RESUMO
This study aimedto evaluate the contamination by Salmonellasp. in the Capinzal River, to determinethe prevalent serovars, patterns of antimicrobial resistance, and the genetic relationships between the serovars identified. A total of 108 samples were collected from 2016 to 2018. The isolation of Salmonellaspp. was conducted accordingto InternationalOrganization for Standardization (ISO) standards. The antimicrobial resistance profile of the Salmonella isolates was evaluated, and isolates were selected for serotyping and verification of genetic similarity using the Pulsed-FieldGel Electrophoresis (PFGE) Technique. Of the 108 samples collected, 35 (32.4%) were positive for Salmonella; 17.2% of the isolates were from the rural area; and 88.6% were from the urban area. Salmonellawas isolated from all collect points along the river, with a higher incidence at the beginning of the urban area, indicating that contamination starts in the rural area and intensifies in the urban area of the city. A percentageof 35.1% of the Salmonellaisolates were resistant to at least two antibiotics, while 18.9% were considered multidrug-resistant (resistant to at least two antibiotics of different classes). Seven serovars were distinguished from the serotyped isolates, with a prevalence rate of 23.5% for S.Infantis, S.Orion, and S. Javiana; 11.8% forS.Senfterberg, and 5.9% forS. Montevideo, S.Heidelberg, and S.entericasubsp. enterica(O: 6.8). The variability in specific restriction sites generated by PFGE resulted in 10 pulsotypes, separating mainly different serotypes.
O objetivo deste estudo foi avaliar a contaminação por Salmonellasp. no rio Capinzal, para determinar os sorovares prevalentes, padrões de resistência antimicrobiana e as relações genéticas entre os sorovaresidentificados. Um total de 108 amostras foram coletadas de 2016 a 2018. O isolamento de Salmonellaspp. foi conduzido de acordo com os padrões da International Organization for Standardization (ISO). O perfil de resistência antimicrobiana dos isolados de Salmonellafoi avaliado, e os isolados foram selecionados para sorotipagem e verificação de similaridade genética por meio da Técnica de Eletroforese em Gel de Campo Pulsado (PFGE). Das 108 amostras coletadas, 35 (32,4%) foram positivaspara Salmonella; 17,2% dos isolados eram da área rural; e 88,6% da área urbana. Salmonellafoi isolada em todos os pontos de coleta ao longo do rio, com maior incidência no início da área urbana, indicando que a contaminação começa na área rural e se intensifica na área urbana da cidade. Um percentual de 35,1%dos isolados de Salmonellaforam resistentes a pelo menos dois antibióticos, enquanto 18,9% foram considerados multirresistentes (resistentes a pelo menos dois antibióticos de classes diferentes). Sete sorovares foram diferenciadosdos isolados sorotipados, com uma taxa de prevalência de 23,5% para S.Infantis,S.Orion e S.Javiana; 11,8% para S.Senfterberg e 5,9% para S.Montevidéu, S.Heidelberg e S.enterica subsp. enterica (O: 6,8). A variabilidade emlocais de restrição específicos gerados por PFGE resultou em 10 pulsotipos, separando principalmente diferentes sorotipos.
