Sorologia e detecção molecular de Coxiella burnetii em bovinos no estado de São Paulo, Brasil.
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Data
2018-12-20
Autores
Mioni, Mateus de Souza Ribeiro [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Coxiella burnetii é uma bactéria intracelular obrigatória responsável por causar a febre Q em humanos, mas também é conhecida como coxielose em animais. No Brasil, pouco é sabido a respeito da epidemiologia da enfermidade. O presente estudo objetiva estabelecer a prevalência do patógeno em bovinos abatidos no estado de São Paulo, além da detecção molecular em soro e fetos de bovinos. A sorologia de 1515 amostras de bovinos coletadas em frigoríficos foi realizada por reação de imunofluorescência indireta (RIFI) para anticorpos anti-C. burnetii. Reação em cadeia da polimerase em tempo real (qPCR) visando detectar o gene IS1111, foi utilizada para o diagnóstico molecular de C. burnetii em amostras de soro e fetos de bovinos. A prevalência aparente para anticorpos anti-C. burnetii em bovinos foi de 23,8% [IC95%=21,7% – 25,9%] (n=360), e a prevalência real de 20,0% [IC95%=17,8 – 22,3%]. A qPCR foi realizada nas 360 amostras soropositivas e apresentou resultado positivo em 92 amostras (25,6% [IC95%=20,1% – 28,8%]), demonstrando a presença do micro-organismo na corrente sanguínea dos bovinos amostrados. Entre as 28 amostras de fetos bovinos analisados, 10,7% (n=3) foram positivas na qPCR, confirmado por sequenciamento. A análise por qPCR quantitativo das amostras de abortamentos indicaram concentração entre 500 – 104 células por grama de tecido. Análise de multilocus de repetições em tandem de número variável (MLVA) e Multispacer Sequence Typing (MST) das amostras de fetos e do controle positivo revelaram novas estirpes de C. burnetii circulando no Brasil e na Argentina. Os resultados aqui apresentados evidenciam a circulação da bactéria alertando para o risco para saúde pública.
Coxiella burnetii is an obligate intracellular bacterium responsible for causing Q fever in humans but is also known as coxiellosis in animals. In Brazil, little is known about the epidemiology of the disease. The present study aims to establish the prevalence of the pathogen in cattle slaughtered in the state of São Paulo, in addition to molecular detection in bovine serum and fetuses. The serology of 1515 bovine samples collected in slaughterhouses was performed by indirect immunofluorescence reaction (IFA) for anti-C. burnetii antibodies. Real-time polymerase chain reaction (qPCR) to detect the IS1111 gene was used for the molecular diagnosis of C. burnetii in bovine serum and fetal samples. The apparent prevalence of anti-C. burnetii antibodies in cattle was 23.8% [95% CI = 21.7% - 25.9%] (n = 360) and the true prevalence was 20.0% [95% = 17.8 - 22.3%]. The qPCR was performed in the 360 seropositive samples and presented a positive result in 92 samples (25.6% [95% CI = 20.1% - 28.8%]), demonstrating the presence of the microorganism in the blood stream of the sampled cattle. Among the 28 samples of bovine fetuses analyzed, 10.7% (n = 3) were positive in qPCR, confirmed by sequencing. Quantitative qPCR analysis of the abortion samples indicated concentration between 500-104 cells per gram of tissue. Multiple-Locus Variable number tandem repeat Analysis (MLVA) and Multispacer Sequence Typing (MST) from fetal samples and positive control revealed new strains of C. burnetii circulating in Brazil and Argentina. The results presented here evidenced the circulation of the bacterium alerting to the risk to public health.
Coxiella burnetii is an obligate intracellular bacterium responsible for causing Q fever in humans but is also known as coxiellosis in animals. In Brazil, little is known about the epidemiology of the disease. The present study aims to establish the prevalence of the pathogen in cattle slaughtered in the state of São Paulo, in addition to molecular detection in bovine serum and fetuses. The serology of 1515 bovine samples collected in slaughterhouses was performed by indirect immunofluorescence reaction (IFA) for anti-C. burnetii antibodies. Real-time polymerase chain reaction (qPCR) to detect the IS1111 gene was used for the molecular diagnosis of C. burnetii in bovine serum and fetal samples. The apparent prevalence of anti-C. burnetii antibodies in cattle was 23.8% [95% CI = 21.7% - 25.9%] (n = 360) and the true prevalence was 20.0% [95% = 17.8 - 22.3%]. The qPCR was performed in the 360 seropositive samples and presented a positive result in 92 samples (25.6% [95% CI = 20.1% - 28.8%]), demonstrating the presence of the microorganism in the blood stream of the sampled cattle. Among the 28 samples of bovine fetuses analyzed, 10.7% (n = 3) were positive in qPCR, confirmed by sequencing. Quantitative qPCR analysis of the abortion samples indicated concentration between 500-104 cells per gram of tissue. Multiple-Locus Variable number tandem repeat Analysis (MLVA) and Multispacer Sequence Typing (MST) from fetal samples and positive control revealed new strains of C. burnetii circulating in Brazil and Argentina. The results presented here evidenced the circulation of the bacterium alerting to the risk to public health.
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Palavras-chave
Abortamento, Coxiella burnetii, Febre Q, Saúde Pública