Listeria innocua and serotypes of Listeria monocytogenes isolated from clinical cases in small ruminants in the northwest of Uruguay / Listeria innocua e serotipos do Listeria monocytogenes isoladas dos casos clínicos em pequenos ruminantes no noroeste do Uruguai

Listeriosis is an infectious disease caused by bacteria of the genus Listeria, the neurological form being more common in ruminants. There are many reports of listeriosis in small ruminants in the region that includes Brazil, Argentina and Uruguay. However, these diagnoses were mainly based on histological lesions in the central nervous system (CNS) without the isolation and characterization of the involved Listeria strains. The aim of this study was to report sheep and goats listeriosis cases from 2016 to 2021 in northwestern Uruguay. The diagnosis was made according to lesions observed at histopathology, plus Listeria isolation in CNS, identifying it at specie and serotype level. Nine animals (n=9) of three outbreaks and five sporadic cases of listeriosis were studied. Sheep was the species with more cases in relation to goats, and adults were the category most affected. Cases occurred in spring and less frequently in winter. All presented neurological clinical signs and the lesions in the CNS were consistent with suppurative meningoencephalitis and micro-abscesses in the brainstem. In eight of nine CNS samples, Listeria strains were isolated (seven L. monocytogenes and one L. innocua). All the L. monocytogenes isolates carried the inlA gene; serotyping showed that four strains belonged to serotype 1/2b, two isolates belonged to serotype 4b, and one to serotype 1/2a. Considering that listeriosis is a common disease in this region and the fact that isolates are scarcely recovered from small ruminants, it would be important to emphasize the need for Listeria isolation to better characterize the strains that affect animals. Not only to improve knowledge about the epidemiology of disease but also with the objective of developing serotype specific vaccines for animal use.

Listeriose uma doença bacteriana causada pelo gênero Listeria, a forma nervosa é a mais comum em ruminantes. No Brasil, Argentina e Uruguai há vários relatos de listeriose em pequenos ruminantes com diagnóstico baseado na histopatologia do sistema nervoso central (SNC), sem o isolamento e a caracterização do agente. O objetivo deste trabalho foi relatar uma série de casos diagnosticados em ovinos e caprinos no período 2016-2021 no noroeste do Uruguai. O diagnóstico foi feito basado nas lesões observadas na histopatologia, e caracterização das cepas de Listeria recuperadas do SNC quanto à espécie e sorotipo. Nove animais (n=9) do três surtos e cinco casos isolados de listeriose foram estudados. Os ovinos foram a espécie com o maior número de casos em relação aos caprinos, sendo os animais adultos a categoria mais afetada em ambas espécies. A doença ocorreu principalmente na primavera com alguns casos observados no inverno. Todos os casos apresentavam sinais clínicos nervosos e as lesões no SNC caracterizavam-se por meningoencefalite supurativa com presença de microabscessos no tronco encefálico. Em oito de nove amostras do SNC foram isoladas cepas de Listeria (sete L. monocytogenes e uma L. innocua). Todos os isolados de L. monocytogenes continham o gene inlA; a sorotipagem apresentou quatro cepas do serotipo 1/2b, duas cepas serotipo 4b e uma cepa 1/2a. Levando em consideração que nesta região a listeriose é uma doença frequente e que existem poucos isolados recuperados de casos clínicos em pequeño ruminantes, torna-se relevante o isolamento deste agente para caracterização das cepas que afetam os animais. Não só para melhorar o conhecimento sobre a epidemiologia da doença, mas também com o objetivo de desenvolver vacinas sorotipo-especificas para uso animal.

Listeriosis outbreak in sheep raised in feedlots in the Southern Region of Rio Grande do Sul state, Brazil

Background: A listeriosis outbreak in a sheep fattening feedlot in the Southern Region of Rio Grande do Sul State, Brazilis described. This disease is caused by Listeria monocytogenes and represents a risk to public health since it affects notonly ruminants but also humans. This agent is widely spread in the environment, such as in the soil and water. It is alsofound in decaying vegetable matter and the feces and fluids of domestic animals. The aim of this study was to describe alisteriosis outbreak in sheep raised in feedlots, its epidemiology, and to establish the importance of this disease in this typeof sheep management system, evaluate the possible sources of infection, and suggest ways to control it.Cases: Sheep were kept in a 2-sector shed, one with east solar orientation and the other with west solar orientation, thelatter with free access to domestic birds. Sheep were fed silage and concentrate. Seven sheep were affected, 5 died and 2recovered. Clinically, the sheep displayed loss of balance, excessive drooling, and tremors; one exhibited circling, headdeviation, apathy, nystagmus, lateral recumbency, paddling, and labored breathing. At necropsy, macroscopic lesions werenot found, and histologically several micro-abscesses and perivascular cuffs with lymphocytes, macrophages, and neutrophils were present in the brain stem. Listeria monocytogenes suspected colonies were observed in the microbiologicalculture, and the bacteria was identified by biochemical analysis. The immunohistochemistry test in brain stem sectionswas positive for the antibody BD DifcoTM Listeria O Antiserum Poly Serotypes 1 and 4.Discussion: A listeriosis outbreak in a feedlot sheep was confirmed through epidemiological findings, histological lesions,bacterial culture, and immunohistochemistry analysis. This infection is frequent...

