This work reports the results of analyses of three complete mycoplasma genomes, a pathogenic (7448) and a nonpathogenic (J) strain of the swine pathogen Mycoplasma hyopneumoniae and a strain of the avian pathogen Mycoplasma synoviae; the genome sizes of the three strains were 920,079 bp, 897,405 bp, and 799,476 bp, respectively. These genomes were compared with other sequenced mycoplasma genomes reported in the literature to examine several aspects of mycoplasma evolution. Strain-specific regions, including integrative and conjugal elements, and genome rearrangements and alterations in adhesin sequences were observed in the M. hyopneumoniae strains, and all of these were potentially related to pathogenicity. Genomic comparisons

We investigated whether primers able to specifically amplify a 0.7-kb DNA fragment from the conserved cpx genes could be applied to analyze A. pleuropneumoniae field isolates. The specific cpx primers were tested on 120 strains of A. pleuropneumoniae and other NAD-dependent field isolates from healthy and diseased animals to analyze A. pleuropneumoniae isolates from pigs in Brazil. We found that PCR and hybridization were able to discriminate between isolates of A. pleuropneumoniae and other bacteria. The 0.7-kb cpx DNA fragments were amplified from all 63 A. pleuropneumoniae isolates from herds with clinical symptoms and were isolated from lesions of acute cases of swine pleuropneumonia, both serotypable and nonserotypable. The PCR was also applied to 57 field isolates obtained from animals of apparently healthy herds, and the amplified cpx product was present in four serotypable and only two out of eleven A. pleuropneumoniae nonserotypable isolates. All nonserotypable A. pleuropneumoniae isolates revealed the apxA amplification pattern compatible with previously known serotypes. Some nonserotypable isolates might represent a population of isolates that originally were serotypable but lost the ability to react with serotype-specific antisera or might belong to novel serotypes. The PCR method applied is highly sensitive for serotypable A. pleuropneumoniae strains and for nonserotypable strains isolated from acute cases of swine pleuropneumoniae in Brazil.

Abstract. The implementation of Salmonella control programs in the pork production chain demands rapid and cost-effective methods to assess the prevalence of infection in pig herds. The objective of the present study was to develop an in-house enzyme-linked immunosorbent assay (ELISA) based on S. Typhimurium lipopolysaccharides (LPS) to measure the prevalence of infection caused by Salmonella in swine herds. Coating antigen was produced by phenol extraction of S. Typhimurium culture. After standardization of ELISA test conditions, the assay was validated by testing serum samples on different animal categories: pigs orally inoculated with S. Typhimurium and sentinel animals in contact with them, naturally infected animals, colostrum-deprived piglets, and bacterin-immunized pigs. Seroconversion was observed in inoculated pigs (7 days postinfection [DPI]) and in the sentinels (21 DPI). Nonspecific reactions were not detected in the sera of colostrum-deprived animals. Serum samples from animals immunized with Salmonella Agona, Salmonella Derby, Salmonella Panama, and Salmonella Bredeney bacterins showed marked cross-reaction with the LPS from the serovar Typhimurium. Moreover, positive results obtained with the in-house ELISA were associated with Salmonella isolation in 75 infected pig herds. Comparisons with 2 commercial kits showed a linear correlation coefficient of 0.847 between the in-house ELISA and kit A and 0.922 with kit B but a low agreement in the qualitative results. In conclusion, the newly developed in-house ELISA based on S. Typhimurium LPS can be a useful tool to determine the intensity of Salmonella sp. infection in swine herds.

Um estudo transversal foi utilizado para identificar fatores associados à prevalência de suínos sorologicamente positivos para Salmonella nos estados de Santa Catarina e Rio Grande do Sul. Sessenta e cinco granjas foram visitadas uma semana antes do abate dos animais para aplicação de questionário e coletas de ração, água e sangue. A ração foi submetida à pesquisa de Salmonella por isolamento e PCR. Foram testados soros de aproximadamente 40 leitões de cada propriedade utilizando ELISA com antígeno do sorovar Typhimurium. Após a análise de distribuição da prevalência, as granjas foram classificadas em três categorias, baixa (até 40%), média (40-70%) e alta (mais de 70%). Estas categorias constituíram a variável explicada e a pesquisa de Salmonella na ração, colimetria da água e as respostas do questionário, as variáveis explicativas. Inicialmente, a associação entre as variáveis explicativas e a explicada foi estudada pelo teste de c2. As variáveis associadas (P£0,1) foram submetidas à análise fatorial de correspondência múltipla, com a qual foi possível identificar a associação da maior soroprevalência com o seguinte conjunto de variáveis: nas granjas terminadoras, uso de ração peletizada, distribuição de dejetos a menos de 100m do local de captação de água, não utilização de comedouro do modelo comedouro/bebedouro, transporte com freteiro misturando animais de várias granjas; nas granjas de ciclo completo, ingredientes de ração desprotegidos de outros animais, ausência de controle de roedores, ração seca, ausência de cerca, não uso da pintura com cal após lavagem e desinfecção e a entrada de outras pessoas, além do técnico, na granja. Das 65 granjas visitadas, 98,5% foram ELISA positivas com soroprevalência 57,6% (intervalo de confiança entre 56-60%).

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