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Mellikeche W, Ricelli A, Casini G, Gallo M, Baser N, Colelli G, D’Onghia AM. Development of Loop-Mediated Isothermal Amplification (LAMP) Assays for the Rapid Detection of Toxigenic Aspergillus flavus and A. carbonarius in Nuts. Int J Mol Sci 2024; 25:3809. [PMID: 38612622 PMCID: PMC11011790 DOI: 10.3390/ijms25073809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 04/14/2024] Open
Abstract
Aspergillus species create major postharvest problems due to the food losses caused by their mere presence and the hazardous mycotoxins they produce, such as aflatoxin B1 (AFB1) and ochratoxin A (OTA). These mycotoxins are mainly produced by A. flavus and A. carbonarius, respectively. In this study, we developed a rapid detection method for the two aforementioned species based on loop-mediated isothermal amplification (LAMP). The primers were designed to target genes belonging to the mycotoxin clusters pks and aflT for A. carbonarius and A. flavus, respectively. Result visualization was carried out in real time via the detection of fluorescent signals. The method developed showed high sensitivity and specificity, with detection limits of 0.3 and 0.03 pg/reaction of purified DNA of A. carbonarius and A. flavus, respectively. The assays were further implemented on inoculated nuts, including pistachios and almonds, after one-step crude DNA extraction. These tests revealed a detection level of 0.5 spore/g that shows the effectiveness of LAMP as a rapid method for detecting potentially toxigenic Aspergillus spp. directly in food. The validation of the assays included tests on a larger scale that further confirmed their sensitivity and specificity, as well as enabling the production of ready-to-use LAMP prototype kits. These kits are easy to use and aim to simplify the screening of food samples in order to monitor the presence of specific Aspergillus contaminations.
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Affiliation(s)
- Wanissa Mellikeche
- Department of Agricultural Sciences, Food, Natural Resources and Engineering, University of Foggia, Via Napoli, 25-71122 Foggia, Italy; (W.M.); (G.C.)
| | - Alessandra Ricelli
- National Research Council—Institute of Molecular Biology and Pathology, P.le A. Moro, 5-00185 Rome, Italy
| | - Giulia Casini
- Enbiotech SRL, Via Del Bersagliere, 45-90143 Palermo, Italy;
| | - Marilita Gallo
- International Centre for Advanced Mediterranean Agronomic Studies, Via Ceglie, 9-70010 Valenzano, Italy; (M.G.); (N.B.); (A.M.D.)
| | - Nuray Baser
- International Centre for Advanced Mediterranean Agronomic Studies, Via Ceglie, 9-70010 Valenzano, Italy; (M.G.); (N.B.); (A.M.D.)
| | - Giancarlo Colelli
- Department of Agricultural Sciences, Food, Natural Resources and Engineering, University of Foggia, Via Napoli, 25-71122 Foggia, Italy; (W.M.); (G.C.)
| | - Anna Maria D’Onghia
- International Centre for Advanced Mediterranean Agronomic Studies, Via Ceglie, 9-70010 Valenzano, Italy; (M.G.); (N.B.); (A.M.D.)
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Kobayashi T, Tsuyuguchi K, Shimatani Y, Matsuda Y, Kagawa T, Takimoto T, Takeuchi N, Arai T, Inoue Y. Utility of a loop-mediated isothermal amplification detection kit to diagnose chronic pulmonary aspergillosis. J Infect Chemother 2024; 30:7-11. [PMID: 37660734 DOI: 10.1016/j.jiac.2023.08.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 08/27/2023] [Accepted: 08/30/2023] [Indexed: 09/05/2023]
Abstract
BACKGROUND Diagnosing chronic pulmonary aspergillosis (CPA) is still challenging, and infection with Aspergillus spp. must be detected early. The aim of this study was to evaluate, for the first time, the usefulness of a new loop-mediated isothermal amplification (LAMP) test kit in diagnosing CPA. METHODS This cross-sectional study was performed at the National Hospital Organization Kinki-Chuo Chest Medical Center. We prospectively enrolled patients with and without CPA. The primary outcomes of this study were the sensitivity and specificity of LAMP for the diagnosis of CPA. RESULTS In total, 34 patients with CPA and 21 without CPA (the control group) were enrolled between October 2019 and December 2021. Among the 34 patients with CPA, cultures were positive for CPA in 16 and negative for 18. The majority of fungi isolated in sputum were A. fumigatus in 15 specimens; Aspergillus flavus was isolated in 1) LAMP demonstrated 55.9% sensitivity (95% confidence interval [CI] 37.9-72.8) and 100.0% specificity (95% CI 77.2-100.0). CONCLUSION LAMP is an acceptable tool for diagnosing CPA, and its application in clinical practice necessitates more studies.