Listeriosis outbreak in sheep raised in feedlots in the Southern Region of Rio Grande do Sul state, Brazil

Background: A listeriosis outbreak in a sheep fattening feedlot in the Southern Region of Rio Grande do Sul State, Brazilis described. This disease is caused by Listeria monocytogenes and represents a risk to public health since it affects notonly ruminants but also humans. This agent is widely spread in the environment, such as in the soil and water. It is alsofound in decaying vegetable matter and the feces and fluids of domestic animals. The aim of this study was to describe alisteriosis outbreak in sheep raised in feedlots, its epidemiology, and to establish the importance of this disease in this typeof sheep management system, evaluate the possible sources of infection, and suggest ways to control it.Cases: Sheep were kept in a 2-sector shed, one with east solar orientation and the other with west solar orientation, thelatter with free access to domestic birds. Sheep were fed silage and concentrate. Seven sheep were affected, 5 died and 2recovered. Clinically, the sheep displayed loss of balance, excessive drooling, and tremors; one exhibited circling, headdeviation, apathy, nystagmus, lateral recumbency, paddling, and labored breathing. At necropsy, macroscopic lesions werenot found, and histologically several micro-abscesses and perivascular cuffs with lymphocytes, macrophages, and neutrophils were present in the brain stem. Listeria monocytogenes suspected colonies were observed in the microbiologicalculture, and the bacteria was identified by biochemical analysis. The immunohistochemistry test in brain stem sectionswas positive for the antibody BD DifcoTM Listeria O Antiserum Poly Serotypes 1 and 4.Discussion: A listeriosis outbreak in a feedlot sheep was confirmed through epidemiological findings, histological lesions,bacterial culture, and immunohistochemistry analysis. This infection is frequent...(AU)

Comparison between immunofluorescence and immunohistochemistry for Listeria monocytogenes detection in formalin-fixed paraffin-embedded tissues / Comparação entre imunofluorescência e imuno-histoquímica para detecção de Listeria monocytogenes em tecidos fixados e parafinizados

Listeria monocytogenes is a bacterium that infect humans and animals and causes a zoonotic disease characterized by encephalitis, septicemia or abortion. In addition, listeriosis leads to significant economic losses due to animal death and sacrifice. This research compared the technique of immunofluorescence (IF) and immunohistochemistry (IHC) for the diagnosis of L. monocytogenes in formalin-fixed and paraffin-embedded (FFPE) tissues. A total of 30 tissue blocks from 15 animals with history and/or lesions compatible with listeriosis were selected. For both IHC and IF, the same diluted (1:200) polyclonal primary antibody was used against L. monocytogenes serotypes 1 and 4. For IHC, a polymer secondary antibody conjugated to peroxidase (HRP) was used. For IF, samples were incubated with a fluorescein-labeled anti-rabbit IgG secondary antibody. Each sample was classified according to the presence and percentage of immunolabeling area. From 30 samples, 10 were positive at least for one technique, whereas eight samples were positive for both IHC and IF with similar score. There was strong immunolabeling in tissue samples from bovines experimentally infected with L. monocytogenes ATCC 7644, as well as in nervous tissues from naturally infected ruminants. Additionally, IF did not show any difference in sensitivity when compared to IHC. Using processed biological materials for IF, instead of fresh tissues, is a quite unique technique, since there are few protocols described. Therefore, this study demonstrated that both techniques are efficient to detect L. monocytogenes in FFPE tissues.

Listeria monocytogenes é uma bactéria que infecta humanos e animais, podendo causar uma doença zoonótica caracterizada por encefalite, septicemia e abortos. Além disso, a listeriose resulta em perdas econômicas significativas pela morte e sacrifício de animais. O objetivo deste trabalho foi comparar a técnica de imunofluorescência (IF) e imuno-histoquímica (IHQ) para detecção de L. monocytogenes em tecidos fixados e parafinizados. Foram selecionados 30 blocos de tecidos de 15 animais com histórico e/ou lesões compatíveis com listeriose. Para ambas as técnicas, foi utilizado o mesmo anticorpo primário policlonal diluído (1:200) para detecção de L. monocytogenes sorotipos 1 e 4. Para a IHQ foi utilizado anticorpo secundário em polímero acoplado a peroxidase (HRP). Para a IF, as amostras foram incubadas com anticorpo secundário anti-IgG de coelho marcado com fluoresceína. Cada amostra foi classificada quanto à presença de imunomarcação e porcentagem de área positiva. Das 30 amostras, 10 foram positivas em pelo menos uma das técnicas, sendo oito amostras positivas em ambas IHQ e IF com o mesmo escore. Houve forte imunomarcação tanto em amostras de bovino experimentalmente infectado com L. monocytogenes ATCC 7644, como em amostras de tecido nervoso de ruminantes naturalmente infectados. Além disso, a IF não apresentou diferença na sensibilidade quando comparada com a IHQ. O uso de materiais biológicos processados para IF, ao invés de tecidos frescos, é algo inovador, uma vez que existem poucos protocolos descritos. Portanto, este estudo demonstrou que as duas técnicas foram eficientes para detectar L. monocytogenes em tecidos fixados em formol e parafinizados.

Causes of death and organs condemnation at slaughter of sheep in a feedlot system in Southern Rio Grande do Sul / Causas de morte e condenação de órgãos no abate de ovinos em sistema de confinamento no Sul do Rio Grande do Sul

In Brazil the second largest sheep herd is in Rio Grande do Sul and in recent years the demand for meat consumption of this specie has increased. Intensive farming systems have made considerable progress in this region with the objective of increasing the production of sheep for slaughter and obtaining a uniform batch to ensure better quality of sheep meat to consumers. However, the agglomeration and stress that animals go through can lead to the occurrence of illnesses and economic loss to producers. The objectives of this paper were to determine the main causes of death that affected sheep in a feedlot system, to establish forms of control and prophylaxis of diagnosed illnesses, and to estimate the economic losses resulting from them. The objective was also to determine the causes of condemnation of organs or carcasses in the slaughterhouses that processed the sheep were sent, and to estimate the losses in this productive sector. For this, a follow-up work was carried out in an establishment located in the city of São Lourenço do Sul, Rio Grande do Sul, from October 2020 to September 2021. The dead sheep at the feedlot were necropsied, and the diagnosis was made based on clinical signs, pathology, and bacteriology. The main diseases diagnosed were parasitic enteritis (15.4%), pneumonia (13%), and listeriosis (9.6%). In the slaughterhouse study, the lesions that led to the highest number of condemnations were hydatidosis (29.9%), renal congestion (26.2%), and renal ischemia (25.8%). The economic losses estimated for the death of sheep in 2021 was R$17,480.00, significantly lower than the approximate losses in 2019 and 2020 of R$50,000.00 and R$54,000.00, respectively. This highlights the importance of technical assistance to reduce these losses due to mortality in sheep raised in a feedlot system. It was also observed the kidneys of the sheep were the organs most frequently selected for condemnation. The economic value of the kidneys sold as disposed waste was eight time lower than that the value of kidneys suitable for consumption.

