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1.
Molecules ; 29(10)2024 May 14.
Article in English | MEDLINE | ID: mdl-38792166

ABSTRACT

Food-borne transmission is a recognized route for many viruses associated with gastrointestinal, hepatic, or neurological diseases. Therefore, it is essential to identify new bioactive compounds with broad-spectrum antiviral activity to exploit innovative solutions against these hazards. Recently, antimicrobial peptides (AMPs) have been recognized as promising antiviral agents. Indeed, while the antibacterial and antifungal effects of these molecules have been widely reported, their use as potential antiviral agents has not yet been fully investigated. Herein, the antiviral activity of previously identified or newly designed AMPs was evaluated against the non-enveloped RNA viruses, hepatitis A virus (HAV) and murine norovirus (MNV), a surrogate for human norovirus. Moreover, specific assays were performed to recognize at which stage of the viral infection cycle the peptides could function. The results showed that almost all peptides displayed virucidal effects, with about 90% of infectivity reduction in HAV or MNV. However, the decapeptide RiLK1 demonstrated, together with its antibacterial and antifungal properties, a notable reduction in viral infection for both HAV and MNV, possibly through direct interaction with viral particles causing their damage or hindering the recognition of cellular receptors. Hence, RiLK1 could represent a versatile antimicrobial agent effective against various foodborne pathogens including viruses, bacteria, and fungi.


Subject(s)
Antiviral Agents , Foodborne Diseases , Norovirus , Antiviral Agents/pharmacology , Antiviral Agents/chemistry , Animals , Foodborne Diseases/prevention & control , Foodborne Diseases/drug therapy , Foodborne Diseases/virology , Norovirus/drug effects , Humans , Mice , Antimicrobial Peptides/pharmacology , Antimicrobial Peptides/chemistry , Hepatitis A virus/drug effects , Virus Diseases/drug therapy , Microbial Sensitivity Tests
2.
Food Microbiol ; 120: 104478, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38431324

ABSTRACT

An optimized digital RT-PCR (RT-dPCR) assay for the detection of human norovirus GI and GII RNA was compared with ISO 15216-conform quantitative real-time RT-PCR (RT-qPCR) assays in an interlaboratory study (ILS) among eight laboratories. A duplex GI/GII RT-dPCR assay, based on the ISO 15216-oligonucleotides, was used on a Bio-Rad QX200 platform by six laboratories. Adapted assays for Qiagen Qiacuity or ThermoFisher QuantStudio 3D were used by one laboratory each. The ILS comprised quantification of norovirus RNA in the absence of matrix and in oyster tissue samples. On average, results of the RT-dPCR assays were very similar to those obtained by RT-qPCR assays. The coefficient of variation (CV%) of norovirus GI results was, however, much lower for RT-dPCR than for RT-qPCR in intra-laboratory replicates (eight runs) and between the eight laboratories. The CV% of norovirus GII results was in the same range for both detection formats. Had in-house prepared dsDNA standards been used, the CV% of norovirus GII could have been in favor of the RT-dPCR assay. The ratio between RT-dPCR and RT-qPCR results varied per laboratory, despite using the distributed RT-qPCR dsDNA standards. The study indicates that the RT-dPCR assay is likely to increase uniformity of quantitative results between laboratories.


Subject(s)
Norovirus , Ostreidae , Animals , Humans , Norovirus/genetics , Real-Time Polymerase Chain Reaction/methods , Seafood/analysis , RNA, Viral/genetics
3.
Viruses ; 15(3)2023 03 04.
Article in English | MEDLINE | ID: mdl-36992391

