Detection and molecular characterization of Chlamydia spp. in poultry and backyard chickens in Brazil

• Ano de defesa: 2023
• Autor(a) principal: Pinto, Maria Catalina Ospina
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: C. gallinacea; C. gallinacean; Chlamydiaceae; Backyard chickens; Galinhas de fundo de quintal; Industria avícola; PCR; Poultry industry
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/10/10133/tde-12062023-145235/

Avian chlamydiosis is an infectious disease that affects several species of birds, caused by bacteria of the Chlamydiaceae family. The recently recognized species Chlamydia gallinacea, has apparently been shown to be predominant in avian productions in different countries, and with incipient information in Brazil. Brazilian poultry production is a very important sector for both the family’s and the countrys economy, as well as Brazil is considered a food supplier and a showcase for the world. Sanitary studies on pathogens that can affect production parameters and cause economic losses are relevant both in industrial and backyard properties. Therefore, the objective of this project was to investigate the presence of Chlamydia spp. and to determine the species involved in commercial and subsistence birds in Brazil. Cloacal swabs were collected from subsistence chickens from three states in the southern region of Brazil (Paraná, Santa Catarina and Rio Grande do Sul), and from four flocks from layer breeder hens in the state of Pernambuco with ages ranging from 5 to 62 weeks. DNA samples were tested using polymerase chain reaction (PCR) for different species of Chlamydia, namely Chlamydiaceae (23S rRNA gene), C. psittaci (ompA gene), C. avium (enoA gene) and C. gallinacea (gidA and enoA genes). Additionally, the 16S rRNA gene was used as confirmation for sequencing and phylogenetic analysis. The gidA gene from C. gallinacea was also used for sequencing. A total of 582 subsistence chicken samples were analyzed in 238 sample pools from 134 properties. From the commercial farm, 60 pools were analyzed. C. gallinacea was the only species identified in both commercial and subsistence birds. The presence of C. psittaci and C. avium was not detected. The phylogenetic analysis of the sequences obtained confirmed that the samples from the subsistence chickens corresponded to C. gallinacea, with a high percentage of identity (99.25% to 100%) with sequences available in GenBank of commercial chickens from Poland, France and China, and turkeys from Switzerland. It is of great relevance that C. psittaci was not detected in any property in both types of farming, considering that it is a zoonosis whose confirmation of a positive case must be notified. This agrees with what was found in poultry from all over the world, since in the case of commercial birds the presence of C. psittaci is commonly related to farms of species such as ducks and turkeys and, equally, in the case of subsistence birds it may be associated with contact with other animal species when it comes to mixed-species farms. This is the first detection of C. gallinacea in commercial chickens in the state of Pernambuco, as well as the first detection in subsistence chickens in Brazil. Considering the importance of Brazilian poultry farming, more studies should be carried out in commercial and backyard farms in other regions of the country to increase knowledge about the epidemiology of this recent Chlamydia species identified in chickens.