Surface conditioning with bacteriophages reduces biofilm formation of Salmonella Heidelberg.

Salmonella remains one of the most common foodborne pathogens worldwide, and its resistance to antimicrobials has increased considerably over the years. In this context, was evaluated the action of three bacteriophages isolated or combined in inhibiting the adhesion and removal of Salmonella Heidelberg biofilm on a polystyrene surface. The bacteriophages UPF_BP1, UPF_BP2, UPF_BP3 and a pool of them were used for biocontrol of Salmonella Heidelberg biofilms on polystyrene surface in the action times of 3, 6 and 9 h. Individual and combined phages exhibited reductions in Salmonella Heidelberg adhesion of up to 83.4% and up to 64.0% in removal of preformed biofilm. The use of synergistic combinations between the phages is the most indicated option due to its potential to reduce biofilms. The use of the bacteriophage pool in surface conditioning is an alternative in the control of Salmonella Heidelberg biofilms.

Comparison of transport crates contamination with Campylobacter spp. before and after the cleaning and disinfection procedure in broiler slaughterhouses.

Campylobacteriosis is one of the most common types of bacterial gastroenteritis affecting humans, and poultry is considered a major source of the causative organism, Campylobacter spp. Broilers may arrive contaminated at slaughterhouses, and transport crates could be considered a potential source of contamination. Thus, cleaning and disinfection procedures are crucial to avoid cross-contamination among flocks. Despite its public health importance in Latin American countries, virulence factors of Campylobacter jejuni remain poorly studied in this region. Thus, this study aimed to: 1) determine the occurrence of contaminated crates at a poultry slaughterhouse, 2) compare the contamination before and after the cleaning and disinfection procedures, and 3) detect virulence-associated genes in C. jejuni strains by PCR. Campylobacter spp. were recovered from 8 of the 10 flocks evaluated, and C. jejuni was detected as the main species. There was no significant difference in the Campylobacter detection or quantification between crates at the reception platform and crates after the cleaning/disinfection processes. However, crates after 24 h of natural drying, presented a significant (P < 0.05) lower amount of Campylobacter cells than before the cleaning and disinfection processes. A negative relationship (R2 = 0.210, P = 0.045) between environmental conditions and Campylobacter quantification was found for transport crates after 24 h of natural drying. There was no significant difference (P > 0.05) in the detection of two C. jejuni virulence genes, flaA (encode a major flagellin protein) and cadF (encode an adhesion and fibronectin-binding protein), among various stages of the cleaning and disinfection processes. Our results demonstrate the high contamination levels of Campylobacter strains in broiler flocks and the potential involvement of poultry transport crates in transmitting these bacteria. This study also suggests that ineffective cleaning and disinfection procedures can increase Campylobacter contamination and facilitate the spread of bacteria in poultry establishments.

Antimicrobial and disinfectant resistance of Salmonella Heidelberg from Brazilian flocks did not increase for ten years (2006-2016) / A resistência a desinfetantes e a antimicrobianos não aumentou em um período de 10 anos (2006 a 2016) em Salmonella Heidelberg isoladas de granjas avícolas brasileiras

Salmonella is a major cause of foodborne illness worldwide, and poultry and its derived products are the most common food products associated with salmonellosis outbreaks. Some countries, including Brazil, have experienced an increased prevalence of Salmonella Heidelberg among their poultry flocks. Some isolates have also presented high resistance to antimicrobial agents and persist in the poultry farm environment. This study aimed to compare the susceptibility of S. Heidelberg strains isolated in 2006 with those isolated in 2016 against disinfectants and antimicrobial agents. The results showed that all the strains were highly susceptible to sodium hypochlorite, regardless of the conditions and year of isolation. Resistance to benzalkonium chloride varied according to the conditions applied, but not to the year of isolation. Increased antimicrobial resistance from 2006-2016 was observed only for tetracycline. The results suggest that the antimicrobial and disinfectant resistance of S. Heidelberg did not increase for ten years (2006-2016). However, further analysis should include a larger number of S. Heidelberg isolates from poultry origin and additional antimicrobial agents for more precise conclusions about the increasing in antimicrobial resistance in the last years.(AU)