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Affiliation(s)
- Takehiko Kobayashi
- Clinical Research Center, National Hospital Organization, Kinki-Chuo Chest Medical Center, Sakai City, Osaka, Japan
| | - Kazunari Tsuyuguchi
- Clinical Research Center, National Hospital Organization, Kinki-Chuo Chest Medical Center, Sakai City, Osaka, Japan; Department of Internal Medicine, National Hospital Organization, Kinki-Chuo Chest Medical Center, Sakai City, Osaka, Japan.
| | - Yasuaki Shimatani
- Department of Clinical Microbiology, National Hospital Organization, Kinki-Chuo Chest Medical Center, Sakai City, Osaka, Japan
| | - Yoshinobu Matsuda
- Clinical Research Center, National Hospital Organization, Kinki-Chuo Chest Medical Center, Sakai City, Osaka, Japan; Department of Internal Medicine, National Hospital Organization, Kinki-Chuo Chest Medical Center, Sakai City, Osaka, Japan
| | - Tomoko Kagawa
- Department of Internal Medicine, National Hospital Organization, Kinki-Chuo Chest Medical Center, Sakai City, Osaka, Japan
| | - Takayuki Takimoto
- Department of Internal Medicine, National Hospital Organization, Kinki-Chuo Chest Medical Center, Sakai City, Osaka, Japan
| | - Naoko Takeuchi
- Department of Internal Medicine, National Hospital Organization, Kinki-Chuo Chest Medical Center, Sakai City, Osaka, Japan
| | - Toru Arai
- Clinical Research Center, National Hospital Organization, Kinki-Chuo Chest Medical Center, Sakai City, Osaka, Japan
| | - Yoshikazu Inoue
- Clinical Research Center, National Hospital Organization, Kinki-Chuo Chest Medical Center, Sakai City, Osaka, Japan
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Palumbo JD, Sarreal SBL, Kim JH. Simultaneous detection of mycotoxigenic Aspergillus species of sections Circumdati and Flavi using multiplex digital PCR. Lett Appl Microbiol 2023; 76:ovad142. [PMID: 38111225 DOI: 10.1093/lambio/ovad142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/20/2023] [Accepted: 12/15/2023] [Indexed: 12/20/2023]
Abstract
Populations of ochratoxin-producing Aspergillus section Circumdati species and aflatoxin-producing Aspergillus section Flavi species frequently coexist in soil and are the main sources of mycotoxin contamination of tree nuts. Identification of mycotoxigenic Aspergillus species in these sections is difficult using traditional isolation and culture methods. We developed a multiplex digital PCR (dPCR) assay to detect and quantify Aspergillus ochraceus, Aspergillus westerdijkiae, and Aspergillus steynii (section Circumdati), as well as Aspergillus flavus and Aspergillus parasiticus (section Flavi), in environmental samples based on species-specific calmodulin gene sequences. Relative quantification of each species by dPCR of mixed-species templates correlated with corresponding DNA input ratios. Target species could be detected in soil inoculated with conidia from each species. Non-target species of sections Circumdati, Flavi, and Nigri were generally not detectable using this dPCR method. Detected non-target species (Aspergillus fresenii, Aspergillus melleus, Aspergillus sclerotiorum, and Aspergillus subramanianii) were discernible from A. ochraceus in dual-template dPCR reactions based on differential fluorescence intensity.
