RESUMO

Os objetivos deste estudo foram avaliar a eficácia dos desinfetantes cloreto de benzalcônio (QAC) e iodóforo (I) sobre 10 cepas APEC (Escherichia coli patogênica aviária), bem como verificar se a característica alta patogenicidade está associada a uma maior resistência a estes compostos. O método utilizado foi o de diluição através do teste qualitativo de suspensão. As variáveis estudadas foram: concentrações do QAC (300, 150, 75 e 50 ppm) e do I (100, 75, 50 e 25 ppm), tempos de contato (5, 10 e 20 minutos) e temperatura ±20°C. O QAC inativou todos os isolados nas concentrações de 300 e 150 ppm, em todos os tempos de contato, porém a 75 e 50 ppm no tempo de 5 minutos o desinfetante não foi eficaz para uma e quatro amostras, respectivamente. O I a 100 e 75 ppm inativou os isolados em todos os tempos avaliados, mas a 50 ppm um foi resistente e a 25 ppm oito foram resistentes em todos os tempos de exposição. A característica alta patogenicidade não pareceu promover resistência, quando comparado com a cepa padrão. Concluiu-se, nas condições do experimento, que os dois desinfetantes podem ser usados em procedimentos de higiene frente às cepas APEC, apenas levando-se em consideração a concentração de uso e o tempo de contato.

The objectives of this study were to evaluate the effectiveness of the disinfectant benzalkonium chloride (QAC) and iodophor (I) on 10 strains APEC (Escherichia coli pathogenic avian) and verify that the high feature pathogenicity provides protection factor against these compounds. The method used was the dilution by the qualitative suspension test. The variables studied were: the concentrations of QAC (300, 150, 75 and 50 ppm) and I (100, 75, 50 and 25 ppm), contact times (5, 10 and 20 minutes) and room temperature (20°C). The QAC inactivated all strains at concentrations of 300 and 150 ppm at all contact times, but at 75 and 50 ppm in time of 5 minutes was not effective disinfectant for one and four APEC strains, respectively. The I 100 and 75 ppm inactivated isolates in all time periods, but 50 ppm one was tough and 25ppm eight were resistant in all exposure times. The highly pathogenic feature does not appear to promote resistance when compared with the standard strain. It was concluded, under the experimental conditions, the two disinfectants can be used in front of the hygiene procedures APEC strains, only taking into account the use concentration and contact time.

Assuntos

RESUMO

Os objetivos deste estudo foram avaliar a eficácia dos desinfetantes cloreto de benzalcônio (QAC) e iodóforo (I) sobre 10 cepas APEC (Escherichia coli patogênica aviária), bem como verificar se a característica alta patogenicidade está associada a uma maior resistência a estes compostos. O método utilizado foi o de diluição através do teste qualitativo de suspensão. As variáveis estudadas foram: concentrações do QAC (300, 150, 75 e 50 ppm) e do I (100, 75, 50 e 25 ppm), tempos de contato (5, 10 e 20 minutos) e temperatura ±20°C. O QAC inativou todos os isolados nas concentrações de 300 e 150 ppm, em todos os tempos de contato, porém a 75 e 50 ppm no tempo de 5 minutos o desinfetante não foi eficaz para uma e quatro amostras, respectivamente. O I a 100 e 75 ppm inativou os isolados em todos os tempos avaliados, mas a 50 ppm um foi resistente e a 25 ppm oito foram resistentes em todos os tempos de exposição. A característica alta patogenicidade não pareceu promover resistência, quando comparado com a cepa padrão. Concluiu-se, nas condições do experimento, que os dois desinfetantes podem ser usados em procedimentos de higiene frente às cepas APEC, apenas levando-se em consideração a concentração de uso e o tempo de contato.(AU)

The objectives of this study were to evaluate the effectiveness of the disinfectant benzalkonium chloride (QAC) and iodophor (I) on 10 strains APEC (Escherichia coli pathogenic avian) and verify that the high feature pathogenicity provides protection factor against these compounds. The method used was the dilution by the qualitative suspension test. The variables studied were: the concentrations of QAC (300, 150, 75 and 50 ppm) and I (100, 75, 50 and 25 ppm), contact times (5, 10 and 20 minutes) and room temperature (20°C). The QAC inactivated all strains at concentrations of 300 and 150 ppm at all contact times, but at 75 and 50 ppm in time of 5 minutes was not effective disinfectant for one and four APEC strains, respectively. The I 100 and 75 ppm inactivated isolates in all time periods, but 50 ppm one was tough and 25ppm eight were resistant in all exposure times. The highly pathogenic feature does not appear to promote resistance when compared with the standard strain. It was concluded, under the experimental conditions, the two disinfectants can be used in front of the hygiene procedures APEC strains, only taking into account the use concentration and contact time.(AU)