No Rio Grande do Sul está localizado o segundo maior rebanho de ovinos do Brasil e a demanda pelo consumo de carne desta espécie animal tem aumentado nos últimos anos. As criações em sistema intensivo têm tido um avanço considerável nesta região com o objetivo de aumentar a produção de ovinos para o abate e obter um lote uniforme, garantindo melhor qualidade da carne aos consumidores. Por outro lado, a aglomeração e o estresse que os animais passam pode levar a ocorrência de enfermidades e trazer prejuízos econômicos aos produtores. Os objetivos deste trabalho foram determinar as principais causas de morte que afetaram ovinos em um sistema intensivo de criação, estabelecer formas de controle e profilaxia das enfermidades diagnosticadas, bem como estimar as perdas econômicas delas decorrentes. Objetivou-se, também, determinar as causas de condenação de órgãos ou carcaças nos frigoríficos aos quais os ovinos eram enviados para o abate, para estimar as perdas neste setor produtivo. Para isso, foi realizado um trabalho de acompanhamento em um estabelecimento localizado no município de São Lourenço do Sul, Rio Grande do Sul, no período de outubro de 2020 até setembro de 2021. Os ovinos mortos eram necropsiados e o diagnóstico realizado com base nos sinais clínicos, patologia e bacteriologia. As principais enfermidades diagnosticadas foram as parasitoses (15,4%) e as pneumonias (13%), seguidas de listeriose (9,6%). As lesões que levaram ao maior número de condenações foram hidatidose (29,9%), congestão renal (26,2%) e isquemia renal (25,8%). A estimativa de perdas econômicas no ano de 2021 foi de R$17.480,00, enquanto as perdas por morte de ovinos nos anos 2019 e 2020 foram de aproximadamente R$50.000,00 e R$54.000,00, respectivamente. Ficou evidenciada a importância da assistência técnica para a redução dessas perdas por mortalidade de ovinos criados em sistema intensivo. Observou-se, ainda, que os rins foram os órgãos mais frequentemente descartados para o consumo e que o valor de descarte como resíduo era oito vezes menor do que o valor dos rins aptos para o consumo.

Principais aspectos de listeria monocytogenes e sua importância para a saúde pública / Main aspects of l. Monocytogenes and its importance to public health

Esta revisão tem como objetivo descrever os principais aspectos relacionados a Listeria monocytogenes e sua ocorrência nos alimentos. Alimentos contaminados com L. monocytogenes representam importante risco para o desenvolvimento das doenças veiculadas por alimentos (DVA). Listeriose é uma doença grave para grupos de risco, como idosos, mulheres grávidas, recém-nascidos e pacientes imunocomprometidos, com taxas de letalidade que podem ultrapassar 80%. É um patógeno amplamente distribuído na natureza, pode ser isolado de diversos produtos de origem animal e vegetal, como carnes de frango, bovinos, suínos, embutidos, leite e derivados e hortaliças. Além disso, possui inúmeros fatores de virulência, que permitem que escape do sistema imune e mantenha a infecção. É um microrganismo capaz de crescer em temperaturas de refrigeração e formar biofilme, sendo esses fatores de risco quando associados às más práticas de manejo e controle da cadeia produtiva dos alimentos, já que estas características propiciam a contaminação cruzada. Como medidas de controle, faz-se necessário implementar métodos que assegurem as boas condições de manipulação dos alimentos na indústria, no varejo e nas residências. Muitas práticas previstas na legislação podem ser empregadas para controlar contaminação nos alimentos, como as Boas Práticas de Fabricação (BPF), os Procedimentos Padrão de Higiene Operacional (PPHO) e o sistema de Análise de Perigos e Pontos Críticos de Controle (APPCC). Porém, a falta de fiscalização pelos órgãos competentes pode ser um fator de incentivo para a não implementação destas práticas, o que pode comprometer a qualidade microbiológica dos alimentos e gerar riscos à saúde pública.

This review aims to list the main aspects of Listeria monocytogenes and its occurrence in foods. Food contaminated with L. monocytogenes poses an important risk for the occurrence of foodborne illnesses. Listeriosis is a serious disease to risk groups, such as the elderly, pregnant women, newborns and immunocompromised patients, with mortality rates that can exceed 80%. It is a widely distributed pathogen in the environment and can be isolated from various animal and greens, such as chicken, beef, pork, sausages, dairy products and vegetables. In addition, the pathogen has numerous of virulence factors, that allows the microorganism to dodge the immune system and continue the infection. It is a microorganism capable of growing at refrigeration temperatures and forming biofilm, which is a risk factor when combined with poor management and control practices in the food production chain, as these features can lead to cross contamination. As control measures, it is necessary to implement methods that ensure good food handling conditions in industry, retail and households. Many practices provided in the legislation can be used to control food contamination, such as Good Manufacturing Practices (GMP), Standard Operating Hygiene Procedures (SOHP) and the Hazard Analysis and Critical Control Points (HACCP) system; however, the lack of inspection by competent bodies can be an encouragement factor for the non-implementation of these practices, which would be able to compromise the microbiological quality of the food and creates a threat to public health.

