Estudo da prevalência de Staphylococcus aureus resistentes à meticilina (MRSA) isolados de águas residuais hospitalares
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2021-02-18
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As águas residuais hospitalares são frequentemente descarregadas em redes de saneamento públicas e, quando não são sujeitas a um tratamento adequado, conduzem ao desenvolvimento e disseminação de bactérias resistentes a antibióticos. Estas bactérias são capazes de entrar em contacto com o ser humano, direta ou indiretamente, podendo levar a uma infeção com consequências graves. Este trabalho teve como principal objetivo o estudo da prevalência de Staphylococcus aureus resistente à meticilina (MRSA) em águas residuais do Centro Hospitalar de Trásos-Montes e Alto Douro (CHTMAD). Para além disso, foi também analisada a prevalência de MRSA em águas tratadas na Estação de Tratamento de Águas Residuais (ETAR) do Hospital de S. Pedro com o intuito de verificar a sua eficácia. Cada um dos isolados foi sujeito a testes de suscetibilidade a antibióticos e foi avaliada a sua capacidade de formação de biofilme. Noventa e seis amostras foram recolhidas entre outubro de 2019 e março de 2020: 24 do Hospital de S. Pedro, 24 do Hospital de Proximidade de Lamego, 24 do Hospital Distrital de Chaves e 24 da ETAR do Hospital de S. Pedro. O isolamento das bactérias foi realizado através de meios seletivos de crescimento e testes bioquímicos para confirmação. A suscetibilidade foi determinada através do método de difusão de disco Kirby-Bauer e, para além disso, foi realizado ainda o Teste-D. Por fim, a capacidade de formação de biofilme das bactérias foi analisada através do ensaio em placa de microtitulação e do método Vermelho do Congo agar. Foram isolados 45 MRSA dos efluentes hospitalares e 1 MRSA das águas residuais tratadas na ETAR do Hospital de S. Pedro, o que revela que o tratamento realizado não é totalmente eficaz. 96% dos isolados foram considerados multirresistentes e 43% apresentou o fenótipo iMLSB. Todos apresentam capacidade de produção de biofilme. Assim, o problema das infeções por MRSA resulta não só da ocorrência de multirresistências, mas também do aparecimento de bactérias capazes de formar biofilmes e, para combater esta problemática, devemos implementar uma perspetiva One Health, tendo em conta MRSA associados a humanos e a animais e, também, potenciais fontes de contaminação ambiental, como as ETARs, integrando os vários sistemas de saúde e o ecossistema.
Hospital wastewater is often discharged into public sanitation networks and, when not properly treated, it leads to the development and spread of antibiotic-resistant bacteria. These bacteria are able to come in contact with humans, directly or indirectly, and can lead to an infection with serious consequences. This work had as main objective the study of the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) from wastewater of Trás-os-Montes and Alto Douro Hospital Center (CHTMAD). In addition, the prevalence of MRSA in water treated by the Wastewater Treatment Plant (WWTP) of S. Pedro’s Hospital was also analyzed in order to evaluate its effectiveness. Each strain was subjected to antibiotic susceptibility tests and their ability to form biofilms was assessed. Ninety-six samples were collected between October 2019 and March 2020: 24 from S. Pedro Hospital, 24 from Lamego Proximity Hospital, 24 from Chaves District Hospital and 24 from S. Pedro Hospital WWTP. The isolation of the bacteria was carried out using selective growth media and biochemical tests for confirmation. The susceptibility test was performed by the Kirby-Bauer disk diffusion method and, in addition, it was also performed the D-Test. Finally, the biofilm production ability was evaluated through the microtiter plate assay and Congo Red agar method. 45 MRSA were isolated from the hospital effluents and 1 MRSA was isolated from treated water from S. Pedro Hospital WWTP, which reveals that the treatment carried out is not totally effective. 96% of the isolates were multidrug-resistant and 43% had the iMLSB phenotype. In addition, all of the isolates also had the ability to produce biofilm. Thus, the problem of MRSA infections results not only from the occurrence of multidrug resistance, but also from the appearance of bacteria capable of forming strong biofilms and, to combat this problem we must take into account a One Health perspective, associating MRSA with humans and animals and also potential sources of environmental contamination, such as WWTPs, and integrating the various health systems and ecosystems.
Hospital wastewater is often discharged into public sanitation networks and, when not properly treated, it leads to the development and spread of antibiotic-resistant bacteria. These bacteria are able to come in contact with humans, directly or indirectly, and can lead to an infection with serious consequences. This work had as main objective the study of the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) from wastewater of Trás-os-Montes and Alto Douro Hospital Center (CHTMAD). In addition, the prevalence of MRSA in water treated by the Wastewater Treatment Plant (WWTP) of S. Pedro’s Hospital was also analyzed in order to evaluate its effectiveness. Each strain was subjected to antibiotic susceptibility tests and their ability to form biofilms was assessed. Ninety-six samples were collected between October 2019 and March 2020: 24 from S. Pedro Hospital, 24 from Lamego Proximity Hospital, 24 from Chaves District Hospital and 24 from S. Pedro Hospital WWTP. The isolation of the bacteria was carried out using selective growth media and biochemical tests for confirmation. The susceptibility test was performed by the Kirby-Bauer disk diffusion method and, in addition, it was also performed the D-Test. Finally, the biofilm production ability was evaluated through the microtiter plate assay and Congo Red agar method. 45 MRSA were isolated from the hospital effluents and 1 MRSA was isolated from treated water from S. Pedro Hospital WWTP, which reveals that the treatment carried out is not totally effective. 96% of the isolates were multidrug-resistant and 43% had the iMLSB phenotype. In addition, all of the isolates also had the ability to produce biofilm. Thus, the problem of MRSA infections results not only from the occurrence of multidrug resistance, but also from the appearance of bacteria capable of forming strong biofilms and, to combat this problem we must take into account a One Health perspective, associating MRSA with humans and animals and also potential sources of environmental contamination, such as WWTPs, and integrating the various health systems and ecosystems.
Descrição
Dissertação de Mestrado em Biologia Clínica Laboratorial
Palavras-chave
águas residuais hospitalares , ETAR