ABSTRACT

The use of natural substances with antiviral properties might reduce foodborne viral diseases. In this study, we evaluated the virucidal effect of Citrus limon and Thymus serpyllum essential oils (EOs) and of Citrus Limon, Thymus serpyllum and Thymus vulgaris hydrolates on murine norovirus (MNV), a human norovirus surrogate. To assess the virucidal effect of these natural substances, the reduction in viral infectivity was estimated by comparing the TCID50/mL of untreated viral suspension and the viral suspension treated with hydrolates and EOs at different concentrations. The results showed a natural loss of infectivity of the untreated virus after 24 h of approx. 1 log. The EO (1%) of T. serpyllum, and hydrolates (1% and 2%) of T. serpyllum and T. vulgaris immediately caused a reduction in MNV infectivity of about 2 log but did not provide a further significant decrease after 24 h. Instead, the EO (1%) and hydrolate (1% and 2%) of C. limon exerted an immediate reduction in the viral infectivity of about 1.3 log and 1 log, respectively, followed by a further reduction in infectivity of 1 log after 24 h for the hydrolate. These results will allow for the implementation of a depuration treatment based on the use of these natural compounds.


Subject(s)
Foodborne Diseases , Norovirus , Oils, Volatile , Animals , Mice , Humans , Oils, Volatile/pharmacology , Antiviral Agents/pharmacology
4.
Transbound Emerg Dis ; 69(5): e2541-e2550, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35575967

ABSTRACT

Wild boar is the main sylvatic reservoir of the genotype 3 of hepatitis E virus (HEV). The occurrence of HEV-3 human cases has been linked to the consumption of raw or undercooked pig and wild boar meat and liver. The zoonotic transmission of HEV-3 has been confirmed by sequencing identical or strictly related viral strains in humans, wild boar and derived food. The HEV sequences classified within the HEV-3 genotype are highly variable, and although only one serotype has been identified so far, the observed differences allow for the further classification of the HEV-3 genotype into subtypes, named in alphabetical order. Compared to human and pig strains, an even higher heterogeneity is observed among strains infecting wild boar. In the present study, the genetic variability of eight HEV-3 strains detected in wild boars sampled in a small geographical area in Central Italy (Lazio and Umbria regions) was investigated by full genome sequencing and phylogenetic analysis. The strains were classified within the HEV-3a, HEV-3c, HEV-3f subtypes and within two new recently proposed subtypes. Results demonstrate - despite the relatively small geographic area of origin - an unexpected divergence within HEV-3 strains hosted by the investigated wild boar population and highlights the need for extensive sequencing of HEV in reservoirs to fully understand diversity, geographical distribution and evolution of this group of viruses.


Subject(s)
Hepatitis E virus , Hepatitis E , Swine Diseases , Animals , Genotype , Hepatitis E/epidemiology , Hepatitis E/veterinary , Hepatitis E virus/genetics , Humans , Italy/epidemiology , Phylogeny , RNA, Viral/genetics , Sus scrofa , Swine
5.
J Virol Methods ; 300: 114420, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34902456

ABSTRACT

The emergence and spread of SARS-CoV-2 has led to a compelling request for accurate diagnostic tests. The aim of this study was assessing the performance of a real-time RT-qPCR (rt RT-qPCR) assay and of a droplet digital RT-PCR (dd RT-PCR) targeting the nsp14 genome region for the detection of SARS-CoV-2 in nasopharyngeal swabs. A total of 258 nasopharyngeal swabs were analyzed with the nsp14 assays and, for comparison, with a reference assay targeting the RdRp and E genes. Conflicting results were further investigated by two additional protocols, the Centers for Disease Control and Prevention (CDC) real-time targeting N1/N2, and a nested RT-PCR for the spike region. Agreement of results was achieved on 226 samples (156 positive and 70 negative), 8 samples were positive in the reference assay and in the nsp14 rt RT-qPCR but negative with the dd RT-PCR, and 24 samples provided different combinations of results with the three assays. Sensitivity, specificity and accuracy (95 %C.I.) of the nsp14 assays were: 100.0 % (97.4-100.0), 98.7 % (92.1-100.0), and 99.6 % (97.5-100.0) for the rt RT-qPCR; 92.4 % (87.4-95.6), 100.0 % (94.2-100.0), and 94.7 % (91.1-97.0) for the dd RT-PCR. The results of the study support the use of the nsp14 real-time RT-qPCR and ddPCR for the detection of SARS-CoV-2 in nasopharyngeal swabs.


