RESUMO: Os javalis europeus (Sus scrofa) são considerados uma espécie exótica invasora em todo o mundo. As invasões de javalis são uma preocupação crescente de saúde pública, pois os javalis podem representar um importante reservatório de patógenos zoonóticos, incluindo bactérias do gênero Salmonella. O objetivo deste estudo foi determinar a prevalência e os sorovares de Salmonella spp. em javalis de vida livre caçados legalmente no Estado de São Paulo, Brasil, e a suscetibilidade dessa Salmonella spp. aos antimicrobianos. Amostras fecais e linfonodos mesentéricos foram adquiridos de 63 javalis. A prevalência de Salmonella spp. em javalis selvagens foi de 9,5% (6/63; intervalo de confiança: 4,4% - 19,2%). Seis sorovares foram isolados: S. enterica subsp. enterica ser. 4,5,12:-:1,2, S. enterica ser. Cerro, S. enterica ser. Madelia, S. enterica ser. Typhimurium, S. enterica ser. I (4,5,12:i:-) e S. enterica ser. Muenster. As análises de resistência antimicrobiana de Salmonella spp. evidenciaram que a maioria dos sorovares era pansensível aos antimicrobianos testados. Apenas S. enterica ser. Typhimurium e S. enterica ser. Muenster mostraram um padrão de resistência a pelo menos um antimicrobiano analisado. A saber, este estudo é o primeiro relato da prevalência e de sorovares de Salmonella spp. em javalis de vida livre no Estado de São Paulo, Brasil. Os resultados indicaram baixa prevalência com variabilidade de sorovares de Salmonella, com algum padrão de resistência antimicrobiana. Este estudo destaca o papel potencial dos javalis como portadores de Salmonella spp. e pode representar um risco para os animais domésticos e selvagens, bem como para os humanos.

ABSTRACT: European wild boars (Sus scrofa) are considered exotic invasive species worldwide. Invasions of wild boars are a growing public health concern, as wild boars may represent an important reservoir of zoonotic pathogens, including bacteria of the genus Salmonella. The aim of this study was to determine the prevalence and serovars of Salmonella spp. in free-ranging wild boars legally hunted in the state of São Paulo, Brazil, and the susceptibility of those Salmonella spp. to antimicrobials. Fecal samples and mesenteric lymph nodes were acquired from 63 wild boars. The prevalence of Salmonella spp. in free-ranging wild boars was 9.5 % (6/63; confidence interval: 4.4 % - 19.2 %). Six serovars were isolated: S. enterica subsp. enterica ser. 4,5,12:-:1,2, S. enterica ser. Cerro, S. enterica ser. Madelia, S. enterica ser. Typhimurium, S. enterica ser. I (4,5,12:i:-) and S. enterica ser. Muenster. Analysis of antimicrobial resistance of Salmonella spp. showed that the majority of serovars were fully susceptible to the tested antimicrobials. Only S. enterica ser. Typhimurium and S. enterica ser. Muenster showed a resistance pattern to at least one antimicrobial analyzed. To our knowledge, this study is the first report the prevalence and serovars of Salmonella spp. in free-ranging wild boars in the State of São Paulo, Brazil. Results indicate a low prevalence with variability of Salmonella serovars, with some pattern of antimicrobial resistance. This study highlights the potential role of wild boars as carriers of Salmonella and could pose a risk to wild and domestic animals as well as humans.

