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Investigation of Conditions for Capture of Live Legionella pneumophila with Polyclonal and Recombinant Antibodies. BIOSENSORS 2022; 12:bios12060380. [PMID: 35735528 PMCID: PMC9221320 DOI: 10.3390/bios12060380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/16/2022] [Accepted: 05/27/2022] [Indexed: 11/30/2022]
Abstract
Since Legionella pneumophila has caused punctual epidemics through various water systems, the need for a biosensor for fast and accurate detection of pathogenic bacteria in industrial and environmental water has increased. In this report, we evaluated conditions for the capture of live L. pneumophila on a surface by polyclonal antibodies (pAb) and recombinant antibodies (recAb) targeting the bacterial lipopolysaccharide. Using immunoassay and PCR quantification, we demonstrated that, when exposed to live L. pneumophila in PBS or in a mixture containing other non-target bacteria, recAb captured one third fewer L. pneumophila than pAb, but with a 40% lower standard deviation, even when using the same batch of pAb. The presence of other bacteria did not interfere with capture nor increase background by either Ab. Increased reproducibility, as manifested by low standard deviation, is a characteristic that is coveted for biosensing. Hence, the recAb provided a better choice for immune adhesion in biosensors even though it was slightly less sensitive than pAb. Polyclonal or recombinant antibodies can specifically capture large targets such as whole bacteria, and this opens the door to multiple biosensor approaches where any of the components of the bacteria can then be measured for detection or characterisation.
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Shi J, Chi H, Cao A, Song Y, Zhu M, Zhang L, Xu F, Huang J. Development of IMBs-qPCR detection method for Yersinia enterocolitica based on the foxA gene. Arch Microbiol 2021; 203:4653-4662. [PMID: 34173855 DOI: 10.1007/s00203-021-02459-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 06/21/2021] [Accepted: 06/23/2021] [Indexed: 11/29/2022]
Abstract
Yersinia enterocolitica is an important zoonotic pathogen, which seriously endangers food-safety risk. In this study, the recombinant outer membrane protein OmpF and its antibody were prepared and coupled with immunomagnetic beads (IMBs) to capture Y. enterocolitica in food samples, combining the quantitative PCR detection with primers of virulence factor gene foxA for Yersinia enterocolitica contamination. The results showed that the capture efficiency of approximately 80% using anti-OmpF antibody-immunomagnetic beads and linearly dependent capture under 101-105 CFU/mL Y. enterocolitica compared with less than 10% capture of other bacteria. The detection limit of 64 CFU/mL was obtained based on foxA gene PCR detection combined with capture of the anti-OmpF antibody-immunomagnetic beads to detect Yersinia enterocolitica in artificially contaminated milk and pork samples. Compared to the culture method, the developed IMBs-qPCR method has higher consistency, was less time consuming, which taken together provides an effective alternative method for rapid detection of Y. enterocolitica in food.
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Affiliation(s)
- Jingxuan Shi
- School of Life Sciences, Tianjin University, China. No. 92, Weijin road, Nankai District, Tianjin, 300072, China
| | - Heng Chi
- School of Life Sciences, Tianjin University, China. No. 92, Weijin road, Nankai District, Tianjin, 300072, China
| | - Aiping Cao
- School of Life Sciences, Tianjin University, China. No. 92, Weijin road, Nankai District, Tianjin, 300072, China
| | - Yinna Song
- School of Life Sciences, Tianjin University, China. No. 92, Weijin road, Nankai District, Tianjin, 300072, China
| | - Min Zhu
- School of Life Sciences, Tianjin University, China. No. 92, Weijin road, Nankai District, Tianjin, 300072, China
| | - Lilin Zhang
- School of Life Sciences, Tianjin University, China. No. 92, Weijin road, Nankai District, Tianjin, 300072, China
| | - Fuzhou Xu
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, 100097, Beijing, People's Republic of China.
| | - Jinhai Huang
- School of Life Sciences, Tianjin University, China. No. 92, Weijin road, Nankai District, Tianjin, 300072, China.
