RESUMO

The Type VI Secretion System (T6SS) is a multiprotein device that has emerged as an important fitness and virulence factor for many Gram-negative bacteria through the injection of effector proteins into prokaryotic or eukaryotic cells via a contractile mechanism. While some effector proteins specifically target bacterial or eukaryotic cells, others can target both types of cells (trans-kingdom effectors). In Salmonella, five T6SS gene clusters have been identified within pathogenicity islands SPI-6, SPI-19, SPI-20, SPI-21, and SPI-22, which are differentially distributed among serotypes. Salmonella enterica serotype Dublin (S. Dublin) is a cattle-adapted pathogen that harbors both T6SSSPI-6 and T6SSSPI-19. Interestingly, while both systems have been linked to virulence and host colonization in S. Dublin, an antibacterial activity has not been detected for T6SSSPI-6 in this serotype. In addition, there is limited information regarding the repertoire of effector proteins encoded within T6SSSPI-6 and T6SSSPI-19 gene clusters in S. Dublin. In the present study, we demonstrate that T6SSSPI-6 and T6SSSPI-19 of S. Dublin CT_02021853 contribute to interbacterial competition. Bioinformatic and comparative genomic analyses allowed us to identify genes encoding three candidate antibacterial effectors located within SPI-6 and two candidate effectors located within SPI-19. Each antibacterial effector gene is located upstream of a gene encoding a hypothetic immunity protein, thus conforming an effector/immunity (E/I) module. Of note, the genes encoding these effectors and immunity proteins are widely distributed in Salmonella genomes, suggesting a relevant role in interbacterial competition and virulence. Finally, we demonstrate that E/I modules SED_RS01930/SED_RS01935 (encoded in SPI-6), SED_RS06235/SED_RS06230, and SED_RS06335/SED_RS06340 (both encoded in SPI-19) contribute to interbacterial competition in S. Dublin CT_02021853.

RESUMO

The Enteritidis and Dublin serovars of Salmonella enterica are phylogenetically closely related yet differ significantly in host range and virulence. S Enteritidis is a broad-host-range serovar that commonly causes self-limited gastroenteritis in humans, whereas S Dublin is a cattle-adapted serovar that can infect humans, often resulting in invasive extraintestinal disease. The mechanism underlying the higher invasiveness of S Dublin remains undetermined. In this work, we quantitatively compared the proteomes of clinical isolates of each serovar grown under gut-mimicking conditions. Compared to S Enteritidis, the S Dublin proteome was enriched in proteins linked to response to several stress conditions, such as those encountered during host infection, as well as to virulence. The S Enteritidis proteome contained several proteins related to central anaerobic metabolism pathways that were undetected in S Dublin. In contrast to what has been observed in other extraintestinal serovars, most of the coding genes for these pathways are not degraded in S Dublin. Thus, we provide evidence that S Dublin metabolic functions may be much more affected than previously reported based on genomic studies. Single and double null mutants in stress response proteins Dps, YciF, and YgaU demonstrate their relevance to S Dublin invasiveness in a murine model of invasive salmonellosis. All in all, this work provides a basis for understanding interserovar differences in invasiveness and niche adaptation, underscoring the relevance of using proteomic approaches to complement genomic studies.

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AIMS: This study compared the capacity of strains of Salmonella enterica serovars Enteritidis and Dublin isolated in Brazil to invade epithelial cells, to be internalized by and survive within macrophages, and to stimulate cytokine release in vitro. METHODS AND RESULTS: Both serovars infected 75 and 73% Caco-2 (human) and MDBK (bovine) epithelial cells respectively. Salmonella Dublin and S. Enteritidis (i) were internalized at the respective rates of 79·6 and 65·0% (P ≤ 0·05) by U937 (human) macrophages, and 70·4 and 66·9% by HD11 (chicken) macrophages; and (ii) multiplied at the respective rates of 3·2- and 2·7-fold within U937 cells, and 1·9- and 1·1-fold (P ≤ 0·05) within HD11 cells respectively. Seventy per cent of 10 S. Dublin strains stimulated IL-8 production, while 70% of S. Enteritidis strains enhanced production of IL-1ß, IL-6, IL-8, IL-10, IL-12p70 and TNF in Caco-2 cells. CONCLUSIONS: Compared with S. Enteritidis, S. Dublin had stronger ability to survive within macrophages and induced weak cytokine production, which may explain the higher incidence of invasive diseases caused by S. Dublin in humans. SIGNIFICANCE AND IMPACT OF THE STUDY: This study compared S. enterica serovars Enteritidis and Dublin to provide comparative data about the profile of the two serovars in cells from humans, the common host and their respective natural animal hosts and vice versa in order to check the differences between these two phylogenetically closely related serovars that share antigenic properties but present different phenotypic behaviours.

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INTRODUCTION: An early and accurate diagnosis of septicemic salmonellosis is critical for implementing timely and proper treatment, prevention, and control measures. METHODOLOGY: Here, we report a study on three outbreaks of septicemic salmonellosis in calves from Midwestern Brazil. RESULTS: the morbidity, mortality and lethality rates were of 10.55%, 2.79%, and 26.4%, respectively. Higher susceptibility was detected in Bos taurus than in Bos indicus cattle. Clinical manifestations consisted of apathy, hyperthermia, difficulty breathing and panting, and pallor of the mucous membranes. Chronic cases had necrosis of the tail tip and ears. Gross findings included enlarged liver, non-collapsed edematous lungs and diphtheritic enteritis. Significant histopathological changes included paratyphoid nodules in the liver and acute interstitial pneumonia. Salmonella enterica subsp. enterica serotype Dublin was detected by culture and by PCR from the blood of live calves, and from the spleen, liver, bile, mesenteric lymph node and lung samples of necropsied calves. CONCLUSIONS: We suggest that in clinical cases of septicemic salmonellosis, blood samples are better than fecal samples for detection of the agent, being a sound test to identify animal carriers in the herd.

