This study assessed biofilm formation on polystyrene by Staphylococcus aureus, Listeria monocytogenes, L. welshimeri and Escherichia coli, isolated from a slaughtering plant, grown on tryptic soy broth (TSB) using different glucose concentrations. The tested bacteria produced biofilm in at least one of the concentrations used, and some of them were strong biofilm producers.
The aim of this study was to assess the frequency and association of virulence factors of Escherichia (E.) coli isolated from weaned piglets with diarrhea and to correlate it with fecal consistency. A total of 152 rectal swabs were collected from 25-40 day-old piglets with diarrhea, in farms of Southern Brazil. Phenotypical and molecular techniques were used for bacterial isolation, characterization and classification of enterotoxigenic E. coli (ETEC) pathotypes. Statistical analysis was carried out to determine the frequency of virulence factors and virotypes, of fimbriae F4, F5, F6, F18, F41 and toxins LT, STa, STb and STx2e. Out of 456 E. coli isolates, 287 (62.9%) samples showed significant growth of E. coli. Among them, 194 (67.6%) samples showed at least one virulence factor, indicating that ETEC is an important etiological agent of diarrhea in weaned piglets. Higher frequencies were found of fimbria F4 and F18 and enterotoxins LT, STa and STb. Significant association was found to F4, LT, STa and STb; between F18 and STa and STx2e; between F5 and LT, STa and STb. The most frequent virotypes were F18-STa, F4-LT-STa-STb, F4-STa, F4-LT-STb and F18-STa-STx2e. Beta-hemolysis was observed in 47.4% of samples and there was significant association between hemolytic samples and virulence factors F4, F18, STa and STx2e. Regarding fecal consistency, there was significant association of liquid feces and F4 fimbria, STa toxin and virotypes F4-STa and F4-F5-LT-STa-STb. Since there was significant association of ETEC and liquid feces in nursery piglets, it is important to prioritize the sampling of liquid feces for the diagnosis etiologic cause of diarrhea.
Bactérias do gênero Salmonella são consideradas a principal causa de infecções alimentares em humanos associadas a produtos avícolas, na maioria dos países. São capazes de formar biofilmes em diferentes superfícies, dificultando sua eliminação por procedimentos de limpeza e sanificação na indústria de alimentos. Estudos demonstram uma melhor adesão microbiana com o aumento da hidrofobicidade, tanto da superfície celular como do substrato de adesão. Neste trabalho, avaliou-se a formação de biofilme em placas de poliestireno por S. Heidelberg isoladas de abatedouros avícolas, cultivadas em caldo TSB com diferentes concentrações de glicose e a hidrofobicidade destas cepas na fase logarítmica (4h) e na fase estacionária (24h) do crescimento bacteriano. No caldo TSB sem suplementação de glicose, todas as amostras foram capazes de formar biofilme, sendo duas amostras fortemente formadoras de biofilme, e a maioria fracamente formadora. Nos caldos TSB com 0,5, 1,0 e 1,5% de glicose, todas as amostras foram fracamente formadoras. Nos caldos TSB com 2,0 a 4,0% de glicose, várias amostras apresentaram-se não formadoras e as demais fracamente formadoras. Após a incubação a 36ºC por 4 horas, o índice de hidrofobicidade foi inferior a 10%, com todas as amostras sendo altamente hidrofílicas. Na incubação a 36ºC por 24 horas, os resultados foram distintos, sendo 1/16 altamente hidrofóbica, 9/16 com média hidrofobicidade e 6/16 altamente hidrofílicas. As S. Heidelberg foram capazes de formar biofilmes no poliestireno, enfatizando a necessidade da sua verificação em outras superfícies, além de avaliar outros hidrocarbonetos e tempos de incubação relacionados aos índices de hidrofobicidade.
1. The aim of the present study was to determine if the 9R-strain of the Salmonella Gallinarum live vaccine was responsible for having fowl typhoid outbreaks in chicken flocks from both chicken and turkey breeders as well as to verify the antimicrobial resistance of the isolates from the outbreaks. 2. The triplex polymerase chain reaction, standard antimicrobial test, beta-lactamase genes identification and Ion Torrent PMG whole-genome sequence were used in the field isolates and in the vaccine strain of S. Gallinarum. 3. The 60 tested isolates were not from vaccine origin and manifested high resistance to drugs from macrolide and quinolone groups. Whole-genome sequencing (WGS) and single nucleotide polymorphism analysis on selected isolates for core genes from Salmonella enterica confirmed the wild origin of these isolates and showed two possible sources of S. Gallinarum in the studied outbreaks. 4. S. Gallinarum isolated from fowl typhoid outbreaks in the studied period were not caused by the use of the SG9R live vaccine. The source of strains sequenced was diverse.
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