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RESUMO

Background: Avian pathogenic E. coli (APEC) and uropathogenic E. coli (UPEC) are responsible, respectively, for avian colibacillosis and for 80% of urinary tract infections in humans. E. coli control is difficult due to the absence of a reliable method to differentiate pathogenic and commensal strains. Genetic similarity between APEC and UPEC suggests a common ancestral origin and the capability of potentially pathogenic strains to affect human health. The classification in phylogenetic groups facilitates the identification of pathogenic strains. The objective of this work was to classify APEC and UPEC E. coli strains into phylogenetic groups and to associate it with in vivo pathogenicity. Materials, Methods & Results: 460 APEC and 450 UPEC strains, stored in BHI with glycerol at -80°C, were selected. APEC strains were isolated from cellulitis, respiratory tract and poultry litter of broiler flocks from Southern Brazil. The UPEC strains from urinary tract infection were provided by a hospital in Porto Alegre. After DNA extraction, APEC and UPEC strains were classified into four phylogenetic groups (A, B1, B2 and D) by a multiplex-PCR protocol for the detection of the chuA and yjaA genes and the TspE4.C2 DNA fragment. Phylogenetic groups were associated with pathogenicity indexes (PI), presented on a scale of 0 to 10, which were previously obtained through the inoculation of APEC strains in one-day-old chicks. Phylogenetic groups were also associated with the presence of 38 virulence-associated genes. The multiplex-PCR protocol was able to differentiate 100% of the APEC and UPEC strains in the four phylogenetic groups. The majority of APEC strains were classified into phylogenetic groups D (31.1%) and B2 (24.1%). On the other hand, the majority of UPEC strains were classified into B2 (53.6%). Among APEC strains, five genes (crl, mat, ompA, fimC and fimH) […](AU)

Assuntos

RESUMO

Background: Avian pathogenic E. coli (APEC) and uropathogenic E. coli (UPEC) are responsible, respectively, for avian colibacillosis and for 80% of urinary tract infections in humans. E. coli control is difficult due to the absence of a reliable method to differentiate pathogenic and commensal strains. Genetic similarity between APEC and UPEC suggests a common ancestral origin and the capability of potentially pathogenic strains to affect human health. The classification in phylogenetic groups facilitates the identification of pathogenic strains. The objective of this work was to classify APEC and UPEC E. coli strains into phylogenetic groups and to associate it with in vivo pathogenicity. Materials, Methods & Results: 460 APEC and 450 UPEC strains, stored in BHI with glycerol at -80°C, were selected. APEC strains were isolated from cellulitis, respiratory tract and poultry litter of broiler flocks from Southern Brazil. The UPEC strains from urinary tract infection were provided by a hospital in Porto Alegre. After DNA extraction, APEC and UPEC strains were classified into four phylogenetic groups (A, B1, B2 and D) by a multiplex-PCR protocol for the detection of the chuA and yjaA genes and the TspE4.C2 DNA fragment. Phylogenetic groups were associated with pathogenicity indexes (PI), presented on a scale of 0 to 10, which were previously obtained through the inoculation of APEC strains in one-day-old chicks. Phylogenetic groups were also associated with the presence of 38 virulence-associated genes. The multiplex-PCR protocol was able to differentiate 100% of the APEC and UPEC strains in the four phylogenetic groups. The majority of APEC strains were classified into phylogenetic groups D (31.1%) and B2 (24.1%). On the other hand, the majority of UPEC strains were classified into B2 (53.6%). Among APEC strains, five genes (crl, mat, ompA, fimC and fimH) […]

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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.

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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: Avian Pathogenic Escherichia coli is the main agent of colibacillosis, a systemic disease that causes considerable economic losses to the poultry industry. In vivo experiments are used to measure the ability of E. coli to be pathogenic. Generally, these experiments have proposed different criteria for results interpretation and did not take into account the death time. The aim of this study was to propose a new methodology for the classification of E. coli pathogenicity by the establishment of a pathogenicity index based in the lethality, death time and the ability of the strain to cause colibacillosis lesions in challenged animals. Materials, Methods & Results: A total of 293 isolates of E. coli were randomly selected to this study. The strains were isolated from cellulitis lesions, broiler bedding material or respiratory diseases and were previously confirmed through biochemical profile. The bacterial isolates were kept frozen at -20C. The strains were retrieved from stocks and cultured in brain-heart infusion broth overnight at 37C to obtain a final concentration of 109 UFC/mL. A total of 2940 one-dayold chicks from commercial breeding hens were randomly assigned to groups containing 10 animals and each group was subcutaneously inoculated in the abdominal region with 0.1 mL of the standard inoculum solution containing each of the strains. A control group [...](AU)