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RESUMO

Salmonella Dublin is a strongly cattle-adapted serovar that has also been responsible for severe invasive infections in humans. Although invasive infections by non-typhoid Salmonella have increased in developed and in developing countries, in sub-Saharan Africa these infections have been frequently related to Salmonella Typhimurium strains from Sequence Type (ST) 313 that harbor a possible virulence marker, the bstA gene, broadly detected in S. Dublin strains. The aims of this study were to verify the frequency of bstA by PCR in 113 Salmonella Dublin strains isolated from humans (83) and animals (30) in Brazil and the expression by RT-PCR of bstA, sopE2 and fliC in six strains isolated from humans (4) and animals (2). Moreover, the invasion capacity in Caco-2 human epithelial cells and U937 human macrophages, plus in vivo virulence analysis in Galleria mellonella and the motility were verified for 20 S. Dublin strains isolated from humans (15) and animals (5). All studied strains presented the bstA gene. The relative expression rates ranged from 0.1 to 2.3 fold change for bstA and from no expression to 16.6 fold change for sopE2, while no expression was detected for fliC. The invasion in Caco-2 cells ranged from 54.0 to 88.9% and in U937 cells from 72.9 to 98.1% in the 20 strains studied. In addition, 17 strains presented a highly virulent profile in the G. mellonella model and 15 strains presented a non-motile profile. In conclusion, the presence and expression of bstA in the S. Dublin strains studied suggested that this gene may influence in the invasive characteristic of this serovar. The low expression of sopE2 in strains from human invasive cases suggested that its expression may not be a limiting factor to the invasion of S. Dublin strains. The absence of fliC expression and the low motility rates observed suggest that the flagella absence may favor the host immune system evasion by S. Dublin and the establishment of infection. Moreover, the high mortality rates observed in vivo in Galleria mellonella reinforce the pathogenic potential of S. Dublin strains.

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RESUMO

Salmonella Dublin is a strongly adapted serovar that causes enteritis and/or systemic disease with high rates of mortality in cattle and occasionally infects humans. Despite the importance of this serovar, there is a lack of studies in Brazil. The aim of this study was to characterize the genetic diversity of 112 S. Dublin strains isolated from humans and animals in Brazil by CRISPR and CRISPR-MVLST and the relatedness among strains by MLST. In addition, the frequency of some important virulence genes was verified. The strains studied belonged to nine different sequence types, being all of them single- or double-locus variants of the ST10. CRISPR discriminated the strains into 69 subtypes with a similarity ≥ 84.4% and CRISPR-MVLST into 72 subtypes with a similarity ≥ 84.7%. The virulence genes ratB, lpfA, mgtC, avrA, sopB, sopE2, sifA, sseA, ssrA, csgA, fliC, and sinH were found in all the strains studied, while spvB, spvC, sodCl, rpoS, sipA, sipD, invA, and hilA were detected in ≥ 93.7% of the strains. In conclusion, the high similarity among the strains reinforces the clonal nature of the strains of this serovar that may have descended from a common ancestor that little differed over 33 years in Brazil. CRISPR and CRISPR-MVLST showed to be good alternatives to type S. Dublin strains. MLST suggested that S. Dublin strains from Brazil were phylogenetically related to strains from other parts of the globe. Moreover, the high frequency of virulence genes among the strains studied reinforces the capacity of S. Dublin to cause invasive diseases.

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Salmonella enterica is an important animal and human pathogen that can cause enteritis and septicaemia in calves. Generally, antibiotics are prescribed for the treatment of salmonellosis in dairy calves. Here, we report the isolation of antibiotic resistant S. enterica serotypes from calves, including multidrug-resistant isolates. A total of 544 faecal samples from live healthy and diarrheic dairy calves from 29 commercial dairy farms and organ samples from 19 deceased calves that succumbed to salmonellosis in 12 commercial dairy farms in Uruguay were processed for selective S. enterica culture. In total, 41 isolates were serotyped, and susceptibility to 14 antibiotics, from 9 classes of compounds, was evaluated by disk-diffusion test. The minimum inhibitory concentration (MIC) was determined by microdilution. Salmonella Typhimurium was the most frequent serotype, followed by S. Dublin and S. Anatum. Whether determined by diffusion assay or microdilution, resistance to tetracycline, streptomycin and ampicillin were the most frequently pattern found. Based on MIC, 5 isolates were resistant to at least one antibiotic, 21 were resistant to 2 antibiotics, and 14 were multidrug-resistant (resistant to at least one antibiotic in 3 different categories of antibiotics). Eleven different resistance patterns were found. Multidrug resistance in S. enterica is a concern for animal and public health not only because of its zoonotic potential but also due to the possibility of transfer resistance determinants to other bacterial genera. This represents the first report of the antibiotic resistance in S. enterica in dairy farms in Uruguay.

