RESUMO
We determined the disinfection efficacy and inactivation mechanisms of peracetic acid (PAA)-based sanitizer using pH values relevant for vegetable sanitation against rotavirus (RV) and Tulane virus (TV; a human norovirus surrogate). TV was significantly more resistant to PAA disinfection than RV: for a 2-log10 reduction of virus titer, RV required 1 mg/liter PAA for 3.5 min of exposure, while TV required 10 mg/liter PAA for 30 min. The higher resistance of TV can be explained, in part, by significantly more aggregation of TV in PAA solutions. The PAA mechanisms of virus inactivation were explored by quantifying (i) viral genome integrity and replication using reverse transcription-quantitative PCR (RT-qPCR) and (ii) virus-host receptor interactions using a cell-free binding assay with porcine gastric mucin conjugated with magnetic beads (PGM-MBs). We observed that PAA induced damage to both RV and TV genomes and also decreased virus-receptor interactions, with the latter suggesting that PAA damages viral proteins important for binding its host cell receptors. Importantly, the levels of genome-versus-protein damage induced by PAA were different for each virus. PAA inactivation correlated with higher levels of RV genome damage than of RV-receptor interactions. For PAA-treated TV, the opposite trends were observed. Thus, PAA inactivates each of these viruses via different molecular mechanisms. The findings presented here potentially contribute to the design of a robust sanitation strategy for RV and TV using PAA to prevent foodborne disease.IMPORTANCE In this study, we examined the inactivation mechanisms of peracetic acid (PAA), a sanitizer commonly used for postharvest vegetable washing, for two enteric viruses: Tulane virus (TV) as a human norovirus surrogate and rotavirus (RV). PAA disinfection mechanisms for RV were mainly due to genome damage. In contrast, PAA disinfection in TV was due to damage of the proteins important for binding to its host receptor. We also observed that PAA triggered aggregation of TV to a much greater extent than RV. These studies demonstrate that different viruses are inactivated via different PAA mechanisms. This information is important for designing an optimal sanitation practice for postharvest vegetable washing to minimize foodborne viral diseases.
Assuntos
Caliciviridae/efeitos dos fármacos , Desinfetantes/farmacologia , Farmacorresistência Viral/fisiologia , Ácido Peracético/farmacologia , Rotavirus/efeitos dos fármacos , Caliciviridae/fisiologia , Desinfecção , Inativação Metabólica , Rotavirus/fisiologiaRESUMO
Human noroviruses (HuNoVs) are the major cause of epidemic nonbacterial gastroenteritis. Although quantitative (real-time) reverse transcription-PCR (qRT-PCR) is widely used for detecting HuNoVs, it only detects the presence of viral RNA and does not indicate viral infectivity. Human blood group antigens (HBGAs) have been identified as receptors/co-receptors for both HuNoVs and Tulane virus (TV) and are crucial for viral infection. We propose that viral infectivity can be evaluated with a molecular assay based on receptor-captured viruses. In this study, we employed TV as an HuNoV surrogate to validate the HBGA-based capture qRT-PCR method against the 50% tissue culture infectious dose (TCID50) method. We employed type B HBGA on an immuno-well module to concentrate TV, followed by amplification of the captured viral genome by in situ qRT-PCR. We first demonstrated that this in situ capture qRT-PCR (ISC-qRT-PCR) method could effectively concentrate and detect TV. We then treated TV under either partial or full inactivation conditions and measured the remaining infectivity by ISC-qRT-PCR and a tissue culture-based amplification method (TCID50). We found that the ISC-qRT-PCR method could be used to evaluate virus inactivation deriving from damage to the capsid and study interactions between the capsid and viral receptor. Heat, chlorine, and ethanol treatment primarily affect the capsid structure, which in turns affects the ability of the capsid to bind to viral receptors. Inactivation of the virus by these methods could be reflected by the ISC-qRT-PCR method and confirmed by TCID50 assay. However, the loss of the infectivity caused by damage to the viral genome (such as that from UV irradiation) could not be effectively reflected by this method. Despite this limitation, the ISC-qRT-PCR provides an alternative approach to determine inactivation of Tulane virus. A particular advantage of the ISC-qRT-PCR method is that it is also a faster and easier method to effectively recover and detect the viruses, as there is no need to extract viral RNA or to transfer the captured virus from magnetic beads to PCR tubes for further amplification. Therefore, ISC-qRT-PCR can be easily adapted for use in automated systems for multiple samples.
