RESUMO
Abstract Objectives: Evaluate the association between rifampicin resistance and the presence of at least one SNP in the rpoB and ponA1 genes and the spoligotype defined lineages. Material and Methods: This study analyzed two databases of 484 genomes of M. tuberculosis from strains isolated from patients in the cities of Lima and Callao, for which the odds ratio (OR) was calculated considering belonging to a certain spoligotype defined lineages as an exposure factor. Results: No statistically significant association (ρ value> 0.05) was found between the presence of at least one SNP in the rpoB gene and the lineages included in the study (LAM, Haarlem, T and Beijing). However, a statistically significant association was found between the presence of at least one SNP in the ponA1 gene and the LAM and Haarlem lineages (ρ value <0.05). An association was found between the P631S SNP in the ponA1 gene and the LAM and Haarlem lineages; and the A516T SNP, of this same gene, presented an association with the LAM lineage. Likewise, an association was found between rifampicin resistance and the LAM lineage. Conclusions: The presence of SNPs in the ponA1 gene is associated with the LAM and Haarlem lineages.
Resumen Objetivos: Evaluar la asociación entre la resistencia a rifampicina y la presencia de al menos un SNP en los genes rpoB y ponA1 y los linajes definidos por espoli gotipos. Material y Métodos: Este estudio analizó dos bases de datos de 484 genomas de M. tuberculosis de cepas aisladas de pacientes de las ciudades de Lima y Callao, para lo cual se calculó el odds ratio (OR) considerando la pertenencia a determinado linaje definido por espoligotipos como un factor de exposición. Resultados: No se encontró una asociación estadísticamente significativa (valor de ρ >0.05) entre la presencia de al menos un SNP en el gen rpoB y los linajes incluidos en el estudio (LAM, Haarlem, T y Beijing). No obstante, se halló una asociación estadísticamente significativa entre la presencia de al menos un SNP en el gen ponA1 y los linajes LAM y Haarlem (valor de ρ <0.05). Se encontró una asociación entre el SNP P631S del gen ponA1 y los linajes LAM y Haarlem; y el SNP A516T, de este mismo gen, presentó una asociación con el linaje LAM. Asimismo, se halló una asociación entre la resistencia a rifampicina y el linaje LAM. Conclusiones: La presencia de SNPs en el gen ponA1 está asociada con los linajes LAM y Haarlem.
RESUMO
O Mycobacterium bovis causa a tuberculose zoonótica, doença que afeta os animais e o homem podendo causar a morte, sendo o leite uma importante via de transmissão da doença para o homem. A pasteurização do leite é a principal medida para quebrar essa cadeia de transmissão, cujos parâmetros de tempo e temperatura foram definidos através de experimentos que datam desde o fim do século XIX, com base na resistência térmica do M. bovis e da Coxiella burnetti, então considerados os mais resistentes patógenos não formadores de esporos que contaminam o leite. No Brasil são aprovados os binômios 62ºC a 65ºC por 30 minutos e 72ºC a 75ºC por 15 a 20 segundos. Entretanto, com o passar dos anos e surgimento de novas tecnologias (PCR, Spoligotyping e outras técnicas biomoleculares) foi possível observar diferenças genéticas intra-espécie. Assim, este projeto tem por objetivo avaliar e comparar o comportamento de dois espoligotipos de M. bovis (SB0120 e SB1033) frente aos dois protocolos de pasteurização utilizados no país. Para tanto, leite integral UHT foi contaminado com esses espoligotipos e submetido aos dois processos térmicos, em Banho-Maria. O leite foi semeado em meio sólido Stonebrink-Leslie e a contagem de colônias foi feita após 45 dias de incubação a 37ºC. Não houve neste experimento diferença entre as resistências térmicas dos dois espoligotipos, no entanto detectou-se uma maior importância da fase de aquecimento na redução do agente do que da fase de manutenção da temperatura, para os dois espoligotipos, nos dois processos.
Mycobacterium bovis causes zoonotic tuberculosis disease that affects animals and humans and can cause death, the milk is an important route of disease transmission to humans. The pasteurization of milk is the main measure to break the transmission chain, whose time and temperature parameters were defined by experiments dating from the late nineteenth century, based on thermal resistance of M. bovis and Coxiella burnetti, considered then the most resistant non-spore-forming pathogens that contaminate the milk. In Brazil, there are two approved binomials 62ºC to 65ºC for 30 minutes and 72ºC to 75ºC for 15 to 20 seconds. However, over the years and the emergence of new technologies (PCR, spoligotyping and other biomolecular techniques) was observed genetic differences intra-species. Thus, this project aims to evaluate and compare the behavior of two spoligotypes of M. bovis (SB0120 and SB1033) compared to the two pasteurization protocols used in the country. To this end, UHT milk was contaminated with these spoligotypes and subjected to two thermal processes in a water bath. The milk was streaked on solid medium Stonebrink-Leslie and colony counting was done after 45 days of incubation at 37ºC. This experiment showed that there was no difference between the thermal resistances of the two spoligotypes, however it was detected a greater importance of the heating phase in reducing the agent that the maintenance phase of temperature for the two spoligotypes, in both cases.