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Salmonellosis is a known cause of enteric disorders in calves. However, cases in the septicemic form may not present enteric lesions, which may lead the veterinary practitioner to not suspect salmonellosis, compromising the diagnosis. The current study describes the epidemiological, clinical, pathological and immunohistochemical aspects of septicemic salmonellosis in calves without enteric lesions. The protocols involving bovine material submitted to the Pathology Laboratory (LAP) of the "Faculdade de Medicina Veterinária e Zootecnia" (FAMEZ) of the "Universidade Federal do Mato Grosso do Sul" (UFMS) from January 1995 to July 2018 were studied. Cases confirmed or suggestive of septicemic salmonellosis in calves without enteric manifestations were selected. Fragments of the liver, lung, and spleen embedded in paraffin were submitted to immunohistochemistry (IHC). Only cases in which there was positive marking on the IHC or culture isolation of Salmonella were included in this study. Of a total of 5,550 cattle examined in the period, ten presented septicemic salmonellosis without enteric lesions. Clinical signs included mucosal pallor, apathy, hyperthermia, and dyspnea. Only three calves presented diarrhea, and two were found dead before clinical changes were observed. The most common necropsy findings were hepatosplenomegaly; yellow, orange or brown discolored livers; pale mucous membranes; inflated and sometimes red lungs; fibrin or fluid within body cavities; and gallbladder filled with inspissated bile. Jaundice was observed in three calves that had a concomitant infection with Anaplasma sp. Microscopically, paratyphoid hepatic nodules and interstitial pneumonia were the most frequent manifestations, followed by thrombosis and bacterial colonies in the spleen, lung, liver, and brain. A strong positive marking was observed in IHC, predominantly in the lung and to a lesser extent in the liver. Polymerase chain reaction (PCR) indicated the Dublin serotype as the causative agent in the samples of the four calves submitted to this procedure. In calves, the septicemic form was the major cause of death due to salmonellosis. Septicemic salmonellosis was usually not accompanied by diarrhea. The clinical signs of septicemia are nonspecific and of little assistance in the diagnosis. IHC has been shown to be efficient in the detection of the agent, mainly in the lung and especially in situations where it is not possible to perform bacterial culture.(AU)

A salmonelose é uma causa conhecida de distúrbios entéricos em bezerros. Porém, casos na forma septicêmica podem não apresentar manifestação entérica, o que leva o médico veterinário a não suspeitar de salmonelose, comprometendo o diagnóstico. Este estudo descreve os aspectos epidemiológicos, clínicos, patológicos e imuno-histoquímicos da salmonelose septicêmica em bezerros sem lesões entéricas. O estudo foi realizado a partir dos protocolos referentes a materiais de bovinos enviados para diagnóstico ao Laboratório de Anatomia Patológica (LAP) da Faculdade de Medicina Veterinária e Zootecnia (FAMEZ) da Universidade Federal de Mato Grosso do Sul (UFMS) de janeiro de 1995 a julho de 2018. Foram selecionados os casos de bezerros confirmados ou sugestivos de salmonelose septicêmica sem lesões entéricas. Fragmentos de fígado, pulmão e baço embebidos em parafina foram submetidos ao exame de imuno-histoquímica (IHQ). Somente foram incluídos neste estudo casos em que houve marcação positiva na IHQ ou isolamento da bactéria em cultura. De um total de 5.550 bovinos examinados no período, dez apresentaram salmonelose septicêmica sem lesão entérica. Os sinais clínicos incluíram palidez de mucosas, apatia, hipertermia e dispneia. Apenas três bezerros apresentaram diarreia e dois foram encontrados mortos sem terem sido observadas alterações clínicas. Os achados mais frequentes de necropsia foram hepatoesplenomegalia, fígado amarelado, alaranjado ou acastanhado, palidez de mucosas, pulmões inflados e, por vezes, vermelhos, fibrina ou líquido nas cavidades do organismo e vesícula biliar repleta de bile grumosa. Icterícia foi observada em três bezerros que apresentavam infecção concomitante por Anaplasma sp. Microscopicamente, os nódulos paratifoides hepáticos e pneumonia intersticial foram as manifestações mais encontradas, seguidas por trombose e colônias bacterianas no baço, pulmão, fígado e encéfalo. Na IHQ, marcação fortemente positiva foi observada, predominantemente, no pulmão e, em menor intensidade, no fígado. A técnica de reação em cadeia de polimerase (PCR) tipificou o sorotipo Dublin como agente etiológico nas amostras dos quatro bezerros submetidos a este procedimento. Em bezerros, a forma septicêmica foi a principal responsável pelas mortes por salmonelose. Na maioria das vezes essa forma não estava acompanhada por diarreia. Os sinais clínicos da forma septicêmica são inespecíficos e de pouco auxílio no direcionamento do diagnóstico. A IHQ mostrou-se eficiente na detecção do agente principalmente no pulmão e especialmente nas situações em que não é possível a realização da cultura bacteriana.(AU)

