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Randazzo W, Piqueras J, Rodríguez-Díaz J, Aznar R, Sánchez G. Improving efficiency of viability-qPCR for selective detection of infectious HAV in food and water samples. J Appl Microbiol 2018; 124:958-964. [PMID: 28649706 DOI: 10.1111/jam.13519] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 06/16/2017] [Accepted: 06/16/2017] [Indexed: 11/27/2022]
Abstract
AIM To improve the efficacy of intercalating dyes to distinguishing between infectious and inactivated hepatitis A virus (HAV) in food. METHODS AND RESULTS Different intercalating dyes were evaluated for the discrimination between infectious and thermally inactivated HAV suspensions combining with the RT-qPCR proposed in the ISO 15216. Among them, PMAxx was the best dye in removing the RT-qPCR signal from inactivated HAV. Applied to lettuce and spinach, PMAxx-Triton pretreatment resulted in complete removal of the RT-qPCR signal from inactivated HAV. Likewise, this study demonstrates that this pretreatment is suitable for the discrimination of inactivated HAV in shellfish without further sample dilution. In mussels and oysters, the developed viability RT-qPCR method reduced the signal of inactivated HAV between 1·7 and 2·2 logs at high inoculation level, and signal was completely removed at low inoculation level. CONCLUSIONS This study showed that the use of PMAxx is an important improvement to assess HAV infectivity by RT-qPCR. It was shown that PMAxx-Triton pretreatment is suitable for the analysis of infectious HAV in complex food samples such as vegetables and shellfish. SIGNIFICANCE AND IMPACT OF THE STUDY The PMAxx-Triton pretreatment can be easily incorporated to the ISO norm for infectious virus detection.
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Affiliation(s)
- W Randazzo
- Department of Microbiology and Ecology, University of Valencia, Burjassot, Valencia, Spain
- Department of Preservation and Food Safety Technologies (IATA-CSIC), Paterna, Valencia, Spain
| | - J Piqueras
- Department of Microbiology and Ecology, University of Valencia, Burjassot, Valencia, Spain
- Department of Preservation and Food Safety Technologies (IATA-CSIC), Paterna, Valencia, Spain
| | - J Rodríguez-Díaz
- Department of Microbiology and Ecology, University of Valencia, Burjassot, Valencia, Spain
- Institute for Clinical Research of the Hospital Clínico Universitario (INCLIVA), Valencia, Spain
| | - R Aznar
- Department of Microbiology and Ecology, University of Valencia, Burjassot, Valencia, Spain
- Department of Preservation and Food Safety Technologies (IATA-CSIC), Paterna, Valencia, Spain
| | - G Sánchez
- Department of Microbiology and Ecology, University of Valencia, Burjassot, Valencia, Spain
- Department of Preservation and Food Safety Technologies (IATA-CSIC), Paterna, Valencia, Spain
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Fraisse A, Niveau F, Hennechart-Collette C, Coudray-Meunier C, Martin-Latil S, Perelle S. Discrimination of infectious and heat-treated norovirus by combining platinum compounds and real-time RT-PCR. Int J Food Microbiol 2018; 269:64-74. [DOI: 10.1016/j.ijfoodmicro.2018.01.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 01/12/2018] [Accepted: 01/15/2018] [Indexed: 01/16/2023]
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Randazzo W, Khezri M, Ollivier J, Le Guyader FS, Rodríguez-Díaz J, Aznar R, Sánchez G. Optimization of PMAxx pretreatment to distinguish between human norovirus with intact and altered capsids in shellfish and sewage samples. Int J Food Microbiol 2017; 266:1-7. [PMID: 29156242 DOI: 10.1016/j.ijfoodmicro.2017.11.011] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 11/19/2022]
Abstract
Shellfish contamination by human noroviruses (HuNoVs) is a serious health and economic problem. Recently an ISO procedure based on RT-qPCR for the quantitative detection of HuNoVs in shellfish has been issued, but these procedures cannot discriminate between inactivated and potentially infectious viruses. The aim of the present study was to optimize a pretreatment using PMAxx to better discriminate between intact and heat-treated HuNoVs in shellfish and sewage. To this end, the optimal conditions (30min incubation with 100μM of PMAxx and 0.5% of Triton, and double photoactivation) were applied to mussels, oysters and cockles artificially inoculated with thermally-inactivated (99°C for 5min) HuNoV GI and GII. This pretreatment reduced the signal of thermally-inactivated HuNoV GI in cockles and HuNoV GII in mussels by >3 log. Additionally, this pretreatment reduced the signal of thermally-inactivated HuNoV GI and GII between 1 and 1.5 log in oysters. Thermal inactivation of HuNoV GI and GII in PBS, sewage and bioaccumulated oysters was also evaluated by the PMAxx-Triton pretreatment. Results showed significant differences between reductions observed in the control and PMAxx-treated samples in PBS following treatment at 72 and 95°C for 15min. In sewage, the RT-qPCR signal of HuNoV GI was completely removed by the PMAxx pretreatment after heating at 72 and 95°C, while the RT-qPCR signal for HuNoV GII was completely eliminated only at 95°C. Finally, the PMAxx-Triton pretreatment was applied to naturally contaminated sewage and oysters, resulting in most of the HuNoV genomes quantified in sewage and oyster samples (12 out of 17) corresponding to undamaged capsids. Although this procedure may still overestimate infectivity, the PMAxx-Triton pretreatment represents a step forward to better interpret the quantification of intact HuNoVs in complex matrices, such as sewage and shellfish, and it could certainly be included in the procedures based on RT-qPCR.
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Affiliation(s)
- Walter Randazzo
- Department of Microbiology and Ecology, University of Valencia, Av. Dr. Moliner, 50, 46100 Burjassot, Valencia, Spain; Department of Preservation and Food Safety Technologies, IATA-CSIC, Av. Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - Mohammad Khezri
- Department of Seafood Processing, Faculty of Marine Science, Tarbiat Modares University, Noor, Iran
| | - Joanna Ollivier
- Laboratoire de Microbiologie, LSEM-SG2M, IFREMER, BP 21105, 44311 Nantes Cedex 03, France
| | - Françoise S Le Guyader
- Laboratoire de Microbiologie, LSEM-SG2M, IFREMER, BP 21105, 44311 Nantes Cedex 03, France
| | - Jesús Rodríguez-Díaz
- Department of Microbiology and Ecology, University of Valencia, Av. Dr. Moliner, 50, 46100 Burjassot, Valencia, Spain; Institute for Clinical Research of the Hospital Clínico Universitario (INCLIVA), Valencia, Spain
| | - Rosa Aznar
- Department of Microbiology and Ecology, University of Valencia, Av. Dr. Moliner, 50, 46100 Burjassot, Valencia, Spain; Department of Preservation and Food Safety Technologies, IATA-CSIC, Av. Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - Gloria Sánchez
- Department of Preservation and Food Safety Technologies, IATA-CSIC, Av. Agustín Escardino 7, 46980 Paterna, Valencia, Spain.
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