Papers by Givanildo Silva
Transboundary and Emerging Diseases, 2020
Staphylococcus aureus is a versatile and highly adaptable pathogen associated with a wide range o... more Staphylococcus aureus is a versatile and highly adaptable pathogen associated with a wide range of infectious diseases in humans and animals. In the last decades, concern has increased worldwide due to the emergence and spread of methicillin-resistant S. aureus (MRSA) strains shortly after this drug became a therapeutic option. In this study, we report the genomic features of the first mecC-mediated, β-lactam resistant MRSA strain associated with livestock in Brazil and in the American continent. Three clonally-related phenotypic MRSA isolates originated from a dairy herd were confirmed by polymerase chain reaction as mecC-harboring MRSA isolates. Whole-genome sequencing was performed by Illumina Miseq platform. Downstream analyses showed that the strain was identified as the sequence type 126 (ST126) and spa type t605. In silico analysis revealed a mecC homolog gene in the orfX region associated with different penicillin-binding proteins. Moreover, genes encoding for efflux pump systems (arlR, mepR, LmrS, norA, mgrA), and antibiotic inactivation enzymes (blaZ and FosB) were also detected. Virulence analyses revealed that the strain harbors genes encoding for exoenzymes (aur, splA, splB, splE), toxin (hlgA, hlgB, hlgC, lukD, lukE), and enterotoxin (sea). The epidemiologic and genomic information provided by this study will support further epidemiological and evolutionary investigations to understand the origin and dissemination of mecC-MRSA among animals and its impact on public health.
The aim of the present study was to investigate the occurrence of anti-Toxoplasma gondii antibodi... more The aim of the present study was to investigate the occurrence of anti-Toxoplasma gondii antibodies and parasite DNA in backyard chickens bred in the metropolitan area of Recife, Brazil. In total, 212 serum samples were collected from 16 properties, and 12 backyard chickens were collected in the six sanitary districts of Recife. An indirect immunofluorescence assay (IFA) was used to investigate the occurrence of anti-Toxoplasma gondii antibodies. Polymerase chain reaction (PCR) was used to detect T. gondii DNA in brain, heart, liver and lung specimens. Of the samples analyzed by serology, 86/212 (40.56%) were positive; of the samples analyzed by PCR, 2/12 (16.7%) were positive, with both samples positive by both tests (serological and molecular). The presence of antibody anti-T. gondii and parasite DNA in tissues of these animals are worrying aspects for public health because there is a risk of transmission of the parasite to humans through eating undercooked or raw meat. Based on the results, the adoption of preventive measures to prevent the cats access to the chickens creations should be encouraged, since these animals were identified in most of the studied properties.
The aim of the present study was to detect the genomic DNA of Toxoplasma gondii in milk samples f... more The aim of the present study was to detect the genomic DNA of Toxoplasma gondii in milk samples from naturally infected goats in the state of Pernambuco, (Brazil). In total, 248 blood serum samples were collected and processed from lac-tating goats and then submitted to a search for antibodies to T. gondii through the indirect immunofluorescence reaction. Samples with a score of 64 or more were considered positive. In total, 248 milk samples were collected and processed from the same group of goats in order to study the DNA of T. gondii using the polymerase chain reaction (PCR) technique. In the serum samples, 56/248 (22.58%) of the animals were positive, whereas the DNA of the parasite was detected in 15/248 (6.05%) of the milk samples. Five of these 15 samples were animals who were also positive in the serology. This study reports the first occurrence of the elimination of T. gondii from the milk of naturally infected goats in the northeast of Brazil. It is suggested that the consumption of in natura goat milk may constitute a potential risk to the health of milk consumers in this region.
