Browsing by Author "Subtil, João"
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- Adenoid bacterial colonization in a paediatric populationPublication . Subtil, João; Rodrigues, João Carlos; Reis, Lúcia; Freitas, Luís; Filipe, Joana; Santos, Alberto; Macor, Carlos; Duarte, Aida; Jordao, LuisaAdenoids play a key role in both respiratory and ear infection in children. It has also been shown that adenoidectomy improves these symptoms in this population. The main goal of the present study was to evaluate adenoid bacterial colonization and document a possible relation with infectious respiratory disease. A prospective observational study was designed to evaluate the proposed hypothesis in a paediatric population submitted to adenoidectomy by either infectious or non-infectious indications and compare these two cohorts. A total of 62 patients with ages ranging from 1 to 12 years old were enrolled in the study. Adenoid surface, adenoid core and middle meatus microbiota were compared. A close association between adenoid colonization and nasal infection was found, supporting that adenoids may function as bacterial reservoir for upper airway infection. The obtained results also contribute to explain the success of adenoidectomy in patients with infectious indications.
- Adenoids, friends or foes?Publication . Subtil, João; Lavado, Paula; Rodrigues, João; Rodrigues, Lúcia; Nogueira, Isabel; Duarte, Aida; Jordao, LuisaThe main goal of this study is to evaluate the existence of a link between biofilm assembly on adenoids and the incidence of recurrent infections within a paediatric population. Thirty-three different bacterial genera were isolated from 186 samples (nasal/adenoid scrubs and adenoid biopsies) being Haemophilus, Neisseria, Streptococcus and Staphylococcus the most frequent. Biofilms were present in 27.4% of the adenoid samples as assessed by SEM. Since the aim of the study is to assess the role of biofilms on adenoid colonization/ invasion and onset of infection a group of samples harbouring clinically relevant bacteria (H.influenzae, S. aureus, S. pyogenes, S. pneumococcus and Moraxella) both on the adenoid surface and core were selected for further studies. Based on biofilm assembly in vitro, assessed by crystal violet assay, bacteria were classified as weak, moderate and strong biofilm assemblers. No direct relation between the ability to assemble biofilms in vitro and the presence of biofilms on the adenoid (biofilm in vivo) was found. A similar result was obtained for antibiotic susceptibility with the majority of bacteria being antibiotic susceptible independently of its origin (sample with or without biofilms). This result might be explained at least partially, by the nature of the sample since the adenoidectomy can only be performed in individuals without infection. H. influenzae, the most isolated bacterium, is an opportunistic pathogen, highly adapted to colonize the upper respiratory tract and easily progresses to infection, especially in children. For this reason, virulence factors such as the capsular type were investigated by PCR. However, all strains were characterized as non-capsulated, which might explain adenoid colonization and biofilm formation, as have been also described in the literature. Further studies must be performed to validate the thesis that adenoids function as a reservoir of etiologic agents of respiratory and ear infections.
- Assessing the role played by biofilms on adenoidal surface in a pediatric populationPublication . Rodrigues, João; Reis, Lúcia; Nogueira, Isabel; Duarte, Aida; Subtil, João; Jordão, LuisaAdenoids are a mass of lymphatic tissue located within the nasopharynge. This work aims assessing the relationship between the formation of bacterial biofilms on the adenoid surface and the incidence of infections in the pediatric age.
- Biofilms within the human body and its clinical implicationsPublication . Jordão, Luísa; Subtil, João; Lavado, Paula; Rodrigues, João; Reis, Lúcia; Faria, Isabel; Pessanha, Maria AnaBiofilms with medical implications could be find on medical devices or on organs. Here we discuss the results obtained in two studies one associated with an organ (adenoid) and another associated with a medical device (central venous catheters- CVC). In the first study, we evaluate the association between biofilm assembly on adenoids and the incidence of recurrent infections in a paediatric population comparing adenoid samples from adenoidectomy groups with and without infectious indication. Biofilms were present in 27.4% of the adenoid samples. For H. influenzae, S. aureus, S. pyogenes, S. pneumococcus and M. catarrhalis, no association was found between ability to assemble biofilms in vitro and the presence of biofilms on adenoids, and the same was found for antibiotic resistance. The most isolated bacterium was H. influenzae that revealed after further characterization to be non-typeable (NT). No statistical difference was found on biofilm presence between the two groups, infectious versus non-infectious diagnosis. The same was true for biofilm assembling ability of bacteria found on adenoid surface and core. As in other studies, we did not find a correlation between biofilm formation and susceptibility or resistance to antibiotics and this raise the question of the importance of biofilms on the pathogenesis of infectious diseases. In the second study, we explore the relation between the presence of biofilms on central venous catheters and central venous catheter-related bloodstream infection (CRBSI). Our preliminary results (relative to data collected over 10 months) show that Staphylococci, either coagulase negative or positive, are major etiologic agents of this healthcare associated infection.
- A importância dos biofilmes em otorrinolaringologia pediátricaPublication . Duarte, Aida; Jordão, Luisa; Subtil, JoãoPontos-chave: Saber o que é um biofilme e como a sua estrutura é relevante par os micro-organismos; Saber que é ubiquitário na natureza e no nosso organismo; Reconhecer a sua importância clínica.
- Relação entre biofilmes na amígdala faríngea e incidência de infeções recorrentes em população pediátrica - estudo observacional transversalPublication . Subtil, João; Jordao, Luisa; Freitas, Luis; Santos, A.; Araujo, J.; Duarte, Aida; Rodrigues, João Carlos; Reis, Lucia; Nogueira, Isabel; Carvalho, Patricia A; Macor, C.Objectivo: Avaliar a relação entre a formação de biofilmes na amígdala faríngea e a incidência de infecções respiratórias altas recorrentes na idade pediátrica. Métodos: Colheita de amostras da superfície do cavum faríngeo e meato médio por zaragatoas e biópsia da profundidade da amígdala faríngea de 70 indivíduos, analisados para identificar população bacteriana por métodos padronizados. A identificação foi obtida ao nível da espécie usado dispositivo VITEK2. Foram ainda colhidas biópsias superficiais da amígdala faríngea para processamento por microscopia electrónica. A avaliação inicial para identificar a presença de biofilmes foi feita por microscopia electrónica de varrimento, sendo as positivas avaliadas por microscopia electrónica de transmissão. A capacidade para formação de biofilme foi avaliada in vitro por teste em placa de micro-titulação. O ensaio foi efectuado a 37ºC em meio Muller-Hinton por durações diferentes. Resultados: Como esperado, um vasto número de bactérias foi identificado nas amostras. A maioria são espécies aeróbicas, entre Gram negativos e positivos. Foi encontrada correlação forte entre as floras das três localizações no mesmo indivíduo. A presença de biofilmes na amígdala faríngea foi identificada em 30% das amostras. Todos os micro-organismos avaliados mostraram in vitro capacidade para formação de biofilmes. Conclusão: A formação de biofilmes constitui aparentemente uma parte importante em ambos a instalação e propagação de infecções respiratórias altas. São necessários estudos posteriores para validar a tese de que a amígdala faríngea actua como reservatório de agentes infecciosos nestas infecções.