Mannheimia varigena as the etiologic agent of lameness and coronary band lesion in cattle / Mannheimia varigena como agente etiológico de claudicação e lesão na banda coronária em bovinos

Mannheimia varigena was identified as the etiologic agent of lameness and coronary band lesion in 30% of cattle in a farm located in Rio Grande do Sul, Brazil. Swab samples from the lesions were cultured in McConkey Agar and Blood Agar for microbiological identification. Culture growth was submitted to Gram staining and Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) identification. Antimicrobial susceptibility test based on disc diffusion was performed for three antibiotics: ceftiofur, gentamicin and florfenicol. Furthermore, molecular characterization of 16S rDNA gene sequencing was performed and the data was used in a phylogenetic analysis. For that purpose, total DNA was extracted by thermo extraction directly from the bacterial colonies and the polymerase chain reaction (PCR) was performed. Gram-negative Mannheimia varigena strain LBV010/22 was identified as the causative of the lesions. The strain was susceptible to all antibiotics tested. The phylogenetic analysis demonstrated that the analyzed strain is closely related to M. varigena strains from pyelonephritis and respiratory tract. Overall, this is the first report of M. varigena as the causative agent of coronary band injury in bovine. Therefore, our findings show the importance of an accurate microbiological identification of infectious agent in lameness cases in order to prevent the occurrence and perform an appropriate treatment in the future.

Mannheimia varigena foi identificada como agente etiológico de claudicação e lesão de banda coronária em 30% dos bovinos de uma fazenda localizada no Rio Grande do Sul, Brasil. Amostras de swab das lesões foram cultivadas em Ágar McConkey e Ágar Sangue para identificação microbiológica. O crescimento da cultura foi submetido à coloração de Gram e identificação por Espectrometria de Massa de Ionização por Dessorção a Laser Assistida por Matriz (MALDI-TOF MS). O teste de suscetibilidade antimicrobiana baseado na difusão em disco foi realizado para três antibióticos: ceftiofur, gentamicina e florfenicol. Além disso, foi realizada a caracterização molecular do sequenciamento do gene 16S rDNA e o resultado utilizado para análise filogenética. Para tanto, o DNA total foi extraído por termoextração diretamente das colônias bacterianas e uma reação em cadeia da polimerase (PCR) foi realizada. Foi identificada como causadora das lesões a cepa gram-negativa de Mannheimia varigenaLBV010/22. Ela foi suscetível a todos os antibióticos testados. A análise filogenética demonstrou que a cepa analisada está intimamente relacionada às M. varigena presentes em pielonefrite e no trato respiratório. No geral, este é o primeiro relato de M. varigenacomo agente causador de lesão de banda coronária em bovinos. Portanto, nossos achados mostram a importância de uma identificação microbiológica precisa do agente infeccioso nos casos de claudicação, a fim de prevenir a ocorrência e realizar um tratamento adequado no futuro.

Complexo respiratório em vacas leiteiras: uma perspectiva / Respiratory disease complex in dairy cows: a perspective

No presente trabalho, descrevem-se as condições predisponentes que facilitam o surgimento do Complexo Respiratório Bovino (CRB) em vacas leiteiras causado por bactérias, vírus e vermes, tanto no seu curso agudo como crônico, destacando-se os meios e métodos exploratórios mais preponderantes para o diagnóstico clínico, os principais exames complementares, assim como indicações de tratamento.(AU)

It is described the predisposing conditions that facilitates the outcome of cattle respiratory disease in dairy cows caused by bacteria, viruses and worms, either acute or chronic, emphasizing the main clinical exploratory and laboratory methods for its diagnosis, as well as the treatments.(AU)

Complexo respiratório em vacas leiteiras: uma perspectiva / Respiratory disease complex in dairy cows: a perspective

No presente trabalho, descrevem-se as condições predisponentes que facilitam o surgimento do Complexo Respiratório Bovino (CRB) em vacas leiteiras causado por bactérias, vírus e vermes, tanto no seu curso agudo como crônico, destacando-se os meios e métodos exploratórios mais preponderantes para o diagnóstico clínico, os principais exames complementares, assim como indicações de tratamento.

It is described the predisposing conditions that facilitates the outcome of cattle respiratory disease in dairy cows caused by bacteria, viruses and worms, either acute or chronic, emphasizing the main clinical exploratory and laboratory methods for its diagnosis, as well as the treatments.