Abstract Salmonella Gallinarum is a host-restrict pathogen that causes fowl typhoid, a severe systemic disease that is one of the major concerns to the poultry industry worldwide. When infecting the bird, SG makes use of evasion mechanisms to survive and to replicate within macrophages. In this context, phoPQ genes encode a two-component regulatory system (PhoPQ) that regulates virulence genes responsible for adaptation of Salmonella spp. to antimicrobial factors such as low pH, antimicrobial peptides and deprivation of bivalent cations. The role of the mentioned genes to SG remains to be investigated. In the present study a phoPQ-depleted SG strain (SG ΔphoPQ) was constructed and its virulence assessed in twenty-day-old laying hens susceptible to fowl typhoid. SG ΔphoPQ did cause neither clinical signs nor mortality in birds orally challenged, being non-pathogenic. Furthermore, this strain was not recovered from livers or spleens. On the other hand, chickens challenged subcutaneously with the mutant strain had discreet to moderate pathological changes and also low bacterial counts in liver and spleen tissues. These findings show that SG ΔphoPQ is attenuated to susceptible chickens and suggest that these genes are important during chicken infection by SG.

ABSTRACT Salmonella Enteritidis causes fowl paratyphoid in poultry and is frequently associated to outbreaks of food-borne diseases in humans. The role of flagella and flagella-mediated motility into host-pathogen interplay is not fully understood and requires further investigation. In this study, one-day-old chickens were challenged orally with a wild-type strain Salmonella Enteritidis, a non-motile but fully flagellated (SE ΔmotB) or non-flagellated (SE ΔfliC) strain to evaluate their ability to colonise the intestine and spread systemically and also of eliciting gross and histopathological changes. SE ΔmotB and SE ΔfliC were recovered in significantly lower numbers from caecal contents in comparison with Salmonella Enteritidis at early stages of infection (3 and 5 dpi). The SE ΔmotB strain, which synthesises paralysed flagella, showed poorer intestinal colonisation ability than the non-flagellated SE ΔfliC. Histopathological analyses demonstrated that the flagellated strains induced more intense lymphoid reactivity in liver, ileum and caeca. Thus, in the present study the flagellar structure and motility seemed to play a role in the early stages of the intestinal colonisation by Salmonella Enteritidis in the chicken.

RESUMO: Salmonella enterica sorovar Gallinarum biovar Gallinarum (SG) é uma bactéria hospedeira específica que causa o tifo aviário (TA). Essa doença é altamente patogênica em aves comerciais, especialmente galinhas poedeiras de linhagem vermelha e aves reprodutoras pesadas, causando septicemia aguda, e consequentemente, alta morbidade e mortalidade. A vacinação é amplamente utilizada no campo como uma ferramenta de biossegurança para a prevenção de infecções isoladas e surtos nas granjas avícolas comerciais. O atual estudo avaliou o potencial vacinal de uma cepa viva atenuada de SG com deleções nos genes cobS e cbiA (SGΔcobSΔcbiA), utilizando esquemas de vacinação formulados para utilização em campo. Para isso, as galinhas poedeiras de linhagem vermelha foram utilizadas em dois experimentos diferentes, para avaliar a proteção a longo prazo, necessária no campo. O esquema de vacinação no primeiro experimento consistiu em duas doses, a primeira na quarta semana de vida e a dose de reforço na oitava, e o desafio na 16ª semana com a estirpe selvagem SG. No segundo experimento, a vacinação foi realizada por diferentes rotas usando três doses da vacina viva, na quarta, na oitava e na décima segunda semana de vida, e o desafio foi feito na 20ª semana de vida. Após o desafio, a mortalidade foi acompanhada por 28 dias, e no experimento 2 a produção de ovos também foi avaliada e comparada com o grupo de galinhas não vacinadas. Em ambos os experimentos, a mortalidade foi significativamente reduzida, e a produção de ovos não foi afetada nos grupos de galinhas poedeiras vacinadas. Este estudo mostra a eficácia da proteção dos diferentes programas de vacinação contra o TA, que podem ser aplicados em granjas comerciais em condições de campo.