Assuntos
Caliciviridae/fisiologia , Viabilidade Microbiana , Reação em Cadeia da Polimerase em Tempo Real/métodos , Virologia/métodos , Inativação de Vírus , Antígenos de Grupos Sanguíneos/metabolismo , Caliciviridae/efeitos dos fármacos , Caliciviridae/efeitos da radiação , Desinfecção/métodos , Humanos , Receptores Virais/metabolismo , Ligação ViralRESUMO
Human norovirus is the leading cause of epidemic and sporadic acute gastroenteritis. Since no cell culture method for human norovirus exists, cultivable surrogate viruses (CSV), including feline calicivirus (FCV), murine norovirus (MNV), porcine enteric calicivirus (PEC), and Tulane virus (TuV), have been used to study responses to inactivation and disinfection methods. We compared the levels of reduction in infectivities of CSV and Aichi virus (AiV) after exposure to extreme pHs, 56°C heating, alcohols, chlorine on surfaces, and high hydrostatic pressure (HHP), using the same matrix and identical test parameters for all viruses, as well as the reduction of human norovirus RNA levels under these conditions. At pH 2, FCV was inactivated by 6 log10 units, whereas MNV, TuV, and AiV were resistant. All CSV were completely inactivated at 56°C within 20 min. MNV was inactivated 5 log10 units by alcohols, in contrast to 2 and 3 log10 units for FCV and PEC, respectively. TuV and AiV were relatively insensitive to alcohols. FCV was reduced 5 log10 units by 1,000 ppm chlorine, in contrast to 1 log10 unit for the other CSV. All CSV except FCV, when dried on stainless steel surfaces, were insensitive to 200 ppm chlorine. HHP completely inactivated FCV, MNV, and PEC at ≥300 MPa, and TuV at 600 MPa, while AiV was completely resistant to HHP up to 800 MPa. By reverse transcription-quantitative PCR (RT-qPCR), genogroup I (GI) noroviruses were more sensitive than GII noroviruses to alcohols, chlorine, and HHP. Although inactivation profiles were variable for each treatment, TuV and MNV were the most resistant CSV overall and therefore are the best candidates for studying the public health outcomes of norovirus infections.
Assuntos
Caliciviridae/efeitos dos fármacos , Caliciviridae/efeitos da radiação , Desinfecção/métodos , Kobuvirus/efeitos dos fármacos , Kobuvirus/efeitos da radiação , Inativação de Vírus/efeitos dos fármacos , Inativação de Vírus/efeitos da radiação , Caliciviridae/fisiologia , Desinfetantes/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Pressão Hidrostática , Kobuvirus/fisiologia , TemperaturaRESUMO
Human norovirus (HuNoV) is regularly involved in food-borne infections. To detect infectious HuNoV in food, RT-qPCR remains state of the art but also amplifies non-infectious virus. The present study combines pre-treatments, RNase and propidium monoazide, with three molecular analyses, including long-range PCR, to predominantly detect infectious Tulane virus (TuV), a culturable HuNoV surrogate. TuV was exposed to inactivating conditions to assess which molecular method most closely approximates the reduction in infectious virus determined by cell culture (TCID50). After thermal treatments (56 °C/5â¯min, 70 °C/5â¯min, 72 °C/20â¯min), TCID50 reductions of 0.3, 4.4 and 5.9â¯log10 were observed. UV exposure (40/100/1000â¯mJ/cm2) resulted in 1.1, 2.5 and 5.9â¯log10 reductions. Chlorine (45/100â¯mg/L for 1â¯h) reduced infectious TuV by 2.0 and 3.0â¯log10. After thermal inactivation standard RT-qPCR, especially with pre-treatments, showed the smallest deviation from TCID50. On average, RT-qPCR with pre-treatments deviated by 1.1-1.3â¯log10 from TCID50. For UV light, long-range PCR was closest to TCID50 results. Long-range reductions deviated from TCID50 by ≤0.1â¯log10 for mild and medium UV-conditions. However, long-range analyses often resulted in qPCR non-detects. At higher UV doses, RT-qPCR with pre-treatments differed by ≤1.0â¯log10 from TCID50. After chlorination the molecular methods repeatedly deviated from TCID50 by >1.0â¯log10, Overall, each method needs to be further optimized for the individual types of inactivation treatment.
