RESUMEN
Haemophilus parasuis infection, known as Glãsser's disease, is characterized by fibrinous polyserositis, arthritis and meningitis in piglets. Although traditional diagnosis is based on herd history, clinical signs, bacterial isolation and serotyping, the molecular-based methods are alternatives for species-specific tests and epidemiologic study. The aim of this study was to characterize H. parasuis strains isolated from different states of Brazil by serotyping, PCR and ERIC-PCR. Serotyping revealed serovar 4 as the most prevalent (24 percent), followed by serovars 14 (14 percent), 5 (12 percent), 13 (8 percent) and 2 (2 percent), whereas 40 percent of the strains were considered as non-typeable. From 50 strains tested 43 (86 percent) were positive to Group 1 vtaA gene that have been related to virulent strains of H.parasuis. ERIC-PCR was able to type isolates tested among 23 different patterns, including non-typeable strains. ERIC-PCR patterns were very heterogeneous and presented high similarity between strains of the same animal or farm origin. The results indicated ERIC-PCR as a valuable tool for typing H. parasuis isolates collected in Brazil.
Asunto(s)
Animales , Infecciones por Haemophilus , Haemophilus parasuis/aislamiento & purificación , Haemophilus parasuis/patogenicidad , Técnicas In Vitro , Reacción en Cadena de la Polimerasa , Análisis de Secuencia de ADN , Pruebas Serológicas , Genotipo , Métodos , Porcinos , Métodos , VirulenciaRESUMEN
Three comparative assays were performed seeking to improve the sensitivity of the diagnosis of Bordetella bronchiseptica infection analyzing swine nasal swabs. An initial assay compared the recovery of B. bronchiseptica from swabs simultaneously inoculated with B. bronchiseptica and some interfering bacteria, immersed into three transport formulations (Amies with charcoal, trypticase soy broth and phosphate buffer according to Soerensen supplemented with 5 percent of bovine fetal serum) and submitted to different temperatures (10ºC and 27ºC) and periods of incubation (24, 72 and 120 hours). A subsequent assay compared three selective media (MacConkey agar, modified selective medium G20G and a ceftiofur medium) for their recovery capabilities from clinical specimens. One last assay compared the polymerase chain reaction to the three selective media. In the first assay, the recovery of B. bronchiseptica from transport systems was better at 27ºC and the three formulations had good performances at this temperature, but the collection of qualitative and quantitative analysis indicated the advantage of Amies medium for nasal swabs transportation. The second assay indicated that MacConkey agar and modified G20G had similar results and were superior to the ceftiofur medium. In the final assay, polymerase chain reaction presented superior capability of B. bronchiseptica detection to culture procedures.
Três ensaios comparativos foram feitos com o objetivo de aperfeiçoar a sensibilidade do diagnóstico da infecção pela Bordetella bronchiseptica a partir de suabes nasais de leitões. O experimento inicial comparou a recuperação de B. bronchiseptica a partir de suabes, simultaneamente inoculados com B. bronchiseptica e algumas bactérias interferentes, imersos em três formulações para transporte (meio Amies com carvão, caldo tripticaseína de soja e tampão de fosfatos segundo Soerensen suplementado com 5 por cento de soro fetal bovino) e submetidos a diferentes temperaturas (10ºC e 27ºC) e períodos de incubação (24, 72 e 120 horas). O experimento subseqüente comparou três meios seletivos (ágar MacConkey, meio seletivo G20G modificado e o meio de ceftiofur) em relação às suas capacidades de recuperação a partir de amostras clínicas. O último experimento comparou a reação em cadeia pela polimerase aos três meios seletivos. No primeiro experimento, a recuperação de B. bronchiseptica nos sistemas de transporte foi melhor a 27ºC e as três formulações tiveram boas performances nesta temperatura, mas o conjunto das análises qualitativa e quantitativa apontou para o uso preferencial do meio Amies para o transporte de suabes nasais. O segundo experimento indicou que o ágar MacConkey e o G20G modificado mostraram resultados similares e foram superiores ao meio de ceftiofur. No experimento final, a técnica de reação em cadeia pela polimerase apresentou uma capacidade de detecção da B. bronchiseptica superior a do cultivo.