Principais aspectos de listeria monocytogenes e sua importância para a saúde pública / Main aspects of l. Monocytogenes and its importance to public health

Esta revisão tem como objetivo descrever os principais aspectos relacionados a Listeria monocytogenes e sua ocorrência nos alimentos. Alimentos contaminados com L. monocytogenes representam importante risco para o desenvolvimento das doenças veiculadas por alimentos (DVA). Listeriose é uma doença grave para grupos de risco, como idosos, mulheres grávidas, recém-nascidos e pacientes imunocomprometidos, com taxas de letalidade que podem ultrapassar 80%. É um patógeno amplamente distribuído na natureza, pode ser isolado de diversos produtos de origem animal e vegetal, como carnes de frango, bovinos, suínos, embutidos, leite e derivados e hortaliças. Além disso, possui inúmeros fatores de virulência, que permitem que escape do sistema imune e mantenha a infecção. É um microrganismo capaz de crescer em temperaturas de refrigeração e formar biofilme, sendo esses fatores de risco quando associados às más práticas de manejo e controle da cadeia produtiva dos alimentos, já que estas características propiciam a contaminação cruzada. Como medidas de controle, faz-se necessário implementar métodos que assegurem as boas condições de manipulação dos alimentos na indústria, no varejo e nas residências. Muitas práticas previstas na legislação podem ser empregadas para controlar contaminação nos alimentos, como as Boas Práticas de Fabricação (BPF), os Procedimentos Padrão de Higiene Operacional (PPHO) e o sistema de Análise de Perigos e Pontos Críticos de Controle (APPCC). Porém, a falta de fiscalização pelos órgãos competentes pode ser um fator de incentivo para a não implementação destas práticas, o que pode comprometer a qualidade microbiológica dos alimentos e gerar riscos à saúde pública.(AU)

This review aims to list the main aspects of Listeria monocytogenes and its occurrence in foods. Food contaminated with L. monocytogenes poses an important risk for the occurrence of foodborne illnesses. Listeriosis is a serious disease to risk groups, such as the elderly, pregnant women, newborns and immunocompromised patients, with mortality rates that can exceed 80%. It is a widely distributed pathogen in the environment and can be isolated from various animal and greens, such as chicken, beef, pork, sausages, dairy products and vegetables. In addition, the pathogen has numerous of virulence factors, that allows the microorganism to dodge the immune system and continue the infection. It is a microorganism capable of growing at refrigeration temperatures and forming biofilm, which is a risk factor when combined with poor management and control practices in the food production chain, as these features can lead to cross contamination. As control measures, it is necessary to implement methods that ensure good food handling conditions in industry, retail and households. Many practices provided in the legislation can be used to control food contamination, such as Good Manufacturing Practices (GMP), Standard Operating Hygiene Procedures (SOHP) and the Hazard Analysis and Critical Control Points (HACCP) system; however, the lack of inspection by competent bodies can be an encouragement factor for the non-implementation of these practices, which would be able to compromise the microbiological quality of the food and creates a threat to public health.(AU)

Lactic acid bacteria against Listeria monocytogenes

Listeria monocytogenes is a pathogenic bacterium that can contaminate food and cause public health problems due its ability to form biofilms and resistance to sanitizers, it is responsible for sanitary and economic losses in food producing establishments. The difficulties in controlling biofilms and increasing resistance to traditional antibacterial agents is motivating studies of alternative potential biological agents for the control of pathogenic biofilms, among which lactic acid bacteria (LABs) are included. The objective of this work was to evaluate the activity of LABs against Listeria monocytogenes biofilm formation on polystyrene plates, a surface commonly used in the food industry. Lyophilized commercial strains of Bifidobacterium animalis, Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus salivaris and Lactobacillus acidophilus were used. The strain of Listeria monocytogenes (L4) was isolated from polystyrene mats from a poultry slaughterhouse cutting room and demonstrated the ability to attach to microplates and resistance to sanitizers (sodium hypochlorite and hydrogen peroxide) at all times, temperatures and tested surfaces. The antimicrobial activity of LABs was evaluated by the agar diffusion method. The LABs that presented action on Listeria monocytogenes were selected for the inhibition and/or removal of biofilms in microplates, and all experiments were carried out in triplicate. Only Bifidobacterium animalis and Lactobacillus plantarum demonstrated action against Listeria monocytogenes in the agar diffusion assays and were selected for inhibition and competition assays. Furthermore, competition of LABs against Listeria monocytogenes adhesion was evaluated. There was no significant difference between LABs and L. monocytogenes, alone or in combination, at temperatures of 30ºC and 37ºC in the Listeria monocytogenes inhibition assays on polystyrene surface. The lactic acid bacteria evaluated did not demonstrate inhibition of L. monocytogenes adhesin testes with optical density visualization, however, it was possible to identify a reduction in L. monocytogenes counts with the application of Bifidobacterium animals and Lactobacillus plantarum in the testes of competition against biofilm formation. In competition tests Bifidobacterium animalis and Lactobacillus plantarum have an injunction in Listeria monocytogenes, indicating that these lactic acid bacteria can retard Listeria biofilm formation on polystyrene surfaces and thus help control the pathogen in the food industry. A potential mechanism to control biofilm adhesion and formation of pathogens for nutrients and fixation on surfaces, multiplication factors and surfaces are a challenge in controlling biofilms of pathogenic microorganisms, alternative measures to traditional methods for inactivating pathogens and biofilm formers bacteria are necessary. In this sense, lactic acid bacteria generate high levels of bacteriocin and are effective in inhibiting the biofilm of pathogenic bacteria, however, our study did not reveal this. We verified that Bifidobacterium animalis and Lactobacillus plantarum have an inhibitory action on Listeria monocytogenes, indicating that these lactic acid bacteria can be used to delay the formation of biofilms by Listeria on polystyrene surfaces, helping to control this pathogen in food industry.(AU)

Lactobacillus acidophilus reduces Listeria monocytogenes infection by inhibiting mitogen-activated protein kinase genes in growing rabbits

We aimed to investigate the effect of Lactobacillus acidophilus ACCC11073 on the growth performance, oxidation, inflammation, and mitogen-activated protein kinase (MAPK) family genes of rabbits infected with Listeria monocytogenes (L. monocytogenes) using antibiotic enrofloxacin hydrochloride (EH) as a reference. There were four treatments including negative control, positive control with L. monocytogenes infection on the first day of feeding trial (PC), PC + EH at 40 mg kg−1, and PC + L. acidophilus at 108 CFU kg−1 of diet using 240 weaned growing rabbits. The results showed that L. monocytogenes infection worsened growth performance of rabbits, whereas EH or L. acidophilus supplementation partially recovered body weight gain, but did not reach the levels of the negative control. Listeria acidophilus and EH decreased L. monocytogenes loads in caecum, liver, spleen, and lymph node, serum oxidative markers including diamine oxidase, malondialdehyde, and protein carbonyl, serum IL-1ß, IL-6, and TNF-α. The decreased effects of EH on IL-1ß and TNF-α were more pronounced than that of the probiotic. Treatments EH and probiotic also de-regulated the mRNA levels of MAPK1, 3, 6, and 14. Listeria acidophilus exhibits a similar effect to EH against L. monocytogenes in rabbits, and the regulation on inflammatory process is via MAPK family genes. The results suggest that L. acidophilus can be used as a feed additive against L. monocytogenes infection.(AU)