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RESUMO

Background: Avian Pathogenic Escherichia coli is the main agent of colibacillosis, a systemic disease that causes considerable economic losses to the poultry industry. In vivo experiments are used to measure the ability of E. coli to be pathogenic. Generally, these experiments have proposed different criteria for results interpretation and did not take into account the death time. The aim of this study was to propose a new methodology for the classification of E. coli pathogenicity by the establishment of a pathogenicity index based in the lethality, death time and the ability of the strain to cause colibacillosis lesions in challenged animals. Materials, Methods & Results: A total of 293 isolates of E. coli were randomly selected to this study. The strains were isolated from cellulitis lesions, broiler bedding material or respiratory diseases and were previously confirmed through biochemical profile. The bacterial isolates were kept frozen at -20C. The strains were retrieved from stocks and cultured in brain-heart infusion broth overnight at 37C to obtain a final concentration of 109 UFC/mL. A total of 2940 one-dayold chicks from commercial breeding hens were randomly assigned to groups containing 10 animals and each group was subcutaneously inoculated in the abdominal region with 0.1 mL of the standard inoculum solution containing each of the strains. A control group [...]

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Para impedir a dispersão de microrganismos patogênicos ao longo da cadeia avícola medidas de biosseguridade são adotadas, sendo a desinfecção procedimento obrigatório e o composto químico cloreto de benzalcônio (quaternário de amônio) largamente usado para essa finalidade. Devido ao fato de que parte das criações brasileiras localizam-se em regiões com grande amplitude térmica, o mesmo ocorrendo entre as diferentes áreas e secções de matadouros-frigoríficos, executou-se este experimento para verificar a atividade desse desinfetante simulando condições de uso frente a 33 isolados de Salmonella Hadar. Pelo teste de suspensão observou-se a inativação bacteriana sob as variáveis concentração (100 e 200 ppm), temperatura (20 ± 2 ºC e 8 ± 2 ºC), carga de matéria orgânica (1 e 3 %) e tempos de contato (5, 10 e 20 minutos). Como resultados, a 20 ± 2 ºC todos os isolados foram inativados nas duas concentrações e cargas orgânicas após 5 minutos de contato. Sob temperatura de 8 ± 2 ºC o desinfetante teve sua atividade comprometida, tendo isolados bacterianos sobrevivido sob todas as variáveis de confronto (33,3% frente 100 ppm e 6,1% frente 200 ppm). Quanto menor a concentração do desinfetante e maior carga orgânica, maior o número de isolados viáveis. Conclui-se que, nas condições do experimento, o cloreto de benzalcônio foi capaz de inativar todos os isolados do sorovar de Salmonella confrontados, podendo ser empregado nos procedimentos de desinfecção. No entanto, a baixa temperatura ambiente é fator de limitação na indicação de seu uso.

Biosafety measures are adopted in order to avoid the spreading of pathogenic microorganisms along the poultry chain, with disinfection being a mandatory procedure and the chemical compound benzalkonium chloride (quaternary ammonium) widely used for this purpose. Due to the fact that part of the farming in Brazil is located in areas with a great thermal amplitude, which is also the case among the different areas and sections of slaughterhouses, we performed an experiment to verify the activity of this disinfectant, simulating conditions of use with 33 Salmonella Hadar isolates. Using the test suspension, the inactivation of the bacteria was monitored under different concentrations (100 and 200 ppm), temperatures (20 ± 2 ºC and 8 ± 2 ºC), organic matter loading (1 and 3 %) and contact times (5, 10 and 20 minutes). As a result, all isolates in the two concentrations and organic loading were inactivated at 20 ± 2 ºC after a contact time of 5 minutes. At a temperature of 8 ± 2 ºC, the disinfectant’s activity was affected, with bacterial isolates surviving under all adverse variables (33,3% in front of 100 ppm and 6,1% in front of 200 ppm). Under the conditions of the experiment, our conclusion is that benzalkonium chloride was able to inactivate all isolates of the Salmonella serovars found and, therefore, it can be used in disinfection procedures. However, a low room temperature is a factor that limits indicating its use.

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