The disease listeriosis is caused by Listeria monocytogenes. This common food-borne disease has been responsible for about 0.1 to 10 cases per million inhabitants per year. However, this disease is serious with its high fatality rates of 20% - 30%, and 40% of all cases reported have been in pregnant women suffered from a foetal abortion. Recently the organism has acquired resistance to antibiotic treatment and the development of an alternative treatment is necessary. Class IIa bacteriocins such as leucocin A have been shown to be active against L. monocytogenes. However, the leucocin A receptor molecule responsible for growth inhibition within L. monocytogenes remains unclear. Various studies have implicated the mannose PTS permease (EIIt Man) of L. monocytogenes as the putative receptor for class IIa bacteriocins. The results from studies reviewed indicate that the EIIt Man of L. monocytogenes could be the chiral receptor needed for bacteriocin interaction at the surface of targeted cells. Specifically, the membrane associated IIDMan and IICMan subunits were implicated in direct interaction with class IIa bacteriocins. Our study focused on cloning, expression and purification of the subunits of the mannose PTS permease of L. monocytogenes EGD. Primers were designed to amplify the subunit genes of the mptACD operon. The mptC, mptD and mptAB genes which were then successfully cloned into pET28a expression vector and transformed into E. coli JM109(DE3) host strain. Recombinant plasmids were screened using colony PCR. Subsequently recombinant pET28-C, pET28-D and pET28-AB was once again transformed and expressed in the E. coli BL21(DE3) pLysS expression host strain. After an induction at 30°C for 5 hours, IICMan and IIDMan were found to be expressed in the cell membrane, whilst IIABMan was expressed in the cytosol of the host expression strain. Membrane proteins His-IICMan, His- IIDMan, and cytosol associated His-IIABMan were purified using Ni2+-NTA affinity chromatography. Results for His-IICMan yielded a 28 kDa protein and a 55 kDa co-purified protein. Results for His-IIDMan yielded a 31 kDa protein and a 60 kDa co-purified protein. Results for His-IIABMan yielded a 35 kDa protein and a 68 kDa co-purified protein. A western blot analysis revealed that all proteins purified carried an attached His-tag as detected by an anti-mouse peroxidase conjugate anti-His-tag antibody. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

Orientador: Helio Langoni / Resumo: A refrigeração é um importante método de conservação do leite, porém quando ocorre por longo período, a qualidade desse produto pode ser alterada devido, principalmente, a multiplicação de bactérias psicrotróficas. Dentro desse grupo de micro-organismos, entre os gêneros patogênicos, destaca-se Listeria monocytogenes. A identificação deste patógeno em alimentos é de interesse não somente pelos efeitos nocivos aos animais, mas também pelos efeitos na saúde humana. O objetivo do presente estudo foi investigar a presença de L. monocytogenes em 95 amostras de leite bovino de conjunto de pequenas propriedades leiteiras de agricultura familiar. As amostras de leite foram cultivadas nos meios seletivos de PALCAM e ALOA e as colônias características foram avaliadas por métodos fenotípicos e moleculares, pela Reação em Cadeia da Polimerase (PCR), para detecção de L. monocytogenes. Apesar dos resultados negativos no cultivo e na PCR, a patogenicidade de L. monocytogenes para os animais e os riscos em saúde pública, justificam estudos continuados para vigilância epidemiológica do agente em produtos de origem animal como o leite. / Abstract: 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 (PCR) 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. / Mestre

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Listeria monocytogenes est une bactérie pathogène intracellulaire facultative responsable d’une pathologie grave, la listériose. Si de très nombreux travaux ont permis de caractériser les mécanismes de virulence de cette bactérie, il existe peu de données sur les mécanismes conduisant au portage asymptomatique de L. monocytogenes dans les hôtes mammifères. L’un de ces mécanismes pourrait être une phase de persistance intracellulaire. Lors d’infections prolongées de cellules épithéliales humaines en culture, comme des hépatocytes et des cellules de trophoblastes, L. monocytogenes change de mode de vie intracellulaire. Après la phase active de