Listeria monocytogenes en leche de vaca producida por granjas lecheras familiares / Listeria monocytogenes in cow's milk produced by family-owned dairy farms / Listeria monocytogenes em leite de vaca produzido por propriedades leiteiras familiares

Refrigeration is an important milk preservation method. However, milk quality may deteriorate if the product is refrigerated for long periods, mainly due to the growth of psychrotrophic bacteria. This group of microorganisms includes pathogenic genera, most notably Listeria monocytogenes. The detection of this bacterium in food is important, given its pathogenic effects on human and animal health and also its economic relevance. This study focused on detecting the presence of L. monocytogenes in milk samples collected at small family-owned dairy farms. Samples were cultivated on PALCAM and ALOA agars for microbiological analysis and a molecular analysis by polymerase chain reaction was performed for the detection of L. monocytogenes. Despite the negative results obtained in both these analyses, further studies are recommended to confirm or refute the negligible effect of L. monocytogenes on small dairy farms.

A refrigeração é um método importante de preservação do leite. No entanto, a qualidade do leite pode piorar se o produto for mantido sob refrigeração por longos períodos, principalmente devido ao crescimento de bactérias psicrotróficas. Este grupo de microorganismos inclui gêneros patogênicos, mais notavelmente Listeria monocytogenes. A detecção dessa bactéria em alimentos é importante, tendo em vista seus efeitos patogênicos na saúde humana e animal e também sua relevância econômica. Este estudo teve como objetivo detectar a presença de L. monocytogenes em amostras de leite coletadas em pequenas fazendas leiteiras de propriedade familiar. As amostras foram cultivadas em ágar PALCAM e ALOA para análise microbiológica e análise molecular por reação em cadeia da polimerase para detecção de L. monocytogenes. Apesar dos resultados negativos obtidos em ambas as análises, estudos adicionais são recomendados para confirmar ou refutar o efeito insignificante de L. monocytogenes em pequenas fazendas leiteiras.

La refrigeración es un método importante de conservación de la leche. Sin embargo, la calidad de la leche puede deteriorarse si el producto se refrigera durante períodos prolongados, principalmente debido al crecimiento de bacterias psicrotróficas. Este grupo de microorganismos incluye géneros patógenos, más notablemente Listeria monocytogenes. La detección de esta bacteria en los alimentos es importante, dados sus efectos patógenos sobre la salud humana y animal y también su relevancia económica. Este estudio se centró en detectar la presencia de L. monocytogenes en muestras de leche recolectadas en pequeñas granjas lecheras familiares. Las muestras se cultivaron en agares PALCAM y ALOA para análisis microbiológico y se realizó un análisis molecular por reacción en cadena de la polimerasa para la detección de L. monocytogenes. A pesar de los resultados negativos obtenidos en ambos análisis, se recomiendan más estudios para confirmar o refutar el efecto insignificante de L. monocytogenesen pequeñas granjas lecheras.

Listeria monocytogenes en leche de vaca producida por granjas lecheras familiares / Listeria monocytogenes in cow's milk produced by family-owned dairy farms / Listeria monocytogenes em leite de vaca produzido por propriedades leiteiras familiares

Refrigeration is an important milk preservation method. However, milk quality may deteriorate if the product is refrigerated for long periods, mainly due to the growth of psychrotrophic bacteria. This group of microorganisms includes pathogenic genera, most notably Listeria monocytogenes. The detection of this bacterium in food is important, given its pathogenic effects on human and animal health and also its economic relevance. This study focused on detecting the presence of L. monocytogenes in milk samples collected at small family-owned dairy farms. Samples were cultivated on PALCAM and ALOA agars for microbiological analysis and a molecular analysis by polymerase chain reaction was performed for the detection of L. monocytogenes. Despite the negative results obtained in both these analyses, further studies are recommended to confirm or refute the negligible effect of L. monocytogenes on small dairy farms.(AU)

A refrigeração é um método importante de preservação do leite. No entanto, a qualidade do leite pode piorar se o produto for mantido sob refrigeração por longos períodos, principalmente devido ao crescimento de bactérias psicrotróficas. Este grupo de microorganismos inclui gêneros patogênicos, mais notavelmente Listeria monocytogenes. A detecção dessa bactéria em alimentos é importante, tendo em vista seus efeitos patogênicos na saúde humana e animal e também sua relevância econômica. Este estudo teve como objetivo detectar a presença de L. monocytogenes em amostras de leite coletadas em pequenas fazendas leiteiras de propriedade familiar. As amostras foram cultivadas em ágar PALCAM e ALOA para análise microbiológica e análise molecular por reação em cadeia da polimerase para detecção de L. monocytogenes. Apesar dos resultados negativos obtidos em ambas as análises, estudos adicionais são recomendados para confirmar ou refutar o efeito insignificante de L. monocytogenes em pequenas fazendas leiteiras.(AU)

La refrigeración es un método importante de conservación de la leche. Sin embargo, la calidad de la leche puede deteriorarse si el producto se refrigera durante períodos prolongados, principalmente debido al crecimiento de bacterias psicrotróficas. Este grupo de microorganismos incluye géneros patógenos, más notablemente Listeria monocytogenes. La detección de esta bacteria en los alimentos es importante, dados sus efectos patógenos sobre la salud humana y animal y también su relevancia económica. Este estudio se centró en detectar la presencia de L. monocytogenes en muestras de leche recolectadas en pequeñas granjas lecheras familiares. Las muestras se cultivaron en agares PALCAM y ALOA para análisis microbiológico y se realizó un análisis molecular por reacción en cadena de la polimerasa para la detección de L. monocytogenes. A pesar de los resultados negativos obtenidos en ambos análisis, se recomiendan más estudios para confirmar o refutar el efecto insignificante de L. monocytogenesen pequeñas granjas lecheras.(AU)

