Caracterização de Staphylococcus spp. numa matriz alimentar e análise da resistência a antimicrobianos: Implicações em Saúde Pública
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2019-07-17
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A introdução dos antibióticos representa uma das intervenções mais importantes a nível da Saúde Pública, tendo permitido a redução da morbilidade e mortalidade causada por infeções de origem bacteriana. No entanto, o uso excessivo e inadequado, em todos os setores, levou ao aumento da resistência (e multirresistência) aos antibióticos e, consequentemente, à sua disseminação global, levando a um grave problema de Saúde Pública. Atualmente, os antibióticos estão a tornar-se cada vez menos eficazes e por essa razão, tem aumentado a procura de novos compostos antimicrobianos e medidas preventivas. Este trabalho focou-se na caracterização microbiológica da matriz alimentar – o Cusco – e na determinação da suscetibilidade a antibióticos, dos isolados obtidos. Para atingir tal objetivo, foram colhidas num total de 17 amostras, em dois períodos distintos. No primeiro período – Primavera/Verão – foram colhidas amostras do cusco pronto a consumir, de 4 produtores diferentes. Dada a carga microbiológica apresentada pelas análises realizadas, foram realizadas novas colheitas – período Outono/Inverno – selecionando-se um produtor, de modo aleatório, com o intuito de verificar possíveis fontes de contaminação e avaliar a estabilidade microbiológica do produto com o tempo de prateleira. Foram obtidos 60 isolados com características fenotípicas pertencentes maioritariamente ao género Staphylococcus. A identificação dos isolados foi realizada por métodos fenotípicos, através do sistema de biotipificação numérica API Staph, e por métodos genotípicos. O método genético utilizado foi a sequenciação parcial do gene 16S rDNA, onde foi obtida a identificação de 7 especies diferentes, nomeadamente, Staphylococcus succinus (25%), Staphylococcus xylosus (21,9%), Staphylococcus saprophyticus (18,8%), Staphylococcus pasteuri (15,6%), Staphylococcus kloosii (12,5%), Staphylococcus aureus (3,1%) e Kocuria uropygioeca (3,1%). Para a avaliação do perfil de suscetibilidade, foram testados 18 antibióticos, verificando-se multirresistência em dois isolados. De notar que, os isolados identificados geneticamente como S. succinus, apresentam resistência à rifampicina, tobramicina e gentamicina, na mesma percentagem. Os isolados identificados geneticamente como S. xylosus, apresentam resistência à levofloxacina e tetraciclina, e ainda, os isolados identificados como S. saprophyticus apresentam resistência à tetraciclina e à tobramicina.
The introduction of antibiotics represents one of the most important interventions at the level of public health, allowing the reduction of morbidity and mortality caused by infections of bacterial origin. However, its excessive and inadequate use in all sectors has led to increased resistance (and multidrug resistance) to antibiotics and, consequently, to its global dissemination, leading to a serious public health problem. Currently, antibiotics are becoming increasingly less effective and for this reason, the demand for new antimicrobial compounds and for preventive measures has increased. This work focused on the microbiological characterization of the food matrix – Cusco – and in the determination of susceptibility to antibiotics of the isolates obtained. To achieve this objective, a total of 17 samples were collected in two different periods. In the first period – spring/summer – samples of the ready-to-consume cusco from 4 different producers were collected. Given the microbiological load presented by the analyses carried out, new harvests were made – autumn/winter period – selecting a producer, randomly, with the aim of verifying possible sources of contamination and evaluating the microbiological stability of the product with shelf time. 60 isolates with phenotypic characteristics belonging to the genus Staphylococcus spp. were obtained. Bacterial isolates were identified by phenotypic methods, using the system of numerical biotyping API Staph, and genotypic methods. The genetic method used was the partial sequencing of the 16S rDNA gene, obtaining 7 different species, namely, Staphylococcus succinus (25%), Staphylococcus xylosus (21.9%), Staphylococcus saprophyticus (18.8%), Staphylococcus pasteuri (15.6%), Staphylococcus kloosii (12.5%), Staphylococcus aureus (3.1%) and Kocuria uropygioeca (3.1%). For the evaluation of the susceptibility profile, 18 antibiotics were tested, and multidrug resistance was verified in two isolates. It should be noted that the isolates genetically identified as S. succinus showed resistance to rifampicin, trobamicin and gentamicin, in the same percentage. The isolates genetically identified as S. xylosus, showed resistance to levofloxacin and tetracycline, and isolates identified as S. saprophyticus showed resistance to tetracycline and tobramycin.
The introduction of antibiotics represents one of the most important interventions at the level of public health, allowing the reduction of morbidity and mortality caused by infections of bacterial origin. However, its excessive and inadequate use in all sectors has led to increased resistance (and multidrug resistance) to antibiotics and, consequently, to its global dissemination, leading to a serious public health problem. Currently, antibiotics are becoming increasingly less effective and for this reason, the demand for new antimicrobial compounds and for preventive measures has increased. This work focused on the microbiological characterization of the food matrix – Cusco – and in the determination of susceptibility to antibiotics of the isolates obtained. To achieve this objective, a total of 17 samples were collected in two different periods. In the first period – spring/summer – samples of the ready-to-consume cusco from 4 different producers were collected. Given the microbiological load presented by the analyses carried out, new harvests were made – autumn/winter period – selecting a producer, randomly, with the aim of verifying possible sources of contamination and evaluating the microbiological stability of the product with shelf time. 60 isolates with phenotypic characteristics belonging to the genus Staphylococcus spp. were obtained. Bacterial isolates were identified by phenotypic methods, using the system of numerical biotyping API Staph, and genotypic methods. The genetic method used was the partial sequencing of the 16S rDNA gene, obtaining 7 different species, namely, Staphylococcus succinus (25%), Staphylococcus xylosus (21.9%), Staphylococcus saprophyticus (18.8%), Staphylococcus pasteuri (15.6%), Staphylococcus kloosii (12.5%), Staphylococcus aureus (3.1%) and Kocuria uropygioeca (3.1%). For the evaluation of the susceptibility profile, 18 antibiotics were tested, and multidrug resistance was verified in two isolates. It should be noted that the isolates genetically identified as S. succinus showed resistance to rifampicin, trobamicin and gentamicin, in the same percentage. The isolates genetically identified as S. xylosus, showed resistance to levofloxacin and tetracycline, and isolates identified as S. saprophyticus showed resistance to tetracycline and tobramycin.
Descrição
Dissertação de Mestrado em Biologia Clínica Laboratorial
Palavras-chave
Cuscos , Doenças de origem alimentar