ABSTRACT: Salmonella enterica serovar Gallinarum biovar Gallinarum (SG) is a host-specific bacteria that causes the fowl typhoid (FT). This disease is highly pathogenic to commercial chickens, specially brown layers and breeders, causing acute septicemia followed by high morbidity and mortality. Vaccination is extensively adopted in the fields as a biosafety tool for prevention of isolated infections and outbreaks in commercial poultry flocks. The present study evaluated the use of an attenuated SG with deletions on genes cobS and cbiA (SGΔcobSΔcbiA) as a live vaccine, using vaccination schemes adjusted for field conditions. To this end, brown layers were used in two different experiments, to evaluate the long-term protection, necessary in the fields. The vaccination scheme on the first experiment consisted of two doses, the first at 4 th week-of-age and the booster dose at 8 th week-of-age with challenge at 16 th week-of-age with wild SG strain. On the second experiment, the vaccination was carried out by different routes using three doses of the live vaccine, at 4 th , 8 th and 12 th weeks-of-age, and the challenge was done at 20 th weeks-of-age. After the challenge, the mortality was recorded during 28 days, and the egg production (experiment 2) was evaluated and compared with the group of unvaccinated layers. In both experiments, the mortality was significantly reduced, and the egg production was not affected in vaccinated layer-hens. In summary, this study shows the efficacy and the protection of different vaccination schemes against FT that can be applied under field conditions in commercial poultry farms.

RESUMO: Salmonella Gallinarum (S. Gallinarum) e Salmonella Pullorum (S. Pullorum) são patógenos hospedeiro-específico de aves, agentes do tifo aviário e pulorose, respectivamente. Estes biovares causam infecções septicêmicas, resultando em alta mortalidade. Surtos são frequentemente relatados em diversos países, causando prejuízos devido à eliminação de lotes infectados e tratamentos. Agentes antimicrobianos são utilizados frequentemente em granjas avícolas para prevenir ou tratar infecções gastrointestinais. No presente trabalho, foi avaliada a susceptibilidade antimicrobiana de 50 isolados de S. Gallinarum e S. Pullorum, obtidos durante surtos que ocorreram entre 1987 a 1991 e entre 2006 a 2013. A comparação dos perfis de sensibilidade mostrou que todas as amostras são sensíveis aos β-lactâmicos. Todos os isolados de 1987-1991 foram sensíveis a todos os antibióticos testados, exceto NAL e CIP (78%). O perfil de susceptibilidade de S. Gallinarum (surtos de 2006 a 2013) foi NAL (58%), CIP (63%), ENR (67%), TET (92%), FFC (96%) e SXT (96%). Isolados de S. Pullorum (surtos de 2006 a 2013) apresentaram as seguintes taxas de sensibilidade: NAL (65%), CIP (71%), ENR (94%) e TET (94%). Todas as amostras foram sensíveis ao β-lactâmicos testados, no entanto, a resistência às quinolonas e fluoroquinolonas aumentou ao longo do tempo. Além disso, baixos níveis de resistência a outros antibióticos foram encontrados em isolados recentes, tais como as tetraciclinas.

ABSTRACT: Salmonella Gallinarum (S. Gallinarum) and Salmonella Pullorum (S. Pullorum) are poultry host-specific, agents of fowl typhoid and pullorum disease, respectively. These biovars cause septicemic infections, resulting in high mortality. Outbreaks are frequently reported worldwide, causing losses due to the elimination of infected flocks and treatments. The use of antimicrobial agents is frequent in poultry farms to prevent or treat gastrointestinal infections. In the present research it was evaluated the antimicrobial susceptibility of 50 S. Gallinarum and S. Pullorum isolates, from outbreaks that occurred between 1987 to 1991 and 2006 to 2013. The comparison of the susceptibility profiles showed that all isolates were susceptible to β-lactams. All isolates from 1987-1991 were susceptible to all antibiotics tested except NAL and CIP (78%). The susceptibility profile of S. Gallinarum (2006 - 2013 period) was the following NAL (58%), CIP (63%), ENR (67%), TET (92%), FFC (96%) and SXT (96%). S. Pullorum isolates (2006 - 2013 period) showed the following susceptibility rates to NAL (65%), CIP (71%), ENR (94%) and TET (94%). All isolates were susceptible to β-lactams tested, however, resistance to quinolones and fluoroquinolones increased over time. Furthermore, low levels of resistance to other antibiotics were found in recent isolates, such as tetracyclines.