Assuntos
Anti-Infecciosos , Eletroforese em Gel de Campo Pulsado/métodos , Microbiologia da Água , Salmonella enterica/imunologia , Águas SuperficiaisRESUMO
This study aimedto evaluate the contamination by Salmonellasp. in the Capinzal River, to determinethe prevalent serovars, patterns of antimicrobial resistance, and the genetic relationships between the serovars identified. A total of 108 samples were collected from 2016 to 2018. The isolation of Salmonellaspp. was conducted accordingto InternationalOrganization for Standardization (ISO) standards. The antimicrobial resistance profile of the Salmonella isolates was evaluated, and isolates were selected for serotyping and verification of genetic similarity using the Pulsed-FieldGel Electrophoresis (PFGE) Technique. Of the 108 samples collected, 35 (32.4%) were positive for Salmonella; 17.2% of the isolates were from the rural area; and 88.6% were from the urban area. Salmonellawas isolated from all collect points along the river, with a higher incidence at the beginning of the urban area, indicating that contamination starts in the rural area and intensifies in the urban area of the city. A percentageof 35.1% of the Salmonellaisolates were resistant to at least two antibiotics, while 18.9% were considered multidrug-resistant (resistant to at least two antibiotics of different classes). Seven serovars were distinguished from the serotyped isolates, with a prevalence rate of 23.5% for S.Infantis, S.Orion, and S. Javiana; 11.8% forS.Senfterberg, and 5.9% forS. Montevideo, S.Heidelberg, and S.entericasubsp. enterica(O: 6.8). The variability in specific restriction sites generated by PFGE resulted in 10 pulsotypes, separating mainly different serotypes.(AU)
O objetivo deste estudo foi avaliar a contaminação por Salmonellasp. no rio Capinzal, para determinar os sorovares prevalentes, padrões de resistência antimicrobiana e as relações genéticas entre os sorovaresidentificados. Um total de 108 amostras foram coletadas de 2016 a 2018. O isolamento de Salmonellaspp. foi conduzido de acordo com os padrões da International Organization for Standardization (ISO). O perfil de resistência antimicrobiana dos isolados de Salmonellafoi avaliado, e os isolados foram selecionados para sorotipagem e verificação de similaridade genética por meio da Técnica de Eletroforese em Gel de Campo Pulsado (PFGE). Das 108 amostras coletadas, 35 (32,4%) foram positivaspara Salmonella; 17,2% dos isolados eram da área rural; e 88,6% da área urbana. Salmonellafoi isolada em todos os pontos de coleta ao longo do rio, com maior incidência no início da área urbana, indicando que a contaminação começa na área rural e se intensifica na área urbana da cidade. Um percentual de 35,1%dos isolados de Salmonellaforam resistentes a pelo menos dois antibióticos, enquanto 18,9% foram considerados multirresistentes (resistentes a pelo menos dois antibióticos de classes diferentes). Sete sorovares foram diferenciadosdos isolados sorotipados, com uma taxa de prevalência de 23,5% para S.Infantis,S.Orion e S.Javiana; 11,8% para S.Senfterberg e 5,9% para S.Montevidéu, S.Heidelberg e S.enterica subsp. enterica (O: 6,8). A variabilidade emlocais de restrição específicos gerados por PFGE resultou em 10 pulsotipos, separando principalmente diferentes sorotipos.(AU)
Assuntos
Anti-Infecciosos , Águas Superficiais , Microbiologia da Água , Salmonella enterica/imunologia , Eletroforese em Gel de Campo Pulsado/métodosRESUMO
BACKGROUND: Pasteurella multocida type A (PmA) is considered a secondary agent of pneumonia in pigs. The role of PmA as a primary pathogen was investigated by challenging pigs with eight field strains isolated from pneumonia and serositis in six Brazilian states. Eight groups of eight pigs each were intranasally inoculated with different strains of PmA (1.5 mL/nostril of 10e7 CFU/mL). The control group (n = 12) received sterile PBS. The pigs were euthanized by electrocution and necropsied by 5 dpi. Macroscopic lesions were recorded, and swabs and fragments of thoracic and abdominal organs were analyzed by bacteriological and pathological assays. The PmA strains were analyzed for four virulence genes (toxA: toxin; pfhA: adhesion; tbpA and hgbB: iron acquisition) by PCR and sequencing and submitted to multilocus sequence typing (MLST). RESULTS: The eight PmA strains were classified as follows: five as highly pathogenic (HP) for causing necrotic bronchopneumonia and diffuse fibrinous pleuritis and pericarditis; one as low pathogenic for causing only focal bronchopneumonia; and two as nonpathogenic because they did not cause injury to any pig. PCR for the gene pfhA was positive for all five HP isolates. Sequencing demonstrated that the pfhA region of the HP strains comprised four genes: tpsB1, pfhA1, tpsB2 and pfhA2. The low and nonpathogenic strains did not contain the genes tpsB2 and pfhA2. A deletion of four bases was observed in the pfhA gene in the low pathogenic strain, and an insertion of 37 kb of phage DNA was observed in the nonpathogenic strains. MLST clustered the HP isolates in one group and the low and nonpathogenic isolates in another. Only the nonpathogenic isolates matched sequence type 10; the other isolates did not match any type available in the MLST database. CONCLUSIONS: The hypothesis that some PmA strains are primary pathogens and cause disease in pigs without any co-factor was confirmed. The pfhA region, comprising the genes tpsB1, tpsB2, pfhA1 and pfhA2, is related to the pathogenicity of PmA. The HP strains can cause necrotic bronchopneumonia, fibrinous pleuritis and pericarditis in pigs and can be identified by PCR amplification of the gene pfhA2.