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Isolamento e caracterização de Enterococcus spp. do ambiente hospitalar e de amostras clínicas humanas: vigilância da resistência a antibióticos
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Resumo(s)
Enterococcus spp. são bactérias comensais do trato gastrointestinal, encontrando-se igualmente
dispersas no meio ambiente. Enquanto microrganismos patogénicos oportunistas, têm sido responsáveis por um elevado número de infeções associadas aos cuidados de saúde (IACS), devido ao seu potencial de virulência e multirresistência a antibióticos. No ambiente hospitalar, Enterococcus spp. contaminam uma variedade de superfícies bióticas e abióticas, o que favorece a sua transmissão e disseminação. Neste sentido, o objetivo do presente estudo foi o isolamento e caracterização de Enterococcus spp. do ambiente hospitalar e de amostras clínicas humanas, com foco na biovigilância da resistência a antibióticos.
A coleção microbiana em estudo (n=276), composta por 128 isolados recuperados do ambiente
hospitalar e 148 enterococos obtidos de amostras clínicas, foi primeiramente analisada por RAPDPCR, para se selecionar isolados geneticamente distintos. Os 115 representantes escolhidos foram
identificados ao nível de espécie, tendo-se confirmado a predominância de E. faecalis e, de seguida,
avaliou-se atividade hemolítica e a resistência a diferentes antibióticos (fenótipo de resistência e pesquisa de alguns genes associados).
Enterococos de amostras clínicas revelaram maior capacidade hemolítica, em relação aos recuperados do ambiente hospitalar. Quanto à resistência antimicrobiana, observaram-se diferentes níveis de
resistência entre isolados de diferentes origens e espécies e, alguns foram considerados multirresistentes (n=2 e n=9, consoante o critério aplicado). A pesquisa de genes de resistência mostrou a ausência
de vanA em isolados resistentes à vancomicina, enquanto 67% dos resistentes à gentamicina apresentaram o gene aacA-aphD, estando ermB presente em 75% dos isolados fenotipicamente resistentes à
eritromicina.
Em conclusão, o presente estudo permitiu avaliar a prevalência de Enterococcus spp. em contexto
clínico, bem como a resistência a antibióticos associada aos isolados em análise. Estudos direcionados
para a monitorização de padrões de resistência são extremamente importantes para ajudar a controlar
infeções e/ou limitar a propagação de enterococos resistentes a antibióticos no ambiente hospitalar.
Enterococcus spp. are commensal bacteria of the gastrointestinal tract and are also dispersed in the environment. As opportunistic pathogenic microorganisms, enterococci have been responsible for a high number of healthcare-associated infections (HAIs), due to their virulence potential and multiresistance to antibiotics. In the hospital environment, Enterococcus spp. contaminates a variety of biotic and abiotic surfaces, which favors its transmission and spread. In this sense, the aim of the present study was the isolation and characterization of Enterococcus spp. from the hospital environment and human clinical samples, with a focus on the biovigilance of antibiotic resistance. The microbial collection under study (n=276), consisting of 128 isolates recovered from the hospital environment and 148 enterococci obtained from clinical samples, was first analyzed by RAPDPCR, to select genetically distinct isolates. The 115 chosen representatives were identified to the species level, having confirmed the predominance of E. faecalis, and then evaluated hemolytic activity and resistance to different antibiotics (resistance phenotype and research of some associated genes). Enterococci from clinical samples revealed greater hemolytic capacity compared to those recovered from the hospital environment. Regarding antimicrobial resistance, different levels of resistance were observed between isolates of different origins and species, and some were considered multidrugresistant (n=2 and n=9, depending on the criterium applied). Research of resistance genes showed the absence of vanA in vancomycin-resistant isolates, while 67% of those resistant to gentamicin presented the aacA-aphD gene, and ermB being present in 75% of isolates phenotypically resistant to erythromycin. In conclusion, the present study allowed to evaluate the prevalence of Enterococcus spp. in the clinical context, as well as the antibiotic resistance associated with the isolates under analysis. Studies aimed at monitoring resistance patterns are extremely important to help control infections and/or limit the spread of antibiotic-resistant enterococci in the hospital environment.
Enterococcus spp. are commensal bacteria of the gastrointestinal tract and are also dispersed in the environment. As opportunistic pathogenic microorganisms, enterococci have been responsible for a high number of healthcare-associated infections (HAIs), due to their virulence potential and multiresistance to antibiotics. In the hospital environment, Enterococcus spp. contaminates a variety of biotic and abiotic surfaces, which favors its transmission and spread. In this sense, the aim of the present study was the isolation and characterization of Enterococcus spp. from the hospital environment and human clinical samples, with a focus on the biovigilance of antibiotic resistance. The microbial collection under study (n=276), consisting of 128 isolates recovered from the hospital environment and 148 enterococci obtained from clinical samples, was first analyzed by RAPDPCR, to select genetically distinct isolates. The 115 chosen representatives were identified to the species level, having confirmed the predominance of E. faecalis, and then evaluated hemolytic activity and resistance to different antibiotics (resistance phenotype and research of some associated genes). Enterococci from clinical samples revealed greater hemolytic capacity compared to those recovered from the hospital environment. Regarding antimicrobial resistance, different levels of resistance were observed between isolates of different origins and species, and some were considered multidrugresistant (n=2 and n=9, depending on the criterium applied). Research of resistance genes showed the absence of vanA in vancomycin-resistant isolates, while 67% of those resistant to gentamicin presented the aacA-aphD gene, and ermB being present in 75% of isolates phenotypically resistant to erythromycin. In conclusion, the present study allowed to evaluate the prevalence of Enterococcus spp. in the clinical context, as well as the antibiotic resistance associated with the isolates under analysis. Studies aimed at monitoring resistance patterns are extremely important to help control infections and/or limit the spread of antibiotic-resistant enterococci in the hospital environment.
Descrição
Tese de mestrado, Microbiologia Aplicada, 2023, Universidade de Lisboa, Faculdade de Ciências
Palavras-chave
Enterococcus spp. ambiente hospitalar amostras clínicas resistência a antibióticos biovigilância Teses de mestrado - 2024