![Research paper thumbnail of Etiologia das Mastites em Cabras e Ovelhas de Raças Naturalizadas Criadas no Semiárido Nordestino [Etiology of Mastitis in native goats and sheeps born and raised in Brazilian semi-arid biom] " Artigo Científico/Scientific Article "](https://attachments.academia-assets.com/49821186/thumbnails/1.jpg)
_____________________________________________________________________________ Resumo Durante muit... more _____________________________________________________________________________ Resumo Durante muito tempo as raças naturalizadas de caprinos e ovinos estiveram ameaçadas de extinção. Atualmente existe uma linha de proteção dos recursos genéticos dessas raças, mas não existem estudos que determinem o status sanitário desses animais, principalmente no que diz respeito às doenças infectocontagiosas, como a mastite. Objetivou-se pesquisar a etiologia das mastites em caprinos e ovinos de raças naturalizadas criados no semiárido dos estados de Pernambuco e Paraíba, Nordeste do Brasil. Foram coletadas 480 amostras de leite caprino e ovino de doze raças nativas, no período de janeiro a julho de 2012. As amostras foram submetidas à análise microbiológica em Ágar Base acrescido de sangue ovino a 5% e as placas foram incubadas em estufa bacteriológica em aerofilia a 37º C por até 72h, posteriormente realizou-se à técnica de coloração de Gram e provas bioquímicas de identificação. Do total de amostras estudadas observou-se isolamento bacteriano em 13,54% (65/480) e os micro-organismos mais frequentes foram: Staphylococcus spp., seguido por Micrococcus spp. Não existem estudos sobre a etiologia da mastite em cabras e ovelhas de raças naturalizadas no semiárido nordestino e os resultados obtidos neste estudo permitirão a implantação de medidas preventivas para esta doença. Palavras-chave: Microbiologia do leite, epidemiologia, mastites. Abstract Goats are important species of livestock for Brazil especially at the Northeast Region. Because of that Native goats breeds represent important genetic resources for conservation and breeding programs. Although there are some of infectious diseases that may affect to the conservation of this endangered breeds, particularly mastitis. The goal of this study study was to investigate the frequency and the etiology of mastitis in native goats and sheep born and raised in Brazilian semi-arid biom of Paraíba and Pernambuco state. A total of 480 fresh milk samples from of twelve native breeds of goat, from January to July 2012. All of the biological material were plated on Sheep blood supplemented with Agar Base, and incubated at 37ºC for 72 h.Gram-staining followed by biochemical tests were made for identification of bacteria. The results of bacteriological examinations showed 13.54% (65/480) of positive samples and the most frequent microorganisms isolated and identified were Staphylococcus spp., followed by Micrococcus spp. This is the first report of isolation of bacteria that may produce mastitis in native goats and sheep from the northeast semiarid region of Brazil. The results obtained in this study will allow authorities to implement preventive measures for this disease.
The present study aimed to determine the prevalence of toxoplasmosis in free-range chickens of th... more The present study aimed to determine the prevalence of toxoplasmosis in free-range chickens of the Fernando de Noronha Archipelago, Brazil and to identify risk factors associated with Toxoplasma gondii infection. Blood samples were collected from all the adult chickens raised in the Archipelago and screened by Indirect Fluorescent Antibody Test (430 samples, in total). Univariate analysis (Chi-square) and logistic regression were used to investigate the relationship between various variables possibly predictive of an increased likelihood of T. gondii infection. The overall prevalence of T. gondii infection in chickens of the Fernando de Noronha Archipelago was 88.4% (380/430; 84.6%–91.0%; 95% CI), ranging from 57.1% to 100.0% among the studied properties. The risk factors associated with T. gondii infection were the number of domestic cats in the properties (p = 0.022), the presence of feral cats (p = 0.006) and the presence of an open water source (p = 0.046). Domestic and feral cats should be prevented from accessing the water and food supplied to chickens.