Assuntos
Azidas , Propídio , Raios Ultravioleta , Inativação de Vírus , Azidas/farmacologia , Propídio/análogos & derivados , Propídio/farmacologia , Inativação de Vírus/efeitos da radiação , Viabilidade Microbiana/efeitos da radiação , Viabilidade Microbiana/efeitos dos fármacos , Humanos , Caliciviridae/genética , Caliciviridae/efeitos dos fármacos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Cloro/farmacologia , Ribonucleases , Temperatura AltaRESUMO
We investigated the virucidal activity of commercially available alcohol-based hand rub products against coxsackievirus A7, B5, feline calicivirus F9, and human adenovirus type 3, type 7, type 8 using susceptible cell lines, Vero cells, CRFK cells, and A549 cells. Fifteen tested hand rub products were ethanol (EtOH) for disinfection (Japanese Pharmacopoeia Grade), two EtOH-based products, one povidone iode-containing product, one alkyldiaminoethylglycine hydrochloride-containing product, six benzalkonium chloride (BAK)-containing products, and four chlorohexidine gluconate (CHG)-containing products. Some active ingredients (BAK, benzetonium chloride, and CHG) were diluted with EtOH to make 0.5% and 0.2% solutions. Virus inactivation rates were calculated after contact with each hand rub product for 10 or 60 seconds. Of the hand rub products tested, only the povidone iode-based product showed antiviral activity superior to that of EtOH against all the strains. EtOH solutions of active ingredients (0.2% and 0.5%) also showed decreased antiviral activity. In conclusion, antiviral activity of all the commercially available alcohol-based hand rub products except that containing povidone idode was dependent on their active ingredients. The povidone idode-containing hand rub product kept its effectiveness even after the dilution with EtOH. Although alcohol-based hand rub products are convenient and suitable for the control of some microbes, they are not generally recommended for the control of viral infections.
Assuntos
Desinfetantes/farmacologia , Etanol/farmacologia , Desinfecção das Mãos , Inativação de Vírus/efeitos dos fármacos , Adenovírus Humanos/efeitos dos fármacos , Caliciviridae/efeitos dos fármacos , Linhagem Celular , Enterovirus/efeitos dos fármacos , HumanosRESUMO
Caliciviruses are contagious pathogens of humans and various animals. They are the most common cause of viral gastroenteritis in humans, and can cause lethal diseases in domestic animals such as cats, rabbits and immunocompromised mice. In this study, we conducted cytopathic effect-based screening of 2080 selected compounds from our in-house library to find antiviral compounds against three culturable caliciviruses: feline calicivirus, murine norovirus (MNV) and porcine sapovirus (PoSaV). We identified active six compounds, of which two compounds, both related to theaflavins, showed broad antiviral activities against all three caliciviruses; three compounds (abamectin, a mixture of avermectin B1a and B1b; avermectin B1a; and (-)-epigallocatechin gallate hydrate) were effective against PoSaV only; and a heterocyclic carboxamide derivative (BFTC) specifically inhibited MNV infectivity in cell cultures. Further studies of the antiviral mechanism and structure-activity relationship of theaflavins suggested the following: (1) theaflavins worked before the viral entry step; (2) the effect of theaflavins was time- and concentration-dependent; and (3) the hydroxyl groups of the benzocycloheptenone ring were probably important for the anti-calicivirus activity of theaflavins. Theaflavins could be used for the calicivirus research, and as potential disinfectants and antiviral reagents to prevent and control calicivirus infections in animals and humans.
Assuntos
Antivirais/farmacologia , Biflavonoides/farmacologia , Caliciviridae/efeitos dos fármacos , Catequina/farmacologia , Flavinas/farmacologia , Animais , Infecções por Caliciviridae , Calicivirus Felino/efeitos dos fármacos , Catequina/análogos & derivados , Gatos , Efeito Citopatogênico Viral/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Humanos , Ivermectina/análogos & derivados , Ivermectina/farmacologia , Camundongos , Norovirus/efeitos dos fármacos , Estrutura Quaternária de Proteína , Sapovirus/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
Viruses of the Caliciviridae cause significant and sometimes lethal diseases, however despite substantial research efforts, specific antivirals are lacking. Broad-spectrum antivirals could combat multiple viral pathogens, offering a rapid solution when no therapies exist. The RNA-dependent RNA polymerase (RdRp) is an attractive antiviral target as it is essential for viral replication and lacks mammalian homologs. To focus the search for pan-Caliciviridae antivirals, the RdRp was probed with non-nucleoside inhibitors (NNIs) developed against hepatitis C virus (HCV) to reveal both allosteric ligands for structure-activity relationship enhancement, and highly-conserved RdRp pockets for antiviral targeting. The ability of HCV NNIs to inhibit calicivirus RdRp activities was assessed using in vitro enzyme and murine norovirus cell culture assays. Results revealed that three NNIs which bound the HCV RdRp Thumb I (TI) site also inhibited transcriptional activities of six RdRps spanning the Norovirus, Sapovirus and Lagovirus genera of the Caliciviridae. These NNIs included JTK-109 (RdRp inhibition range: IC50 4.3-16.6 µM), TMC-647055 (IC50 range: 18.8-45.4 µM) and Beclabuvir (IC50 range: 23.8->100 µM). In silico studies and site-directed mutagenesis indicated the JTK-109 binding site was within the calicivirus RdRp thumb domain, in a pocket termed Site-B, which is highly-conserved within all calicivirus RdRps. Additionally, RdRp inhibition assays revealed that JTK-109 was antagonistic with the previously reported RdRp inhibitor pyridoxal-5'-phosphate-6-(2'-naphthylazo-6'-nitro-4',8'-disulfonate) tetrasodium salt (PPNDS), that also binds to Site-B. Moreover, like JTK-109, PPNDS was also a potent inhibitor of polymerases from six viruses spanning the three Caliciviridae genera tested (IC50 range: 0.1-2.3 µM). Together, this study demonstrates the potential for de novo development of broad-spectrum antivirals that target the highly-conserved RdRp thumb pocket, Site-B. We also revealed three broad-spectrum HCV NNIs that could be used as antiviral scaffolds for further development against caliciviruses and other viruses.