Salmonella é uma das principais causas das doenças transmitidas por alimento em todo o mundo, e a carne de frango e produtos derivados são os principais alimentos associados com surtos de salmonelose em humanos. Alguns países, incluindo o Brasil, têm observado um aumento da ocorrência de Salmonella Heidelberg nas suas granjas avícolas. Além disto, alguns isolados têm apresentado alta resistência aos antimicrobianos e têm persistido no ambiente de produção avícola. Neste contexto, o objetivo deste estudo foi comparar a susceptibilidade de cepas de S. Heidelberg isoladas em 2006 com aquelas isoladas em 2016 contra desinfetantes e agentes antimicrobianos. Os resultados demonstraram que as cepas foram altamente resistentes a hipoclorito de sódio, independentemente das condições e do ano de isolamento. A resistência ao cloreto de benzalcônio variou de acordo com as condições testadas, mas não com o ano de isolamento. Um aumento da resistência aos antimicrobianos de 2006 a 2016 foi observado apenas para tetraciclina. Os resultados sugerem que a resistência aos desinfetantes e aos antimicrobianos não aumentou em um período de dez anos (2006-2016). Entretanto, novas análises devem incluir um número maior de cepas de S. Heidelberg isoladas de fontes avícolas e outros agentes antimicrobianos para uma conclusão mais precisa sobre o aumento da resistência antimicrobiana nos últimos anos.(AU)

Antimicrobial and disinfectant resistance of Salmonella Heidelberg from Brazilian flocks did not increase for ten years (2006-2016)

ABSTRACT: Salmonella is a major cause of foodborne illness worldwide, and poultry and its derived products are the most common food products associated with salmonellosis outbreaks. Some countries, including Brazil, have experienced an increased prevalence of Salmonella Heidelberg among their poultry flocks. Some isolates have also presented high resistance to antimicrobial agents and persist in the poultry farm environment. This study aimed to compare the susceptibility of S. Heidelberg strains isolated in 2006 with those isolated in 2016 against disinfectants and antimicrobial agents. The results showed that all the strains were highly susceptible to sodium hypochlorite, regardless of the conditions and year of isolation. Resistance to benzalkonium chloride varied according to the conditions applied, but not to the year of isolation. Increased antimicrobial resistance from 2006-2016 was observed only for tetracycline. The results suggest that the antimicrobial and disinfectant resistance of S. Heidelberg did not increase for ten years (2006-2016). However, further analysis should include a larger number of S. Heidelberg isolates from poultry origin and additional antimicrobial agents for more precise conclusions about the increasing in antimicrobial resistance in the last years.

RESUMO: Salmonella é uma das principais causas das doenças transmitidas por alimento em todo o mundo, e a carne de frango e produtos derivados são os principais alimentos associados com surtos de salmonelose em humanos. Alguns países, incluindo o Brasil, têm observado um aumento da ocorrência de Salmonella Heidelberg nas suas granjas avícolas. Além disto, alguns isolados têm apresentado alta resistência aos antimicrobianos e têm persistido no ambiente de produção avícola. Neste contexto, o objetivo deste estudo foi comparar a susceptibilidade de cepas de S. Heidelberg isoladas em 2006 com aquelas isoladas em 2016 contra desinfetantes e agentes antimicrobianos. Os resultados demonstraram que as cepas foram altamente resistentes a hipoclorito de sódio, independentemente das condições e do ano de isolamento. A resistência ao cloreto de benzalcônio variou de acordo com as condições testadas, mas não com o ano de isolamento. Um aumento da resistência aos antimicrobianos de 2006 a 2016 foi observado apenas para tetraciclina. Os resultados sugerem que a resistência aos desinfetantes e aos antimicrobianos não aumentou em um período de dez anos (2006-2016). Entretanto, novas análises devem incluir um número maior de cepas de S. Heidelberg isoladas de fontes avícolas e outros agentes antimicrobianos para uma conclusão mais precisa sobre o aumento da resistência antimicrobiana nos últimos anos.

Characterization of Pectoralis Major Muscle Satellite Cell Population Heterogeneity, Macrophage Density, and Collagen Infiltration in Broiler Chickens Affected by Wooden Breast.