Assuntos

RESUMO

Salmonellosis is a known cause of enteric disorders in calves. However, cases in the septicemic form may not present enteric lesions, which may lead the veterinary practitioner to not suspect salmonellosis, compromising the diagnosis. The current study describes the epidemiological, clinical, pathological and immunohistochemical aspects of septicemic salmonellosis in calves without enteric lesions. The protocols involving bovine material submitted to the Pathology Laboratory (LAP) of the "Faculdade de Medicina Veterinária e Zootecnia" (FAMEZ) of the "Universidade Federal do Mato Grosso do Sul" (UFMS) from January 1995 to July 2018 were studied. Cases confirmed or suggestive of septicemic salmonellosis in calves without enteric manifestations were selected. Fragments of the liver, lung, and spleen embedded in paraffin were submitted to immunohistochemistry (IHC). Only cases in which there was positive marking on the IHC or culture isolation of Salmonella were included in this study. Of a total of 5,550 cattle examined in the period, ten presented septicemic salmonellosis without enteric lesions. Clinical signs included mucosal pallor, apathy, hyperthermia, and dyspnea. Only three calves presented diarrhea, and two were found dead before clinical changes were observed. The most common necropsy findings were hepatosplenomegaly; yellow, orange or brown discolored livers; pale mucous membranes; inflated and sometimes red lungs; fibrin or fluid within body cavities; and gallbladder filled with inspissated bile. Jaundice was observed in three calves that had a concomitant infection with Anaplasma sp. Microscopically, paratyphoid hepatic nodules and interstitial pneumonia were the most frequent manifestations, followed by thrombosis and bacterial colonies in the spleen, lung, liver, and brain. A strong positive marking was observed in IHC, predominantly in the lung and to a lesser extent in the liver. Polymerase chain reaction (PCR) indicated the Dublin serotype as the causative agent in the samples of the four calves submitted to this procedure. In calves, the septicemic form was the major cause of death due to salmonellosis. Septicemic salmonellosis was usually not accompanied by diarrhea. The clinical signs of septicemia are nonspecific and of little assistance in the diagnosis. IHC has been shown to be efficient in the detection of the agent, mainly in the lung and especially in situations where it is not possible to perform bacterial culture.(AU)

A salmonelose é uma causa conhecida de distúrbios entéricos em bezerros. Porém, casos na forma septicêmica podem não apresentar manifestação entérica, o que leva o médico veterinário a não suspeitar de salmonelose, comprometendo o diagnóstico. Este estudo descreve os aspectos epidemiológicos, clínicos, patológicos e imuno-histoquímicos da salmonelose septicêmica em bezerros sem lesões entéricas. O estudo foi realizado a partir dos protocolos referentes a materiais de bovinos enviados para diagnóstico ao Laboratório de Anatomia Patológica (LAP) da Faculdade de Medicina Veterinária e Zootecnia (FAMEZ) da Universidade Federal de Mato Grosso do Sul (UFMS) de janeiro de 1995 a julho de 2018. Foram selecionados os casos de bezerros confirmados ou sugestivos de salmonelose septicêmica sem lesões entéricas. Fragmentos de fígado, pulmão e baço embebidos em parafina foram submetidos ao exame de imuno-histoquímica (IHQ). Somente foram incluídos neste estudo casos em que houve marcação positiva na IHQ ou isolamento da bactéria em cultura. De um total de 5.550 bovinos examinados no período, dez apresentaram salmonelose septicêmica sem lesão entérica. Os sinais clínicos incluíram palidez de mucosas, apatia, hipertermia e dispneia. Apenas três bezerros apresentaram diarreia e dois foram encontrados mortos sem terem sido observadas alterações clínicas. Os achados mais frequentes de necropsia foram hepatoesplenomegalia, fígado amarelado, alaranjado ou acastanhado, palidez de mucosas, pulmões inflados e, por vezes, vermelhos, fibrina ou líquido nas cavidades do organismo e vesícula biliar repleta de bile grumosa. Icterícia foi observada em três bezerros que apresentavam infecção concomitante por Anaplasma sp. Microscopicamente, os nódulos paratifoides hepáticos e pneumonia intersticial foram as manifestações mais encontradas, seguidas por trombose e colônias bacterianas no baço, pulmão, fígado e encéfalo. Na IHQ, marcação fortemente positiva foi observada, predominantemente, no pulmão e, em menor intensidade, no fígado. A técnica de reação em cadeia de polimerase (PCR) tipificou o sorotipo Dublin como agente etiológico nas amostras dos quatro bezerros submetidos a este procedimento. Em bezerros, a forma septicêmica foi a principal responsável pelas mortes por salmonelose. Na maioria das vezes essa forma não estava acompanhada por diarreia. Os sinais clínicos da forma septicêmica são inespecíficos e de pouco auxílio no direcionamento do diagnóstico. A IHQ mostrou-se eficiente na detecção do agente principalmente no pulmão e especialmente nas situações em que não é possível a realização da cultura bacteriana.(AU)