Assuntos
Antivirais/farmacologia , Caliciviridae/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , RNA Polimerase Dependente de RNA/antagonistas & inibidores , Animais , Antivirais/química , Benzazepinas/farmacologia , Benzimidazóis/farmacologia , Sítios de Ligação/efeitos dos fármacos , Cristalografia por Raios X , Inibidores Enzimáticos/química , Hepacivirus/efeitos dos fármacos , Indóis/farmacologia , Concentração Inibidora 50 , Norovirus/efeitos dos fármacos , Relação Estrutura-Atividade , Replicação Viral/efeitos dos fármacosRESUMO
The present study investigated the effects of dielectric barrier discharge atmospheric cold plasma (DACP) treatment on the inactivation of Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and Tulane virus (TV) on Romaine lettuce, assessing the influences of moisture vaporization, modified atmospheric packaging (MAP), and post-treatment storage on the inactivation of these pathogens. Romaine lettuce was inoculated with E. coli O157:H7, Salmonella, L. monocytogenes (~6logCFU/g lettuce), or TV (~2logPFU/g lettuce) and packaged in either a Petri dish (diameter: 150mm, height: 15mm) or a Nylon/polyethylene pouch (152×254mm) with and without moisture vaporization. Additionally, a subset of pouch-packaged leaves was flushed with O2 at 5% or 10% (balance N2). All of the packaged lettuce samples were treated with DACP at 34.8kV for 5min and then analyzed either immediately or following post-treatment storage for 24h at 4°C to assess the inhibition of microorganisms. DACP treatment inhibited E. coli O157:H7, Salmonella, L. monocytogenes, and TV by 1.1±0.4, 0.4±0.3, 1.0±0.5logCFU/g, and 1.3±0.1logPFU/g, respectively, without environmental modifications of moisture or gas in the packages. The inhibition of the bacteria was not significantly affected by packaging type or moisture vaporization (p>0.05) but a reduced-oxygen MAP gas composition attenuated the inhibition rates of E. coli O157:H7 and TV. L. monocytogenes continued to decline by an additional 0.6logCFU/g in post-treatment cold storage for 24h. Additionally, both rigid and flexible conventional plastic packages appear to be suitable for the in-package decontamination of lettuce with DACP.
Assuntos
Caliciviridae/efeitos dos fármacos , Escherichia coli O157/efeitos dos fármacos , Contaminação de Alimentos , Lactuca/microbiologia , Listeria monocytogenes/efeitos dos fármacos , Salmonella/efeitos dos fármacos , Anti-Infecciosos/química , Contagem de Colônia Microbiana , Indústria Alimentícia , Microbiologia de Alimentos , Oxigênio/química , Folhas de Planta/microbiologia , Gases em Plasma/farmacologia , PlásticosRESUMO
Fresh produce is a high risk food for human norovirus (NoV) contamination. To help control this pathogen in fresh produce, a better understanding of the interaction of human NoV and fresh produce needs to be established. In this study the attachment of human NoV and animal caliciviruses (murine norovirus, MNV-1; Tulane virus, TV) to fresh produce was evaluated, using both visualization and viral enumeration techniques. It was found that a human NoV GII.4 strain attached efficiently to the Romaine lettuce leaves and roots and green onion shoots, and that washing with PBS or 200 ppm of chlorine removed less than 0.4 log of viral RNA copies from the tissues. In contrast, TV and MNV-1 bound more efficiently to Romaine lettuce leaves than to the roots, and simple washing removed less than 1 log of viruses from the lettuce leaves and 1-4 log PFU of viruses from roots. Subsequently, the location of virus particles in fresh produce was visualized using a fluorescence-based Quantum Dots (Q-Dots) assay and confocal microscopy. It was found that human NoV virus-like particles (VLPs), TV, and MNV-1 associated with the surface of Romaine lettuce and were found aggregating in and around the stomata. In green onions, human NoV VLPs were found between the cells of the epidermis and cell walls of both the shoots and roots. However, TV and MNV-1 were found to be covering the surface of the epidermal cells in both the shoots and roots of green onions. Collectively, these results demonstrate that (i) washing with 200 ppm chlorine is ineffective in removing human NoV from fresh produce; and (ii) different viruses vary in their localization patterns to different varieties of fresh produce.