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Affiliation(s)
- Jeffrey D Palumbo
- Foodborne Toxin Detection and Prevention Research Unit, US Department of Agriculture, Agricultural Research Service, Albany, CA 94710, United States
| | - Siov Bouy L Sarreal
- Foodborne Toxin Detection and Prevention Research Unit, US Department of Agriculture, Agricultural Research Service, Albany, CA 94710, United States
| | - Jong H Kim
- Foodborne Toxin Detection and Prevention Research Unit, US Department of Agriculture, Agricultural Research Service, Albany, CA 94710, United States
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Multiple Year Influences of the Aflatoxin Biocontrol Product AF-X1 on the A. flavus Communities Associated with Maize Production in Italy. Toxins (Basel) 2023; 15:toxins15030184. [PMID: 36977075 PMCID: PMC10057891 DOI: 10.3390/toxins15030184] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 02/16/2023] [Accepted: 02/24/2023] [Indexed: 03/06/2023] Open
Abstract
AF-X1 is a commercial aflatoxin biocontrol product containing the non-aflatoxigenic (AF-) strain of Aspergillus flavus MUCL54911 (VCG IT006), endemic to Italy, as an active ingredient. The present study aimed to evaluate the long-term persistence of VCG IT006 in the treated fields, and the multi-year influence of the biocontrol application on the A. flavus population. Soil samples were collected in 2020 and 2021 from 28 fields located in four provinces in north Italy. A vegetative compatibility analysis was conducted to monitor the occurrence of VCG IT006 on the total of the 399 isolates of A. flavus that were collected. IT006 was present in all the fields, mainly in the fields treated for 1 yr or 2 consecutive yrs (58% and 63%, respectively). The densities of the toxigenic isolates, detected using the aflR gene, were 45% vs. 22% in the untreated and treated fields, respectively. After displacement via the AF- deployment, a variability from 7% to 32% was noticed in the toxigenic isolates. The current findings support the long-term durability of the biocontrol application benefits without deleterious effects on each fungal population. Nevertheless, based on the current results, as well as on previous studies, the yearly applications of AF-X1 to Italian commercial maize fields should continue.
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Şen L, Civil O. Presence of aflatoxins in hazelnut paste in Turkey and a risk assessment study. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2022; 39:1474-1486. [PMID: 35652906 DOI: 10.1080/19440049.2022.2081367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Two hundred and two hazelnut paste samples from various hazelnut processing plants in the Black Sea Region of Turkey were analysed for the incidence of aflatoxins (AFs) by liquid chromatography coupled with fluorescence detection (LC-FLD). All 202 (100%) hazelnut paste samples were contaminated with various AFs ranged from 0.17 to 12.96 µg kg-1. AF contamination level of four (1.98%) samples exceeded legal limits. Risk assessment for hazelnut paste was determined by using AF incidence results, and the margin of exposure (MOE) and hepatocellular carcinoma (HCC) risk approach were applied. For the adult Turkish population (15+ years age group), the average lower bound (LB) and upper bound (UB) exposure levels for aflatoxin B1 (AFB1) and total aflatoxins (AFT) were 0.0106-0.0107 ng kg-1 body weight (bw) per day and 0.0250 ng kg-1 bw per day, respectively. MOE estimates for mean and 95th percentile exposures to AFB1 for hazelnut paste were higher than 10,000, which indicates no potential health concern for Turkish adults. HCC for the Turkish population was 0.00023 cases per 100,000 people per year. The study indicates that Turkish population is not under this toxicological risk when consuming hazelnut paste containing food products.
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Affiliation(s)
- Levent Şen
- Food Engineering Department, Engineering Faculty, Giresun University, Giresun, Turkey
| | - Onur Civil
- Food Engineering Department, Engineering Faculty, Giresun University, Giresun, Turkey
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Silva JJ, Fungaro MHP, Soto TS, Taniwaki MH, Iamanaka BT. Low-cost, specific PCR assays to identify the main aflatoxigenic species of Aspergillus section Flavi. METHODS IN MICROBIOLOGY 2022; 196:106470. [PMID: 35447279 DOI: 10.1016/j.mimet.2022.106470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 03/26/2022] [Accepted: 04/12/2022] [Indexed: 01/10/2023]
Abstract
Aflatoxins are fungal metabolites that are present as contaminants in food globally. Most aflatoxigenic species belong to Aspergillus section Flavi, and the main ones are grouped in the A. flavus clade, where many cryptic species that are difficult to discriminate are found. In this study, we investigated inter- and intraspecific diversity of the A. flavus clade to develop low-cost, species-specific PCR assays for identifying aflatoxigenic species. A total of 269 sequences of the second largest subunit of RNA polymerase II (RPB2) locus were retrieved from GenBank, and primer pairs were designed using data mining to identify A. flavus, A. parasiticus, and A. novoparasiticus. Species-specific amplicons of approximately 620, 350, and 860 bp enabled identification of target species as A. flavus, A. parasiticus, and A. novoparasiticus, respectively.
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Affiliation(s)
- Josué J Silva
- Institute of Food Technology - ITAL, Campinas, SP, Brazil.
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