Assuntos

RESUMO

ABSTRACT: Salmonellosis is a known cause of enteric disorders in calves. However, cases in the septicemic form may not present enteric lesions, which may lead the veterinary practitioner to not suspect salmonellosis, compromising the diagnosis. The current study describes the epidemiological, clinical, pathological and immunohistochemical aspects of septicemic salmonellosis in calves without enteric lesions. The protocols involving bovine material submitted to the Pathology Laboratory (LAP) of the Faculdade de Medicina Veterinária e Zootecnia (FAMEZ) of the Universidade Federal do Mato Grosso do Sul (UFMS) from January 1995 to July 2018 were studied. Cases confirmed or suggestive of septicemic salmonellosis in calves without enteric manifestations were selected. Fragments of the liver, lung, and spleen embedded in paraffin were submitted to immunohistochemistry (IHC). Only cases in which there was positive marking on the IHC or culture isolation of Salmonella were included in this study. Of a total of 5,550 cattle examined in the period, ten presented septicemic salmonellosis without enteric lesions. Clinical signs included mucosal pallor, apathy, hyperthermia, and dyspnea. Only three calves presented diarrhea, and two were found dead before clinical changes were observed. The most common necropsy findings were hepatosplenomegaly; yellow, orange or brown discolored livers; pale mucous membranes; inflated and sometimes red lungs; fibrin or fluid within body cavities; and gallbladder filled with inspissated bile. Jaundice was observed in three calves that had a concomitant infection with Anaplasma sp. Microscopically, paratyphoid hepatic nodules and interstitial pneumonia were the most frequent manifestations, followed by thrombosis and bacterial colonies in the spleen, lung, liver, and brain. A strong positive marking was observed in IHC, predominantly in the lung and to a lesser extent in the liver. Polymerase chain reaction (PCR) indicated the Dublin serotype as the causative agent in the samples of the four calves submitted to this procedure. In calves, the septicemic form was the major cause of death due to salmonellosis. Septicemic salmonellosis was usually not accompanied by diarrhea. The clinical signs of septicemia are nonspecific and of little assistance in the diagnosis. IHC has been shown to be efficient in the detection of the agent, mainly in the lung and especially in situations where it is not possible to perform bacterial culture.

RESUMO: A salmonelose é uma causa conhecida de distúrbios entéricos em bezerros. Porém, casos na forma septicêmica podem não apresentar manifestação entérica, o que leva o médico veterinário a não suspeitar de salmonelose, comprometendo o diagnóstico. Este estudo descreve os aspectos epidemiológicos, clínicos, patológicos e imuno-histoquímicos da salmonelose septicêmica em bezerros sem lesões entéricas. O estudo foi realizado a partir dos protocolos referentes a materiais de bovinos enviados para diagnóstico ao Laboratório de Anatomia Patológica (LAP) da Faculdade de Medicina Veterinária e Zootecnia (FAMEZ) da Universidade Federal de Mato Grosso do Sul (UFMS) de janeiro de 1995 a julho de 2018. Foram selecionados os casos de bezerros confirmados ou sugestivos de salmonelose septicêmica sem lesões entéricas. Fragmentos de fígado, pulmão e baço embebidos em parafina foram submetidos ao exame de imuno-histoquímica (IHQ). Somente foram incluídos neste estudo casos em que houve marcação positiva na IHQ ou isolamento da bactéria em cultura. De um total de 5.550 bovinos examinados no período, dez apresentaram salmonelose septicêmica sem lesão entérica. Os sinais clínicos incluíram palidez de mucosas, apatia, hipertermia e dispneia. Apenas três bezerros apresentaram diarreia e dois foram encontrados mortos sem terem sido observadas alterações clínicas. Os achados mais frequentes de necropsia foram hepatoesplenomegalia, fígado amarelado, alaranjado ou acastanhado, palidez de mucosas, pulmões inflados e, por vezes, vermelhos, fibrina ou líquido nas cavidades do organismo e vesícula biliar repleta de bile grumosa. Icterícia foi observada em três bezerros que apresentavam infecção concomitante por Anaplasma sp. Microscopicamente, os nódulos paratifoides hepáticos e pneumonia intersticial foram as manifestações mais encontradas, seguidas por trombose e colônias bacterianas no baço, pulmão, fígado e encéfalo. Na IHQ, marcação fortemente positiva foi observada, predominantemente, no pulmão e, em menor intensidade, no fígado. A técnica de reação em cadeia de polimerase (PCR) tipificou o sorotipo Dublin como agente etiológico nas amostras dos quatro bezerros submetidos a este procedimento. Em bezerros, a forma septicêmica foi a principal responsável pelas mortes por salmonelose. Na maioria das vezes essa forma não estava acompanhada por diarreia. Os sinais clínicos da forma septicêmica são inespecíficos e de pouco auxílio no direcionamento do diagnóstico. A IHQ mostrou-se eficiente na detecção do agente principalmente no pulmão e especialmente nas situações em que não é possível a realização da cultura bacteriana.

RESUMO

Salmonella Dublin is strongly adapted to cattle causing enteritis and/or systemic disease with high rates of mortality. However, it can be sporadically isolated from humans, usually causing serious disease, especially in patients with underlying chronic diseases. The aim of this study was to molecularly type S. Dublin strains isolated from humans and animals in Brazil to verify the diversity of these strains as well as to ascertain possible differences between strains isolated from humans and animals. Moreover, the presence of the capsular antigen Vi and the plasmid profile was characterized in addition to the anti-microbial resistance against 15 drugs. For this reason, 113 S. Dublin strains isolated between 1983 and 2016 from humans (83) and animals (30) in Brazil were typed by PFGE and MLVA. The presence of the capsular antigen Vi was verified by PCR, and the phenotypic expression of the capsular antigen was determined serologically. Also, a plasmid analysis for each strain was carried out. The strains studied were divided into 35 different PFGE types and 89 MLVA-types with a similarity of ≥80% and ≥17.5%, respectively. The plasmid sizes found ranged from 2 to >150 kb and none of the strains studied presented the capsular antigen Vi. Resistance or intermediate resistance was found in 23 strains (20.3%) that were resistant to ampicillin, ciprofloxacin, chloramphenicol, imipenem, nalidixic acid, piperacillin, streptomycin and/or tetracycline. The majority of the S. Dublin strains studied and isolated over a 33-year period may descend from a common subtype that has been contaminating humans and animals in Brazil and able to cause invasive disease even in the absence of the capsular antigen. The higher diversity of resistance phenotypes in human isolates, as compared with animal strains, may be a reflection of the different anti-microbial treatments used to control S. Dublin infections in humans in Brazil.

