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Park SM, Kim HW, Choi C, Rhee MS. Pathogenicity and seasonal variation of Aeromonas hydrophila isolated from seafood and ready-to-eat sushi in South Korea. Food Res Int 2021; 147:110484. [PMID: 34399480 DOI: 10.1016/j.foodres.2021.110484] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 05/22/2021] [Accepted: 05/23/2021] [Indexed: 11/29/2022]
Abstract
Aeromonas hydrophila is an emerging foodborne pathogen capable of causing human gastroenteritis, and the main reservoir is the aquatic environment. In this study, the prevalence and virulence of A. hydrophila in seafoods and ready-to-eat (RTE) sushi distributed in various conditions (refrigerated, dried, or frozen) or seasons was investigated. Strains were isolated from seafood (refrigerated or frozen oysters, sashimi, and processed fish; n = 333) and RTE sushi (n = 88) samples collected in South Korea and then genetically analyzed for gastroenteritis-related virulence genes (aer, ast, and alt). Raw oysters showed the highest prevalence of A. hydrophila (57.1%; 47/91) among all seafoods. Among the sashimi samples, flatfish sashimi (54.8%; 34/62) and salmon sushi (51.4%; 18/35) were the most prevalent. A. hydrophila was not detected in the oysters or anchovies distributed as either frozen or dried products. Seasonal investigations of sashimi and sushi showed that the summer prevalence of A. hydrophila with putative virulence genes was significantly lower in sashimi but highest in sushi. These results indicated that sushi could have been contaminated from several sources during the manufacturing or distribution processes. Significant correlations among the prevalence of putative virulence genes were confirmed, although no combination of genes presented a Phi correlation coefficient above 0.5 (0.26-0.43). To our knowledge, this is the first study to investigate the prevalence of A. hydrophila in various types of retail seafoods and RTE sushi in the East Asia region and then relate the prevalence to the distribution conditions of the samples. This study provides background information on the level of potential risk posed by A. hydrophila in retail seafoods and RTE sushi.
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Affiliation(s)
- Sun Min Park
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Hye Won Kim
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, IL 61820, USA
| | - Changsun Choi
- Department of Food and Nutrition, School of Food Science and Technology, Chung-Ang University, Gyeonggi Province 17546, Republic of Korea
| | - Min Suk Rhee
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea.
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De Silva LADS, Wickramanayake MVKS, Heo GJ. Virulence and antimicrobial resistance potential of Aeromonas spp. associated with shellfish. Lett Appl Microbiol 2021; 73:176-186. [PMID: 33891720 DOI: 10.1111/lam.13489] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 04/18/2021] [Accepted: 04/19/2021] [Indexed: 12/17/2022]
Abstract
Aeromonas spp. are associated with seafood-related outbreaks worldwide. In seafood industry, shellfish play a major role in global seafood production. With this emerging trend of shellfish consumption, shellfish-related bacterial infections are being reported frequently. Aeromonas spp. are natural contaminants found in shellfish. Although 36 species have been identified, some species including Aeromonas hydrophila, Aeromonas caviae and Aeromonas veronii biotype sobria have dragged major attention as foodborne pathogenic bacteria. The ability to elaborate a variety of virulence factors of Aeromonas spp. contributes to the pathogenic activities. Also, emerging antimicrobial resistance in Aeromonas spp. has become a huge challenge in seafood industry. Furthermore, multidrug resistance increases the risk of consumer health. Studies have supplied pieces of evidence about the emerging health risk of Aeromonas spp. isolated from seafood. Therefore, the present review was intended to highlight the prevalence, virulence and antimicrobial resistance of Aeromonas spp. isolated from various types of shellfish.
