Geovana Brenner Michael

COMPARISON OF DIFFERENT SELECTIVE ENRICHMENT STEPS TO ISOLATE SALMONELLA SP. FROM FECES OF FINISHING SWINE

A two-phase study was conducted to compare the efficacy of several enrichment selective-broth steps associated to different plating media for recovery of Salmonella sp. from finishing swine feces. In a first phase, Rappaport-Vassiliadis broth (RV) incubated at 42oC, Tetrathionate Muller-Kauffmann broth at 37oC (TMK37) and 42oC (TMK42), and Selenite Cystine broth (SC) at 37oC, in combination with three selective plating media Rambach agar (RA), Xylose-Lysine-Tergitol 4 agar (XLT4), and Brilliant-Green Phenol-Red Lactose Sucrose agar (VB) were compared for recovery of Salmonella from artificially contaminated swine feces. In a second phase, RV, TMK37, and TMK42, associated with XLT4 and VB , were tested with naturally contaminated swine feces. In this study RV, TMK42 and TMK37 were superior to SC for isolating Salmonella sp. from artificially contaminated feces. TMK42 and RV were more productive than TMK37 for recovery of Salmonella from naturally contaminated feces samples. Selectivity and indication capability of the plating media were remarkably affected by the selective enrichment step effectiveness. The TMK42/XLT4 association was the most sensitive and RV/XLT4 the most specific. The use of VB agar is also recommended to increase the likelihood of isolating atypical H 2S-late producing/ non-producing Salmonella. In this study RV and TMK42 were the most efficient selective enrichment for recovery of Salmonella sp. from swine feces.

Molecular analysis of multiresistant porcine Salmonella enterica subsp. enterica serovar Bredeney isolates from Southern Brazil: identification of resistance genes, integrons and a group II intron

The relationships of 83 porcine Salmonella enterica subsp. enterica serovar Bredeney isolates obtained at two slaughterhouses in Southern Brazil were analysed by XbaI and BlnI macrorestriction analysis, plasmid profiling and determination of antimicrobial resistance patterns. Twenty-nine XbaI and 30 BlnI macrorestriction patterns were identified. The 72 plasmid-bearing isolates exhibited 20 different plasmid profiles. Multiresistance was detected in 49 isolates (59%), of which 39 isolates showed at least resistance to sulfonamides, tetracyclines, chloramphenicol, streptomycin, kanamycin and/or ampicillin. A representative subset of 12 isolates was chosen for identification of resistance genes, their localisation and transferability. The sulfonamide resistance genes sul1, sul2 and sul3, the tetracycline resistance genes tet(A) and tet(B), the phenicol resistance genes catA1 and floR, the streptomycin resistance gene strA, the kanamycin resistance gene aphA1 and the ampicillin resistance gene bla(TEM) were detected and found to be located most frequently on plasmids. In addition, class 1 and 2 integrons with the cassette arrangements dfrA21/bla OXA-129/aadA1 and dfrA1/sat1/aadA1, respectively, were detected. A group II intron was found to be inserted into the 59-base element of an aadA1 gene cassette in a class 1 integron. This study revealed a wide genomic variety among the S. Bredeney isolates, and the high number of multiresistant isolates may point towards the risks that these S. Bredeney isolates can represent to human health.

Detection of virulence genes in Salmonella Enteritidis isolated from different sources

The presence of three virulence genes, invA, spvR, and spvC, was determined in Salmonella Enteritidis isolated from poultry, pigs, humans and food. All isolates were positive for the invA gene, with 91.2% being positive for spvR and 90.2% for spvC. There was no significant difference in the prevalence of the virulence genes between isolates from different sources. The results indicate that there is a putative high virulence potential for the S. Enteritidis isolates characterized.

Sorotipos de Salmonella isolados em uma propriedade de suínos de terminação no Sul do Brasil

Fifteen different serovars of Salmonella were isolated from a swine farm, two of the isolated serovars, Mbandaka and Tennessee, were also found in the feed supplied to the animals. This study demonstrated the diversity of serovars that could occur in a farm and the need of a better understanding on epidemiology of Salmonella infection.