Nervous form of listeriosis in buffaloes / Listeriose nervosa em búfalos

ABSTRACT: Listeriosis is a disease that affects several animal species, including humans, and has three different forms of presentation: encephalic, reproductive, or septicemic. The nervous form is caused mainly by the bacterium Listeria monocytogenes. In Brazil, this disease has already been described in sheep, goats, and cattle. There are no reports of the disease in buffaloes in Brazil and worldwide. The objective of this study was to describe an outbreak of listeric meningoencephalitis in buffaloes in the state of Pará, Brazil. The outbreak occurred in a property located in the municipality of Bujaru, in the eastern Amazon, from May to July 2016. In a herd of 47 buffaloes, three animals (Cases 1, 2 and 3), aged <40 days, presented a neurological condition with locomotion difficulty characterized by paralysis of the four limbs, hypoesthesia, lateral recumbency, and death. Morbidity was 6.38% and lethality was 100%. At necropsy, no significant macroscopic lesions were found. Samples of the central nervous system were collected, fixed in 10% buffered formalin, and routinely processed for histopathological analysis. The main microscopic changes observed were unilateral microabscesses in the brainstem composed predominantly of mononuclear cells, with fewer polymorphonuclear cells, and perivascular cuffs composed mostly of mononuclear cells and few neutrophils. Samples of Cases 1 and 2 revealed Gram-positive bacteria in the areas of necrosis by the Gram's stain technique. Samples of Case 1 were positive in immunohistochemistry for L. monocytogenes. Diagnosis of the nervous form of listeriosis was based on epidemiological data, clinical profile, and immunostaining for Listeria monocytogenes. Results showed that listeriosis should be considered in the differential diagnosis in buffaloes with nervous signs.

RESUMO: A listeriose é uma doença que afeta várias espécies animais, incluindo o homem, e possui três formas diferentes de apresentação: nervosa, abortiva ou septicêmica. A forma nervosa é causada principalmente pela bactéria Listeria monocytogenes. No Brasil a doença já foi descrita em bovinos, ovinos e caprinos, mas não foram encontrados relatos desta doença em búfalos no Brasil e no mundo. O objetivo deste trabalho foi descrever um surto de listeriose nervosa em búfalos no estado do Pará, Brasil. O surto ocorreu de maio a julho de 2016, em uma propriedade localizada no município de Bujaru, na Amazônia Oriental. Três bubalinos de um total de 47 animais (Casos 1, 2 e 3), menores de 40 dias, apresentaram um quadro clínico neurológico caracterizado por dificuldade de locomoção, paralisia dos quatro membros, diminuição da sensibilidade cutânea, decúbito lateral e morte. A morbidade foi de 6,38% e a letalidade de 100%. Na necropsia não foram encontradas lesões macroscópicas significativas. Amostras do sistema nervoso central foram coletadas e fixadas em formalina tamponada a 10% e processadas rotineiramente para análise histopatológica. As principais alterações microscópicas observadas foram microabscessos unilaterais no tronco encefálico, compostos predominantemente por células mononucleares, com menor número de polimorfonucleares, e manguitos perivasculares compostos predominantemente por células mononucleares e poucos neutrófilos. Amostras dos Casos 1 e 2 revelaram bactérias Gram positivas nas áreas de necrose na técnica de Gram. Amostras do Caso 1 resultaram positivas na imuno-histoquímica para L. monocytogenes. O diagnóstico da forma nervosa da listeriose foi baseado nos dados epidemiológicos, no quadro clínico patológico e na imunomarcação para Listeria monocytogenes. Os resultados demostram que a listeriose deve ser considerada no diagnóstico diferencial em bubalinos com sinais nervosos.

Nervous form of listeriosis in buffaloes / Listeriose nervosa em búfalos

Listeriosis is a disease that affects several animal species, including humans, and has three different forms of presentation: encephalic, reproductive, or septicemic. The nervous form is caused mainly by the bacterium Listeria monocytogenes. In Brazil, this disease has already been described in sheep, goats, and cattle. There are no reports of the disease in buffaloes in Brazil and worldwide. The objective of this study was to describe an outbreak of listeric meningoencephalitis in buffaloes in the state of Pará, Brazil. The outbreak occurred in a property located in the municipality of Bujaru, in the eastern Amazon, from May to July 2016. In a herd of 47 buffaloes, three animals (Cases 1, 2 and 3), aged <40 days, presented a neurological condition with locomotion difficulty characterized by paralysis of the four limbs, hypoesthesia, lateral recumbency, and death. Morbidity was 6.38% and lethality was 100%. At necropsy, no significant macroscopic lesions were found. Samples of the central nervous system were collected, fixed in 10% buffered formalin, and routinely processed for histopathological analysis. The main microscopic changes observed were unilateral microabscesses in the brainstem composed predominantly of mononuclear cells, with fewer polymorphonuclear cells, and perivascular cuffs composed mostly of mononuclear cells and few neutrophils. Samples of Cases 1 and 2 revealed Gram-positive bacteria in the areas of necrosis by the Gram's stain technique. Samples of Case 1 were positive in immunohistochemistry for L. monocytogenes. Diagnosis of the nervous form of listeriosis was based on epidemiological data, clinical profile, and immunostaining for Listeria monocytogenes. Results showed that listeriosis should be considered in the differential diagnosis in buffaloes with nervous signs.(AU)

