Eliana Knackfuss Vaz

Agentes bacterianos enteropatogênicos em suínos de diferentes faixas etárias e perfil de resistência a antimicrobianos de cepas de Escherichia coli e Salmonella spp

As enterites infecciosas bacterianas provocam severas perdas para a industria suina em todo o mundo. Os objetivos deste trabalho foram determinar os agentes bacterianos, associados com a ocorrencia de diarreia em suinos, em diferentes faixas etarias, no Estado de Santa Catarina, Brasil, e verificar o perfil de resistencia das cepas de Escherichia coli e Salmonella spp, frente aos principais antimicrobianos utilizados em granjas de suinos. Os principais generos/especies bacterianos diagnosticados foram Escherichia coli, Clostridium spp, Salmonella spp Brachyspira hyodysenteriae, Brachyspira pilosicoli e Lawsonia intracellularis. Os fatores de virulencia de E. coli mais prevalentes na fase de maternidade foram F5 / (K99) 20%, F6 / (987P) 16,3%, F42 6,8% e F41 5,7%, ja nas fases de creche e terminacao, predominaram cepas com fimbrias F4 (K88) 11,2% e 5,4%, respectivamente. Para E. coli os maiores indices de resistencia foram encontrados para oxitetraciclina (94%) e tetraciclina (89,5%) e os menores indices de resistencia para neomicina (55%), ceftiofur (57,4%). Quanto as amostras de Salmonella spp, estas apresentaram maior resistencia a oxitetraciclina (77%), e a tetraciclina (42,1%) e menor a gentamicina (3,5%) e amoxicilina (4,8%).

Ocorrência de Actinomyces suis em fêmeas em produção provenientes de granjas com transtornos reprodutivos localizadas no planalto Catarinense - Santa Catarina

This study took place in seven farms in the Santa Catarina highlands, in which there were reproductive disorders. One hundred and one urine samples were collected from sows in production. One sample from the first urine in the morning was collected and indirect fluorescense was performed in the urinary sediment. The samples were examined and classified as negative (bacilli absent or rare with light fluorescense) and positive (bacilli with bright fluorescense). 16.8% samples were positive for A. suis, with a variation range from 14 to 80%, which cames from 4 farms. This results showed that in farms with reproductive disorders, A. suis can be involved in the etiology of the problem.

Characterisation of penicillin and tetracycline resistance in Staphylococcus aureus isolated from bovine milk samples in Minas Gerais, Brazil

This Regional Research Communication describes the characterisation of ampicillin, penicillin and tetracycline resistance in Staphylococcus aureus isolated from bovine subclinical mastitis in Minas Gerais State, Brazil. Ninety S. aureus isolates from bovine mastitis exhibiting phenotypic resistance to ampicillin, penicillin and/or tetracycline were selected for this study. The minimum inhibitory concentration (MIC) of each antibiotic was determined using the E-Test® and the production of beta-lactamase was determined by cefinase disks. The resistance genes blaZ, tet(K), tet(L), tet(M), and tet(O) were investigated by PCR in all of the isolates. The MIC results classified 77, 83 and 71% of the isolates as resistant to ampicillin, penicillin and tetracycline, respectively. The MIC50 and MIC90 were, respectively, 1 and 2 µg/ml for ampicillin, 0·5 and 1 µg/ml for penicillin and 32 and 64 µg/ml for tetracycline. Eighty-six per cent of beta-lactamase producing isolates were detected. Of the 90 isolates investigated, 97% amplified blaZ, 84% amplified tet(K), 9% amplified tet(L), 2% amplified tet(M) and 1% amplified tet(O). Seventy-nine isolates (88%) showed blaZ together with at least one tet gene. S. aureus isolates showed high MIC50 and MIC90 values for the three antimicrobials. The blaZ and tet(K) genes were widespread in the herds studied, and most of the isolates harboured blaZ and tet(K) concomitantly.

Desenvolvimento e avaliação de novas estratégias de imunização contra colibacilose suína

Swine colibacillosis caused by enterotoxigenic Escherichia coli remains one of the main sanitary problems in pig farms. The recombinant DNA technology offers the possibility of developing new immunization strategies. This paper describes the development of a subunit vaccine through the expression and purification of the E. coli K88 FaeC fimbrial protein. The gene that codes for this antigen was amplified by PCR and cloned into an E. coli expression vector fused to a 6X histidine tag. The recombinant protein was purified by affinity chromatography and used for mice immunization. In parallel, the same gene was cloned into an eucariotic expression vector with the addition of the Kozak sequence for improving translation of this gene in muscle cells. The resulting plasmid named pUP310 was purified in large scale and used to immunize mice. The immune response afforded by both forms of immunization was monitored by ELISA. There was an immune response in mice inoculated with pUP310 and purified FaeC. It was possible to detect anti-FaeC antibodies 42 days after the first inoculation. The antibody titer increased with time, being still detectable 7 months after the first inoculation. It is concluded that recombinant FaeC and pUP310 are potential tools for immunization of swine against E. coli K88.

Low occurrence of pathogenic Yersinia enterocolitica in pig tonsils at slaughter in Southern Brazil

Yersinia enterocolitica is a foodborne pathogen and pigs are the main reservoir of it in their tonsils. As Brazil is a large producer and exporter of pork meat and information regarding this pathogen is still quite scarce, this study aimed at evaluating the direct detection of Y. enterocolitica followed by pathogenic Y. enterocolitica (PYE) determination in tonsils of slaughtered pigs. For this purpose, 400 pig tonsils were collected from 15 farms in four federally certified slaughterhouses in Southern Brazil. Initially, samples were screened using conventional PCR targeting of the 16sRNA gene, followed by multiplex PCR (mPCR) in order to detect three virulence genes (ail, yadA, and virF) and quantitative real-time PCR (qPCR) for the detection of the ail gene. One hundred and one (25.2%) of the samples tested positive for the 16sRNA gene. However, a PYE was detected in one out of the 101 Y. enterocolitica positive samples. The three virulence genes were determined by mPCR and confirmed by partial DNA sequencing. Thus, a significant occurrence of Y. enterocolitica was observed in pig tonsils from federally inspected slaughterhouses in Brazil, although the presence of pathogenic strains was quite low.