Microbiota bacteriana e citologia da região traqueobrônquica de bezerros no período neonatal / Bacterial pathogens and cytology or tracheobronchial region in calves during neonatal period

As broncopneumonias são afecções importantes na pecuária mundial, representando uma das principais causas de mortalidade de bezerros nos primeiros meses de vida. As medidas preventivas e terapêuticas adotadas geralmente são baseadas em resultados de estudos internacionais, não se conhecendo as bactérias implicadas nos quadros pneumônicos em animais criados no Brasil. Aliado a isso, no primeiro mês de vida, os bezerros demonstram imaturidade do sistema imune, o que tem sido pouco estudado em quadros pneumônicos. Desta maneira, objetivou-se estudar as broncopneumonias em bezerros neonatos, identificando bactérias do trato respiratório posterior de bezerros sadios e com pneumonias naturalmente adquiridas, bem como analisar citologicamente a resposta pulmonar frente a estes patógenos. Para isso amostras de lavado do trato respiratório foram colhidas por traqueocentese durante o primeiro mês de vida dos animais. Verificou-se que não houve diferença na microbiota traqueobrônquica de bezerros sadios em relação aos doentes, discordando dos relatos da literatura internacional, sendo constituída principalmente por: Staphylococcus sp., Bacillus sp., Streptococcus sp., Pseudomonas aeruginosa e enterobactérias, permitindo inferir que as medidas profiláticas e terapêuticas adotadas internacionalmente possam não ser tão efetivas para as criações brasileiras. Observou-se também que bezerros neonatos têm uma proporção aproximada de 1:1 de macrófagos e neutrófilos na região traqueobrônquica quando saudáveis, atingindo uma relação aproximada de 1:3 durante os quadros de broncopneumonias, sendo estes perfis provavelmente característicos da idade, período conhecido pela imaturidade do sistema imune e agravado por fatores de manejo que favoreçam uma maior inalação de agentes bacterianos.(AU)

Bronchopneumonia is important for world livestock production and one of the major causes of calf mortality during the first months of life. The preventive and therapeutic measures adopted for the disease in calves in Brazil are usually based on the results of international studies; however there is not enough known which bacteria are implicated. In the first month of life calves show immaturity of their immune system, what has been little studied in regard to pneumonia. The present investigation sought to study neonate bronchopneumonia in calves, to identify which bacteria are present in the respiratory tract of healthy and, with naturally acquired pneumonia calves, to analyze the pulmonary cytological response against pathogens. For this purpose, samples of the respiratory tract were collected by tracheocenthesis. It was noted that the microflora of the tracheobronchial region of healthy and diseased calves was the same, but they were different from the one reported by international papers. The flora was constituted mainly by Staphylococcus sp., Bacillus sp., Streptococcus sp., Pseudomonas aeruginosa and enterobacteriae, allowing to infer that the prophylactic and therapeutic measures adopted internationally may not be as effective for the Brazilian condition. It was also found that newborn calves have an approximate ratio of 1:1 of macrophages and neutrophils in the tracheobronchial region when they were healthy, reaching a ratio of approximately 1:3 of macrophages and neutrophils when they were with bronchopneumonia. Probably, these profiles are characteristic of the age, a period when exists immaturity of the immune system and influenced by management factors which lead to greater inhalation of bacterial agents.(AU)

Microbiota bacteriana e citologia da região traqueobrônquica de bezerros no período neonatal / Bacterial pathogens and cytology or tracheobronchial region in calves during neonatal period

As broncopneumonias são afecções importantes na pecuária mundial, representando uma das principais causas de mortalidade de bezerros nos primeiros meses de vida. As medidas preventivas e terapêuticas adotadas geralmente são baseadas em resultados de estudos internacionais, não se conhecendo as bactérias implicadas nos quadros pneumônicos em animais criados no Brasil. Aliado a isso, no primeiro mês de vida, os bezerros demonstram imaturidade do sistema imune, o que tem sido pouco estudado em quadros pneumônicos. Desta maneira, objetivou-se estudar as broncopneumonias em bezerros neonatos, identificando bactérias do trato respiratório posterior de bezerros sadios e com pneumonias naturalmente adquiridas, bem como analisar citologicamente a resposta pulmonar frente a estes patógenos. Para isso amostras de lavado do trato respiratório foram colhidas por traqueocentese durante o primeiro mês de vida dos animais. Verificou-se que não houve diferença na microbiota traqueobrônquica de bezerros sadios em relação aos doentes, discordando dos relatos da literatura internacional, sendo constituída principalmente por: Staphylococcus sp., Bacillus sp., Streptococcus sp., Pseudomonas aeruginosa e enterobactérias, permitindo inferir que as medidas profiláticas e terapêuticas adotadas internacionalmente possam não ser tão efetivas para as criações brasileiras. Observou-se também que bezerros neonatos têm uma proporção aproximada de 1:1 de macrófagos e neutrófilos na região traqueobrônquica quando saudáveis, atingindo uma relação aproximada de 1:3 durante os quadros de broncopneumonias, sendo estes perfis provavelmente característicos da idade, período conhecido pela imaturidade do sistema imune e agravado por fatores de manejo que favoreçam uma maior inalação de agentes bacterianos.