Subject(s)
COVID-19 , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , COVID-19/diagnosis , Exonucleases , Humans , Nasopharynx/virology , RNA, Viral/genetics , SARS-CoV-2/isolation & purification , Sensitivity and Specificity
6.
Food Environ Virol ; 13(3): 329-336, 2021 09.
Article in English | MEDLINE | ID: mdl-33730340

ABSTRACT

Kinetics of hepatitis A virus (HAV) accumulation and depuration from mussels (Mytilus galloprovincialis) was studied in an experimental depuration system. Different parameters likely to influence the rate of virus accumulation and elimination were evaluated. Analyses were carried out by both real-time RT-qPCR and digital PCR. Results demonstrated that the animals start to concentrate the virus already after one hour and reach the maximum level of contamination in 6 h of experiment. With respect to depuration, HAV showed a rapid reduction of the concentration (89%) during the first 24-48 h of experiment and a very slow virus decrement in the following days with a 1% residual RNA at the ninth day of depuration. When process parameters likely to increase the depuration rate (presence of ozone, microalgal feeding, presence of lactic bacteria, pre-treatment with digestive enzymes) were tested, no significant differences in the kinetics were observed. Only treatment with pancreatin seemed to positively affect depuration in the first two days of the experiment.


Subject(s)
Bivalvia , Hepatitis A virus , Mytilus , Animals , Hepatitis A virus/genetics , Kinetics , Real-Time Polymerase Chain Reaction , Seafood
7.
Heliyon ; 6(10): e05110, 2020 Oct.
Article in English | MEDLINE | ID: mdl-33088938

ABSTRACT

BACKGROUND: Hepatitis E virus (HEV) genotype 3 has a worldwide distribution. The food-borne transmission of HEV associated with the consumption of products derived from domestic pig, wild boar has been reported in various countries. In this study the genetic diversity, evolutionary rates of HEV 3f, 3c among swine and wild boar in Italy were estimated. METHODS: Sampling was performed on a wild boar population living in an area located in Abruzzo region. The HEV RNA amplification was performed by real-time RT-PCR. Nested RT-PCR and sequencing of the ORF2 region were carried out by the Super Script III First-Strand Synthesis System. Sequencing of purified PCR products was carried out by the Genome Lab Dye Terminator Cycle Sequencing (DTCS) Quick Start Kit. The maximum likelihood trees were generated by using Phyml. The mean evolutionary rates and the dated trees were co-estimated by BEAST. RESULTS: The phylogenetic analysis showed that the HEV ORF2 isolates from Abruzzo region belonged to 3f subtype. The prevalent subtypes in Italy were those belonging to 3f and 3c. The estimated mean values of the HEV ORF2 capsid gene evolutionary rates were 1.915 × 10-2 substitutions/site/year (95% HPD: 1.64 × 10-3 - 3.97 × 10-2) and 2.81 × 10-2 substitutions/site/year (1.83 × 10-2 - 3.8 × 10-2) for 3f and 3c subtype datasets, respectively.The HEV 3f dated back to 1985 (1960-2000), whereas the 3c subtype entered in Italy during the year 2006 (2005-2006). The majority of the HEV 3f sequences collected from swine didn't appear intermixed, except in two cases. The HEV 3c population circulating in Italy remained segregated without significant transfer to swine. CONCLUSION: Our study provide insight into the evolution, circulation of HEV 3f and 3c in Italy.Continued genomic surveillance of HEV in animal reservoir, as well as improving sanitary control measures are required.