Muscle satellite cells (MSCs) are myogenic stem cells that play a critical role in post-hatch skeletal muscle growth and regeneration. Activation of regeneration pathways to repair muscle fiber damage requires both the proliferation and differentiation of different MSC populations as well as the function of resident phagocytic cells such as anti-inflammatory and pro-inflammatory macrophages. The Wooden Breast (WB) phenotype in broiler chickens is characterized by myofiber degeneration and extensive fibrosis. Previous work indicates that the resident MSC populations expressing the myogenic regulatory factors, Myf-5 and Pax7 are larger and more proliferative in broilers severely affected with WB vs. unaffected broilers. To further characterize the cellular and molecular changes occurring in WB-affected muscles, samples from pectoralis major (PM) muscles with varying severity of WB (WB score 0 = normal; 1 = mildly affected; 2 = severely affected) were collected at 25 and 43 days post-hatch (n = 8 per score per age) and processed for cryohistological and protein expression analyses. Collagen per field and densities of macrophages and MyoD+, Myf-5+, and Pax7+ MSC populations were quantified on immunofluorescence-stained cryosections. Relative collagen protein expression was quantified by fluorescent Western Blotting. In both 25 and 43-days-old broilers, the proportion of collagen per field (P ≤ 0.021) and macrophage density (P ≤ 0.074) were greater in PM exhibiting severe WB compared with normal. At day 43, populations of MyoD+, Myf-5+:MyoD+ MSC were larger and relative collagen protein expression was greater in WB-affected vs. unaffected broilers (P ≤ 0.05). Pax7+ MSC relative to total cells was also increased as WB severity increased in 43-days-old broilers (P ≤ 0.05). Densities of Myf-5+ (P = 0.092), MyoD+ (P = 0.030), Myf5+:MyoD+ (P = 0.046), and Myf-5+:MyoD+:Pax7+ (P = 0.048) MSC were greater in WB score 1 birds compared with WB score 0 and 2 birds. Overall, alterations in the resident MSC and macrophage populations and collagen protein content were observed in WB-affected muscle. Further investigation will be required to determine how these changes in cell population kinetics and local autocrine and paracrine signaling are involved in the apparent dysregulation of muscle maintenance in WB-affected broilers.

Detection and quantification of Campylobacter spp. in Brazilian poultry processing plants.

INTRODUCTION: Campylobacteriosis is considered the most common bacteria-caused human gastroenteritis in the world. Poultry is a major reservoir of Campylobacter. Human infection may occur by consumption of raw and undercooked poultry or by contamination of other foods by these items. The aim of this study was to assess the prevalence of Campylobacter spp. in poultry processing plants with conventional culture method and real-time PCR. METHODOLOGY: A total of 108 poultry processing plant samples were collected to test with conventional microbiology and qPCR. Sampling included cloacal swabs, swabs of transport crates (before and after the cleaning and disinfection process) and carcasses (after the chiller, cooled at 4°C and frozen at -12°C). RESULTS: Positivity in cloacal swabs indicated that poultry arrived contaminated at the slaughterhouse. Contamination in transport cages was substantially increased after the cleaning process, indicating that the process was ineffective. The detection of Campylobacter on carcasses was higher than that on cloacal swabs, which could indicate cross-contamination during the slaughtering process. Conventional microbiology and molecular methods revealed a prevalence of 69.4% and 43.5%, respectively. Lower detection by qPCR can be attributed to the high specificity of the kit and to biological components that could inhibit PCR reactions. CONCLUSIONS: Our results indicate that poultry arrive contaminated at the slaughterhouse and that contamination can increase during the slaughtering process due to cross-contamination. The isolation of Campylobacter in cooled and frozen carcasses corroborates the bacterial survival even at temperatures considered limiting to bacterial growth which are routinely used for food preservation.

Biofilm Formation by Avian Pathogenic Escherichia coli is Not Related to In Vivo Pathogenicity.