dissémination de cellule en cellule, les bactéries arrêtent de polymériser l’actine et se retrouvent piégées dans des vacuoles à simple membrane marquées par la protéine endosomale LAMP1. L’objectif de ma thèse était de caractériser ces « Listeria-Containing Vacuoles » (LisCVs). Nous avons montré que les LisCVs sont des compartiments acides, partiellement-dégradatifs, marquées par la protéase lysosomale cathépsine D. Leur formation coïncide avec la disparition du facteur de polymérisation d’actine ActA de la surface bactérienne et la capture des bactéries cytosoliques dépourvues d’actine par des membranes cellulaires. Dans ces compartiments, les bactéries entrent en croissance ralentie ; une sous-population résiste aux stress et peut survivre au-delà de trois jours d’infection. L’utilisation de la gentamicine lors du protocole d’infection n’est pas responsable de la formation des LisCVs. Cependant, cet antibiotique permet la sélection des bactéries vacuolaires, en inhibant spécifiquement la croissance des bactéries cytosoliques. La formation des LisCVs n’est pas spécifique des souches de laboratoire. Toutefois l’efficacité du phénomène pourrait diverger selon les séquençotypes des souches de L. monocytogenes. Les bactéries vacuolaires ont la capacité de sortir des vacuoles et de retourner vers un état motile et réplicatif, après le passage des cellules infectées. Lorsque l’expression du gène actA reste inactive, comme dans les mutants ∆actA, des formes de Listeria vacuolaires persistent dans les cellules hôtes dans un état viable mais non cultivable (VBNC). Ces formes VBNC peuvent être transmises au cours des divisions des cellules hôtes. L’ensemble de ces résultats révèle une nouvelle phase de persistance dans le processus infectieux intracellulaire de L. monocytogenes lors des infections prolongées de certaines cellules épithéliales. Cette propriété pourrait contribuer au portage asymptomatique de ce pathogène dans les tissus épithéliaux, allonger la période d'incubation de la listériose, et rendre les bactéries tolérantes à l’antibiothérapie. / Listeria monocytogenes is a facultative intracellular pathogenic bacterium responsible for a serious disease, listeriosis. Although much work has been done to characterize the virulence mechanisms of this bacterium, there is little data on the mechanisms leading to the asymptomatic carriage of L. monocytogenes in mammalian hosts. One of these mechanisms could be a phase of intracellular persistence. During prolonged infections of human epithelial cells in culture, such as hepatocytes and trophoblast cells, L. monocytogenes changes its intracellular lifestyle. After the active phase of cell-to-cell spread, the bacteria stop polymerizing actin and become trapped in single-membrane vacuoles labeled with the endosomal protein LAMP1.The aim of my thesis was to characterize these "Listeria-Containing Vacuoles" (LisCVs). We have shown that LisCVs are acidic, partially degradative compartments, labeled by the lysosomal protease cathepsin D. Their formation coincides with the disappearance of actin polymerization factor ActA from the bacterial surface and the capture of actin-free cytosolic bacteria by cell membranes. In these compartments, bacterial growth is slowed; a subpopulation is resistant to stress and can survive beyond three days of infection. The use of gentamicin during the infection protocol is not responsible for the formation of LisCVs. However, this antibiotic allows selection of vacuolar bacteria, by specifically inhibiting the growth of cytosolic bacteria. The formation of LisCVs is not specific to laboratory strains. However, the efficacy of the phenomenon could diverge according to the sequence types of L. monocytogenes strains. Vacuolar bacteria have the ability to exit the vacuoles and return to a motile and replicative state during the subculture of infected cells. When expression of the actA gene remains inactive, as in ΔactA mutants, vacuolar Listeria forms persist in host cells in a viable but non-culturable (VBNC) state. These VBNC forms can be transmitted during host cell divisions. All these results reveal a new phase of persistence in the intracellular infectious process of L. monocytogenes during prolonged infections of a subset of epithelial cells. This property could contribute to asymptomatic carriage of this pathogen in epithelial tissues, extend the incubation period of listeriosis, and make bacteria tolerant to antibiotic therapy.

