No abstract

Salmonella is the most common etiological agent of cases and outbreaks of foodborne diarrheal illnesses. The emergence and spread of Salmonella spp., which has become multi-drug resistant and potentially more pathogenic, have increased the concern with this pathogen. In this study, 237 Salmonella spp., associated or not with foodborne salmonellosis in Brazil, belonging mainly to serotype Enteritidis, were tested for antimicrobial susceptibility and the presence of the virulence genes spvC, invA, sefA and pefA. Of the isolates, 46.8% were sensitive to all antimicrobials and 51.9% were resistant to at least one antimicrobial agent. Resistance to more than one antimicrobial agent was observed in 10.5% of the strains. The highest rates of resistance were observed for streptomycin (35.9%) and nalidixic acid (16.9%). No strain was resistant to cefoxitin, cephalothin, cefotaxime, amikacin, ciprofloxacin and imipenem. The invA gene was detected in all strains. Genes spvC and pefA were found in 48.1% and 44.3% of strains, respectively. The gene sefA was detected in 31.6% of the strains and only among S. Enteritidis. Resistance and virulence determinants were detected in Salmonella strains belonging to several serotypes. The high rates of antibiotic-resistance in strains isolated from poultry products demonstrate the potential risk associated with the consumption of these products and the need to ensure good food hygiene practices from farm to table to reduce the spread of pathogens relevant to public health.

The genomic DNA of thirty strains of Aujeszky's disease virus (ADV) isolated in the South and Southeast regions of Brazil from 1982 to 1996 were characterized by restriction endonuclease analysis with BamHI. Twenty seven strains were isolated from pigs, 1 from cattle, 1 from cat and 1 from dog. Using a systematization previously described, the 30 ADV strains could be classified as genomic types I (n = 2) and II (n = 28). Genomic type III was not observed. In this first study of genomic type characterization of brazilian ADV strains, we could demonstrate the occurence in Brazil of the genomic types I and II, with a large predominance of genomic type II.

A polymerase chain reaction (PCR) assay to detect Clostridium perfringens alpha toxin gene (cpa) was used to identify eighty-nine C. perfringens strains obtained from bovine clinical material. The strains were biochemically characterized as C. perfringens. The isolated strains were cultured on plates containing brain heart infusion agar with 5% sheep blood under anaerobic conditions. DNA extraction was performed by boiling. The 324 bp amplification product of cpa was observed in all isolates. C. sordellii, C. botulinum, C. novyi, and C. septicum were also tested but did not produce any alpha toxin gene amplification. These findings suggest that PCR is a useful assay in identifying C. perfringens toxin types

RESUMO O presente estudo foi realizado na Unidade de Pesquisa e Desenvolvimento de Gália, Pólo Regional de Desenvolvimento Tecnológico dos Agronegócios do Centro Oeste, em 2004, com o objetivo de avaliar a biologia e produção do bicho-da-seda quando exposto ao extrato de Mirabilis jalapa (família: Nyctaginaceae). Esse trabalho foi baseado em estudos prévios, em condições de laboratório, que mostraram a ação do extrato aquoso de Mirabilis jalapa, na concentração de 10%, sobre o controle do vírus da poliedrose (NPVBm), conferindo 100% de proteção ao inseto. Em condições de criação comercial, o extrato foi empregado nas diferentes fases larvais do inseto. Tanto em condições de laboratório como em condições de criação comercial o extrato não causou alterações na biologia e produção do bicho-da-seda, quando comparado com grupos não tratados. Embora os insetos estivessem infectados com NPVBm, não foram observados sintomas de infecção, sugerindo que a população viral, apesar de presente, foi mantida em níveis reduzidos não afetando o desempenho produtivo. Não foi observada uma ação anticontaminante do extrato contra outros patógenos oportunistas, uma vez que foram boas as condições sanitárias de criação, ocorrendo poucas mortes, provavelmente relacionadas mais com fatores naturais do que com a ocorrência de doenças.