The present study aimed to conduct a serosurvey of toxoplasmosis in domestic rabbits of Northeast... more The present study aimed to conduct a serosurvey of toxoplasmosis in domestic rabbits of Northeastern Brazil. Blood samples and tissue fragments (brain, heart and diaphragm) were collected from 150 and 54 rabbits from the state of Pernambuco, Brazil, respectively. The serum samples were subjected to serological analysis (Modified Agglutination Test -MAT) and the tissue samples were assessed by PCR and histopathological analysis. Data collected through questionnaires were subjected to analysis of risk factors. According to the MAT and the PCR results, 6.7% (10/150; CI 3.2%-11.9%) of the rabbits were positive for anti-T. gondii antibodies and 9.25% (5/54) of the tissue fragments were positive for T. gondii DNA, respectively. Lesions associated with T. gondii infection, mainly characterized by granuloma, mononuclear cell infiltrates, degeneration areas and necrosis in brain and heart, were detected in the histopathological analysis. The risk factors associated with T. gondii infection identified in the present study were homemade food (odds ratio = 39.00) and contact between cats and rabbits (odds ratio = 52.00). This is the first report of toxoplasmosis in rabbits of Northeastern Brazil. The management problems identified in the present study must be corrected to reduce the frequency of positive animals in herds of rabbits.
RESUMO Hambúrgueres foram elaborados manualmente com carne mecanicamente separada (CMS) de tilápi... more RESUMO Hambúrgueres foram elaborados manualmente com carne mecanicamente separada (CMS) de tilápia, em um planejamento fatorial 22 completo, visando determinar o efeito da fibra de trigo e óleo de milho no encolhimento e na capacidade de retenção de água. A melhor formulação obtida foi a interação de 1% de óleo de milho e 2,5% de fibra de trigo e como resposta 4,3% de encolhimento e 87% de capacidade de retenção de água. Na segunda etapa, a melhor formulação de CMS foi elaborada manualmente em quatro bateladas e submetidas às análises microbiológicas, físico-químicas e sensorial, em triplicata. Os hambúrgueres encontravam-se dentro dos padrões permitidos pela legislação brasileira. A fibra de trigo e o óleo vegetal de milho podem ser utilizados na elaboração de fishbúrguer de CMS de tilápia, com excelente aceitação sensorial. PALAVRAS-CHAVE: Análise descritiva quantitativa. Hambúrguer. Peixe. SUMMARY Fish burgers were made manually using mechanically recovered meat (MRM) from tilapia in a 22 full factorial design to determine the effect of wheat fibre and corn oil shrinkage on the water retention capacity of fish burgers. The best formulation was obtained using 1% corn oil and 2.5% wheat fibre, which resulted in a 4.3% shrinkage rate and 87% water retention capacity. In the second step, the best formulation was again prepared manually in four batches and subjected to bacteriological, physico-chemical and sensory tests in triplicate. The fish burgers were found to be within the standard microbiological and physical chemical parameters required by Brazilian law. Fibre from wheat and vegetable oil corn can be used to prepare fish burgers from MRM tilapia with excellent sensory acceptance.
The aim of the present study was to detect Toxoplasma gondii DNA in raw milk samples of goats and... more The aim of the present study was to detect Toxoplasma gondii DNA in raw milk samples of goats and sheep of local breeds from the semi-arid region of the states of Pernambuco and Paraíba, Northeastern Brazil. Serum and milk samples were collected from 243 animals (186 goats and 57 sheep). The Indirect fluorescent antibody test (IFAT) was used to search for anti-T. gondii IgG antibodies with a cutoff of 64. Subsequently, the raw milk samples were subjected to DNA extraction and PCR to detect DNA of T. gondii. The IFAT results showed a 6.58% (16/243) positivity when all the samples were considered and a positivity of 15.78% (9/57) and 3.76% (7/186) for goats and sheep samples, respectively. The PCR assay detected T. gondii DNA in 2.06% (5/243) of all the samples tested. All the PCR positive samples were from goats. This result shows the importance of adopting measures of flock's sanitary management and avoiding the consumption of raw milk may constitute a potential risk to the health of milk consumers in this region.
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Papers by Givanildo Silva