Assuntos
Caliciviridae/fisiologia , Lactuca/virologia , Norovirus/fisiologia , Cebolas/virologia , Animais , Caliciviridae/efeitos dos fármacos , Cloro/farmacologia , Contaminação de Alimentos/análise , Manipulação de Alimentos , Humanos , Camundongos , Norovirus/efeitos dos fármacos , Folhas de Planta/virologia , Raízes de Plantas/virologiaRESUMO
Our recent results demonstrated that bile acids facilitate virus escape from the endosomes into the cytoplasm for successful replication of porcine enteric calicivirus (PEC). We report a novel finding that bile acids can be substituted by cold treatment for endosomal escape and virus replication. This endosomal escape by cold treatment or bile acids is associated with ceramide formation by acid sphingomyelinase (ASM). ASM catalyzes hydrolysis of sphingomyelin into ceramide, which is known to destabilize lipid bilayer. Treatment of LLC-PK cells with bile acids or cold led to ceramide formation, and small molecule antagonists or siRNA of ASM blocked ceramide formation in the endosomes and significantly reduced PEC replication. Inhibition of ASM resulted in the retention of PEC, feline calicivirus or murine norovirus in the endosomes in correlation with reduced viral replication. These results suggest the importance of viral escape from the endosomes for the replication of various caliciviruses.
Assuntos
Caliciviridae/fisiologia , Ceramidas/metabolismo , Endossomos/enzimologia , Endossomos/metabolismo , Esfingomielina Fosfodiesterase/metabolismo , Internalização do Vírus , Animais , Ácidos e Sais Biliares/metabolismo , Caliciviridae/efeitos dos fármacos , Caliciviridae/efeitos da radiação , Gatos , Linhagem Celular , Temperatura Baixa , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/enzimologia , Células Epiteliais/efeitos da radiação , Células Epiteliais/virologia , Camundongos , Suínos , Replicação ViralRESUMO
Feline calicivirus (FCV) strains isolated from feces (E-FCV) were compared with FCV strains of respiratory origin (R-FCV). All strains were shown to be labile at pH 3.0. All strains except one strain of E-FCV were found to be sensitive to the action of trypsin. When exposed to bile salt (deoxycholic acid sodium salt), all R-FCV strains were markedly inactivated, but none of the E-FCV strains was inactivated. It was possible to select bile-resistant substrains from a bile-sensitive strain.
Assuntos
Bile/metabolismo , Caliciviridae/efeitos dos fármacos , Ácido Desoxicólico/farmacologia , Fezes/microbiologia , Sistema Respiratório/microbiologia , Animais , Antígenos Virais/análise , Caliciviridae/imunologia , Doenças do Gato/microbiologia , Gatos , Testes de Fixação de Complemento , Diarreia/microbiologia , Diarreia/veterinária , Testes de Neutralização , Infecções Respiratórias/microbiologia , Infecções Respiratórias/veterináriaRESUMO
Norwalk and Norwalk-like viruses (NLVs) are important causes of foodborne gastroenteritis in restaurant-related outbreaks. Efficacy of common disinfection methods against these viruses on food-contact surfaces and fresh produce is not known partially because of their nonculturability. Seven commercial disinfectants for food-contact surfaces and three sanitizers for fruits and vegetables were tested against cultivable feline calicivirus (FCV). Disks of stainless steel, strawberry, and lettuce were contaminated with known amounts of FCV. The disinfectants were applied at one, two, and four times the manufacturer's recommended concentrations for contact times of 1 and 10 min. The action of disinfectant was stopped by dilution, and the number of surviving FCVs was determined by titration in cell cultures. An agent was considered effective if it reduced the virus titer by at least 3 log10 from an initial level of 10(7) 50% tissue culture infective dose. None of the disinfectants was effective when used at the manufacturer's recommended concentration for 10 min. Phenolic compounds, when used at two to four times the recommended concentration, completely inactivated FCV on contact surfaces. A combination of quaternary ammonium compound and sodium carbonate was effective on contact surfaces at twice the recommended concentration. Rinsing of produce with water alone reduced virus titer by 2 log10. On artificially contaminated strawberry and lettuce, peroxyacetic acid and hydrogen peroxide was the only effective formulation when used at four times the manufacturers' recommended concentration for 10 min. These findings suggest that FCV and perhaps NLVs are very resistant to commercial disinfectants. However, phenolic compounds at two to four times their recommended concentrations appear to be effective at decontaminating environmental surfaces and may help control foodborne outbreaks of calicivirus in restaurants.