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Affiliation(s)
- L A D S De Silva
- Veterinary Medical Center and College of Veterinary Medicine, Chungbuk National University, Cheongju, Korea
| | - M V K S Wickramanayake
- Veterinary Medical Center and College of Veterinary Medicine, Chungbuk National University, Cheongju, Korea
| | - G-J Heo
- Veterinary Medical Center and College of Veterinary Medicine, Chungbuk National University, Cheongju, Korea
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Lee HJ, Hoel S, Lunestad BT, Lerfall J, Jakobsen AN. Aeromonas spp. isolated from ready-to-eat seafood on the Norwegian market: prevalence, putative virulence factors and antimicrobial resistance. J Appl Microbiol 2021; 130:1380-1393. [PMID: 33025711 DOI: 10.1111/jam.14865] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/28/2020] [Accepted: 09/17/2020] [Indexed: 12/14/2022]
Abstract
AIMS We aim to investigate the prevalence, putative virulence factors and antimicrobial resistance of mesophilic Aeromonas isolated from ready-to-eat (RTE) seafood available on the Norwegian market, and to assess the potential risks by consuming RTE seafood to consumers. METHODS AND RESULTS The prevalence of mesophilic Aeromonas in 148 RTE seafood was investigated and the highest prevalence was found in retail sushi (17%), followed by oysters (10%), fresh salmon loins (10%) and scallops (4%). Among 43 Aeromonas isolates, 75% of them were identified as A. media, 23% as A. salmonicida and 2% as A. bestiarum based on partial gryB gene sequencing. Aeromonas isolates were potentially pathogenic due to the presence of four virulence genes: alt (73%), hylA (22%), aerA (17%) and act (6%). In addition, all isolates were resistant to ampicillin and erythromycin. Most of the isolates (98%) were multidrug resistant. CONCLUSIONS The occurrence of potentially pathogenic and multidrug-resistant Aeromonas strains in RTE seafood implies a potential risk to consumers. Our finding suggests that RTE seafood could be a potential vehicle for the transfer of virulent and multidrug-resistant Aeromonas. SIGNIFICANCE AND IMPACT OF THE STUDY To our knowledge, this is the first study to report multiple antibiotic resistance in Aeromonas associated with RTE seafood in Norway.
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Affiliation(s)
- H-J Lee
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - S Hoel
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - B-T Lunestad
- Section for Contaminants and Biohazards, Institute of Marine Research, Bergen, Norway
| | - J Lerfall
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - A N Jakobsen
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
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Kim KT, Lee SH, Lee KK, Han JE, Kwak D. Enhanced Virulence of Aeromonas hydrophila Is Induced by Stress and Serial Passaging in Mice. Animals (Basel) 2021; 11:ani11020508. [PMID: 33669173 PMCID: PMC7919638 DOI: 10.3390/ani11020508] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/10/2021] [Accepted: 02/13/2021] [Indexed: 11/17/2022] Open
Abstract
Simple Summary Aeromonas hydrophila, which is an opportunistic zoonotic bacterium, has the ability to infect animals with injuries involving the condition of the aquatic environments. Factors including poor sanitation and water quality, stress, overcrowding, and rough handling can make animals more sensitive to infections and trigger outbreaks of A. hydrophila. A. hydrophila was previously isolated from an African black-footed penguin that died while in captivity at a zoo, following clinical signs of depression and anorexia, and in this study, we investigated the effect of stress and serial passaging in mice on A. hydrophila virulence. Serial passaging in mice enhanced the virulence of A. hydrophila, and A. hydrophila infection combined with administration of stress hormones or fasting increased mortality. Abstract Aeromonas hydrophila was isolated from an African black-footed penguin (Spheniscus demersus) that died while in zoo captivity. At necropsy, the virulence of A. hydrophila appeared to be enhanced by stress, so was assessed in the presence of in vitro and in vivo stressors and serial passaging in mice. Virulence genes from the isolate were amplified by PCR. In vitro assays were conducted to test the hemolytic activity, cytotoxicity, and effect of stress hormones on A. hydrophila virulence. In vivo assays were conducted to test the stress effect on mortality of A. hydrophila-infected mice and virulence in mice. Two virulence genes coding for hemolysin (ahh1) and aerolysin (aerA) were detected, and the cytotoxic potential of the isolate was demonstrated in baby hamster kidney and Vero cells. Some or all mice inoculated with A. hydrophila and exposed to stress hormones (epinephrine and norepinephrine) or low temperature died, while mice inoculated with A. hydrophila and exposed to fasting or agitation stressors or no stressors survived. We concluded that stress can be fatal in mice experimentally infected with A. hydrophila and that serial passaging in mice dramatically enhances the virulence of A. hydrophila.