Listeria monocytogenes is food-borne pathogen that causes listeriosis in individuals with a compromised immune system and pregnant women. This pathogen can survive in anaerobic conditions present in specially packaged foods as well as the gastrointestinal tract. The purpose of this study is to evaluate virulence of L. monocytogenes F2365 in anaerobic conditions. Another goal of this study is to establish gerbils as the ideal animal model since descrepancies exist in current models. Gerbils were orally infected with one of four doses: 1) phosphate buffered saline, 2) 5X106CFU aerobic dose, 3) 5X108CFU aerobic dose, and 4) 5X106CFU anaerobic dose. Results indicate anaerobically cultured F2365 colonized the intestines consistently throughout the study unlike aerobic cultures. Additionally, intestinal damage was observed in challenged gerbils. Further goals include evaluating how viurlence is influenced in anaerobic conditions with varying bile concentrations and pH levels.

Fresh produce may be contaminated by bacterial pathogens including Listeria monocytogenes during harvesting, packaging, or transporting. Consumers may be at risk of foodborne illness if produce become contaminated. In this project, a cavitation process (formation of bubbles in water) was studied to determine the efficacy of microbubbles at inactivating the pathogen L. monocytogenes on stainless steel and the surface of fresh cucumber and avocado. Stainless steel coupons (1"×2''), cucumber, and avocado surfaces were inoculated with L. monocytogenes (LCDC strain). After 1, 24 or 48 h, loosely attached cells were washed off, and inoculated areas were targeted by microbubbles (~0.5 mm dia.) through an air stone (1.0 L air/min) for 1, 2, 5, or 10 min. After treatment, samples were transferred to sterile containers and serial diluted in peptone water and plated on Oxford agar. Plates were incubated for 48 h at 35℃. For stainless steel, the mean log reduction of L. monocytogenes (48 h drying) peaked at 2.95 after 10 min of microbubbles when compared to a no bubble treatment. After 48 h pathogen drying, cucumbers treated for 10 min resulted in a 1.78 mean log reduction of L. monocytogenes. For avocados, the mean log reduction of L. monocytogenes (24 hr drying) peaked at 1.65 after 10 min of microbubbles. This cavitation treatment (10 mins) reduced over 95% of L. monocytogenes on the surface of stainless steel, cucumber, and avocado. Microbubble applications may be an effective, economical, and environmental-friendly way to remove L. monocytogenes and possibly other bacterial pathogens from food impact surfaces and the surface of whole, intact fresh produce. / Master of Science in Life Sciences / Fresh produce may be contaminated by bacterial pathogens like Listeria monocytogenes during the process of harvesting, packaging, or transport. Consuming contaminated fresh produce without enough and proper decontaminated measures, consumers are in risk of being infected with foodborne illness. A cavitation process (formation of bubbles in water) was conducted to determine the efficacy of microbubbles at inactivating the pathogen Listeria monocytogenes on the impact surface of fresh produce (stainless steel), fresh cucumber, and fresh avocado. Stainless steel coupons (1"×2''), fresh cucumbers, and fresh avocados were inoculated respectively with Listeria monocytogenes (LCDC strain). After removing loosely attached pathogen cells on the surface of inoculated steel coupons, cucumbers, and avocados, their inoculated areas were targeted by microbubbles (~0.5 mm dia.) for 1, 2, or 10 minutes, with a constant air flow rate of 1.0 L/min through an air stone. The L. monocytogenes on stainless steel and cucumber, and avocado surfaces was reduced by 95% to 99%. This study suggests that microbubbles may remove, and possibly inactivate, L. monocytogenes effectively from the surface of fresh produce and their impact surfaces. Microbubbles thus could be an effective, economical, and environmental-friendly tool for minimizing produce contamination.