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RESUMO

The aim of this study was to evaluate serum protein concentrations in calves experimentally inoculated with Salmonella Dublin. Twelve healthy 10 to 15-day-old Holstein calves were randomly allotted into two groups, control and infected with 10(8) CFU of Salmonella Dublin orally. The calves were subjected to physical evaluation and blood samples were collected shortly before administration of the bacteria and also 24, 48, 72, 96, 120 and 168 hours post-infection. The concentration of serum proteins was determined through sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Thirty serum proteins ranging from molecular weight of 24,000 Da to molecular weight of 236,000 Da were detected. Serum concentrations of ceruloplasmin (125,000 Da), haptoglobin (45,000 Da), acid glycoprotein (40,000 Da) and a 34,000 Da protein were significantly increased in the experimentally infected calves, when compared with their concentrations in the control animals. Therefore, this study showed that S. Dublin infection could lead to the increase of certain serum proteins in calves.(AU)

O objetivo do estudo foi avaliar as concentrações séricas de proteínas em bezerros inoculados experimentalmente com Salmonella Dublin. Foram examinados 12 bezerros sadios da raça Holandesa com 10 a 15 dias de idade, distribuídos aleatoriamente em dois grupos, controle e infectado experimentalmente com 10(8) UFC de Salmonella Dublin. As amostras de sangue foram colhidas minutos antes e 12, 24, 48, 72, 96, 120 e 168 horas após a inoculação. As concentrações séricas das proteínas ceruloplasmina (125.000 Da), haptoglobina (45.000 Da), glicoproteína ácida (40.000 Da) e proteína de peso molecular de 34.000 Da foram significativamente maiores nos bezerros infectados do que nos do grupo controle. Portanto, o estudo mostrou que a infecção por S. Dublin pode elevar a concentração de certas proteínas séricas em bezerros.(AU)

Assuntos

RESUMO

The aim of this study was to evaluate serum protein concentrations in calves experimentally inoculated with Salmonella Dublin. Twelve healthy 10 to 15-day-old Holstein calves were randomly allotted into two groups, control and infected with 10(8) CFU of Salmonella Dublin orally. The calves were subjected to physical evaluation and blood samples were collected shortly before administration of the bacteria and also 24, 48, 72, 96, 120 and 168 hours post-infection. The concentration of serum proteins was determined through sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Thirty serum proteins ranging from molecular weight of 24,000 Da to molecular weight of 236,000 Da were detected. Serum concentrations of ceruloplasmin (125,000 Da), haptoglobin (45,000 Da), acid glycoprotein (40,000 Da) and a 34,000 Da protein were significantly increased in the experimentally infected calves, when compared with their concentrations in the control animals. Therefore, this study showed that S. Dublin infection could lead to the increase of certain serum proteins in calves.

O objetivo do estudo foi avaliar as concentrações séricas de proteínas em bezerros inoculados experimentalmente com Salmonella Dublin. Foram examinados 12 bezerros sadios da raça Holandesa com 10 a 15 dias de idade, distribuídos aleatoriamente em dois grupos, controle e infectado experimentalmente com 10(8) UFC de Salmonella Dublin. As amostras de sangue foram colhidas minutos antes e 12, 24, 48, 72, 96, 120 e 168 horas após a inoculação. As concentrações séricas das proteínas ceruloplasmina (125.000 Da), haptoglobina (45.000 Da), glicoproteína ácida (40.000 Da) e proteína de peso molecular de 34.000 Da foram significativamente maiores nos bezerros infectados do que nos do grupo controle. Portanto, o estudo mostrou que a infecção por S. Dublin pode elevar a concentração de certas proteínas séricas em bezerros.

RESUMO

The efficiency of the Polymerase Chain Reaction (PCR) combined with selective enrichment broth was compared with the standard microbiological techniques for detection of Salmonella Dublin in fecal samples of 10 to 15-days-old Holstein calves, experimentally infected with 10(8) CFU of Salmonella Dublin. Seventy-six fecal samples were analyzed using PCR associated with selenite cystine (SC) and Muller-Kauffmann tetrathionate (TMK) broths and standard microbiological techniques. Regardless of the selective enrichment broth used, the standard microbiological techniques were significantly better than PCR in detection of positive samples of Salmonella Dublin. However, the simultaneous use of both techniques provided detection of a larger number of positive samples. The SC broth was the best option as selective enrichment in both techniques.(AU)

Assuntos

RESUMO

The efficacy of florfenicol associated or not to intravenous fluid therapy for treatment of Salmonella Dublin-infected calves was determined. Twenty-four healthy 10 to 15-day-old Holstein calves were randomly allotted into four groups, with six animals each: control (group 1); infected with 10(8)CFU Salmonella Dublin and not treated (group 2); infected with 10(8)CFU Salmonella Dublin and treated with florfenicol (group 3); and infected with 10(8)CFU Salmonella Dublin and treated with florfenicol associated to fluid therapy (group 4). All animals were submitted to physical examination just before inoculation and every 24 hours, during seven days after experimental infection. Rectal swabs and blood samples were collected for Salmonella Dublin isolation and pH and blood electrolytes determination. The experimental infection with Salmonella Dublin induced clinical signs of salmonellosis, such as diarrhea and fever, and caused reduction in blood concentrations of pH, sodium, potassium and chlorides. The treated calves showed good clinical recovery, and the group treated with antibiotic in combination to fluid therapy presented a faster and more efficient correction of the hydro-electrolyte balance.(AU)