8.
Food Microbiol ; 82: 194-201, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31027773

ABSTRACT

Hepatitis E is an emerging disease in industrialized countries. The food-borne transmission of hepatitis E virus (HEV) is associated principally with products derived from the domestic pig, the wild boar, and deer; however, few quantitative data are available on HEV loads in animals used in food production. This study assessed HEV occurrence, viral load and genetic variability in wild boar hunted for domestic consumption in the district of Viterbo (Central Italy) where high anti-HEV IgG seroprevalence values are reported in humans. A total of 332 liver and 69 intestine samples were obtained from wild boar hunted between 2011 and 2014. The liver tissue in 54 of the animals (16.3%) was HEV-positive. Viral loads in quantifiable liver samples (n = 29) ranged between 3.2 × 102 and 3.8 × 105 genome copies (g.c.)/g with a mean value of 1.85 × 104 g.c./g. A statistically significant positive correlation was found between viral concentration in liver and intestinal tissue, though mean viral load in the intestines was lower (3.13 × 103 g.c./g). Twenty-six samples were characterized molecularly as genotype 3 (G3) and four subtypes (a, c, f and l) were detected. Finally, twelve samples with near identical sequences were identified as G3 but could not be assigned to any of the known subtypes, and could therefore represent a potentially new subtype.


Subject(s)
Food Microbiology , Hepatitis E virus/genetics , Hepatitis E/veterinary , Sus scrofa/virology , Swine Diseases/virology , Animals , Animals, Wild , Genetic Variation , Genotype , Hepatitis E/epidemiology , Hepatitis E/virology , Hepatitis E virus/classification , Humans , Intestines/virology , Italy/epidemiology , Liver/virology , RNA, Viral/genetics , Swine , Swine Diseases/epidemiology , Viral Load
9.
Food Environ Virol ; 9(4): 423-433, 2017 12.
Article in English | MEDLINE | ID: mdl-28452010

ABSTRACT

The aim of this study was to assess the trend of hepatitis A virus (HAV) in a coastal zone impacted by a contamination event, providing data for the development of management strategies. A total of 352 samples, including four bivalve mollusc species (Mytilus galloprovincialis, Solen vagina, Venus gallina and Donax trunculus), were taken over a period of 6 months from 27 production areas of the coast and analysis were performed according to ISO/TS 15216-1:2013. HAV presence was detected in 77 samples from 11 production areas and all positive results were related to samples collected in the first 3 months of the surveillance, during which HAV prevalence was 39.9% and values as high as 5096 genome copies/g were detected. A progressive reduction of viral contamination was evident during the first trimester of the monitoring, with prevalence decreasing from 78.8% in the first month, to 37.8% in the second and 3.9% in the third and quantitative levels reduced from an average value of 672 genome copies/g to 255 genome copies/g over a period of 4 weeks (virus half-life: 21.5 days). A regression analysis showed that, during the decreasing phase of the contamination, the data fitted a reciprocal quadratic model (Ra2 = 0.921) and, based on the model, a residual presence of HAV could be estimated after negativization of the production areas. The statistical analysis of the results per shellfish species and per production area showed that there were limited differences in contamination prevalence and levels among diverse bivalve species, while a statistically significant difference was present in quantitative levels of one production area. These data could be useful for the development of both risk assessment models and code of practice for the management of viral contamination in primary production.


Subject(s)
Bivalvia/virology , Hepatitis A virus/isolation & purification , Norovirus/isolation & purification , Shellfish/virology , Animals , Consumer Product Safety , Food Contamination/analysis , Hepatitis A virus/classification , Hepatitis A virus/genetics , Humans , Norovirus/classification , Norovirus/genetics
10.
J Med Microbiol ; 66(3): 342-349, 2017 Mar.
Article in English | MEDLINE | ID: mdl-28086079

ABSTRACT

PURPOSE: In 2013/2014, Italy experienced one of the largest community-wide prolonged outbreaks of hepatitis A virus (HAV) throughout the country. The article provides a comprehensive description of the outbreak and the investigation carried out by a multidisciplinary National Task Force, in collaboration with regional and local public health authorities. Control strategies of food-borne HAV infection in both the human and food sectors are also described. METHODOLOGY: Enhanced human epidemiological and microbiological surveillance together with microbiological monitoring of HAV in food and trace-back investigation were conducted. RESULTS: A total of 1803 HAV cases were identified from 1 January 2013 to 31 August 2014, in Italy. Sequencing was possible for 368 cases (20.4 %), mostly collected between 1 January 2013 and 28 February 2014, and 246 cases (66.8 %) harboured an HAV outbreak strain. Imported frozen berries contaminated with HAV were identified as the vehicle of the outbreak which also involved many other European countries in 2013 and 2014. Epidemiological evidence obtained through a case-control study was supported by the finding of a 100 % nucleotide similarity of the VP1/2A sequences of HAVs detected in human and food samples. Trace-back investigation revealed an extremely complex supplying network with no possibility for a point source potentially explaining the vast contamination of berries found in Italy. CONCLUSION: The investigation benefited from an excellent collaboration among different sectors who shared proactively the available information. Our findings highlight the importance of considering frozen berries among the highest risk factors for HAV.