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Cervero-Aragó S, Schrammel B, Dietersdorfer E, Sommer R, Lück C, Walochnik J, Kirschner A. Viability and infectivity of viable but nonculturable Legionella pneumophila strains induced at high temperatures. WATER RESEARCH 2019; 158:268-279. [PMID: 31048196 PMCID: PMC6520252 DOI: 10.1016/j.watres.2019.04.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/05/2019] [Accepted: 04/06/2019] [Indexed: 06/09/2023]
Abstract
Thermal disinfection is commonly used to prevent the proliferation of culturable Legionella in engineered water systems (EWS). In response to such stress, culturable Legionella populations can switch into a viable but nonculturable (VBNC) state. The importance of such VBNC Legionella cells is currently hotly debated. Here, we investigated the stress response patterns and transitions of the bacteria to the VBNC state at 55 °C, 60 °C and 70 °C on two L. pneumophila strains for >80 days using a combination of cell-based viability indicators. Complete loss of culturability at 55 °C, 60 °C and 70 °C occurred after 3-8 h, 60 min and <2 min, respectively. In contrast, L. pneumophila strains required 9 days at 55 °C, 8 h at 60 °C and 20 min at 70 °C to achieve a 2 log reduction in cells with intact membranes and high esterase activity; a 4 log reduction was achieved only after 150, 8-15 and 1-4 days, respectively. In parallel, the presence of diagnostic outer-membrane epitopes (OMEs) and changes in the infectivity patterns of the two strains towards amoebae and THP-1 cells were assessed. OMEs were more persistent than viability indicators, showing their potential as targets for VBNC Legionella detection. L. pneumophila strains infected amoebae and THP-1 cells for at least 85 days at 55 °C and 60 °C and for up to 8 days at 70 °C. However, they did so with reduced efficiency, requiring prolonged co-incubation times with the hosts and higher Legionella cell numbers in comparison to culturable cells. Consequently, infection of amoebae by thermally induced VBNC L. pneumophila with lowered virulence can be expected in EWS. Although the gold standard method cannot detect VBNC Legionella, it provides important information about the most virulent bacterial subpopulations. Our results indicate that a prolonged thermal regime ≥60 °C at the central parts of warm water systems is not only effective against culturable L. pneumophila but in the long run even against VBNC cells.
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Affiliation(s)
- Sílvia Cervero-Aragó
- Medical University of Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene, Kinderspitalgasse 15, A-1090, Vienna, Austria; Interuniversity Cooperation Centre for Water & Health, Vienna, Austria.
| | - Barbara Schrammel
- Medical University of Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene, Kinderspitalgasse 15, A-1090, Vienna, Austria
| | - Elisabeth Dietersdorfer
- Medical University of Vienna, Institute of Specific Prophylaxis and Tropical Medicine, Kinderspitalgasse 15, A-1090, Vienna, Austria
| | - Regina Sommer
- Medical University of Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene, Kinderspitalgasse 15, A-1090, Vienna, Austria; Interuniversity Cooperation Centre for Water & Health, Vienna, Austria
| | - Christian Lück
- Technical University Dresden, Institute for Medical Microbiology and Hygiene, Medical Faculty "Carl Gustav Carus", Helmholtzstr. 10, D 01069, Dresden, Germany
| | - Julia Walochnik
- Medical University of Vienna, Institute of Specific Prophylaxis and Tropical Medicine, Kinderspitalgasse 15, A-1090, Vienna, Austria
| | - Alexander Kirschner
- Medical University of Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene, Kinderspitalgasse 15, A-1090, Vienna, Austria; Interuniversity Cooperation Centre for Water & Health, Vienna, Austria; Karl Landsteiner University of Health Sciences, Division Water Quality and Health, Dr. Karl Dorrekstraße 30, A-3400, Krems, Austria
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