Assuntos
Caliciviridae/efeitos dos fármacos , Desinfetantes/farmacologia , Frutas/virologia , Lactuca/virologia , Relação Dose-Resposta a Droga , Microbiologia Ambiental , Propriedades de Superfície , Fatores de Tempo , Resultado do TratamentoRESUMO
Compared with other parts of the hand, the area beneath fingernails harbors the most microorganisms and is most difficult to clean. Artificial fingernails, which are usually long and polished, reportedly harbor higher microbial populations than natural nails. Hence, the efficacy of different hand washing methods for removing microbes from natural and artificial fingernails was evaluated. Strains of nonpathogenic Escherichia coli JM109 and feline calicivirus (FCV) strain F9 were used as bacterial and viral indicators, respectively. Volunteers with artificial or natural nails were artificially contaminated with ground beef containing E. coli JM109 or artificial feces containing FCV. Volunteers washed their hands with tap water, regular liquid soap, antibacterial liquid soap, alcohol-based hand sanitizer gel, regular liquid soap followed by alcohol gel, or regular liquid soap plus a nailbrush. The greatest reduction of inoculated microbial populations was obtained by washing with liquid soap plus a nailbrush, and the least reduction was obtained by rubbing hands with alcohol gel. Lower but not significantly different (P > 0.05) reductions of E. coli and FCV counts were obtained from beneath artificial than from natural fingernails. However, significantly (P < or = 0.05) higher E. coli and FCV counts were recovered from hands with artificial nails than from natural nails before and after hand washing. In addition, microbial cell numbers were correlated with fingernail length, with greater numbers beneath fingernails with longer nails. These results indicate that best practices for fingernail sanitation of food handlers are to maintain short fingernails and scrub fingernails with soap and a nailbrush when washing hands.
Assuntos
Caliciviridae/isolamento & purificação , Desinfetantes/farmacologia , Escherichia coli/isolamento & purificação , Desinfecção das Mãos/métodos , Unhas/microbiologia , Álcoois/farmacologia , Animais , Caliciviridae/efeitos dos fármacos , Contagem de Colônia Microbiana , Cosméticos , Escherichia coli/efeitos dos fármacos , Géis/farmacologia , Humanos , Carne/microbiologia , Sabões/farmacologiaRESUMO
Two similar calici agents, San Miguel sea lion virus (SMSV) and vesicular exanthema of swine virus (VESV) are susceptible to the virucidal activity of disinfectants of differing formulation. Ten of 12 compounds were effective against six log10 plaque forming units (PFU) of SMSV in a 2-min exposure at 4, 25 and 37 degrees C. However, only seven of these 10 SMSV-positive compounds inactivated VESV under the same conditions of temperature and time. Two compounds were not effective against SMSV in a 20-min exposure at 4 and 25 degrees C, but were effective at 37 degrees C. Two of the three compounds not effective against VESV in a 20-min exposure at 4 and 25 degrees C were also effective at 37 degrees C. The test iodophor compound inactivated SMSV completely but had only minimal inactivating activity against VESV at the three temperatures tested.
Assuntos
Caliciviridae/efeitos dos fármacos , Desinfetantes/farmacologia , Animais , Compostos de Benzalcônio/farmacologia , Caliciviridae/crescimento & desenvolvimento , Caniformia/microbiologia , Formaldeído/farmacologia , Suínos , Temperatura , Fatores de Tempo , Exantema Vesicular de Suínos/microbiologiaRESUMO
Ribavirin had marked in vitro activity against feline calcivirus, strain 255, and canine parainfluenza virus, but showed only slight antiviral effect on feline viral rhinotracheitis virus. Antiviral activity was manifested by partial to complete suppression of viral cytopathic effect and of viral replication, depending on concentration of ribavirin in the culture medium and dosage of viral inoculum. Concentrations of ribavirin as small as 3.2 microgram/ml and 1.0 microgram/ml showed some activity against feline calcivirus and canine parainfluenza virus, respectively.