Made available in DSpace on 2014-08-20T14:37:55Z (GMT). No. of bitstreams: 1 dissertacao_marcelo_mendonca.pdf: 563837 bytes, checksum: b7cfe13cc7ba52f1c762a5c48b290205 (MD5) Previous issue date: 2008-03-10 / The food pathogen Listeria monocytogenes is the causative agent of listeriosis, a severe disease that courses with high rates of morbid and mortality. The conventional methods used for detection of this bacterium are laborious and expensive, requiring several days for final identification. Monoclonal antibody (Mab) based immunoassays used for rapid detection of L. monocytogenes have the advantage of being highly specific, particularly if the MAbs are directed against virulence factors conserved among pathogenic strains. Membrane protein internalin A (InlA) from L. monocytogenes is a well characterized virulence factor involved in its adhesion to and internalization in non-phagocytic cells of the host. This work reports on the production and characterization of a panel of MAbs against InlA of L. monocytogenes. For MAbs production, isogenic BALB/c mice were immunized with a recombinant fragment of InlA (rInlA) expressed in Escherichia coli. Five hybridomas secreting MAbs anti-rInlA were generated. The MAbs affinity constants (Ka) were among 7x107 L.mol-1 e 4x106 L.mol-1. The MAbs recognized specifically the species L. monocytogenes by indirect ELISA and Western blot. In indirect ELISA using live or heat-killed L. monocytogenes the MAbs recognized InlA only in bacteria that were grown in Listeria enrichment broth and that were not heated. Western blot analysis revealed that MAbs recognized a band around 88kDa in the L. monocytogenes strains, the molecular mass expected for InlA in its native form. The MAbs produced in this study have potential for use in immunoassays for the detection of L. monocytogenes. / O patógeno alimentar Listeria monocytogenes é o agente causador da listeriose, uma doença severa que cursa com altas taxas de morbidade e de mortalidade. Os métodos convencionais empregados para detecção desta bactéria são laboriosos e onerosos, requerendo vários dias para sua identificação final. Imunoensaios usados para detecção rápida desta bactéria que utilizam anticorpos monoclonais (MAbs) tem como vantagem a alta especificidade, especialmente quando os MAbs são dirigidos contra fatores de virulência conservados nas cepas patogênicas. Entre os diversos fatores de virulência de L. monocytogenes, a proteína de membrana internalina A (InlA), necessária para a aderência e internalização em células não fagocíticas do hospedeiro, é umas das mais bem caracterizadas. Neste trabalho é relatado a produção e caracterização de um painel de MAbs contra a InlA. Na produção dos MAbs, camundongos isogênicos BALB/c foram imunizados com um fragmento recombinante da proteína InlA (rInlA) expresso em Escherichia coli. Foram gerados cinco hibridomas secretores de MAbs anti-rInlA. A constante de afinidade (Ka) dos cinco MAbs situou-se entre 7x107 L.mol-1 e 4x106 L.mol-1. Na caracterização por ELISA indireto e Western blot os MAbs reconheceram especificamente a espécie L. monocytogenes. No ELISA indireto com células de L. monocytogenes vivas ou mortas por tratamento térmico, os MAbs reconheceram somente a InlA nas bactérias que não sofreram tratamento térmico e que foram cultivadas em caldo de enriquecimento para Listeria (LEB). No Western blot os MAbs reconheceram uma banda de aproximadamente 88kDa nas cepas de L. monocytogenes, massa molecular esperada para a proteína InlA em sua forma nativa. Os resultados obtidos nesse trabalho indicam que os MAbs produzidos possuem potencial para serem utilizados em imunoensaios de detecção de L. monocytogenes.

