)
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (S.C.); (M.L.); (F.S.); (P.J.)
- Correspondence: ; Tel.: +49-761-203-73243
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Diversity of Antibiotic Resistance genes and Transfer Elements-Quantitative Monitoring (DARTE-QM): a method for detection of antimicrobial resistance in environmental samples. Commun Biol 2022; 5:216. [PMID: 35301418 PMCID: PMC8931014 DOI: 10.1038/s42003-022-03155-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 02/02/2022] [Indexed: 12/01/2022] Open
Abstract
Effective monitoring of antibiotic resistance genes and their dissemination in environmental ecosystems has been hindered by the cost and efficiency of methods available for the task. We developed the Diversity of Antibiotic Resistance genes and Transfer Elements-Quantitative Monitoring (DARTE-QM), a method implementing TruSeq high-throughput sequencing to simultaneously sequence thousands of antibiotic resistant gene targets representing a full-spectrum of antibiotic resistance classes common to environmental systems. In this study, we demonstrated DARTE-QM by screening 662 antibiotic resistance genes within complex environmental samples originated from manure, soil, and livestock feces, in addition to a mock-community reference to assess sensitivity and specificity. DARTE-QM offers a new approach to studying antibiotic resistance in environmental microbiomes, showing advantages in efficiency and the ability to scale for many samples. This method provides a means of data acquisition that will alleviate some of the obstacles that many researchers in this area currently face. Smith et al. present DARTE-QM, a highthroughput sequencing method for screening environmental DNA samples for antibiotic resistance genes on a broad scale. This method is demonstrated as effective on soil, manure and livestock fecal samples, as well as a synthetic mock-community reference.
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Kachiprath B, Jayanath G, Solomon S, Sarasan M. CTAB influenced differential elution of metagenomic DNA from saltpan and marine sediments. 3 Biotech 2018; 8:44. [PMID: 29354355 DOI: 10.1007/s13205-017-1078-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 12/27/2017] [Indexed: 11/26/2022] Open
Abstract
A simple, reliable method for genomic DNA extraction from sediments with minimum contaminants was developed to address the risk of poor quality DNA in metagenomic studies. Nine DNA extraction methods using 20% cetyl-trimethyl-ammonium bromide (CTAB) were performed and compared to develop an extraction protocol that can offer humic acid-free metagenomic DNA from marine and saltpan sediments. Community DNA extraction was executed via., Zhou et al. modified protocol using 20% CTAB treatment at different steps to compare the efficacy of humic acid removal. Out of nine DNA extraction methods, method 6 significantly improved the quality of DNA with efficient removal of humic substances. 16S rRNA gene amplification and spectrophotometric analysis confirmed the efficiency of method 6 to remove DNA inhibitors from marine sediments as well as saltpan samples. Inhibitors extracted along with metagenomic DNA outcome increased DNA yield and PCR inhibition in method 1 and 3. However, repeated 20% CTAB wash in method 6 ensured 16S amplification and least yield and concentration. Current study explains a detailed protocol based on 20% CTAB wash for the extraction of humic acid-free DNA from diverse sediment samples.
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Affiliation(s)
- Bhavya Kachiprath
- Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Cochin, Kerala 682016 India
| | - G Jayanath
- Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Cochin, Kerala 682016 India
| | - Solly Solomon
- Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Cochin, Kerala 682016 India
| | - Manomi Sarasan
- Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Cochin, Kerala 682016 India
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Ilha EC, Scariot MC, Treml D, Pereira TP, Sant′Anna ES, Prudêncio ES, Arisi ACM. Comparison of real-time PCR assay and plate count for Lactobacillus paracasei enumeration in yoghurt. ANN MICROBIOL 2015. [DOI: 10.1007/s13213-015-1137-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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Desneux J, Chemaly M, Pourcher AM. Experimental design for the optimization of propidium monoazide treatment to quantify viable and non-viable bacteria in piggery effluents. BMC Microbiol 2015; 15:164. [PMID: 26276157 PMCID: PMC4537567 DOI: 10.1186/s12866-015-0505-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 08/07/2015] [Indexed: 01/20/2023] Open
Abstract
Background Distinguishing between viable and dead bacteria in animal and urban effluents is a major challenge. Among existing methods, propidium monoazide (PMA)-qPCR is a promising way to quantify viable cells. However, its efficiency depends on the composition of the effluent, particularly on total suspended solids (TSS)) and on methodological parameters. The aim of this study was evaluate the influence of three methodological factors (concentration of PMA, incubation time and photoactivation time) on the efficiency of PMA-qPCR to quantify viable and dead cells of Listeria monocytogenes used as a microorganism model, in two piggery effluents (manure and lagoon effluent containing 20 and 0.4 TSS g.kg−1, respectively). An experimental design strategy (Doehlert design and desirability function) was used to identify the experimental conditions to achieve optimal PMA-qPCR results. Results The quantification of viable cells of L. monocytogenes was mainly influenced by the concentration of PMA in the manure and by the duration of photoactivation in the lagoon effluent. Optimal values differed with the matrix: 55 μM PMA, 5 min incubation and 56 min photoactivation for manure and 20 μM PMA, 20 min incubation and 30 min photoactivation for lagoon effluent. Applied to five manure and four lagoon samples, these conditions resulted in satisfactory quantification of viable and dead cells. Conclusion PMA-qPCR can be used on undiluted turbid effluent with high levels of TSS, provided preliminary tests are performed to identify the optimal conditions.
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Affiliation(s)
- Jérémy Desneux
- IRSTEA, 17 avenue de Cucillé, 35044, Rennes, France. .,Université Européenne de Bretagne, Rennes, France.
| | - Marianne Chemaly
- Université Européenne de Bretagne, Rennes, France. .,French Agency for Food Environmental and Occupational Health Safety, Anses, Laboratory of Ploufragan-Plouzané, F-22440, Ploufragan, France.
| | - Anne-Marie Pourcher
- IRSTEA, 17 avenue de Cucillé, 35044, Rennes, France. .,Université Européenne de Bretagne, Rennes, France.
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