Assuntos
Caliciviridae/efeitos dos fármacos , Herpesviridae/efeitos dos fármacos , Vírus da Parainfluenza 2 Humana/efeitos dos fármacos , Picornaviridae/efeitos dos fármacos , Respirovirus/efeitos dos fármacos , Ribavirina/farmacologia , Ribonucleosídeos/farmacologia , Animais , Caliciviridae/crescimento & desenvolvimento , Gatos/microbiologia , Células Cultivadas , Efeito Citopatogênico Viral , Cães/microbiologia , Herpesviridae/crescimento & desenvolvimento , Vírus da Parainfluenza 2 Humana/crescimento & desenvolvimentoRESUMO
Thirty-five commonly used commercial disinfectants (disinfectants, antiseptics, sanitizers, and detergents) were evaluated for their virucidal activity against three feline viruses; feline viral rhinotracheitis virus (a herpesvirus), feline calicivirus, and feline panleukopenia virus (a parvovirus). Disinfectants were diluted as recommended by the manufacturer and were reacted with virus for 10 minutes at room temperature. Viruses were separated from disinfectants by gel filtration in special centrifuge tubes, and were assayed for infectivity in feline cell cultures. All 22 products tested were virucidal for feline viral rhinotracheitis virus, 11 of 35 were virucidal for feline calicivirus, but only 3 of 27 tested were effective against feline panleukopenia virus. A 0.175% sodium hypochlorite solution was the most effective and practical broad-spectrum virucidal product used alone or in combination with other disinfectants/detergents.
Assuntos
Antivirais/farmacologia , Caliciviridae/efeitos dos fármacos , Gatos/microbiologia , Desinfetantes/farmacologia , Vírus da Panleucopenia Felina/efeitos dos fármacos , Herpesviridae/efeitos dos fármacos , Parvoviridae/efeitos dos fármacos , Animais , Anti-Infecciosos Locais/farmacologia , Detergentes/farmacologiaRESUMO
Five disinfectants, Venno FF super, Venno Vet 1 super, Venno Oxygen, M&Enno-Veterinär B neu und Neopredisan 135-1, were tested to evaluate their efficacy against caliciviruses at 20 and 10 degrees C. As model test virus served feline calicivirus type F9 (FCV F9). All disinfectants were tested according to Guidelines of the German Veterinary Association (DVG). The investigations were performed in suspension tests and germ carrier tests. The suspension tests were carried out without and with protein load. As protein was used foetal calf serum at the concentration of 40%. Venno FF super showed less protein dependence, however a considerable temperature dependence. This matter can be corrected by increase of concentration on 2%. Venno Vet 1 super was without protein especially effective. The losses on the effectiveness through low temperature and protein load can be annulled also here by increase of concentration. Venno Oxygen was more effective in the comparison to that here named both preparations. The effects of temperature can be corrected by extension of reaction time. The most effective preparation was M&Enno Veterinär B neu. The disinfection occurred at 20 degrees C with 0.5% solution within 120 min and at 10 degrees C with 1.0% solution within 60 min. The fifth disinfectant Neopredisan was in suspension tests without protein load and carrier tests with gauze at 20 and 10 degrees C relative convincing but in germ carrier tests with poplar wood, no complete disinfection could be achieved within tested concentrations and reaction times.
Assuntos
Caliciviridae/efeitos dos fármacos , Desinfetantes/farmacologia , Animais , Caliciviridae/crescimento & desenvolvimento , Relação Dose-Resposta a Droga , Temperatura , Resultado do TratamentoRESUMO
Viral surrogates are widely used by researchers to predict human norovirus behavior. Murine norovirus (MNV) is currently accepted as the best surrogate and is assumed to mimic the survival and inactivation of human noroviruses. Recently, a new calicivirus, the Tulane virus (TV), was discovered, and its potential as a human norovirus surrogate is being explored. This study aimed to compare the behavior of the two potential surrogates under varying treatments of pH (2.0 to 10.0), chlorine (0.2 to 2,000 ppm), heat (50 to 75°C), and survival in tap water at room (20°C) and refrigeration (4°C) temperatures for up to 30 days. Viral infectivity was determined by the plaque assay for both MNV and TV. There was no significant difference between the inactivation of MNV and TV in all heat treatments, and for both MNV and TV survival in tap water at 20°C over 30 days. At 4°C, MNV remained infectious over 30 days at a titer of approximately 5 log PFU/ml, whereas TV titers decreased significantly by 5 days. MNV was more pH stable, as TV titers were reduced significantly at pH 2.0, 9.0, and 10.0, as compared with pH 7.0, whereas MNV titers were only significantly reduced at pH 10.0. After chlorine treatment, there was no significant difference in virus with the exception of at 2 ppm, where TV decreased significantly compared with MNV. Compared with TV, MNV is likely a better surrogate for human noroviruses, as MNV persisted over a wider range of pH values, at 2 ppm of chlorine, and without a loss of titer at 4°C.