Thesis (M. Tech. Environmental health) -- Central University of technology, Free State, 2011 / Microbial pathogens play an important role in the food industry where they could cause disease and subsequently significant economic losses. Limited information is available on the situation with regard to Listeria in food products in South Africa. However, much research is being done in the rest of the world on Listeria indicating serious problems as a result of resistance development against various antimicrobial agents, including the organic acids. It is hypothesised that the situation with regard to resistance development may be more serious than generally admitted. Isolation of 200 different food samples was done by using a slightly modified EN ISO 11290-1/A1:2004 standard method. Identification of presumptive positive colonies was confirmed as Listeria by API (Analytical profile index) Listeria. API positive cultures were subjected to 16S rDNA sequencing to compare and confirm identification. Isolates and standard strains were screened for resistance to food preservatives such as organic acids and antibiotics used in the current treatment regime for Listeria infections. The organisms evaluated included isolated strains namely Listeria monocytogenes, Listeria welshimeri, Listeria innocua and their corresponding ATCC (American type culture colletion) strains. An agar dilution method as described by the Clinical and Laboratory Standard Institute (CLSI) was used to determine the minimum inhibitory concentrations (MICs) of 11 antibiotics and 13 organic acids and salts for all the isolates. Overall antibiotic susceptibility patterns of all the isolates indicated high level susceptibility to all the antibiotics tested. Susceptibility to all the organic acids was notably reduced at pH 7 in all the isolates and control strains. Eight highly susceptible strains were selected for induction and represented each of the species isolated. These isolates were exposed to increasing concentrations of three antibiotics and three organic acids. MICs were again determined for all the induced strains for five antibiotics and three organic acids. Proteins extracted from the induced strains were separated on discontinuous SDS-PAGE slab gels to generate total protein profiles. Notable variations were observed in MICs, although induction with antibiotics as well as organic acids did not result in general resistance development. However, evidence was provided that continuous exposure to antimicrobial agents may cause Listeria spp. to develop resistance to different antimicrobial agents. Further research and in depth studies on mechanisms involved in the development of resistance to food preservatives would, therefore, be required. Finally, it is concluded that Listeria monocytogenes may be a possible threat in the Central South African food industry, which deserves more attention. The situation may actually pose a problem that is overseen, because only a small percentage of people that get sick from food, would seek medical advice.

Distúrbios do sistema nervoso central (SNC) em ruminantes abrangem um importante grupo de enfermidades responsáveis por grandes perdas econômicas em todo o mundo. As principais doenças neurológicas causadas por bactérias em ruminantes e que envolvem processos inflamatórios incluem listeriose, leptomeningites e meningoencefalites supurativas, abscessos cerebrais e medulares, empiema basilar e neurotuberculose. Esta dissertação teve por objetivo a caracterização epidemiológica, patológica, microbiológica e imuno-histoquímica das doenças inflamatórias de origem bacteriana que afetam o SNC de ruminantes no Rio Grande do Sul. Foi realizado um estudo retrospectivo no período compreendido entre janeiro de 1996 a dezembro de 2015, onde um total de 3.274 bovinos, 596 ovinos e 391 caprinos foram avaliados. Destes, 219 bovinos, 21 ovinos e sete caprinos foram diagnosticados com doenças inflamatórias no SNC. As doenças neurológicas inflamatórias de origem bacteriana totalizaram 60 casos divididos em 