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Affiliation(s)
- Kyoo-Tae Kim
- Animal Health Center of Zoo Land, Daejeon O-World Theme Park, Daejeon 35073, Korea;
| | - Seung-Hun Lee
- College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea;
| | - Kyoung-Ki Lee
- Animal Disease Diagnostic Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Korea;
| | - Jee Eun Han
- College of Veterinary Medicine, Kyungpook National University, Daegu 41566, Korea;
| | - Dongmi Kwak
- College of Veterinary Medicine, Kyungpook National University, Daegu 41566, Korea;
- Cardiovascular Research Institute, Kyungpook National University, Daegu 41944, Korea
- Correspondence: ; Tel.: +82-53-950-7794
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Koutsoumanis K, Allende A, Alvarez‐Ordóñez A, Bolton D, Chemaly M, Davies R, De Cesare A, Herman L, Hilbert F, Lindqvist R, Nauta M, Peixe L, Ru G, Simmons M, Skandamis P, Suffredini E, Arason S, Bekaert K, García MR, Georgiadis M, Messens W, Mosbach‐Schulz O, Bover‐Cid S. The use of the so-called 'tubs' for transporting and storing fresh fishery products. EFSA J 2020; 18:e06091. [PMID: 32874299 PMCID: PMC7448070 DOI: 10.2903/j.efsa.2020.6091] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
On-land transport/storage of fresh fishery products (FFP) for up to 3 days in 'tubs' of three-layered poly-ethylene filled with freshwater and ice was compared to the currently authorised practice (fish boxes of high-density poly-ethylene filled with ice). The impact on the survival and growth of biological hazards in fish and the histamine production in fish species associated with a high amount of histidine was assessed. In different modelling scenarios, the FFP are stored on-board in freshwater or seawater/ice (in tubs) and once on-land they are 'handled' (i.e. sorted or gutted and/or filleted) and transferred to either tubs or boxes. The temperature of the FFP was assumed to be the most influential factor affecting relevant hazards. Under reasonably foreseeable 'abusive' scenarios and using a conservative modelling approach, the growth of the relevant hazards (i.e. Listeria monocytogenes, Aeromonas spp. and non-proteolytic Clostridium botulinum), is expected to be < 0.2 log10 units higher in tubs than in boxes after 3 days when the initial temperature of the fish is 0°C ('keeping' process). Starting at 7°C ('cooling-keeping' process), the expected difference in the growth potential is higher (< 1 log10 for A. hydrophila and < 0.5 log10 for the other two hazards) due to the poorer cooling capacity of water and ice (tub) compared with ice (box). The survival of relevant hazards is not or is negligibly impacted. Histamine formation due to growth of Morganella psychrotolerans under the 'keeping' or 'cooling-keeping' process can be up to 0.4 ppm and 1.5 ppm higher, respectively, in tubs as compared to boxes after 3 days, without reaching the legal limit of 100 ppm. The water uptake associated with the storage of the FFP in tubs (which may be up to 6%) does not make a relevant contribution to the differences in microbial growth potential compared to boxes.