Salmonella enterica serovar Typhimurium synthesizes cobalamin (vitamin B12) only during anaerobiosis. Two percent of the S. Typhimurium genome is devoted to the synthesis and uptake of vitamin B12 and to B12-dependent reactions. To understand the requirement for cobalamin synthesis better, we constructed mutants of Salmonella serovars Enteritidis and Pullorum that are double-defective in cobalamin biosynthesis (ΔcobSΔcbiA). We compared the virulence of these mutants to that of their respective wild type strains and found no impairment in their ability to cause disease in chickens. We then assessed B12 production in these mutants and their respective wild type strains, as well as in S. Typhimurium ΔcobSΔcbiA, Salmonella Gallinarum ΔcobSΔcbiA, and their respective wild type strains. None of the mutants was able to produce detectable B12. B12 was detectable in S. Enteritidis, S. Pullorum and S. Typhimurium wild type strains but not in S. Gallinarum. In conclusion, the production of vitamin B12 in vitro differed across the tested Salmonella serotypes and the deletion of the cbiA and cobS genes resulted in different levels of alteration in the host parasite interaction according to Salmonella serotype tested.

Infecções experimentais por Salmonella enterica serovar Gallinarum foram realizadas em aves de postura comercial, incluindo uma linhagem branca resistente e uma linhagem vermelha susceptível ao desenvolvimento da enfermidade clínica. As aves de linhagem susceptível apresentaram doença clínica dependente da dose administrada. Excreção fecal foi observada em aves da linhagem susceptível próximo ao momento da morte e, eventualmente, em aves da linhagem resistente e aves convalescentes. A remoção das aves mortas do meio ambiente reduziu a taxa de mortalidade/morbidade, procedimento este que pode ser utilizado como medida de controle.

Experimental infections were set up in commercial laying birds, comprising a white relatively resistant line and a red susceptible line infecting with Salmonella enterica serovar Gallinarum. The major findings were that in susceptible birds clinical disease occurred in a dose-dependent manner. Faecal excretion occurred in susceptible birds almost up to death but also occurred in the more resistant line and in birds, which were convalescing. Removal of birds, which had died from the disease, from the environment, reduced the resultant mortality/morbidity and may be regarded as a useful measure for control.

Foram examinadas caixas de transporte de pintos de um dia com o objetivo de investigar a presença de Salmonella no momento em que chegaram à granja. 1611 caixas foram amostradas em 15 propriedades, sendo uma granja de avós, quatro granjas de matrizes, duas de frangos de corte e seis de aves de postura comercial. Foram feitas 19 visitas a essas granjas e Salmonella foi encontrada em 10 delas. Salmonella Heidelberg foi encontrada em caixas de cinco granjas, S. Heidelberg e S. Mbandaka em caixa de uma granja de matriz. S. Enteritidis somente, S. Enteritidis e S. Mbandaka simultaneamente, e S. Cerro somente, foram detectadas em caixas de três, uma e uma granjas de postura comercial, respectivamente.

The presence of Salmonella was investigated in transport boxes of newly hatched chicks in the moment they were received in the farms. 1,611 boxes, delivered to 15 farms (one broiler grand-parent farm, four broiler parent farms, two commercial broiler chick farms and seven laying hens farms) were tested. A total of 19 visits to these farms were done, and Salmonella was detected in ten of these visits. Salmonella Heidelberg was detected in boxes in five farms. S. Heidelberg and S. Mbandaka were simultaneously detected in one broiler breeder farm. Salmonella Enteritidis alone, S. Enteritidis and S. Mbandaka and S. Cerro alone were detected in three, one and one laying hens farms, respectively.