Avian pathogenic Escherichia coli (APEC) is one of the pathogens that most concerns the poultry industry worldwide due to the economic losses it can cause. APEC persistence and survival, both in the environment and in the host, may be a consequence of biofilm-producing capabilities. The aim of this study was to evaluate APEC strains' biofilm production and its relationship to in vivo pathogenicity. Two hundred thirty-eight APEC isolates from three different origins (broiler bedding material, cellulite lesions, and respiratory diseases) were selected. The in vivo pathogenicity index (PI) was determined. Biofilm formation was evaluated using a microplate assay with analysis of colony morphology in Congo Red agar in order to detect the phenotypic expression of curli fimbriae and cellulose. Regarding biofilm production, it was observed that 55.8% of the strains produced biofilms. In the morphological test, 88.2% of the isolates expressed one or both components at one of the temperatures at least, and 11.8% of the isolates did not express curli or cellulose. Cellulose production was significantly higher at 25 °C. On the other hand, curli production was significantly higher at 37 °C. The study data indicate that there is no association between biofilm production and in vivo pathogenicity.

Biofilm formation capacity of Salmonella serotypes at different temperature conditions / Capacidade de produção de biofilme por cepas de diferentes sorovares de Salmonella em quatro temperaturas de incubação

Salmonella spp. are one of the most important agents of foodborne disease in several countries, including Brazil. Poultry-derived products are the most common food products, including meat and eggs, involved in outbreaks of human salmonellosis. Salmonella has the capacity to form biofilms on both biotic and abiotic surfaces. The biofilm formation process depends on an interaction among bacterial cells, the attachment surface and environmental conditions. These structures favor bacterial survival in hostile environments, such as slaughterhouses and food processing plants. Biofilms are also a major problem for public health because breakage of these structures can cause the release of pathogenic microorganisms and, consequently, product contamination. The aim of this study was to determine the biofilm production capacity of Salmonella serotypes at four different temperatures of incubation. Salmonella strains belonging to 11 different serotypes, isolated from poultry or from food involved in salmonellosis outbreaks, were selected for this study. Biofilm formation was investigated under different temperature conditions (37°, 28°, 12° and 3°C) using a microtiter plate assay. The tested temperatures are important for the Salmonella life cycle and to the poultry-products process. A total of 92.2% of the analyzed strains were able to produce biofilm on at least one of the tested temperatures. In the testing, 71.6% of the strains produced biofilm at 37°C, 63% at 28°C, 52.3% at 12°C and 39.5% at 3°C, regardless of the serotype. The results indicate that there is a strong influence of temperature on biofilm production, especially for some serotypes, such as S. Enteritidis, S. Hadar and S. Heidelberg. The production of these structures is partially associated with serotype. There were also significant differences within strains of the same serotype, indicating that biofilm production capacity may be strain-dependent.(AU)

Salmonella spp. são um dos mais importantes agentes causadores de doenças transmitidas por alimentos em vários países, inclusive no Brasil. Produtos avícolas e ovos são os principais alimentos envolvidos na transmissão dos sorovares de Salmonella que são responsáveis por surtos de salmonelose em humanos. Salmonella possui a capacidade de formar biofilmes em diversas superfícies. O processo de formação de biofilme depende da interação entre as células bacterianas, a superfície de adesão e as condições do ambiente onde a bactéria se encontra. Estas estruturas favorecem a sobrevivência bacteriana em ambientes hostis, como em matadouros-frigoríficos e em indústrias processadoras de alimentos. Biofilmes são um grande problema em saúde pública, pois a ruptura destas estruturas pode provocar a liberação de microrganismos patogênicos e, consequentemente, a contaminação dos produtos. O objetivo deste estudo foi avaliar a capacidade de produção de biofilme por diferentes sorovares de Salmonella submetidos a quatro temperaturas de incubação. Cepas de Salmonella de 11 sorovares foram selecionadas. A produção de biofilme foi avaliada através do método de incubação em microplacas de poliestireno incubadas a 37°, 28°, 12° e 3°C. Estas temperaturas são importantes durante o ciclo de vida de Salmonella e para o processamento de produtos avícolas. Do total de cepas avaliadas, 92,2% foram capazes de produzir biofilme em pelo menos uma das quatro temperaturas testadas. Neste estudo, 71,6% das cepas produziram biofilme a 37°C, 63% a 28°C, 52,3% a 12°C e 39,5% a 3°C, independentemente do sorovar. Os resultados indicam uma forte influência da temperatura na produção de biofilme, especialmente para os sorovares S. Enteritidis, S. Hadar e S. Heidelberg. A produção de biofilme está parcialmente associada com o sorovar da cepa. Também foi observado que existe variação quanto à produção destas estruturas dentro de um mesmo sorovar, indicando que possivelmente a produção de biofilme é cepa-dependente.(AU)