A listeriose é uma doença que afeta várias espécies animais, incluindo o homem, e possui três formas diferentes de apresentação: nervosa, abortiva ou septicêmica. A forma nervosa é causada principalmente pela bactéria Listeria monocytogenes. No Brasil a doença já foi descrita em bovinos, ovinos e caprinos, mas não foram encontrados relatos desta doença em búfalos no Brasil e no mundo. O objetivo deste trabalho foi descrever um surto de listeriose nervosa em búfalos no estado do Pará, Brasil. O surto ocorreu de maio a julho de 2016, em uma propriedade localizada no município de Bujaru, na Amazônia Oriental. Três bubalinos de um total de 47 animais (Casos 1, 2 e 3), menores de 40 dias, apresentaram um quadro clínico neurológico caracterizado por dificuldade de locomoção, paralisia dos quatro membros, diminuição da sensibilidade cutânea, decúbito lateral e morte. A morbidade foi de 6,38% e a letalidade de 100%. Na necropsia não foram encontradas lesões macroscópicas significativas. Amostras do sistema nervoso central foram coletadas e fixadas em formalina tamponada a 10% e processadas rotineiramente para análise histopatológica. As principais alterações microscópicas observadas foram microabscessos unilaterais no tronco encefálico, compostos predominantemente por células mononucleares, com menor número de polimorfonucleares, e manguitos perivasculares compostos predominantemente por células mononucleares e poucos neutrófilos. Amostras dos Casos 1 e 2 revelaram bactérias Gram positivas nas áreas de necrose na técnica de Gram. Amostras do Caso 1 resultaram positivas na imuno-histoquímica para L. monocytogenes. O diagnóstico da forma nervosa da listeriose foi baseado nos dados epidemiológicos, no quadro clínico patológico e na imunomarcação para Listeria monocytogenes. Os resultados demostram que a listeriose deve ser considerada no diagnóstico diferencial em bubalinos com sinais nervosos.(AU)

Resistência antimicrobiana em isolados de Listeria monocytogenes provenientes de alimentos e ambientes de processamento de alimentos / Antimicrobial resistance in Listeria monocytogenes isolates from food and food processing environments

Diversos estudos relatam distintos níveis de resistência antimicrobiana entre os isolados de L. monocytogenes, o que pode ter implicações no tratamento de listeriose. Este estudo avaliou o perfil de resistência de 30 isolados de L. monocytogenes provenientes de alimentos e ambientes de processamento de alimentos do sul do Brasil. Todos os isolados apresentaram resistência ao ácido nalidíxico e a cefoxitina, além de ter sido observada alta ocorrência de isolados resistentes à clindamicina. Para alguns antimicrobianos (rifampicina, tetraciclina, eritromicina, estreptomicina, meropenem, trimetoprim-sulfametoxazol) foi detectado baixo percentual de resistência e, para os demais antimicrobianos testados, não foi observada resistência. Como conclusão, apesar de ter sido observado perfil de resistência para alguns antimicrobianos, os isolados foram suscetíveis aos antimicrobianos comumente utilizados no tratamento de listeriose.(AU)

Resistência antimicrobiana em isolados de Listeria monocytogenes provenientes de alimentos e ambientes de processamento de alimentos / Antimicrobial resistance in Listeria monocytogenes isolates from food and food processing environments

Diversos estudos relatam distintos níveis de resistência antimicrobiana entre os isolados de L. monocytogenes, o que pode ter implicações no tratamento de listeriose. Este estudo avaliou o perfil de resistência de 30 isolados de L. monocytogenes provenientes de alimentos e ambientes de processamento de alimentos do sul do Brasil. Todos os isolados apresentaram resistência ao ácido nalidíxico e a cefoxitina, além de ter sido observada alta ocorrência de isolados resistentes à clindamicina. Para alguns antimicrobianos (rifampicina, tetraciclina, eritromicina, estreptomicina, meropenem, trimetoprim-sulfametoxazol) foi detectado baixo percentual de resistência e, para os demais antimicrobianos testados, não foi observada resistência. Como conclusão, apesar de ter sido observado perfil de resistência para alguns antimicrobianos, os isolados foram suscetíveis aos antimicrobianos comumente utilizados no tratamento de listeriose.

Isolamento de Listeria monocytogenes em salsichas comercializadas no Distrito Federal / Isolation of Listeria monocytogenesin sausages commercialized in the Distrito Federal

A bactéria Listeria monocytogenes é o patógeno causador da listeriose, importante doença transmitida por alimentos que acomete humanos e animais podendo causar morte. Foram coletadas 100 amostras de salsicha de mercados do Distrito Federal. A metodologia usada para o isolamento foi a descrita na Instrução Normativa Nº 40 do Ministério da Agricultura, Pecuária e Abastecimento. As amostras que apresentaram motilidade característica de Listeria sp p. foram submetidas a técnica de PCR para confirmação da espécie L. monocytogenes. Os resultados positivos para Listeria sp p. foram vistos em 14 amostras e em 5 confirmou-se a presença de L. monocytogenes. Através dos resultados desse experimento conclui-se que salsichas podem estar contaminadas com bactérias do gênero Listeria sp p. e L. monocytogenes, oferecendo risco de listeriose aos consumidores.(AU)

Isolamento de Listeria monocytogenes em salsichas comercializadas no Distrito Federal / Isolation of Listeria monocytogenesin sausages commercialized in the Distrito Federal

A bactéria Listeria monocytogenes é o patógeno causador da listeriose, importante doença transmitida por alimentos que acomete humanos e animais podendo causar morte. Foram coletadas 100 amostras de salsicha de mercados do Distrito Federal. A metodologia usada para o isolamento foi a descrita na Instrução Normativa Nº 40 do Ministério da Agricultura, Pecuária e Abastecimento. As amostras que apresentaram motilidade característica de Listeria sp p. foram submetidas a técnica de PCR para confirmação da espécie L. monocytogenes. Os resultados positivos para Listeria sp p. foram vistos em 14 amostras e em 5 confirmou-se a presença de L. monocytogenes. Através dos resultados desse experimento conclui-se que salsichas podem estar contaminadas com bactérias do gênero Listeria sp p. e L. monocytogenes, oferecendo risco de listeriose aos consumidores.

