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The aim of this study was to evaluate 140 Salmonella Derby isolates collected over a 10-year period from porcine origins (environment, pig carcass, lymph nodes, intestinal content, and pork) for their phenotypic and genotypic antimicrobial resistance, their ability to produce biofilm, and their genetic relatedness. The minimum inhibitory concentration (MIC) was determined using microdilution broth method and antimicrobial resistance genes were investigated by PCR. The quantification of biofilm formation was performed in sterile polystyrene microtiter plates. Genetic relatedness was determined by Xba-I macrorestriction analysis. The highest frequencies of non-wildtype (nWT) populations were observed against tetracycline (75.7%), streptomycin (70%), and colistin (11.4%), whereas wildtype populations were observed against ciprofloxacin, ceftazidime, and gentamicin. The resistance genes found were blaTEM (ampicillin), aadA variant (streptomycin/spectinomycin), tetA (tetracycline), and floR (florfenicol). On 96-well polystyrene microtiter plate, 68.6% of the isolates proved to be biofilm producers. Among 36 S. Derby isolates selected to PFGE analysis, 22 were clustered with 83.6% of similarity. Additionally, 27 isolates were clustered in 11 pulsotypes, which presented more than one strain with 100% of similarity. Most of S. Derby isolates were able to form biofilm and were classified as nWT or resistant to tetracycline, streptomycin, and colistin. PFGE allowed the identification of closely related S. Derby isolates that circulated in pig slaughterhouses and pork derived products along a decade.

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Avian pathogenic Escherichia coli (APEC) is one of the pathogens that most concerns the poultry industry worldwide due to the economic losses it can cause. APEC persistence and survival, both in the environment and in the host, may be a consequence of biofilm-producing capabilities. The aim of this study was to evaluate APEC strains' biofilm production and its relationship to in vivo pathogenicity. Two hundred thirty-eight APEC isolates from three different origins (broiler bedding material, cellulite lesions, and respiratory diseases) were selected. The in vivo pathogenicity index (PI) was determined. Biofilm formation was evaluated using a microplate assay with analysis of colony morphology in Congo Red agar in order to detect the phenotypic expression of curli fimbriae and cellulose. Regarding biofilm production, it was observed that 55.8% of the strains produced biofilms. In the morphological test, 88.2% of the isolates expressed one or both components at one of the temperatures at least, and 11.8% of the isolates did not express curli or cellulose. Cellulose production was significantly higher at 25 °C. On the other hand, curli production was significantly higher at 37 °C. The study data indicate that there is no association between biofilm production and in vivo pathogenicity.

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Abstract Pasteurella multocida causes atrophic rhinitis in swine and fowl cholera in birds, and is a secondary agent in respiratory syndromes. Pathogenesis and virulence factors involved are still poorly understood. The aim of this study was to detect 22 virulence-associated genes by PCR, including capsular serogroups A, B and D genes and to evaluate the antimicrobial susceptibility of P. multocida strains from poultry and swine. ompH, oma87, plpB, psl, exbD-tonB, fur, hgbA, nanB, sodA, sodC, ptfA were detected in more than 90% of the strains of both hosts. 91% and 92% of avian and swine strains, respectively, were classified in serogroup A. toxA and hsf-1 showed a significant association to serogroup D; pmHAS and pfhA to serogroup A. Gentamicin and amoxicillin were the most effective drugs with susceptibility higher than 97%; however, 76.79% of poultry strains and 85% of swine strains were resistant to sulphonamides. Furthermore, 19.64% and 36.58% of avian and swine strains, respectively, were multi-resistant. Virulence genes studied were not specific to a host and may be the result of horizontal transmission throughout evolution. High multidrug resistance demonstrates the need for responsible use of antimicrobials in animals intended for human consumption, in addition to antimicrobial susceptibility testing to P. multocida.

Assuntos

RESUMO

Pasteurella multocida causes atrophic rhinitis in swine and fowl cholera in birds, and is a secondary agent in respiratory syndromes. Pathogenesis and virulence factors involved are still poorly understood. The aim of this study was to detect 22 virulence-associated genes by PCR, including capsular serogroups A, B and D genes and to evaluate the antimicrobial susceptibility of P. multocida strains from poultry and swine. ompH, oma87, plpB, psl, exbD-tonB, fur, hgbA, nanB, sodA, sodC, ptfA were detected in more than 90% of the strains of both hosts. 91% and 92% of avian and swine strains, respectively, were classified in serogroup A. toxA and hsf-1 showed a significant association to serogroup D; pmHAS and pfhA to serogroup A. Gentamicin and amoxicillin were the most effective drugs with susceptibility higher than 97%; however, 76.79% of poultry strains and 85% of swine strains were resistant to sulphonamides. Furthermore, 19.64% and 36.58% of avian and swine strains, respectively, were multi-resistant. Virulence genes studied were not specific to a host and may be the result of horizontal transmission throughout evolution. High multidrug resistance demonstrates the need for responsible use of antimicrobials in animals intended for human consumption, in addition to antimicrobial susceptibility testing to P. multocida.