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De Silva B, Hossain S, Dahanayake P, Heo GJ. Aeromonasspp. from marketed Yesso scallop (Patinopecten yessoensis): molecular characterization, phylogenetic analysis, virulence properties and antimicrobial susceptibility. J Appl Microbiol 2018; 126:288-299. [DOI: 10.1111/jam.14106] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/05/2018] [Accepted: 09/08/2018] [Indexed: 11/28/2022]
Affiliation(s)
- B.C.J. De Silva
- Veterinary Medical Center and College of Veterinary Medicine; Chungbuk National University; Cheongju Korea
| | - S. Hossain
- Veterinary Medical Center and College of Veterinary Medicine; Chungbuk National University; Cheongju Korea
| | - P.S. Dahanayake
- Veterinary Medical Center and College of Veterinary Medicine; Chungbuk National University; Cheongju Korea
| | - G.-J. Heo
- Veterinary Medical Center and College of Veterinary Medicine; Chungbuk National University; Cheongju Korea
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Abstract
Seafood is often associated with foodborne illnesses, and Vibrio parahaemolyticus is the most common pathogen implicated in outbreaks in Taiwan. In this study, the microbiological quality of 300 raw or mixed ready-to-eat (RTE) and other cooking-needed seafood samples was examined. The total aerobic and coliform counts of the RTE samples were significantly higher than those of other cooking-needed samples. On average, 55.8 and 29.7% of the RTE samples failed to meet the local microbiological standards for total aerobic (5 log CFU/g) and coliform (3 log most probable number [MPN] per g), counts respectively; the corresponding percentages for the RTE samples from Taipei City were 9.1 and 18.2%, respectively. The total aerobic and coliform counts in the RTE samples from supermarkets and chain restaurants were significantly lower than those from traditional restaurants. The Vibrio species were more frequently identified in the cooking-needed samples than in RTE samples. Low incidences of V. parahaemolyticus (1.4%), V. vulnificus (1.9%), and V. cholerae (0%) were detected in most RTE samples. High densities of V. parahaemolyticus and V. vulnificus (1,200 MPN/g) were detected in a few RTE samples, only one of which contained toxigenic (tdh(+)) V. parahaemolyticus. The results of this investigation reveal that better hygiene of seafood providers such as chain restaurants, supermarkets, and traditional restaurants in Taipei City would effectively improve the microbiological quality of the seafood. The results will facilitate the establishment of measures for controlling the risks associated with seafood in Taiwan.
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Affiliation(s)
- Hin-Chung Wong
- Department of Microbiology, Soochow University, Taipei, Taiwan 111, Republic of China.
| | - Huai-Yu Jiang
- Department of Microbiology, Soochow University, Taipei, Taiwan 111, Republic of China
| | - Hsu-Yang Lin
- Food and Drug Administration, Ministry of Health and Welfare, Taipei, Taiwan 115, Republic of China
| | - Yu-Ting Wang
- Food and Drug Administration, Ministry of Health and Welfare, Taipei, Taiwan 115, Republic of China
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Tavares AB, Cereser ND, Timm CD. Ocorrência de Aeromonas spp. em alimentos de origem animal e sua importância em saúde pública. ARQUIVOS DO INSTITUTO BIOLÓGICO 2015. [DOI: 10.1590/1808-1657000662013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Aeromonas spp. são bactérias Gram negativas, opor-tunistas, de natureza ubíqua, isoladas principalmente de amostras de água. Até o presente momento foram reconhecidas 31 espé-cies, sendo as de maior importância médica Aeromonas hydrophila, Aeromonas caviae e Aeromonas veronii. A patogenicidade do gênero é considerada multifatorial, sendo este produtor de diversos tipos de toxinas e com envolvimento de outros fatores capazes de facilitar a penetração e o estabelecimento do agente no hospedeiro, causando doença. O objetivo desta revisão é elucidar o papel dos alimentos de origem animal como fontes de contaminação de bactérias do gênero Aeromonas para o ser humano. Isolamentos de aeromonas de diversos produtos de origem animal têm sido relatados, como carne, leite e seus derivados, além de frutos do mar, e em ambientes de processamento, como abatedouros, frigorífcos e laticínios. Tem-se buscado determinar fontes de contaminação dos alimentos, e a água foi definida como o principal disseminador. Aeromonas já foi defnida como sendo a causadora de diversas enfermidades, desde afecções gastrointestinais até casos de meningite e morte. Considerando os alimentos de origem animal como importantes veículos de transmissão para o ser humano e o reconhecimento da água como fonte de disseminação do agente, torna-se imprescindível o tratamento adequado da água utilizada nos estabelecimentos processadores de alimentos para a segurança alimentar.