First report of an outbreak of cerebral coenurosis in Dhofari goats in Oman / Primeiro relato de um surto de coenurose cerebral em cabras Dhofari em Omã

This study documented the first outbreak of cerebral coenurosis in goats in Salalah, southern Oman. Deaths of 130 (16.6%) adult native goats in a herd (n=780) were reported from January to June 2017. Affected goats showed various nervous signs ended by death. Investigations for thiamine deficiency, polioencephalomalacia, caprine arthritis encephalitis, and listeriosis were negative. Upon necropsy, multiple (1-4) thin-walled cysts 2-3.5 cm in diameter containing clear fluid with numerous clusters of protoscolices in the cerebrum and cerebellum had replaced the brain parenchyma, causing space-occupying lesions. Parasitologically, the recovered cysts were Coenurus cerebralis, based on the arrangement of protoscolices, and the number and size of their hooks. Morphologically, each protoscolex had four suckers and a rostellum with double-crown hooks. The large and small hooks were 157.7±0.5 µm and 115±0.6 µm in length, respectively. Histopathologically, the parasite destroyed the affected tissues associated with multifocal to diffuse lymphocytic, non-suppurative meningoencephalitis; ischemic neuronal necrosis; and malacia. This is the first report of cerebral coenurosis in livestock in Oman, which should alert the local public health authorities for the application of prevention and control measures.(AU)

Este estudo documentou o primeiro surto de coenurose cerebral em cabras em Salalah, Oman. A morte de 130 (16,6%) caprinos adultos nativos (n=780) foi relatada de janeiro a junho de 2017. As cabras afetadas mostraram distúrbios neurológicos, que culminaram em óbito. Investigações para deficiência de tiamina, polioencefalomalácia, encefalite por artrite caprina e listeriose foram negativas. Na necropsia, múltiplos (1-4) cistos de paredes finas com 2-3,5 cm de diâmetro contendo líquido claro com numerosos aglomerados de protoescólices no cérebro e no cerebelo haviam substituído o parênquima cerebral, causando compressão nas estruturas adjacentes. Os cistos recuperados foram identificados como sendo de Coenurus cerebralis, com base no arranjo dos protoescólices, e no número e tamanho de seus ganchos. Morfologicamente, cada protoescólice tinha quatro ventosas e um rostelo com dupla coroa de ganchos. Os ganchos grandes e pequenos tinham 157,7±0,5 µm e 115±0,6 µm de comprimento, respectivamente. Histopatologicamente, o parasita causou a destruição dos tecidos afetados associada à meningoencefalite linfocítica não-supurativa, que variou de multifocal a difusa, necrose neuronal isquêmica e malacia. Este é o primeiro relato de coenurose em ruminantes no Oman, o que deve servir de alerta para as autoridades locais da área de saúde para a aplicação de medidas de prevenção e controle.(AU)

Nitric oxide synthase expression in naturally infected sheep brain with Listeria monocytogenes and relationship with cell death

Background: Nitric oxide is synthesized from L-arginine and catalyzed by a family of NOS. There are three different NOS isoforms: neuronal (nNOS), inducible (iNOS) and endothelial (eNOS). Nitric oxide is an important apoptosis regulator in mammalian system that can induce and prevent apoptosis depending on levels of NO production and environmental conditions of the cell. NOS expression and its relationship with apoptosis has not been well elucidated in listerial meningoencephalitis in sheep. The aim of this study was to investigate eNOS and iNOS expressions in the brain of sheep with natural listeriosis and to compare them with apoptosis which is shaped in the region.Materials, Methods & Results: In the study, formalin fixed and paraffin embedded brainstem tissue from 25 sheep naturally infected with LM were used from archives. Five μm-thick section was taken from each block. Histopathologically, sections were stained with H&E. Five normal sheep brain tissues were used as control. At the end of the study, Histopathologically in brainstem tissue infected with LM, multifocal microabscesses in different sizes mixed with neutrophils and macrophages were detected and perivascular mononuclear cell infiltration and meningitis characterized by mononuclear cell infiltration were found. All sections were also immunohistochemically stained with LM, eNOS and iNOS antibodies. In addition, TUNEL method was used to determine apoptosis in brain tissues. As a result of immunostaining, listeria immunoreactivity was observed in microabscesses. The Listeria antigens were detected mainly in the cytoplasm of the neutrophils and macrophages and located extracellulary in microabscesses. Both eNOS and iNOS immunoreactivity were observed in very few neurons and glial cells in normal control sheep. Neurons and glial cells in brain tissues of infected animals stained with eNOS and iNOS.[...][

Nitric oxide synthase expression in naturally infected sheep brain with Listeria monocytogenes and relationship with cell death

Background: Nitric oxide is synthesized from L-arginine and catalyzed by a family of NOS. There are three different NOS isoforms: neuronal (nNOS), inducible (iNOS) and endothelial (eNOS). Nitric oxide is an important apoptosis regulator in mammalian system that can induce and prevent apoptosis depending on levels of NO production and environmental conditions of the cell. NOS expression and its relationship with apoptosis has not been well elucidated in listerial meningoencephalitis in sheep. The aim of this study was to investigate eNOS and iNOS expressions in the brain of sheep with natural listeriosis and to compare them with apoptosis which is shaped in the region.Materials, Methods & Results: In the study, formalin fixed and paraffin embedded brainstem tissue from 25 sheep naturally infected with LM were used from archives. Five μm-thick section was taken from each block. Histopathologically, sections were stained with H&E. Five normal sheep brain tissues were used as control. At the end of the study, Histopathologically in brainstem tissue infected with LM, multifocal microabscesses in different sizes mixed with neutrophils and macrophages were detected and perivascular mononuclear cell infiltration and meningitis characterized by mononuclear cell infiltration were found. All sections were also immunohistochemically stained with LM, eNOS and iNOS antibodies. In addition, TUNEL method was used to determine apoptosis in brain tissues. As a result of immunostaining, listeria immunoreactivity was observed in microabscesses. The Listeria antigens were detected mainly in the cytoplasm of the neutrophils and macrophages and located extracellulary in microabscesses. Both eNOS and iNOS immunoreactivity were observed in very few neurons and glial cells in normal control sheep. Neurons and glial cells in brain tissues of infected animals stained with eNOS and iNOS.[...][(AU)