Detecção dos genes codificantes da toxina CDT, e pesquisa de fatores que influenciam na produção de hemolisinas em amostras de Campylobacter jejuni de origem avícola / Detection of the genes encoding the toxin CDT, and research factors which influence the production of hemolysin in Campylobacter jejuni from poultry products

Membros termofílicos do gênero Campylobacter são reconhecidos como importantes enteropatógenos para o ser humano e animais. A grande diversidade ecológica destes micro-organismos em diferentes habitats tais como água, animais e alimentos predispõem ao aparecimento de novos fatores de virulência. Este trabalho teve por objetivo detectar os genes codificantes da Toxina Distensiva Citoletal (CDT) por meio da técnica de PCR, pesquisar a atividade de hemolisinas e a influência de soluções quelantes e de íons nesta atividade. Foram utilizadas 45 amostras de Campylobacter jejuni de origem avícola para pesquisa de atividade hemolítica, cultivadas em Caldo Triptona de Soja (TSB). Após o crescimento bacteriano, as amostras foram semeadas em Ágar tríptico de soja (TSA) contendo 5% de sangue de ovino. Para verificar a influência de agentes quelantes e solução de íons na atividade hemolítica, as amostras de C. jejuni foram cultivadas em TSB contendo separadamente os quelantes EDTA, ácido acético, soluções de íons CaCl2, MgCl2 e FeCl3, em atmosfera de microaerofilia. Quanto à atividade de hemolisina de C. jejuni em placas de TSA - sangue ovino foi possível observar que houve hemólise em 40% das amostras analisadas apenas com caldo TSB. Somente o ácido acético apresentou ação quelante sobre a atividade de hemolisinas em amostras de C. jejuni semeadas em placas de TSA - sangue ovino. Para detecção dos genes cdtA, cdtB e cdtC através da técnica da Reação em Cadeia da Polimerase (PCR) foram utilizadas 119 amostras de C. jejuni de origem avícola. Foi possível observar que 37,8% possuíam o perfil de genes cdtABC. Os resultados demonstraram em amostras avícolas a presença de cepas de C. jejuni com potencial virulento, devido à presença dos genes da toxina CDT e potencial hemolítico, que apresentou ação reduzida in vitro com ácido acético...

Thermophilic members of the Campylobacter genus are recognized as important enteropathogenics for humans and animals. The great variety of ecological habitats, such as water, food and milk, may promote new virulence factors. To detect the encoding genes distending cytolethal toxin (CDT) by PCR and study the hemolytic activity with influence of chelation solutions and ions, 45 Campylobacter jejuni samples from poultry production origin were used to perform the hemolytic research. To check the influence of chelation agents and solution of ions in the hemolytic activity, samples of C. jejuni strains were grown in tryptone soy broth TSB containing chelation agents separately EDTA, acetic acid, CaCl2, MgCl2 and FeCl3 ions solutions in microaerophilic atmosphere and then streaked on 5% sheep blood tryptic soy agar (TSA). To perform the detection of cdtA, cdtB and cdtC genes the technique of Polymerase Chain Reaction (PCR) was used in 119 samples of C. jejuni from poultry production origin. We found 40% of samples showing hemolysis after growing with TSB. Only the acetic acid showed reduction in hemolysis. The prevalent gene profile was cdtABC in 37.8 % of the samples. It was observed that the results showed the presence of C. jejuni strains with virulent potential, due to presence of the CDT toxin genes and the hemolytic activity, which showed in vitro reduced when acetic acid was added...

Classification of antimicrobial resistance using artificial neural networks and the relationship of 38 genes associated with the virulence of escherichia coli isolates from broilers

Avian pathogenic Escherichia coli (APEC) is responsible for various pathological processes in birds and is considered as one of the principal causes of morbidity and mortality, associated with economic losses to the poultry industry. The objective of this study was to demonstrate that it is possible to predict antimicrobial resistance of 256 samples (APEC) using 38 different genes responsible for virulence factors, through a computer program of artificial neural networks (ANNs). A second target was to find the relationship between (PI) pathogenicity index and resistance to 14 antibiotics by statistical analysis. The results showed that the RNAs were able to make the correct classification of the behavior of APEC samples with a range from 74.22 to 98.44%, and make it possible to predict antimicrobial resistance. The statistical analysis to assess the relationship between the pathogenic index (PI) and resistance against 14 antibiotics showed that these variables are independent, i.e. peaks in PI can happen without changing the antimicrobial resistance, or the opposite, changing the antimicrobial resistance without a change in PI.