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Nespolo NM, Martineli TM, Rossi OD. Microbiological quality of salmon (Salmo salar) sold in cities of the state of SãO Paulo, Brazil. Braz J Microbiol 2012; 43:1393-400. [PMID: 24031968 PMCID: PMC3769026 DOI: 10.1590/s1517-838220120004000021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 01/30/2012] [Accepted: 06/07/2012] [Indexed: 11/30/2022] Open
Abstract
The present paper evaluated the microbiology of salmon by quantifying mesophilic heterotrophic microorganisms, total and thermotolerant coliforms, and the presence of Vibrio parahaemolyticus, Staphylococcus aureus, Salmonella sp., Escherichia coli and Aeromonas sp. in the meat. This study can provide technical support for the suggestion of a new regulation of a Brazilian legislation through specific microbiological standards concerning the consumption of raw fish. A number of 31 (16 cooled and 15 frozen) samples of salmon were collected in the retail market network of a few cities in the State of São Paulo, Brazil. Results presented populations of mesophilic heterotrophic microorganisms ranging from 1.0 × 10 and 3.9 × 106 CFU/g, total and thermotolerant coliforms in 32.25% and 19.35% of the samples, respectively, and Aeromonas sp. in 41.95% of the samples with a populational variation ranging from 2.0 × 102 to 8.0 × 103 CFU/g. Staphylococcus aureus was found in one sample whereas Vibrio parahaemolyticus, Salmonella sp. and Escherichia coli were not found. These results demonstrated the presence of potencially pathogenic microorganisms in fresh fish consumed in Brazil, highlighting the necessity of control measures to avoid public health problems related to the consumption of raw fish.
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Affiliation(s)
- Natália Maramarque Nespolo
- Programa de Pós-Graduação em Medicina Veterinária Preventiva, Universidade Estadual Paulista , Jaboticabal, SP , Brasil
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Martineli T, Rossi Junior O, Cereser N, Cardozo M, Kamimura B, Nespolo N, Pinto F. OCORRÊNCIA DE AEROMONAS SPP. EM ABATEDOURO BOVINO E SENSIBILIDADE A ANTIMICROBIANOS. ARQUIVOS DO INSTITUTO BIOLÓGICO 2010. [DOI: 10.1590/1808-1657v77p1952010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
RESUMO O gênero Aeromonas compreende espécies consideradas importantes patógenos para os seres humanos, sendo as gastroenterites as infecções mais comumente atribuídas a estas bactérias. Tendo em vista sua importância como patógeno de origem alimentar, a ocorrência deAeromonas spp. foi estudada em carcaças bovinas e ambiente do abatedouro em uma indústria do Estado de São Paulo. Foram colhidas 285 amostras de 19 locais. Foi realizada a contagem direta por semeadura em meio seletivo, caracterização bioquímica das espécies após enriquecimento seletivo e teste de sensibilidade a antimicrobianos. A contagem direta permitiu a quantificação dessas bactérias em apenas 12 amostras, variando de 0,5 a 9,2 x 100 UFC/cm2, sendo cinco delas de ambiente, com populações que variaram de 1,0 x 100 a 3,0 x 100 UFC/placa. Entretanto, após o enriquecimento seletivo, Aeromonas spp. foram isoladas de 38 amostras que, somadas às amostras de ambiente não submetidas ao enriquecimento, forneceram 62 isolados para análise. A caracterização bioquímica das espécies permitiu verificar a ocorrência de 59 isolados de A. caviae, um de A. sobria, um de A. trota e um de A. schubertii. O teste com antimicrobianos revelou resistência de todos os isolados pela ampicilina e cefalotina, enquanto, para os demais antimicrobianos, esta foi variável. A resistência da totalidade dos isolados a determinados antimicrobianos indica que estes devem ser utilizados criteriosamente com a finalidade de evitar o surgimento precoce de cepas deAeromonas spp. multirresistentes. Ainda, a maior prevalência deA. caviae deve ser considerada relevante, pois trata-se de uma das espécies causadoras de gastroenterite em humanos.
