Browsing by Author "Reis, Lúcia"
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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.
- 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.
- Avaliação do risco para a saúde pública resultante do contacto com águas recreativas e ornamentaisPublication . Fernandes, Vera; Paulino, Sérgio; Costa, Clélia; Rodrigues, João Carlos; Reis, Lúcia; Nogueira, Isabel; Carvalho, Patricia; Duarte, Aida; Jordão, LuísaObjetivos: Este trabalho teve como objetivo caraterizar a população de microrganismos presente em águas recreativas (piscinas) e ornamentais (lagos), bem como avaliar o risco para a saúde pública do contacto com as mesmas.
- 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.
- Caracterização molecular e suscetibilidade aos antimicrobianos de isolados de L. monocytogenes na região de LVT em 2015Publication . Silveira, Leonor; Pista, Ângela; Maia, Carla; Barreira, Maria João; Rodrigues, João; Reis, Lúcia; Machado, JorgeCaracterização molecular e suscetibilidade aos antimicrobianos de isolados de L. monocytogenes na região de LVT em 2015.
- Caraterização molecular e suscetibilidade aos antimicrobianos de isolados clínicos de Listeria monocytogenes na região de Lisboa e Vale do Tejo em 2015Publication . Silveira, Leonor; Pista, Ângela; Maia, Carla; Barreira, Maria João; Rodrigues, João; Reis, Lúcia; Machado, JorgeListeria monocytogenes é o agente causal da listeriose, uma doença grave considerada de vigilância prioritária a nível europeu, com taxas de hospitalização (98,9%) e de letalidade (15,0%) elevadas. Este estudo teve como objetivo a caraterização das estirpes de L. monocytogenes recebidas no Instituto Nacional de Saúde Doutor Ricardo Jorge em 2015. A serotipagem foi realizada por PCR multiplex, a tipagem por PFGE e também foi estudada a suscetibilidade aos antimicrobianos. O serotipo mais comum foi IVb (85,7%). A maioria das estirpes é sensível aos antimicrobianos em apreciação, com exceção de uma estirpe que apresentou resistência ao meropenemo e outra que apresentou resistência à eritromicina e ao trimetoprim/sulfametoxazol. Existe uma grande heterogeneidade de perfis de PFGE entre os isolados estudados, tendo sido detetados alguns clusters. A utilização de sequenciação de genoma completo para caraterização de estirpes, nomeadamente de L. monocytogenes está a ganhar terreno a nível mundial, vindo substituir as técnicas goldstandard. A sua aplicação no Laboratório Nacional de Referência de Infeções Gastrintestinais permitiu em 2015 a confirmação laboratorial de um surto.
- Espécies exóticas em lagos ornamentais: adorno ou fonte de desequilíbrio?Publication . Nascimento, Maria; Paulino, Sérgio; Faria, Sónia; Cano, Manuela; Rosa, Nuno; Rodrigues, João Carlos; Reis, Lúcia; Jordão, LuísaEste trabalho teve como objetivo analisar a evolução sazonal da população de microrganismos dum lago ornamental da região de Lisboa.
- Estudo da etiologia das infeções gastrintestinais agudas em crianças hospitalizadas na área de LisboaPublication . Costa, Inês; Júlio, Cláudia; Rodrigues, João; Simões, Maria João; Machado, Jorge; Reis, Lúcia; Sarioglou, Konstantina; Santos, Andrea; Marques, Adelaide; Benoliel, João; Correia, Cristina; Escobar, Carlos; Silva, Tiago; Costa, Beatriz; Oliveira, Marisa; Correia, Paula; Ferreira, Gonçalo Cordeiro; Brito, Maria João; Oleastro, Mónica
- Exploitation of a link between antibacterial agent-resistance and biofilm-formation by classical and emergent pathogensPublication . João, Inês; Reis, Lúcia; Carvalho, Patrícia; Duarte, Aida; Jordão, LuísaObjectives: In recent years nosocomial infections have gained growing importance. Among their etiological agents are “classical” pathogens such as S.aureus and also emergent pathogens, previously neglected, such as nontuberculous mycobacteria (MTM). The ability to resist to antibacterial agents, such as antibiotics and disinfectants, is shared by all of them. Here we aim to establish a link between bacterial virulence, antibacterial agents’ resistance and biofilm formation. Methods: Bacterial reference strains and clinical isolates were grown in adequate medium. Among the “classical” pathogens used are E.coli, K. pneumoniae, S. aureus and P. aeroginosa. The group of emergent pathogens includes M.fortuitum, M.abcessus, M.chelonae, M.avium etc. NTM susceptibility test to antibiotics was evaluated by broth based microdilution method and interpreted according to NCCLS guidelines. The desinfectant (oxygen peroxide, ammonium quaternary salts [AQS] and glutaraldehyde [GA) efficacy was performed according to the approved guidelines. The susceptibility was performed by two different methods: broth microdilution and diffusion in solid medium. In order to evaluate the effect of these agents in bacteria a scanning electron microscopy (SEM) study was performed. Biofilm forming ability was evaluated by the microtiter-plate test. The assay was performed at 25ºC and 37ºC in optimal growth media, phosphate saline buffer pH 7.4 and water during for different periods of time. Fast growing bacteria were assayed for 3 days while slow growers were assayed for 15 days.
- Exploiting a link between resistance to antimicrobial agents and pathogens structurePublication . João, Inês; Reis, Lúcia; Carvalho, Patrícia A.; Duarte, Aida; Jordão, LuísaIn recent years nosocomial infections have gained growing importance. Among their etiological agents are pathogens such as S.aureus, E. coli and also emergent pathogens, previously neglected, such as nontuberculous mycobacteria (MTM). The ability to resist to antibacterial agents, such as antibiotics and disinfectants, is shared by all of them. Here we aim to establish a link between bacterial virulence, antibacterial agents' resistance and structure. Bacterial reference strains and clinical isolates (E.coli, K. pneumoniae, S. aureus and P. aeroginosa, M.smegmatis) were grown in adequate medium. NTM susceptibility test to antibiotics was evaluated by broth based microdilution method and interpreted according to NCCLS guidelines. The desinfectant (oxygen peroxide, ammonium quaternary salts [AQS] and glutaraldehyde [GA]) efficacy was performed according to the approved guidelines. The susceptibility was performed by two different methods: broth microdilution and diffusion in solid medium. In order to evaluate the effect of these agents in bacteria a scanning electron microscopy (SEM) study was performed. The results of the antibiotic susceptibility test showed, with no surprise, that the resistant strains are the most prevalent. The resistance spectrum ranged from 1 to 5 antibiotics currently used in therapeutic schemes. Oxygen peroxide was the most effective disinfectant followed by QAS and GA. Nevertheless, among NTM we identified one isolate resistant to all disinfectants tested. The SEM analysis showed that different disinfectants caused different effects on bacteria suggesting different action mechanisms. Bacterial resistance to antibiotics and disinfectants vary in the same manner. The mechanisms involved in the resistance are not fully elucidated and more studies are needed to provide effective conclusions. Biofilm formation can be part of the mechanism involved both in resistance development and propagation of infections by these agents.