Escherichia coli patogênica (APEC) para as aves é responsável por vários processos patológicos em aves, sendo considerado como uma das principais causas de morbidade e mortalidade, associado com perdas econômicas para a indústria avícola. O objetivo do presente trabalho foi demonstrar que é possível predizer a resistência antimicrobiana de 256 amostras de APEC utilizando 38 genes responsáveis por distintos fatores de virulência, através de um programa computacional de redes neurais artificiais (RNAs). O segundo objetivo foi verificar por análise estatística a relação entre o índice de patogenicidade (IP) e a resistência aos 14 antimicrobianos. Os resultados demostraram que as RNAs foram capazes de realizar a classificação correta do comportamento das amostras APEC com uma amplitude de 74,22 a 98,44%, desta forma tornando possível predizer a resistência antimicrobiana. A análise estatística realizada para verificar a relação entre o IP e a resistência aos antimicrobianos demostrou que estas variáveis são independentes, ou seja, podem haver picos no IP sem alteração na resistência, ou até mesmo o contrário, alteração na resistência antimicrobiana sem mudança no IP.

Serotype and antimicrobial resistance patterns of Salmonella isolates from commercial birds and poultry environment in Mississippi.

To obtain information about Salmonella from commercial birds and poultry environments within Mississippi, 50 Salmonella enterica isolates were collected and characterized by intergenic sequence ribotyping (ISR) serotyping and by determining antimicrobial resistance. ISR assigned serotype to all 50 Salmonella enterica isolates whereas the Kauffman-White-LeMinor antibody-based scheme assigned serotype to 48. Agreement between both methods was K = 89.58. Within the set, 12 serotypes were detected. The antimicrobial resistance patterns (ARP) of 12 serotypes, namely Enteritidis, Typhimurium, Kentucky, Bredeney, Mbandaka, Saintpaul, Montevideo, Cubana, Lille, Senftenberg, Johannesburg, and one serotype UN0094, were determined using minimum inhibitory concentration values. The antibiograms demonstrated differences between Salmonella serotypes and among isolates of the same serotype. All isolates were 100% susceptible to enrofloxacin and trimethoprim/sulfamethoxazole. The number of antimicrobials to which the isolates were resistant ranged from two to nine. Twenty-two different ARPs were identified and ARP1, with resistance to spectinomycin and sulfadimethoxine, was most frequently observed. Forty isolates (80%) were resistant to three or more antimicrobials and were thus designated multidrug resistant. Detection of a unique serotype, and variation in antibiograms within the set, demonstrates that it is important to survey isolates periodically from a region to follow epidemiologic trends.

Detection of virulence-associated genes in Salmonella Enteritidis isolates from chicken in South of Brazil / Detecção de genes associados à virulência em cepas de Salmonella Enteritidis isoladas de frangos na região sul do Brasil

Salmonella spp. are considered the main agents of foodborne disease and Salmonella Enteritidis is one of the most frequently isolated serovars worldwide. The virulence of Salmonella spp. and their interaction with the host are complex processes involving virulence factors to overcome host defenses. The purpose of this study was to detect virulence genes in S. Enteritidis isolates from poultry in the South of Brazil. PCR-based assays were developed in order to detect nine genes (lpfA, agfA, sefA, invA, hilA, avrA, sopE, sivH and spvC) associated with the virulence in eighty-four isolates of S. Enteritidis isolated from poultry. The invA, hilA, sivH, sefA and avrA genes were present in 100% of the isolates; lpfA and sopE were present in 99%; agfA was present in 96%; and the spvC gene was present in 92%. It was possible to characterize the isolates with four different genetic profiles (P1, P2, P3 and P4), as it follows: P1, positive for all genes; P2, negative only for spvC; P3, negative for agfA; and P4, negative for lpfA, spvC and sopE. The most prevalent profile was P1, which was present in 88% of the isolates. Although all isolates belong to the same serovar, it was possible to observe variations in the presence of these virulence-associated genes between different isolates. The characterization of the mechanisms of virulence circulating in the population of Salmonella Enteritidis is important for a better understanding of its biology and pathogenicity. The frequency of these genes and the establishment of genetic profiles can be used to determine patterns of virulence. These patterns, associated with in vivo studies, may help develop tools to predict the ability of virulence of different strains.