O presente trabalho avaliou a prevenção da disseminação de quatro sorotipos de Salmonella, de interesse em avicultura e saúde pública (Salmonella Typhimurium, Salmonella Agona, Salmonella Infantis e Salmonella Enteritidis), entre aves recém-nascidas, com o intuito de diminuir a disseminação de salmonelas em rebanhos avícolas por aves que contraíram a infecção pela via vertical. Analisou-se experimentalmente a administração de microbiota intestinal de aves adultas em aves recém-nascidas, a incorporação de uma mistura de ácidos orgânicos na ração e a associação desses dois tratamentos, em grupos onde colocou-se uma ave infectada, para provocar a transmissão por contato. A microbiota intestinal de aves adultas mostrou-se eficiente no controle da colonização cecal nos quatro ensaios realizados, com os diferentes sorotipos. A mistura de ácidos orgânicos na ração não foi eficaz em prevenir a colonização cecal e a associação dos tratamentos demonstrou que não há interferência entre eles, permanecendo a ação da microbiota de aves adultas.

This study was carried out to assess the ability of competitive exclusion and a mixture of organic acids to prevent Salmonella infection by contact between newly hatched chicks. A bird infected with Salmonella was placed in a box containing non-infected birds, previously treated with a broth culture of faeces of adult birds (CE) and/or a mixture of organic acids. The number of Salmonella organisms in the caeca of the contact birds was estimated at 4 and 8 days post-challenge. The birds were infected with Salmonella Typhimurium, Salmonella Enteritidis (both repeated 5 times), Salmonella Agona and Salmonella Infantis (3 repetitions). The same approach was used to test the mixture of organic acids alone. In this case the birds received feed containing 0.8% of a mixture of formic acid (70%) and propionic acid (30%). Also, a third trial was carried out with birds inoculated with the broth culture of faeces and fed with feed containing the mixture of organic acids. Appropriate controls were included. Whereas the birds from the control groups and the groups treated with the mixture of organic acids were heavily infected with Salmonella, those pre-treated with CE or CE plus the mixture of organic acids had no viable cells per gram of caecal contents.

Um total de 150 carcaças de frango congeladas, de quatro marcas comerciais, foram analisadas para pesquisa de Salmonella. Foram examinadas 43 carcaças de cada uma das marcas A, B, D e 21 da marca C. Observou-se um percentual de 32,0% de contaminação. Foram identificados 11 sorotipos: S. Agona, S. Anatum, S. Enteritidis, S. Hadar, S. Havana, S. Mbandaka, S. Montevideo, S. Ouakam, S. Poona, S. Schwarzengrund e S. I 4, 5, 12: -. O antibiograma das cepas mostrou 100% de resistência à ampicilina, 75,0% à cefalotina, 52,1% à cefoxitina, 22,9% à tobramicina, 6,2% à polimixina B e à tetraciclina, 4,2% à gentamicina e 2,1% à netilmicina, ao aztreonam e à amicacina. Todas as cepas apresentaram sensibilidade total ao cloranfenicol e ao sulfazotrim.

Hundred and fifty frozen broiler carcasses of four commercial brands, purchased at retail stores for Salmonella research, were examined: 43 of the carcasses referred to each of the brands A, B, D and 21 of brand C. Thirty-two percent of the samples were found positive; 11 serotypes were identified as S. Agona, S. Anatum, S. Enteritidis, S. Hadar, S. Havana, S. Mbandaka, S. Montevideo, S. Ouakam, S. Poona, S. Schwarzengrund and S.I4, 5, 12:-. Antibiogram testing of the isolated strains showed 100% resistance to ampicilin, 75.0% to cefhalotin, 52.1% to cephoxitin, 22.9% to tobramicin, 6.2% to polimixin B and to tetracyclines, 4.2% to gentamicin, and 2.1% to netilmicin, to aztreonam and to amicacin. All strains showed total sensibility to chloramphenicol and to sulfazotrim.