Subject(s)
Disease Outbreaks , Frozen Foods/microbiology , Fruit/virology , Hepatitis A Virus, Human/genetics , Hepatitis A/epidemiology , Population Surveillance , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Food Microbiology , Hepatitis A/virology , Humans , Infant , Italy/epidemiology , Male , Middle Aged , Public Health , RNA, Viral/genetics , Young Adult
11.
PLoS One ; 11(2): e0149642, 2016.
Article in English | MEDLINE | ID: mdl-26901877

ABSTRACT

BACKGROUND: Foodborne Hepatitis A Virus (HAV) outbreaks are being recognized as an emerging public health problem in industrialized countries. In 2013 three foodborne HAV outbreaks occurred in Europe and one in USA. During the largest of the three European outbreaks, most cases occurred in Italy (>1,200 cases as of March 31, 2014). A national Task Force was established at the beginning of the outbreak by the Ministry of Health. Mixed frozen berries were early demonstrated to be the source of infection by the identity of viral sequences in patients and in food. In the present study the molecular characterization of HAV isolates from 355 Italian cases is reported. METHODS: Molecular characterization was carried out by PCR/sequencing (VP1/2A region), comparison with reference strains and phylogenetic analysis. RESULTS: A unique strain was responsible for most characterized cases (235/355, 66.1%). Molecular data had a key role in tracing this outbreak, allowing 110 out of the 235 outbreak cases (46.8%) to be recognized in absence of any other link. The data also showed background circulation of further unrelated strains, both autochthonous and travel related, whose sequence comparison highlighted minor outbreaks and small clusters, most of them unrecognized on the basis of epidemiological data. Phylogenetic analysis showed most isolates from travel related cases clustering with reference strains originating from the same geographical area of travel. CONCLUSIONS: In conclusion, the study documents, in a real outbreak context, the crucial role of molecular analysis in investigating an old but re-emerging pathogen. Improving the molecular knowledge of HAV strains, both autochthonous and circulating in countries from which potentially contaminated foods are imported, will become increasingly important to control outbreaks by supporting trace back activities, aiming to identify the geographical source(s) of contaminated food, as well as public health interventions.


Subject(s)
Contact Tracing , Disease Outbreaks , Hepatitis A virus/genetics , Hepatitis A/epidemiology , Hepatitis A/virology , Amino Acid Substitution , Europe , Genetic Variation , Genotype , Hepatitis A/transmission , Humans , Italy , Phylogeny , Risk Factors , Sequence Analysis, DNA , Spatio-Temporal Analysis , Viral Structural Proteins/genetics
12.
Biosecur Bioterror ; 11 Suppl 1: S235-40, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23971811

ABSTRACT

Detection of avian influenza virus (AIV) in poultry meat is hampered by the lack of an efficient analytical method able to extract and concentrate viral RNA prior to PCR. In this study we developed a method for extracting and detecting AIV from poultry meat by a previously standardized 1-step real-time reverse transcriptase PCR (RRT-PCR) assay. In addition, a new process control, represented by feline calicivirus (FCV), was included in the original protocol, to evaluate all analytical steps from sample preparation to the detection phase. The detection limit was below 1×10(-1) TCID50 of AIV per sample, and the quantification limit corresponded to 1×10(1) TCID50 of AIV per sample. Moreover, the addition of 1×10(2) TCID50/sample of FCV did not affect the quantification and detection limit of the reaction. These results show that the developed assay is suitable for detecting small amounts of AIV in poultry meat. In addition, the developed biopreparedness protocol can be applied to detect AIV in legal or illegal imported broiler chicken meat. The availability of a rapid and sensitive diagnostic method based on molecular identification of AIV in poultry meat provides an important tool in the prevention of AIV circulation.