Salmonella spp. estão entre os principais agentes causadores de doenças transmitidas por alimentos, e o sorovar Salmonella Enteritidis é o mais frequentemente isolado no mundo. A virulência de Salmonella spp. e a sua interação com o hospedeiro são processos complexos que envolvem fatores de virulência para sobreviver às defesas do hospedeiro. O objetivo deste estudo foi detectar genes de virulência em cepas de S. Enteritidis isoladas a partir de fontes avícolas no sul do Brasil. Ensaios de PCR foram desenvolvidos para a detecção de nove genes (lpfA, agfA, sefA, invA, hilA, avrA, sopE, sivH e spvC) associados à virulência em oitenta e quatro amostras de S. Enteritidis. Os genes invA, hilA, sivH, sefA e avrA estavam presentes em 100% dos isolados; lpfA e sopE estavam presentes em 99%; agfA em 96%; e o gene spvC estava presente em 92%. Foi possível caracterizar os isolados em quatro perfis genéticos distintos (P1, P2, P3 e P4), sendo P1 positivo para todos os genes; P2 negativo apenas para spvC; P3 negativo para agfA e P4 negativo para lpfA, spvC e sopE. O perfil de maior frequência foi P1, presente em 88% dos isolados. Apesar de todos os isolados pertencerem ao mesmo sorovar, foi possível observar variações na presença de genes associados à virulência entre os mesmos. A caracterização dos mecanismos de virulência circulantes na população de Salmonella Enteritidis é importante para um maior entendimento da sua biologia e patogenicidade. A frequência destes genes e o estabelecimento de perfis genéticos podem ser utilizados para determinar os padrões de virulência dos isolados. Estes padrões, associados a estudos in vivo, podem auxiliar na elaboração de ferramentas que permitam predizer a capacidade de virulência das diferentes cepas.

Effects of fumonisin B1 on selected biological responses and performance of broiler chickens / Efeitos da fumonisina B1 sobre respostas biológicas e desempenho de frangos de corte

The objective of this study was to determine the effects of three doses of fumonisin B1 (0, 100, and 200mg/kg of feed) on biological variables (relative weight of liver [RWL], total plasma protein [TPP], albumin [Alb], calcium [Ca], phosphorus [P], uric acid [UA], alanine aminotransferase [ALT], aspartate aminotransferase [AST], gamma glutamyltransferase [GGT], alkaline phosphatase [AP], total cholesterol [Chol], triglycerides [Tri], sphinganine-to-sphingosine ratio [SA:SO], and C-reactive protein [CRP]), morphological evaluation of the small intestine (villus height [VH], crypt depth [CD], and villus-to-crypt ratio [V:C]), histological evaluation, and on performance (body weight [BW], feed intake [FI], and feed conversion rate [FCR]) of broiler chickens. Significant effects of FB were observed on BW and FI (reduced), on RWL, TPP, Ca, ALT, AST, GGT, Chol, and Tri (increased) at both 14 and 28 days evaluations. In addition, significant increase was observed on FCR, Alb, P, SA:SO, and CRP and significant reduction in UA, VH, and V:C only at the 28 days evaluation. Significant histological lesions were observed on liver and kidney of FB inoculated broilers at 14 and 28 days. Those results show that FB has a significant effect on biological and histological variables and on performance of broiler chickens.