34 bovinos, 19 ovinos e sete caprinos, os quais foram subdivididas em: meningoencefalite por L. monocytogenes (oito ovinos, cinco caprinos e quatro bovinos), leptomeningite e meningoencefalite supurativa (14 bovinos, dois caprinos e um ovino), abscessos cerebrais (seis bovinos e dois ovinos) e medulares (sete ovinos), empiema basilar (quatro bovinos e um ovino) e neurotuberculose (seis bovinos). O exame imuno-histoquímica foi realizado em todos os casos diagnosticados com listeriose (anticorpo anti-L. monocytogenes), meningite e meningoencefalite supurativa (anticorpo anti-Escherichia coli) e neurotuberculose (anticorpo anti-Mycobacterium tuberculosis). A meningoencefalite por L. monocytogenes representou a principal enfermidade neurológica em ovinos e caprinos, seguido dos abscessos medulares em ovinos. Nos bovinos, a leptomeningite e meningoencefalite supurativa foi a doença neurológica mais prevalente para a espécie, frequentemente relacionada com a falha na transmissão da imunidade passiva. O empiema basilar, frequentemente diagnosticado em bezerros, está diretamente relacionado com o manejo do desmame interrompido através da utilização de tabuletas nasais. A neurotuberculose causada por Mycobacterium spp. é uma importante doença neurológica em bovinos jovens e deve ser considerada como diagnóstico diferencial de doenças neurológicas. Dos dados analisados neste período, as doenças neurológicas inflamatórias bacterianas representaram um total de 24,3% entre as doenças neurológicas inflamatórias diagnosticadas neste período e, com isso, conclui-se que representam importantes causas de mortalidade para os ruminantes domésticos. / Central nervous system (CNS) diseases are worldwide economically important conditions in ruminants. The main neurological bacterial diseases which involve inflammation in ruminants are listeriosis, suppurative leptomeningitis and meningoencephalitis, brain and spinal cord abscesses, basilar empyema and neurotuberculosis. This study aim to describe the epidemiological, pathological, microbiological and immunohistochemical findings of the bacterial inflammatory diseases that affect the CNS of ruminants in Rio Grande do Sul state. A retrospective study was performed from January 1996 to December 2015, during which samples of 3.274 cattle, 596 sheep and 391 goats were evaluated. Of these, 219 cattle, 21 sheep and seven goats were diagnosed with inflammatory diseases affecting the CNS. The neurological inflammatory bacterial diseases accounted for 60 cases, which corresponded to 34 cases in cattle, 19 in sheep and seven in goats. These were further subdivided in: meningoencephalitis by L. monocytogenes (eigth sheep, five goats and four cattle), suppurative leptomeningitis and meningoencephalitis (14 cattle, two goats and one sheep), brain abscesses (six cattle and two sheep) and spinal cord (seven sheep), basilar empyema (four cattle and one sheep) and neurotuberculosis (six cattle). Immunohistochemical exam was performed in all cases diagnosed as listeriosis (antibody anti-L. monocytogenes), as suppurative leptomeningitis and meningoencephalitis (antibody anti-E. coli), and as neurotuberculosis (antibody anti-Mycobacterium tuberculosis). L. monocytogenes meningoencephalitis was the main neurological disease in sheep and goats, followed by spinal cord abscesses in sheep. In cattle, suppurative leptomeningitis and meningoencephalitis was the most frequent neurological disease, and its ocorrunce is related to the failure in passive immunity transmission. Basilar empyema is frequently diagnosed in calves and is directly related to early weaning handling through the use of nose-flaps. Neurotuberculosis caused by Mycobacterium spp. is an important neurological disease in young cattle and should be consired as a differential diagnosis of granulomatous meningoencephalitis. During the described period, neurological inflammatory bacterial diseases accounted for 24.3% of the neurological inflammatory diseases, and, thus, these are important causes of death in domestic ruminants.