Assuntos

RESUMO

Pasteurella multocida causes atrophic rhinitis in swine and fowl cholera in birds, and is a secondary agent in respiratory syndromes. Pathogenesis and virulence factors involved are still poorly understood. The aim of this study was to detect 22 virulence-associated genes by PCR, including capsular serogroups A, B and D genes and to evaluate the antimicrobial susceptibility of P. multocida strains from poultry and swine. ompH, oma87, plpB, psl, exbD-tonB, fur, hgbA, nanB, sodA, sodC, ptfA were detected in more than 90% of the strains of both hosts. 91% and 92% of avian and swine strains, respectively, were classified in serogroup A. toxA and hsf-1 showed a significant association to serogroup D; pmHAS and pfhA to serogroup A. Gentamicin and amoxicillin were the most effective drugs with susceptibility higher than 97%; however, 76.79% of poultry strains and 85% of swine strains were resistant to sulphonamides. Furthermore, 19.64% and 36.58% of avian and swine strains, respectively, were multi-resistant. Virulence genes studied were not specific to a host and may be the result of horizontal transmission throughout evolution. High multidrug resistance demonstrates the need for responsible use of antimicrobials in animals intended for human consumption, in addition to antimicrobial susceptibility testing to P. multocida. (AU)

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Background: The contamination of products with Salmonella is a major threat to the poultry industry because the possible transmission to humans and animals can produce a huge negative impact. The diversity of Salmonella enterica serotypes complicates the diagnostic systems and the transport of live cultures to the diagnostic labs may represent a biohazard. Current methods for serotyping using antibodies do not work well for many Salmonella serotypes and reagents are not often available. For these reasons, methods that assign serotype by the analysis of DNA are preferred. One step that is currently in development is streamlining methods for DNA submission to the laboratories for sequencing. For this purpose, we investigated fi lter papers commercially available (Flinders Technology Associates - FTA) to ship DNA samples. Filter papers are impregnated with a chemical formulation that lyses cells, immobilizes DNA, and protects it from degradation. The objective of this study was to assess the feasibility of the FTA cards for transporting Salmonella DNA samples in order to reduce biohazards and if they would yield enough DNA in quantity and quality for molecular analyses.Material, Methods & Results: In this study 156 samples of Salmonella enterica serotypes Enteritidis, Heidelberg, Hadar, Gallinarum, Typhimurium, Agona and Pullorum were isolated from poultry products and environ

Background: The contamination of products with Salmonella is a major threat to the poultry industry because the possible transmission to humans and animals can produce a huge negative impact. The diversity of Salmonella enterica serotypes complicates the diagnostic systems and the transport of live cultures to the diagnostic labs may represent a biohazard. Current methods for serotyping using antibodies do not work well for many Salmonella serotypes and reagents are not often available. For these reasons, methods that assign serotype by the analysis of DNA are preferred. One step that is currently in development is streamlining methods for DNA submission to the laboratories for sequencing. For this purpose, we investigated fi lter papers commercially available (Flinders Technology Associates - FTA) to ship DNA samples. Filter papers are impregnated with a chemical formulation that lyses cells, immobilizes DNA, and protects it from degradation. The objective of this study was to assess the feasibility of the FTA cards for transporting Salmonella DNA samples in order to reduce biohazards and if they would yield enough DNA in quantity and quality for molecular analyses.Material, Methods & Results: In this study 156 samples of Salmonella enterica serotypes Enteritidis, Heidelberg, Hadar, Gallinarum, Typhimurium, Agona and Pullorum were isolated from poultry products and environ

RESUMO

Background: The contamination of products with Salmonella is a major threat to the poultry industry because the possible transmission to humans and animals can produce a huge negative impact. The diversity of Salmonella enterica serotypes complicates the diagnostic systems and the transport of live cultures to the diagnostic labs may represent a biohazard. Current methods for serotyping using antibodies do not work well for many Salmonella serotypes and reagents are not often available. For these reasons, methods that assign serotype by the analysis of DNA are preferred. One step that is currently in development is streamlining methods for DNA submission to the laboratories for sequencing. For this purpose, we investigated fi lter papers commercially available (Flinders Technology Associates - FTA) to ship DNA samples. Filter papers are impregnated with a chemical formulation that lyses cells, immobilizes DNA, and protects it from degradation. The objective of this study was to assess the feasibility of the FTA cards for transporting Salmonella DNA samples in order to reduce biohazards and if they would yield enough DNA in quantity and quality for molecular analyses.Material, Methods & Results: In this study 156 samples of Salmonella enterica serotypes Enteritidis, Heidelberg, Hadar, Gallinarum, Typhimurium, Agona and Pullorum were isolated from poultry products and environ