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Affiliation(s)
- T.M. Martineli
- Universidade Estadual Paulista “Júlio de Mesquita Filho”, Brasil
| | - O.D Rossi Junior
- Universidade Estadual Paulista “Júlio de Mesquita Filho”, Brasil
| | - N.D. Cereser
- Universidade Estadual Paulista “Júlio de Mesquita Filho”, Brasil
| | - M.V. Cardozo
- Universidade Estadual Paulista “Júlio de Mesquita Filho”, Brasil
| | - B.A. Kamimura
- Universidade Estadual Paulista “Júlio de Mesquita Filho”, Brasil
| | - N.M. Nespolo
- Universidade Estadual Paulista “Júlio de Mesquita Filho”, Brasil
| | - F.R. Pinto
- Universidade Estadual Paulista “Júlio de Mesquita Filho”, Brasil
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Chang YC, Wang JY, Selvam A, Kao SC, Yang SS, Shih DYC. Multiplex PCR detection of enterotoxin genes in Aeromonas spp. from suspect food samples in northern Taiwan. J Food Prot 2008; 71:2094-9. [PMID: 18939759 DOI: 10.4315/0362-028x-71.10.2094] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Aeromonads possess an array of virulence factors and are causative agents of a number of human infections. Among them, genes of one cytotoxic (Act) and two cytotonic (Alt, Ast) enterotoxins are implicated in a human diarrheal disease. A rapid, specific, simultaneous detection of these enterotoxin genes in suspected food poisoning samples is not yet reported. Hence, a multiplex PCR assay was designed to amplify the cytotoxic (act), heat-labile cytotonic (alt), and heat-stable cytotonic (ast) enterotoxin genes of aeromonads. The PCR assay was tested with 133 Aeromonas spp. isolated from suspect food poisoning samples and retail samples of poultry and fish from wet markets in and around Taipei, Northern Taiwan. The Aeromonas spp. isolates were divided into six genotypes based on absence or presence of one or more enterotoxin genes. Of these 133 isolates, Aeromonas caviae (52.5%) and Aeromonas hydrophila (43.4%) were the most frequently isolated species from food poisoning samples and retail samples, respectively. Among the species, A. hydrophila had a significantly higher proportion for harboring three enterotoxin genes than had the others, whereas Aeromonas encheleia, considered a nonpathogen, was found harboring three enterotoxin genes. The multiplex PCR assays are rapid and specific, and provide a useful tool for the detection and genotyping of enterotoxin genes of aeromonads.
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Affiliation(s)
- Yu-Chang Chang
- Food Microbiology Division, Bureau of Food and Drug Analysis, Department of Health, Executive Yuan, Taipei 115, Taiwan
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Papageorgiou DK, Melas DS, Abrahim A, Angelidis AS. Growth of Aeromonas hydrophila in the whey cheeses Myzithra, Anthotyros, and Manouri during storage at 4 and 12 degrees C. J Food Prot 2006; 69:308-14. [PMID: 16496570 DOI: 10.4315/0362-028x-69.2.308] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The fresh whey cheeses Myzithra, Anthotyros, and Manouri were inoculated with Aeromonas hydrophila strain NTCC 8049 (type strain) or with an A. hydrophila strain isolated from food (food isolate) at levels of 3.0 to 5.0 x 10(2) CFU/g of cheese and stored at 4 or 12 degrees C. Duplicate samples of cheeses were tested for levels of A. hydrophila and pH after up to 29 days of storage. At 4 degrees C, A. hydrophila grew in Myzithra and Anthotyros with a generation time of ca. 19 h, but no growth was observed in Manouri. In Myzithra, average maximum populations of 8.87 log CFU/g (type strain) and 8.79 log CFU/g (food isolate) were recorded after 20 and 22 days of storage at 4 degrees C, respectively. The average maximum populations observed in Anthotyros stored at 4 degrees C were 6.72 log CFU/g (food isolate) and 6.13 log CFU/g (type strain) and were observed after 15 and 16 days of storage, respectively. A. hydrophila grew rapidly and reached high numbers in cheeses stored at 12 degrees C. The average generation times were 3.7 and 3.9 h (Myzithra), 4.1 and 6.1 h (Anthotyros), and 8.0 and 9.2 h (Manouri) for the type strain and the food isolate, respectively. Among the different whey cheese trials, the highest A. hydrophila population recorded (10.13 log CFU/g) was in Myzithra that had been inoculated with the food isolate after 8 days of storage at 12 degrees C. To prevent A. hydrophila growth in whey cheeses, efforts must be focused on preventing postprocessing contamination and temperature abuse during transportation and storage.
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Affiliation(s)
- Demetrios K Papageorgiou
- Laboratory of Milk Hygiene and Technology, Department of Food Hygiene and Technology, School of Veterinary Medicine, Aristotle University of Thessaloniki, Greece.
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