Distúrbios do sistema nervoso central (SNC) em ruminantes abrangem um importante grupo de enfermidades responsáveis por grandes perdas econômicas em todo o mundo. As principais doenças neurológicas causadas por bactérias em ruminantes e que envolvem processos inflamatórios incluem listeriose, leptomeningites e meningoencefalites supurativas, abscessos cerebrais e medulares, empiema basilar e neurotuberculose. Esta dissertação teve por objetivo a caracterização epidemiológica, patológica, microbiológica e imuno-histoquímica das doenças inflamatórias de origem bacteriana que afetam o SNC de ruminantes no Rio Grande do Sul. Foi realizado um estudo retrospectivo no período compreendido entre janeiro de 1996 a dezembro de 2015, onde um total de 3.274 bovinos, 596 ovinos e 391 caprinos foram avaliados. Destes, 219 bovinos, 21 ovinos e sete caprinos foram diagnosticados com doenças inflamatórias no SNC. As doenças neurológicas inflamatórias de origem bacteriana totalizaram 60 casos divididos em 34 bovinos, 19 ovinos e sete caprinos, os quais foram subdivididas em: meningoencefalite por L. monocytogenes (oito ovinos, cinco caprinos e quatro bovinos), leptomeningite e meningoencefalite supurativa (14 bovinos, dois caprinos e um ovino), abscessos cerebrais (seis bovinos e dois ovinos) e medulares (sete ovinos), empiema basilar (quatro bovinos e um ovino) e neurotuberculose (seis bovinos). O exame imuno-histoquímica foi realizado em todos os casos diagnosticados com listeriose (anticorpo anti-L. monocytogenes), meningite e meningoencefalite supurativa (anticorpo anti-Escherichia coli) e neurotuberculose (anticorpo anti-Mycobacterium tuberculosis). A meningoencefalite por L. monocytogenes representou a principal enfermidade neurológica em ovinos e caprinos, seguido dos abscessos medulares em ovinos. Nos bovinos, a leptomeningite e meningoencefalite supurativa foi a doença neurológica mais prevalente para a espécie, frequentemente relacionada com a falha na transmissão da imunidade passiva. O empiema basilar, frequentemente diagnosticado em bezerros, está diretamente relacionado com o manejo do desmame interrompido através da utilização de tabuletas nasais. A neurotuberculose causada por Mycobacterium spp. é uma importante doença neurológica em bovinos jovens e deve ser considerada como diagnóstico diferencial de doenças neurológicas. Dos dados analisados neste período, as doenças neurológicas inflamatórias bacterianas representaram um total de 24,3% entre as doenças neurológicas inflamatórias diagnosticadas neste período e, com isso, conclui-se que representam importantes causas de mortalidade para os ruminantes domésticos. / Central nervous system (CNS) diseases are worldwide economically important conditions in ruminants. The main neurological bacterial diseases which involve inflammation in ruminants are listeriosis, suppurative leptomeningitis and meningoencephalitis, brain and spinal cord abscesses, basilar empyema and neurotuberculosis. This study aim to describe the epidemiological, pathological, microbiological and immunohistochemical findings of the bacterial inflammatory diseases that affect the CNS of ruminants in Rio Grande do Sul state. A retrospective study was performed from January 1996 to December 2015, during which samples of 3.274 cattle, 596 sheep and 391 goats were evaluated. Of these, 219 cattle, 21 sheep and seven goats were diagnosed with inflammatory diseases affecting the CNS. The neurological inflammatory bacterial diseases accounted for 60 cases, which corresponded to 34 cases in cattle, 19 in sheep and seven in goats. These were further subdivided in: meningoencephalitis by L. monocytogenes (eigth sheep, five goats and four cattle), suppurative leptomeningitis and meningoencephalitis (14 cattle, two goats and one sheep), brain abscesses (six cattle and two sheep) and spinal cord (seven sheep), basilar empyema (four cattle and one sheep) and neurotuberculosis (six cattle). Immunohistochemical exam was performed in all cases diagnosed as listeriosis (antibody anti-L. monocytogenes), as suppurative leptomeningitis and meningoencephalitis (antibody anti-E. coli), and as neurotuberculosis (antibody anti-Mycobacterium tuberculosis). L. monocytogenes meningoencephalitis was the main neurological disease in sheep and goats, followed by spinal cord abscesses in sheep. In cattle, suppurative leptomeningitis and meningoencephalitis was the most frequent neurological disease, and its ocorrunce is related to the failure in passive immunity transmission. Basilar empyema is frequently diagnosed in calves and is directly related to early weaning handling through the use of nose-flaps. Neurotuberculosis caused by Mycobacterium spp. is an important neurological disease in young cattle and should be consired as a differential diagnosis of granulomatous meningoencephalitis. During the described period, neurological inflammatory bacterial diseases accounted for 24.3% of the neurological inflammatory diseases, and, thus, these are important causes of death in domestic ruminants.