Subject(s)
Influenza A virus/isolation & purification , Meat/virology , RNA, Viral/analysis , Virology/methods , Animals , Chickens/virology , Influenza A virus/genetics , Limit of Detection , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction
13.
J Pediatr Orthop ; 32(5): 521-6, 2012.
Article in English | MEDLINE | ID: mdl-22706470

ABSTRACT

BACKGROUND: Empirical findings show that the child's illness can interfere with parental well-being and with the construction of a well-functioning effective relationship between the child and his/her caregivers. In line with these findings, the present study aims at investigating the negative impact of the baby's diagnosis of clubfoot on the mother and the protective function of social support; moreover, the study aims at implementing, as a pilot experience, an intervention protocol directed to the same sample of mothers, providing emotional and informational support. METHODS: A sample of 34 mothers was recruited within the first 3 months of the baby's life, including 2 groups: a clinical one, with 17 mothers of babies diagnosed with clubfoot, and a control one, with 17 mothers of healthy full-term babies. The participants completed the following instruments in 1 session: the Beck Depression Inventory-II, the Rapid Stress Assessment questionnaire, the Brief COPE, and the Multidimensional Scale of Perceived Social Support. RESULTS: The results show that the mothers in the clinical group, compared with those in the control group, reported more stress and depressive symptoms in reaction to the birth of their baby. Moreover, they displayed a pattern of coping strategies different from those of control mothers and coherent with the meaning of having a baby with a malformation. Lastly, the group condition (clinical vs. control) significantly moderated the association of social support with stress and depression. CONCLUSIONS: These preliminary findings highlight the negative impact that the congenital malformation of clubfoot can have on mothers' psychological well-being and the protective role of social support. Moreover, the positive feedback from the mothers receiving emotional and informational support confirms the importance of implementing intervention protocols in the hospital unit directed to parents of babies with a congenital malformation.


Subject(s)
Clubfoot/pathology , Depression/epidemiology , Mothers/psychology , Stress, Psychological/epidemiology , Case-Control Studies , Depression/etiology , Female , Humans , Infant , Male , Mother-Child Relations , Pilot Projects , Social Support , Stress, Psychological/etiology , Surveys and Questionnaires
14.
Int J Food Microbiol ; 145 Suppl 1: S158-66, 2011 Mar 01.
Article in English | MEDLINE | ID: mdl-20724015

ABSTRACT

Enteric viruses, including norovirus (NoV) and hepatitis A virus (HAV), have emerged as a major cause of waterborne outbreaks worldwide. Due to their low infectious doses and low concentrations in water samples, an efficient and rapid virus concentration method is required for routine control. Three newly developed methods, A, B and C, for virus concentration in bottled water were compared against the reference method D: (A) Convective Interaction Media (CIM) monolithic chromatography; filtration of viruses followed by (B) direct lysis of viruses on membrane; (C) concentration of viruses by ultracentrifugation; and (D) concentration of viruses by ultrafiltration, for each methods' (A, B and C) efficacy to recover 10-fold dilutions of HAV and feline calicivirus (FCV) spiked in bottles of 1.5L of mineral water. Within the tested characteristics, all the new methods showed better performance than method D. Methods A, B and C shared a limit of detection (LOD(50)) of nine 50%-tissue culture infectious dose (TCID(50)) of FCV/1.5L, but differed with regard to the LOD(50)'s of HAV with 45, 361 and 3607 TCID(50)/1.5L, respectively, and the percentage of recoveries of HAV/FCV with 34/6, 32/25 and 0.3/0.5, respectively. Method B resulted in significantly (p<0.0001) lower C(t)-values for both HAV and FCV relative to the reference method D than any of the other methods. The most efficient method (B) was evaluated through a collaborative trial by five laboratories for the detection of HAV, FCV and NoV genogroup I and II (GI and GII), which resulted in the corresponding average LOD(50)'s and percentage of recoveries: 211 TCID(50)/1.5L and 51% for HAV; 66 TCID(50)/1.5L and 34% for FCV; 9 reverse transcriptase-PCR Units (RT-PCR U)/1.5L and 61% for NoV GI and 286 RT-PCR U/1.5L and 35% for NoV GII. The results indicate that method B could be considered robust enough for routine control and useful for harmonized data generation.