Bronchopneumonia is important for world livestock production and one of the major causes of calf mortality during the first months of life. The preventive and therapeutic measures adopted for the disease in calves in Brazil are usually based on the results of international studies; however there is not enough known which bacteria are implicated. In the first month of life calves show immaturity of their immune system, what has been little studied in regard to pneumonia. The present investigation sought to study neonate bronchopneumonia in calves, to identify which bacteria are present in the respiratory tract of healthy and, with naturally acquired pneumonia calves, to analyze the pulmonary cytological response against pathogens. For this purpose, samples of the respiratory tract were collected by tracheocenthesis. It was noted that the microflora of the tracheobronchial region of healthy and diseased calves was the same, but they were different from the one reported by international papers. The flora was constituted mainly by Staphylococcus sp., Bacillus sp., Streptococcus sp., Pseudomonas aeruginosa and enterobacteriae, allowing to infer that the prophylactic and therapeutic measures adopted internationally may not be as effective for the Brazilian condition. It was also found that newborn calves have an approximate ratio of 1:1 of macrophages and neutrophils in the tracheobronchial region when they were healthy, reaching a ratio of approximately 1:3 of macrophages and neutrophils when they were with bronchopneumonia. Probably, these profiles are characteristic of the age, a period when exists immaturity of the immune system and influenced by management factors which lead to greater inhalation of bacterial agents.

Efeito da Mannheimia granulomatis sobre cultivo de fibroblastos / Effect of Mannheimia granulomatis on fibroblastos cultures

Primary cultures of Mannheimia granulomatis were established in chicken embryos to assess their capacity to stimulate fibroblast proliferation. The capacity of the bacterium-activated macrophages to stimulate cytokine and enzyme proliferation was assessed in a mouse peritoneum macrophage culture. To evaluate the bacteria infection on fibroblasts and their growth within 48h in relation to the active macrophages, cultures were washed and trypsinized and the cells counted. Results showed no significant differences when the bacteria-infected fibroblasts were mixed with bacterial extract (P=0.9682). The treatment using just products of macrophages resulted similar to the negative control. Significant differences on cell proliferation were established (P=0,0039) when the products of M. granulomatis-activated macrophages were used, meaning that bacterial components were unable to promote fibroblast increase. Further research is needed to elucidate the effect of M. granulomatis on the macrophages.(AU)

Efeito da Mannheimia granulomatis sobre cultivo de fibroblastos / Effect of Mannheimia granulomatis on fibroblastos cultures

Primary cultures of Mannheimia granulomatis were established in chicken embryos to assess their capacity to stimulate fibroblast proliferation. The capacity of the bacterium-activated macrophages to stimulate cytokine and enzyme proliferation was assessed in a mouse peritoneum macrophage culture. To evaluate the bacteria infection on fibroblasts and their growth within 48h in relation to the active macrophages, cultures were washed and trypsinized and the cells counted. Results showed no significant differences when the bacteria-infected fibroblasts were mixed with bacterial extract (P=0.9682). The treatment using just products of macrophages resulted similar to the negative control. Significant differences on cell proliferation were established (P=0,0039) when the products of M. granulomatis-activated macrophages were used, meaning that bacterial components were unable to promote fibroblast increase. Further research is needed to elucidate the effect of M. granulomatis on the macrophages.

Molecular and ultrastructural studies of the fibrotic lesions of bovine focal proliferative fibrogranulomatous panniculitis (Lechiguana).

This work aimed to investigate some aspects related to the pathogenicity of Lechiguana, a bovine fibroproliferative lesion characterized by rapid collagen accumulation. Light and transmission electron microscopy and in situ hybridization studies were performed in order to elucidate the fibrogenic activity of this lesion. The characterization of fibroblastic plasticity in the lesion was done by immunohistochemical study for alpha-smooth-muscle cell actin. The ovoid-shaped cells presented positive reaction for alpha-smooth-muscle cell actin in their cytoplasm and, at the electron-microscopic level demonstrated basal lamina-like material adjacent to the external surface and collagen fibrils that corresponded to a cell population phenotypically similar to the myofibroblast. We also investigated alpha1 collagen type I mRNA at different times of evolution of Lechiguana lesions, using isotopic and non-isotopic in situ hybridization. The results strongly suggest the involvement of a myofibroblast-like cell population that expresses mRNA for type I collagen and is probably associated with the increase of collagen deposition.

Characterisation of Mannheimia spp. strains isolated from bovine nasal exudate and factors associated to isolates, in dairy farms in the Central Valley of Mexico.

Mannheimia spp. strains obtained from bovine nasal exudates of either clinically healthy or clinically affected by respiratory tract disease animals were isolated and characterised to estimate the prevalence of isolated serotypes in dairy farms in Mexico, by means of a trans-sectional descriptive study. Strains were isolated and typified through biochemical and immunological tests. chi(2) or Fisher statistical tests were applied, as well as odds ratio calculation and logistic regression analysis to evaluate the association and effect of some variables on Mannheimia spp. isolation. The apparent prevalence rates of Mannheimia haemolytica was significantly higher in diseased bovines (OR = 1.94; p < 0.05), as well as in bovines younger than 1 year of age (OR = 23.98; p < 0.05), and in bovines not vaccinated against bovine pasteurellosis (OR = 1.52; p < 0.05). Age was the variable that remained in the logistic regression model. Serotype A1 showed the highest prevalence, even when most isolates were not-typable. Bovines younger than one year of age and those with disease were the groups with the highest frequency of M. haemolytica and Mannheimia glucosida isolates.