O objetivo deste trabalho foi determinar os efeitos de três doses de fumonisina B1 (0, 100 e 200 mg/kg de ração) sobre variáveis biológicas (peso relativo de fígado [RWL], proteínas plasmáticas totais [TPP], albumina [Alb], cálcio [Ca], fósforo [P], ácido úrico [UA], alanina aminotransferase [ALT], aspartato aminotransferase [AST], gama glutamiltransferase [GGT] fosfatase alcalina [AP], colesterol total [Chol], triglicerídeos [Tri], relação esfinganina:esfingosina [SA:SO] e proteína C-reativa [CRP]), avaliação morfológica do intestino delgado (altura de vilosidades [VH], profundidade de criptas [CD] e relação entre vilosidade e cripta [V:C]), avaliações histológicas e no desempenho (peso corporal [BW], consumo de ração [FI] e conversão alimentar [FCR]) de frangos de corte. Efeitos significativos da FB foram observados sobre BW e FI (diminuição), sobre RWL, TPP, Ca, ALT, AST, GGT, Chol e Tri (aumento) aos 14 e 28 dias. Além disso, houve aumento significativo nos parâmetros FCR, Alb, P, SA:SO e CRP e redução nos parâmetros UA, VH e V:C somente aos 28 dias. Lesões histológicas significativas foram observadas no fígado e rins das aves intoxicadas, tanto aos 14 quanto aos 28 dias. Estes resultados indicam que a FB tem um efeito significativo sobre variáveis biológicas e de desempenho de frangos de corte.

Detection of virulence-associated genes of Pasteurella multocida isolated from cases of fowl cholera by multiplex-PCR / Pesquisa de genes associados à virulência em cepas de Pasteurella multocida isoladas em casos de cólera aviária através da técnica de multiplex-PCR

The current systems of breeding poultry, based on high population density, increase the risk of spreading pathogens, especially those causing respiratory diseases and those that have more than one host. Fowl Cholera (FC) is one such pathogen, and even though it represents one of several avian diseases that should be considered in the differential diagnosis of notifiable diseases that present with sudden death, the pathogenesis and virulence factors involved in FC are still poorly understood. The objective of this study was to investigate twelve genes related to virulence in 25 samples of Pasteurella multocida isolated from FC cases in the southern region of Brazil through the development of multiplex PCR protocols. The protocols developed were capable of detecting all of the proposed genes. The ompH, oma87, sodC, hgbA, hgbB, exBD-tonB and nanB genes were present in 100% of the samples (25/25), the sodA and nanH genes were present in 96% (24/25), ptfA was present in 92% (23/25), and pfhA was present in 60% (15/25). Gene toxA was not identified in any of the samples studied (0/25). Five different genetic profiles were obtained, of which P1 (negative to toxA) was the most common. We concluded that the multiplex-PCR protocols could be useful tools for rapid and simultaneous detection of virulence genes. Despite the high frequency of the analyzed genes and the fact that all samples belonged to the same subspecies of P. multocida, five genetic profiles were observed, which should be confirmed in a study with a larger number of samples.

Os atuais sistemas de criação na avicultura, baseados na alta densidade populacional, aumentam os riscos de disseminação de patógenos, especialmente das doenças respiratórias e daquelas cujos agentes etiológicos possuam mais de um hospedeiro. A Cólera Aviária (CA) apresenta estas características e apesar de representar uma das patologias aviárias que deve ser considerada para o diagnóstico diferencial de enfermidades com notificação obrigatória que cursam com morte súbita, a patogenia e os fatores de virulência envolvidos na CA ainda estão pouco elucidados. O objetivo deste trabalho foi pesquisar doze genes associados à virulência em 25 amostras de Pasteurella multocida isoladas de casos de CA na região sul do Brasil através do desenvolvimento de protocolos de multiplex-PCR. Os protocolos de multiplex-PCR desenvolvidos foram capazes de detectar todos os genes propostos. Os genes ompH, oma87, sodC, hgbA, hgbB, exBD-tonB, nanB estiveram presentes em 100% das amostras (25/25). Os genes sodA e nanH em 96% (24/25), o gene ptfA em 92% (23/25) e o gene pfhA em 60% (15/25). O gene toxA não foi identificado em nenhuma das amostras pesquisadas (0/25). Foram obtidos cinco diferentes perfis genéticos, sendo P1 (negativo para o gene toxA) o mais comum. Com este trabalho, concluiu-se que os protocolos de multiplex-PCR desenvolvidos tornam-se uma ferramenta bastante útil e rápida para a detecção simultânea dos genes de virulência. Apesar da alta frequência dos genes estudados e de todas as amostras pertencerem à mesma subespécie de P. multocida, foram observados cinco perfis genéticos, os quais devem ser confirmados em um estudo com um maior número de amostras.