Avaliou-se a eficácia terapêutica do florfenicol associado ou não à fluidoterapia intravenosa no tratamento de bezerros infectados experimentalmente com Salmonella Dublin. Foram utilizados 24 bezerros sadios da raça Holandesa com 10 a 15 dias de idade, distribuídos aleatoriamente em quatro grupos experimentais, constituídos por seis animais cada: controle (grupo 1); infectado com 10(8)UFC de Salmonella Dublin e não tratado (grupo 2); infectado com 10(8)UFC de Salmonella Dublin e tratado com florfenicol (grupo 3); e infectado com 10(8)UFC de Salmonella Dublin (grupo 4) e tratado com florfenicol associado à fluidoterapia. Todos os animais foram submetidos ao exame físico logo antes da inoculação e a cada 24 horas, durante sete dias após a infecção experimental. Foram colhidas amostras de suabes retais para o isolamento de Salmonella Dublin e amostras de sangue para determinação dos valores de pH e dosagem de eletrólitos sanguíneos. A infecção experimental com Salmonella Dublin induziu sinais clínicos de salmonelose, como diarreia e febre, e provocou redução do valor do pH e das concentrações sanguíneas de sódio, potássio e cloreto. Os bezerros submetidos aos tratamentos mostraram boa recuperação clínica, sendo que o grupo tratado com antibiótico combinado à fluidoterapia apresentou correção mais rápida e eficiente do equilíbrio hidroeletrolítico.(AU)

Assuntos

RESUMO

The efficacy of florfenicol associated or not to intravenous fluid therapy for treatment of Salmonella Dublin-infected calves was determined. Twenty-four healthy 10 to 15-day-old Holstein calves were randomly allotted into four groups, with six animals each: control (group 1); infected with 10(8)CFU Salmonella Dublin and not treated (group 2); infected with 10(8)CFU Salmonella Dublin and treated with florfenicol (group 3); and infected with 10(8)CFU Salmonella Dublin and treated with florfenicol associated to fluid therapy (group 4). All animals were submitted to physical examination just before inoculation and every 24 hours, during seven days after experimental infection. Rectal swabs and blood samples were collected for Salmonella Dublin isolation and pH and blood electrolytes determination. The experimental infection with Salmonella Dublin induced clinical signs of salmonellosis, such as diarrhea and fever, and caused reduction in blood concentrations of pH, sodium, potassium and chlorides. The treated calves showed good clinical recovery, and the group treated with antibiotic in combination to fluid therapy presented a faster and more efficient correction of the hydro-electrolyte balance.

Avaliou-se a eficácia terapêutica do florfenicol associado ou não à fluidoterapia intravenosa no tratamento de bezerros infectados experimentalmente com Salmonella Dublin. Foram utilizados 24 bezerros sadios da raça Holandesa com 10 a 15 dias de idade, distribuídos aleatoriamente em quatro grupos experimentais, constituídos por seis animais cada: controle (grupo 1); infectado com 10(8)UFC de Salmonella Dublin e não tratado (grupo 2); infectado com 10(8)UFC de Salmonella Dublin e tratado com florfenicol (grupo 3); e infectado com 10(8)UFC de Salmonella Dublin (grupo 4) e tratado com florfenicol associado à fluidoterapia. Todos os animais foram submetidos ao exame físico logo antes da inoculação e a cada 24 horas, durante sete dias após a infecção experimental. Foram colhidas amostras de suabes retais para o isolamento de Salmonella Dublin e amostras de sangue para determinação dos valores de pH e dosagem de eletrólitos sanguíneos. A infecção experimental com Salmonella Dublin induziu sinais clínicos de salmonelose, como diarreia e febre, e provocou redução do valor do pH e das concentrações sanguíneas de sódio, potássio e cloreto. Os bezerros submetidos aos tratamentos mostraram boa recuperação clínica, sendo que o grupo tratado com antibiótico combinado à fluidoterapia apresentou correção mais rápida e eficiente do equilíbrio hidroeletrolítico.

RESUMO

The efficiency of the Polymerase Chain Reaction (PCR) combined with selective enrichment broth was compared with the standard microbiological techniques for detection of Salmonella Dublin in fecal samples of 10 to 15-days-old Holstein calves, experimentally infected with 10(8) CFU of Salmonella Dublin. Seventy-six fecal samples were analyzed using PCR associated with selenite cystine (SC) and Muller-Kauffmann tetrathionate (TMK) broths and standard microbiological techniques. Regardless of the selective enrichment broth used, the standard microbiological techniques were significantly better than PCR in detection of positive samples of Salmonella Dublin. However, the simultaneous use of both techniques provided detection of a larger number of positive samples. The SC broth was the best option as selective enrichment in both techniques.