Background: The contamination of products with Salmonella is a major threat to the poultry industry because the possible transmission to humans and animals can produce a huge negative impact. The diversity of Salmonella enterica serotypes complicates the diagnostic systems and the transport of live cultures to the diagnostic labs may represent a biohazard. Current methods for serotyping using antibodies do not work well for many Salmonella serotypes and reagents are not often available. For these reasons, methods that assign serotype by the analysis of DNA are preferred. One step that is currently in development is streamlining methods for DNA submission to the laboratories for sequencing. For this purpose, we investigated fi lter papers commercially available (Flinders Technology Associates - FTA) to ship DNA samples. Filter papers are impregnated with a chemical formulation that lyses cells, immobilizes DNA, and protects it from degradation. The objective of this study was to assess the feasibility of the FTA cards for transporting Salmonella DNA samples in order to reduce biohazards and if they would yield enough DNA in quantity and quality for molecular analyses.Material, Methods & Results: In this study 156 samples of Salmonella enterica serotypes Enteritidis, Heidelberg, Hadar, Gallinarum, Typhimurium, Agona and Pullorum were isolated from poultry products and environ

RESUMO

Background: The contamination of products with Salmonella is a major threat to the poultry industry because the possible transmission to humans and animals can produce a huge negative impact. The diversity of Salmonella enterica serotypes complicates the diagnostic systems and the transport of live cultures to the diagnostic labs may represent a biohazard. Current methods for serotyping using antibodies do not work well for many Salmonella serotypes and reagents are not often available. For these reasons, methods that assign serotype by the analysis of DNA are preferred. One step that is currently in development is streamlining methods for DNA submission to the laboratories for sequencing. For this purpose, we investigated fi lter papers commercially available (Flinders Technology Associates - FTA) to ship DNA samples. Filter papers are impregnated with a chemical formulation that lyses cells, immobilizes DNA, and protects it from degradation. The objective of this study was to assess the feasibility of the FTA cards for transporting Salmonella DNA samples in order to reduce biohazards and if they would yield enough DNA in quantity and quality for molecular analyses. Material, Methods & Results: In this study 156 samples of Salmonella enterica serotypes Enteritidis, Heidelberg, Hadar, Gallinarum, Typhimurium, Agona and Pullorum were isolated from poultry products and environments in southern Brazil. Samples were stored in the Avian Diagnostic and Research Center of the Federal University of Rio Grande do Sul. Following instructions for spotting cards with cell cultures at a density that visually matched a McFarland Turbidity Standard 0,5; they were shipped to the Agriculture Research Service of the United States Department of Agriculture (USDA-ARS, Athens, GA-USA), using FTA cards. Upon the reception of the cards, safety testing was performed by transferring one disk from each sample into 10 mL of brain heart infusion (BHI) tubes and incubated at 37°C for 24 h. The BHI tube that showed turbidity after incubation was transferred to brilliant green (BG) agar and incubated at 37°C for 24 h to 48 h. If colonies were obtained in BG, biochemical analyses were performed by using the Enterotube method. Only one sample (S. Enteritidis) showed turbidity in BHI, but any bacterial growth was observed in the BG agar. The average DNA concentration, as measured by spectrophotometry, was 42,32 (± 9,84) ng/µL and the average 280/260 ratio was 1,9 (± 0,09). All the analyzed samples were negative for live cultures of Salmonella and the DNA obtained was suitable for molecular testing. Discussion: FTA cards can be used to transport DNA samples from pathogenic bacteria, reducing biohazards associated with shipping live cultures. The possibility of shipping DNA, in an economic and safe way, for testing samples at the laboratories facilitates the identification of Salmonella enterica serotypes that are circulating in the environment of poultry. Turbidity in BHI tubes that did not result in colonies on agar media may be caused by the presence of other contaminants such as environmental saprophytic microorganisms that may occurred during the process of handling the cards. DNA samples of Salmonella enterica shipped from Brazil to the United States for this set of isolates did not show bacterial growth. Thus the FTA cards provided safe and effective inactivation of the pathogen, and the DNA obtained from the cards were adequate for downstream analyses.

Assuntos