Subject(s)
Viruses/isolation & purification , Water Microbiology , Calicivirus, Feline/genetics , Calicivirus, Feline/isolation & purification , Chromatography/methods , Filtration/methods , Hepatitis A virus/genetics , Hepatitis A virus/isolation & purification , Norovirus/genetics , Norovirus/isolation & purification , RNA, Viral/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction/methods , Ultrafiltration/methods
15.
J Virol Methods ; 163(1): 96-100, 2010 Jan.
Article in English | MEDLINE | ID: mdl-19755130

ABSTRACT

The consumption of bivalve shellfish is a common cause of foodborne outbreaks of viral origin. The evaluation of the sanitary quality of these products, however, is still based on bacterial indicators of fecal contamination (Reg. (EC) No. 2073/2005 and No.1441/2007) even if it is known that they are not reliable indicators of viral contamination. In this study a duplex Real Time PCR method for quantitative detection of hepatitis A (HAV) in shellfish was developed. Feline Calicivirus (FCV) was used as a control for assessing the effectiveness of the concentration and extraction process and the ability to eliminate PCR inhibitors present in the food matrix. The specific primers and probes for detection of HAV and FCV, chosen respectively from the 5'-UTR region and in the ORF1 region, were labeled with two different dyes and detected simultaneously. The method was applied on spiked and non-spiked shellfish from a local market. The amplification of HAV in the presence of FCV showed good linearity (R(2)=0.994) and the sensitivity limit of the reaction was at least 5 x 10(2)TCID(50)g(-1) of an hepatopancreas extract.


Subject(s)
Food Microbiology , Hepatitis A virus/isolation & purification , Mytilus/virology , Reverse Transcriptase Polymerase Chain Reaction/methods , Animals , Calicivirus, Feline/isolation & purification , Cell Line , Sensitivity and Specificity
16.
Int J Food Microbiol ; 114(2): 252-7, 2007 Mar 10.
Article in English | MEDLINE | ID: mdl-17196284

ABSTRACT

Incidence and circulation of different strains of hepatitis A and Norovirus in shellfish were studied on 235 samples (Tapes philippinarum, Mytilus galloprovincialis, Ostrea spp. and Chlamys spp.) obtained from different sites, representing the shellfish production areas of the northern Adriatic sea. Shellfish were harvested in the period of one year and, after depuration, were examined for bacterial (Escherichia coli and Salmonella) and viral (HAV and NoV) contamination. Viral contamination was present on average in 22% of samples: specifically, 6% of samples tested positive for HAV, 14% for NoV and 2% for both viruses. None of the samples revealed the presence of Salmonella, and in most of them (93%) the number of E. coli was below the European legislation limit of 230 MPN/100 g. T. philippinarum was the species most often contaminated, as well as being the only species in which the legal limit for E. coli was, in some cases, exceeded. Both HAV and NoV contamination were detected throughout the year; NoV detection was slightly more frequent during winter months, but positive samples were also present in summer. The sequencing of the PCR products showed the circulation of only one HAV genotype (IA) and four different NoV genotypes (Hawaii, Melksham, Lordsdale and GGIIb) with a prevalence of the GGIIb genotype in the second period of the monitoring.