Assuntos

RESUMO

O objetivo do estudo foi avaliar o hemograma e o perfil bioquímico sérico, inclusive hemogasométrico, de bezerros infectados experimentalmente com Salmonella Dublin. Foram utilizados 12 bezerros sadios da raça Holandesa com 10 a 15 dias de idade, distribuídos aleatoriamente em dois grupos experimentais: grupo-controle (n= 6) e grupo infectado com 10(8)UFC de Salmonella Dublin (n=6). Os bezerros foram submetidos ao exame físico diário, e as amostras de sangue foram coletadas minutos antes da inoculação (0h) e 24, 48, 72, 96, 120, 144 e 168h após a inoculação. Além do hemograma e das análises hemogasométricas, foram mensuradas as atividades séricas das enzimas aspartato aminotransferase (AST), fosfatase alcalina (ALP), creatina cinase (CK), gamaglutamiltransferase (GGT) e lactato desidrogenase (LDH), e os teores de albumina, bilirrubinas, cálcio total, cálcio ionizado, sódio, potássio, cloretos, creatinina, ferro, fibrinogênio, fósforo, glicose, magnésio, proteína totais e ureia. As principais alterações foram: redução das concentrações de albumina, ferro, glicose, magnésio e proteína total, aumento do teor de fibrinogênio, leucocitose e acidose metabólica e hiponatremia.(AU)

The blood cell counts and biochemical profile, including blood gas levels, were evaluated, in Salmonella Dublin-infected calves. Twelve healthy 10 to 15-day old Holstein calves were randomly allotted into two groups: control (n=6) and group orally infected with 10(8) CFU Salmonella Dublin (n=6). The calves were submitted to physical examination and the blood samples were taken just before the inoculation (0h) and at 24, 48, 72, 96, 120, 144, and 168h later. Besides, blood cell counts, blood gas levels, and the serum concentrations of aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatine kinase (CK), gammaglutamyltransferase (GGT), lactate desidrogenase (LDH), albumin, bilirubin, total calcium, ionic calcium, sodium, potassium, chlorides, creatinine, iron, fibrinogen, phosphorus, glucose, magnesium, total protein, and urea were measured. The main findings included decrease in albumin, iron, glucose, magnesium, and total protein concentrations, and increase in fibrinogen level, leukocytosis, metabolic acidosis, and hyponatremia.(AU)

Assuntos

RESUMO

O objetivo do estudo foi avaliar o hemograma e o perfil bioquímico sérico, inclusive hemogasométrico, de bezerros infectados experimentalmente com Salmonella Dublin. Foram utilizados 12 bezerros sadios da raça Holandesa com 10 a 15 dias de idade, distribuídos aleatoriamente em dois grupos experimentais: grupo-controle (n= 6) e grupo infectado com 10(8)UFC de Salmonella Dublin (n=6). Os bezerros foram submetidos ao exame físico diário, e as amostras de sangue foram coletadas minutos antes da inoculação (0h) e 24, 48, 72, 96, 120, 144 e 168h após a inoculação. Além do hemograma e das análises hemogasométricas, foram mensuradas as atividades séricas das enzimas aspartato aminotransferase (AST), fosfatase alcalina (ALP), creatina cinase (CK), gamaglutamiltransferase (GGT) e lactato desidrogenase (LDH), e os teores de albumina, bilirrubinas, cálcio total, cálcio ionizado, sódio, potássio, cloretos, creatinina, ferro, fibrinogênio, fósforo, glicose, magnésio, proteína totais e ureia. As principais alterações foram: redução das concentrações de albumina, ferro, glicose, magnésio e proteína total, aumento do teor de fibrinogênio, leucocitose e acidose metabólica e hiponatremia.

The blood cell counts and biochemical profile, including blood gas levels, were evaluated, in Salmonella Dublin-infected calves. Twelve healthy 10 to 15-day old Holstein calves were randomly allotted into two groups: control (n=6) and group orally infected with 10(8) CFU Salmonella Dublin (n=6). The calves were submitted to physical examination and the blood samples were taken just before the inoculation (0h) and at 24, 48, 72, 96, 120, 144, and 168h later. Besides, blood cell counts, blood gas levels, and the serum concentrations of aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatine kinase (CK), gammaglutamyltransferase (GGT), lactate desidrogenase (LDH), albumin, bilirubin, total calcium, ionic calcium, sodium, potassium, chlorides, creatinine, iron, fibrinogen, phosphorus, glucose, magnesium, total protein, and urea were measured. The main findings included decrease in albumin, iron, glucose, magnesium, and total protein concentrations, and increase in fibrinogen level, leukocytosis, metabolic acidosis, and hyponatremia.

Assuntos

RESUMO

The aim of this study was to compare three different selective enrichment broths: Rappaport-Vassiliadis (RV), selenite cystine (SC) and Muller-Kauffmann tetrathionate (MKT) for Salmonella Dublin isolation from faecal samples of calf experimentally infected. The bacteriological procedure involved pre-enrichment stages in Hajna-GN broth (only for the samples inoculated in RV broth), selective enrichment, culture in modified brilliant green agar (BGA), presumptive biochemistry tests (using triple-sugar-iron agar and lysine-agar) and slide agglutination test with poli-O and poli-H Salmonella antiserum. The effects of enrichment temperatures using RV broth were also evaluated (37ºC and 42ºC). SC broth was significantly more efficient in the isolation of Salmonella Dublin (P<0,05), whereas RV broth incubated at 42ºC had a lower efficiency in the microbiological isolation.(AU)

Assuntos