Ocorrência de Campylobacter spp. em fígados de frangos com e sem lesões de necrose hepática
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2010
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Este estudo foi desenvolvido com a finalidade de compreender a possível intervenção de Campylobacter spp. como agente etiológico de lesões de necrose em fígados de frangos abatidos para consumo.
Desta forma, procedeu-se ao isolamento de Campylobacter spp. de amostras de fígado de frango com e sem lesões necróticas. Adicionalmente foram analisados factores de virulência (cadF e cdtB) e perfil de resistência a antibióticos das estirpes isoladas. De um total de 45 amostras de fígados analisadas, 24 apresentavam lesões e 21 não possuíam lesões. Campylobacter spp. foi isolado de 70,8% das amostras de fígado com lesões necróticas (17/24) e de 33,3% das amostras de fígado sem lesões (7/21). Este resultado permite afirmar que existe uma associação altamente significativa (Phi =0,472, valor de p <0,01) entre a presença de fígados com lesões de necrose hepática e o isolamento de Campylobacter. Foi observada uma elevada resistência ao ácido nalidíxico (100%), norfloxacina (100%), ciprofloxacina (95,8%), ampicilina (91,6%) e tetraciclina (75%) nos isolados de Campylobacter spp. Adicionalmente, pela técnica de PCR, identificou-se a presença de genes de virulência, cdtB e cadF, em 75% e 68,8% de amostras positivas, respectivamente. Estirpes isoladas de fígado com e sem lesões apresentaram resultados semelhantes no que diz respeito aos factores de virulência e perfil de resistência aos antibióticos, demonstrando que estirpes potencialmente patogénicas são comuns entre os isolados de fígados de aves.
A relação entre a presença de lesões necróticas hepáticas e a infecção por Campylobacter spp. observada neste estudo, indica a possibilidade de utilizar essas lesões macroscópicas como indicador visível e de confiança da presença de Campylobacter spp. no bando de aves, tornando-se assim uma importante ferramenta para apoiar a implementação de medidas de correcção a nível de explorações avícolas. Esta metodologia pode contribuir para uma monitorização rápida e eficaz dos efectivos, permitindo a aplicação de medidas de intervenção efectivas e atempadas na exploração com vista a reduzir a infecção por Campylobacter spp.
This study was developed in order to understand the possible intervention of Campylobacter spp. as etiological agent of necrotic hepatic lesions in poultry. This way, Campylobacter spp. was isolated from poultry liver with and without necrotic lesions. Additionally, virulence factors (cadF and cdtB) and antimicrobial resistance profile of the isolated strains were analysed. From a total of 45 liver samples analysed, 24 presented lesions and 21 were clean. Campylobacter spp. was isolated from 70.8% of liver samples with necrotic lesions (17/24) and from 33.3% of liver samples without lesions (7/21). This result enables to state that exists a highly significant association (Phi = 0.472; p-value < 0.01) between the presence of livers with hepatic necrosis lesions and Campylobacter isolation. A high resistance to nalidixic acid (100%), norfloxacin (100%), ciprofloxacin (95.8%), ampicillin (91.6%) and tetracycline (75%) was observed among Campylobacter spp. isolates. Also, PCR detection of cdtB and cadF virulence and toxin genes, revealed 75% and 68.8% of positive samples, respectively. Strains isolated from livers with and without lesions presented similar results with respect to virulence factors and to antimicrobial resistance profiles, demonstrating that these putative pathogenic determinants are widespread among the isolates from poultry livers. The relationship between the presence of hepatic necrotic lesions and Campylobacter spp. infection observed in this study, indicates the possibility of using these macroscopic lesions as visible and reliable indicator of Campylobacter spp. presence in poultry flock, and, thus, becoming an important tool to support the implementation of corrective measures at poultry farms level. This methodology could contribute for an accurate time-efficient monitoring and to the development of effective prevention and intervention measures for Campylobacter spp. infection as well as cost reduction.
This study was developed in order to understand the possible intervention of Campylobacter spp. as etiological agent of necrotic hepatic lesions in poultry. This way, Campylobacter spp. was isolated from poultry liver with and without necrotic lesions. Additionally, virulence factors (cadF and cdtB) and antimicrobial resistance profile of the isolated strains were analysed. From a total of 45 liver samples analysed, 24 presented lesions and 21 were clean. Campylobacter spp. was isolated from 70.8% of liver samples with necrotic lesions (17/24) and from 33.3% of liver samples without lesions (7/21). This result enables to state that exists a highly significant association (Phi = 0.472; p-value < 0.01) between the presence of livers with hepatic necrosis lesions and Campylobacter isolation. A high resistance to nalidixic acid (100%), norfloxacin (100%), ciprofloxacin (95.8%), ampicillin (91.6%) and tetracycline (75%) was observed among Campylobacter spp. isolates. Also, PCR detection of cdtB and cadF virulence and toxin genes, revealed 75% and 68.8% of positive samples, respectively. Strains isolated from livers with and without lesions presented similar results with respect to virulence factors and to antimicrobial resistance profiles, demonstrating that these putative pathogenic determinants are widespread among the isolates from poultry livers. The relationship between the presence of hepatic necrotic lesions and Campylobacter spp. infection observed in this study, indicates the possibility of using these macroscopic lesions as visible and reliable indicator of Campylobacter spp. presence in poultry flock, and, thus, becoming an important tool to support the implementation of corrective measures at poultry farms level. This methodology could contribute for an accurate time-efficient monitoring and to the development of effective prevention and intervention measures for Campylobacter spp. infection as well as cost reduction.
Descrição
Dissertação de Mestrado em Segurança Alimentar
Palavras-chave
Campylobacter , Fígado , Frango , Necrose hepática , Matadouro , Liver , Poultry , Hepatic necrosis , Slaughterhouse