Subject(s)
Bivalvia/virology , Food Contamination/analysis , Hepatitis A virus/isolation & purification , Norovirus/isolation & purification , Shellfish/virology , Animals , Bivalvia/microbiology , Consumer Product Safety , Escherichia coli/isolation & purification , Genotype , Hepatitis A virus/genetics , Humans , Norovirus/genetics , Salmonella/isolation & purification , Seasons , Shellfish/microbiology , Species Specificity , Water Microbiology
17.
Int J Food Microbiol ; 105(2): 139-44, 2005 Nov 25.
Article in English | MEDLINE | ID: mdl-16054720

ABSTRACT

Hepatitis A is a worldwide infectious disease. Shellfish consumption has always been one of the major risk factors for hepatitis A infection, especially when these products are eaten raw or slightly cooked. Moreover, the cooking does not always guarantee the harmlessness of shellfish. The aim of the present study was to evaluate the hepatitis A virus (HAV) resistance in experimentally contaminated mussels, subjected to domestic cooking. Three different domestic preparations (mussel hors-d'oevre, mussel au gratin, mussels with tomato sauce) were performed according to the traditional Italian cookery using different time and temperature conditions. To detect HAV-RNA, RT-nested-PCR was used; the presence of the infectious virus in the positive samples was confirmed by an integrated cell culture-RT-PCR method. The infectious virus was completely inactivated only in "mussels in tomato sauce", while it was still present, even if not quantitatively determinable, in the other preparations. The study confirmed that some factors can influence the HAV sensitivity to thermal inactivation preventing a complete decontamination of the product.


Subject(s)
Bivalvia/virology , Cooking/methods , Hepatitis A virus/growth & development , Hot Temperature , Shellfish/virology , Animals , Consumer Product Safety , Food Contamination , Food Microbiology , Hepatitis A/prevention & control , Hepatitis A virus/isolation & purification , Humans , Reverse Transcriptase Polymerase Chain Reaction , Time Factors
18.
Appl Environ Microbiol ; 69(6): 3456-61, 2003 Jun.
Article in English | MEDLINE | ID: mdl-12788750

ABSTRACT

The objective of this study was to develop a rapid, reproducible, and robust method for detecting Salmonella enterica serotype Enteritidis in poultry samples. First, for the extraction and purification of DNA from the preenrichment culture, four methods (boiling, alkaline lysis, Nucleospin, and Dynabeads DNA Direct System I) were compared. The most effective method was then combined with a real-time PCR method based on the double-stranded DNA binding dye SYBR Green I used with the ABI Prism 7700 system. The specificity of the reaction was determined by the melting temperature (T(m)) of the amplicon obtained. The experiments were conducted both on samples of chicken experimentally contaminated with serotype Enteritidis and on commercially available poultry samples, which were also used for comparisons with the standard cultural method (i.e., ISO 6579/2001). The results of comparisons among the four DNA extraction methods showed significant differences except for the results from the boiling and Nucleospin methods (the two methods that produced the lowest threshold cycles). Boiling was selected as the preferred extraction method because it is the simplest and most rapid. This method was then combined with SYBR Green I real-time PCR, using primers SEFA-1 and SEFA-2. The specificity of the reaction was confirmed by the T(m), which was consistently specific for the amplicon obtained; the mean peak T(m) obtained with curves specific for serotype Enteritidis was 82.56 +/- 0.22 degrees C. The standard curve constructed using the mean threshold cycle and various concentrations of serotype Enteritidis (ranging from 10(3) to 10(8) CFU/ml) showed good linearity (R(2) = 0.9767) and a sensitivity limit of less than 10(3) CFU/ml. The results of this study demonstrate that the SYBR Green I real-time PCR constitutes an effective and easy-to-perform method for detecting serotype Enteritidis in poultry samples.


Subject(s)
Chickens/microbiology , DNA, Bacterial/isolation & purification , Fluorescent Dyes/metabolism , Organic Chemicals , Polymerase Chain Reaction/methods , Salmonella enteritidis/isolation & purification , Turkeys/microbiology , Animals , Benzothiazoles , Culture Media , Diamines , Poultry Diseases/microbiology , Quinolines , Reproducibility of Results , Salmonella Infections, Animal/microbiology , Salmonella enteritidis/classification , Salmonella enteritidis/genetics , Serotyping
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