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Equine Vet J ; 52(1): 98-103, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30991461


BACKGROUND: Salmonella enterica subsp. enterica serovar Abortusequi (S. Abortusequi) is a serotype restricted to equines, which produces abortion outbreaks. Nowadays the disease is being reported in different countries including Argentina thus generating an important impact in the equine industry. Molecular characterization of the 95 kb virulence plasmid and the spvC gene of S. Abortusequi demonstrated their importance in the pathogenicity of the serotype. In the last decades, high clonality of S. Abortusequi was identified in Japan, Mongolia and Croatia. OBJECTIVES: The aim of this work was to characterize S. Abortusequi isolates obtained in Argentina between 2011 and 2016 by virulence-gene profiling and pulsed-field gel electrophoresis. STUDY DESIGN: Case report. METHODS: S. Abortusequi isolates were studied by virulence-gene profiling and pulsed-field gel electrophoresis. RESULTS: Four virulence profiles and nine pulsed-field gel electrophoresis pulsotypes were identified among the 27 isolates included in the study. Different strains were found in the same outbreak and/or farm suggesting the presence of different sources of infection or mutation of isolates. MAIN LIMITATIONS: The number of related and nonrelated strains. More isolates may be necessary for a more intensive study. CONCLUSIONS: Most strains presented the same virulence profile, being positive for all the studied genes except gipA and sopE1, which are involved in intestinal virulence. Only few isolates showed different results in the same outbreak or farm. Unlike other studies, our results demonstrate a considerable diversity of S. Abortusequi pulsed-field gel electrophoresis pulsotypes, which suggests that different sources of infection may be involved within the same outbreak.

Genótipo , Doenças dos Cavalos/microbiologia , Salmonelose Animal/microbiologia , Salmonella enterica/genética , Animais , Argentina/epidemiologia , Doenças dos Cavalos/epidemiologia , Cavalos , Salmonelose Animal/epidemiologia , Salmonella enterica/classificação , Salmonella enterica/patogenicidade , Transcriptoma , Virulência
Artigo em Inglês | MEDLINE | ID: mdl-22919675


Enterohemorrhagic Escherichia coli (EHEC), a subset of Shiga toxin producing E. coli (STEC) is associated with a spectrum of diseases that includes diarrhea, hemorrhagic colitis and a life-threatening hemolytic-uremic syndrome (HUS). Regardless of serotype, Shiga toxins (Stx1 and/or Stx2) are uniformly expressed by all EHEC, and so exploitable targets for laboratory diagnosis of these pathogens. In this study, a sandwich ELISA for determination of Shiga toxin (Stx) was developed using anti-Stx2B subunit antibodies and its performance was compared with that of the Vero cell assay and a commercial immunoassay kit. Chicken IgY was used as capture antibody and a HRP-conjugated rabbit IgG as the detection antibody. The anti-Stx2B IgY was harvested from eggs laid by hens immunized with a recombinant protein fragment. Several parameters were tested in order to optimize the sandwich ELISA assay, including concentration of antibodies, type and concentration of blocking agent, and incubation temperatures. Supernatants from 42 STEC strains of different serotypes and stx variants, including stx(2EDL933), stx(2vha), stx(2vhb), stx(2g), stx(1EDL933), and stx(1d) were tested. All Stx variants were detected by the sandwich ELISA, with a detection limit of 115 ng/ml Stx2. Twenty three strains negative for stx genes, including different bacteria species, showed no activity in Vero cell assay and produced negative results in ELISA, except for two strains. Our results show that anti-Stx2B IgY sandwich ELISA could be used in routine diagnosis as a rapid, specific and economic method for detection of Shiga toxin-producing E. coli.

Anticorpos Antibacterianos , Técnicas Bacteriológicas/métodos , Imunoglobulinas , Escherichia coli Shiga Toxigênica/isolamento & purificação , Animais , Anticorpos Antibacterianos/isolamento & purificação , Sobrevivência Celular/efeitos dos fármacos , Galinhas , Gema de Ovo/química , Ensaio de Imunoadsorção Enzimática/métodos , Infecções por Escherichia coli/diagnóstico , Infecções por Escherichia coli/microbiologia , Humanos , Imunoglobulinas/isolamento & purificação , Sensibilidade e Especificidade , Células Vero
Toxicon ; 58(4): 380-8, 2011 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-21803069


Shiga toxins (Stx1 and Stx2) are the main virulence factors of enterohemorrhagic Escherichia coli (EHEC), a foodborne pathogen associated with diarrhea, hemorrhagic colitis and hemolytic uremic syndrome. The aim of this study was to evaluate the antibodies against Stx2 obtained from egg yolks of laying hens immunized with a recombinant Stx2B subunit. A high specific response in serum was observed 25 days after the first immunization and IgY antibodies were extracted from day 47th and purified from egg yolk. A concentration of 0.84 mg of total IgY/ml of egg yolk was obtained, of which 8% were antigen specific. The ability of anti-Stx2B IgY to recognize Stx2B and Stx2 either in solid-phase or in solution were evaluated and compared with anti-Stx2B rabbit antibodies by Western blotting and ELISA. The protective efficacy of IgY against Stx2 was determined by in vitro and in vivo experiments. The results show that IgY was able to recognize Stx2B and Stx2 in denatured conditions, attached to a solid-phase and free in solution. The anti-Stx2B IgY could effectively block the biological activity of Stx2 on Vero cells and protect mice from Stx2 challenge. The data suggest that immunization of hens with Stx2B could be a strategy to obtain at low cost a relatively high concentration of anti-Stx2 egg yolk IgY, able to neutralize Stx2 lethal activity. IgY technology could be an useful tool for research, diagnosis and therapy of EHEC infection.