Assuntos
Caliciviridae , Cloro/farmacologia , Microbiologia de Alimentos , Norovirus , Animais , Caliciviridae/efeitos dos fármacos , Caliciviridae/crescimento & desenvolvimento , Caliciviridae/patogenicidade , Humanos , Concentração de Íons de Hidrogênio , Cinética , Camundongos , Norovirus/efeitos dos fármacos , Norovirus/crescimento & desenvolvimento , Norovirus/patogenicidade , Especificidade da Espécie , Temperatura , Fatores de Tempo , Ensaio de Placa ViralRESUMO
Human noroviruses (HuNoVs) are the major cause of nonbacterial gastroenteritis epidemics. The culturable feline calicivirus and murine norovirus have been used extensively as surrogates to study HuNoV biology, as HuNoV does not grow in vitro. Additional efforts to identify new surrogates are needed, because neither of these common surrogates are truly intestinal pathogens. The newly described Tulane virus (TV) is a typical calicivirus, it is isolated from macaque stools, is cultivable in vitro, and recognizes human histo-blood group antigens. Therefore, TV is a promising surrogate for HuNoVs. In this study, we evaluated the resistance or stability of TV under various physical and environmental conditions by measuring a 50% reduction of tissue culture infective dose (TCID50) by using a TV cell culture system. Due to the nature of this virus, it is hard to produce a high-titer stock through tissue culture. In our study, the maximal reduction in virus titers was 5D (D = 1 log) in heat-denaturation and EtOH experiments, and 4D in UV, chlorine, and pH-stability experiments. Therefore in this study, we defined the inactivation of TV as reaching a TCID50/ml of 0 (a 4- to 5-D reduction in TCID50, depending on the detection limit). TV was inactivated after incubation at 63 °C for 5 min, incubation at 56 °C for 30 min (5D), exposure to 60 mJ/cm2 of UVC radiation (4D), or incubation at 300 ppm of free chlorine for 10 min (4D). TV was shown to be stable from pH 3.0 to 8.0, though an obvious reduction in virus titer was observed at pH 2.5 and 9.0, and was inactivated at pH 10.0 (4D). TV was resistant to a low concentration of EtOH (40% or lower) but was fully inactivated (5D) by 50 to 70% EtOH after a short exposure (20 s). In contrast, quantitative real-time PCR was unable to detect, or poorly detected, virus titer reductions between treated and untreated samples described in this study.
Assuntos
Caliciviridae/efeitos dos fármacos , Caliciviridae/crescimento & desenvolvimento , Cloro/farmacologia , Inativação de Vírus , Animais , Caliciviridae/patogenicidade , Gatos , Contagem de Colônia Microbiana/métodos , Microbiologia de Alimentos , Humanos , Concentração de Íons de Hidrogênio , Cinética , Camundongos , Norovirus/efeitos dos fármacos , Norovirus/crescimento & desenvolvimento , Norovirus/patogenicidade , Especificidade da Espécie , Temperatura , Fatores de TempoRESUMO
Caliciviridae are human or non-human pathogenic viruses with a high diversity. Some members of the Caliciviridae, i.e. human pathogenic norovirus or rabbit hemorrhagic disease virus (RHDV), are worldwide emerging pathogens. The norovirus is the major cause of viral gastroenteritis worldwide, accounting for about 85% of the outbreaks in Europe between 1995 and 2000. In the United States, 25 million cases of infection are reported each year. Since its emergence in 1984 as an agent of fatal hemorrhagic diseases in rabbits, RHDV has killed millions of rabbits and has been dispersed to all of the inhabitable continents. In view of their successful and apparently increasing emergence, the development of antiviral strategies to control infections due to these viral pathogens has now become an important issue in medicine and veterinary medicine. Antiviral strategies have to be based on an understanding of the epidemiology, transmission, clinical symptoms, viral replication and immunity to infection resulting from infection by these viruses. Here, we provide an overview of the mechanisms underlying calicivirus infection, focusing on the molecular aspects of replication in the host cell. Recent experimental data generated through an international collaboration on structural biology, virology and drug design within the European consortium VIZIER is also presented. Based on this analysis, we propose antiviral strategies that may significantly impact on the epidemiological characteristics of these highly successful viral pathogens.