Anticorpos Antibacterianos/fisiologia , Galinhas/imunologia , Gema de Ovo/imunologia , Imunoglobulinas/fisiologia , Toxina Shiga II/imunologia , Animais , Anticorpos Antibacterianos/isolamento & purificação , Afinidade de Anticorpos , Imunoglobulinas/isolamento & purificação , Camundongos , Camundongos Endogâmicos , Testes de Neutralização , Coelhos
Vet Immunol Immunopathol ; 142(3-4): 156-69, 2011 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-21652087


Bovine rotavirus (BRV) is an important cause of diarrhea in newborn calves. Local passive immunity is the most efficient protective strategy to control the disease. IgY technology (the use of chicken egg yolk immunoglobulins) is an economic and practical alternative to prevent BRV diarrhea in dairy calves. The aim of this study was to evaluate the protection and immunomodulation induced by the oral administration of egg yolk enriched in BRV specific IgY to experimentally BRV infected calves. All calves in groups Gp 1, 2 and 3 received control colostrum (CC; BRV virus neutralization Ab titer - VN=65,536; ELISA BRV IgG(1)=16,384) prior to gut closure. After gut closure, calves received milk supplemented with 6% BRV-immune egg yolk [(Gp 1) VN=2048; ELISA IgY Ab titer=4096] or non-immune control egg yolk [(Gp 2) VN<4; ELISA IgY Ab titer<4] twice a day, for 14 days. Calves receiving CC only or colostrum deprived calves (CD) fed antibody (Ab) free milk served as controls (Gp 3 and 4, respectively). Calves were inoculated with 10(5.85)focus forming units (FFU) of virulent BRV IND at 2 days of age. Control calves (Gp 3 and 4) and calves fed control IgY (Gp 2) were infected and developed severe diarrhea. Around 80% calves in Gp 1 (IgY 4096) were infected, but they showed 80% (4/5) protection against BRV diarrhea. Bovine RV-specific IgY Ab were detected in the feces of calves in Gp 1, indicating that avian antibodies (Abs) remained intact after passage through the gastrointestinal tract. At post infection day 21, the duodenum was the major site of BRV specific antibody secreting cells (ASC) in all experimental groups. Mucosal ASC responses of all isotypes were significantly higher in the IgY treated groups, independently of the specificity of the treatment, indicating that egg yolk components modulated the immune response against BRV infection at the mucosal level. These results indicate that supplementing newborn calves' diets for the first 14 days of life with egg yolk enriched in BRV-specific IgY represents a promising strategy to prevent BRV diarrhea. Moreover a strong active ASC immune response is induced in the intestinal mucosa following BRV infection after the administration of egg yolk, regardless the specificity of the treatment.

Doenças dos Bovinos/virologia , Diarreia/veterinária , Gema de Ovo/imunologia , Imunoglobulinas/imunologia , Infecções por Rotavirus/veterinária , Rotavirus/imunologia , Animais , Animais Recém-Nascidos , Anticorpos Antivirais/análise , Bovinos , Doenças dos Bovinos/imunologia , Doenças dos Bovinos/prevenção & controle , Diarreia/imunologia , Diarreia/prevenção & controle , Diarreia/virologia , Relação Dose-Resposta a Droga , Ensaio de Imunoadsorção Enzimática/veterinária , Fezes/virologia , Imunoglobulinas/farmacologia , Masculino , Testes de Neutralização/veterinária , Projetos Piloto , Distribuição Aleatória , Infecções por Rotavirus/imunologia , Infecções por Rotavirus/prevenção & controle , Infecções por Rotavirus/virologia , Estatísticas não Paramétricas
Avian Dis ; 50(2): 280-3, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16863082


Fowl typhoid is under control in poultry farms of developed countries, but it still endemically subsists in commercial laying hen farms of some countries. It has been demonstrated that Salmonella live vaccines can elicit cross-immunity against members of the same Kauffmann-White scheme serogroup. In this work, we explored the protection conferred by TAD Salmonella vac E, a live Salmonella enterica serovar Enteritidis vaccine, against fowl typhoid. Three groups of laying hens were vaccinated with different vaccination schedules starting on the first day of life, and afterwards were infected with 2 x 10(5) CFU of a virulent Salmonella Gallinarum strain, either at wk 28 or wk 52. Mortality, fecal shedding, and organ invasion of Salmonella Gallinarum were assessed. In this work we demonstrated that this Salmonella Enteritidis vaccine is able to cross-immunize against Salmonella Gallinarum. At wk 28, hens vaccinated with three oral doses or with two oral doses combined with one subcutaneous dose were protected by the vaccine. At wk 52, when hens were infected 36 wk after the final immunization, the vaccine was not able to confer protection. Thus, revaccination every 3 mo would be highly recommended. In countries where Salmonella Gallinarum subsists together with Salmonella Enteritidis, control programs should include vaccination of laying hens using safe attenuated Salmonella strains.

Galinhas/imunologia , Galinhas/microbiologia , Doenças das Aves Domésticas/prevenção & controle , Salmonelose Animal/imunologia , Salmonelose Animal/prevenção & controle , Vacinas contra Salmonella/imunologia , Salmonella enteritidis/imunologia , Animais , Fezes/microbiologia , Feminino , Oviposição , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/mortalidade , Salmonelose Animal/mortalidade