DSA - Posters/abstracts em congressos internacionais
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- Activated carbons: efficient materials for the removal of multi- resistant bacteriaPublication . Silva, Sandra; Jordao, Luisa; Duarte, Aida; Carvalho, Ana PaulaThe rapid emergence of multi-resistant bacteria is occurring worldwide being hospital effluent a major source of these microorganisms. To remove these bacteria possible strategies are those involving activated carbon that due to their tunable properties can be suitable adsorbents for different types of microorganisms, for example Gram + or Gram – bacteria. The objective of this study was to test an activated carbon (AC) commercialized for water treatment purpose to reduce the content of bacteria commonly detected in hospital wastewater. The assays were made using the carbon in two different granulometries against multi-resistant strains: Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus. The adsorption tests were performed following a procedure adapted from Naka et al. [1]. In any case in parallel with the adsorption assays, the growth of the bacteria was also assessed.The results displayed at Figure 1 show that carbon AC allows a continue decrease of bacteria amount in the liquid media, despite the continuous increase of bacteria demonstrated by the blank experiment. The images displayed in Figure 2 (b) and (c) show the cells adherent to carbon, after 90 minutes of contact. These preliminary results allow us to conclude that activated carbon can be used to increase the removal efficiency of multi-resistant bacteria present in hospital wastewater. Acknowledgments The financial support of FCT to CQB (PEst-OE/QUI/UI0612/2013) is acknowledged. [1] K. Naka, S.T. Watarai, K. Inoue, Y. Kodama, K. Oguma, T.Yasuda, H.J. Kodama, 2001, Veter. Med. Science., 63, 281-285.
- Actividade antibacteriana de extractos de Planktothrix agardhii contra Staphylococcus aureusPublication . Menezes, Carina; Dias, ElsaA resistência de bactérias patogénicas à antibioterapia é um dos principais problemas de saúde pública, face à crescente ineficácia dos antibióticos no tratamento de doenças infeciosas. Assim, a pesquisa de novos antibióticos é um importante desafio da investigação em saúde. O potencial farmacológico de cianobactérias tem sido avaliado e descrito, mas, no entanto, ainda não há nenhum composto cianobacteriano que tenha sido aprovado pelas autoridades do medicamento como agente antibacteriano. Neste trabalho avaliámos a atividade de extratos de 40 estirpes de Planktothrix agardhii contra duas bactérias patogénicas: Klebsiella pneumonia e Staphylococus aureus. Para cada espécie bacteriana alvo usou-se uma estirpe de referência (ATCC) e uma estirpe clínica, isolada a partir de amostras de pacientes e estudadas no Laboratório de Resistência aos Antibióticos e Infeções Associadas aos Cuidados de Saúde. As estirpes de P. agardhii foram isoladas de albufeiras portuguesas e têm sido mantidas na coleção “Estela Sousa e Silva Algae Culture Collection” do Laboratório de Biologia e Ecotoxicologia. A biomassa de P. agardhii (200mg) foi extraída com metanol (70%, 10mL/100mg) overnight e sujeita a ciclos de sonicação. O metanol dos extratos foi evaporado e os extratos aquosos resultantes foram purificados em cartuchos C18. A atividade dos extratos contra as bactérias K. pneumonia e S.aureus foi avaliada através do método da Difusão em Disco (EUCAST), usando discos impregnados com 2, 4, 6, 8 e 10 mg de cada extrato. De acordo com os resultados preliminares, nenhum dos extratos apresenta atividade contra K. pneumonia, mas o extrato de P. agardhii LMECYA 256 apresenta um ligeiro halo de inibição relativamente às estirpes de S. aureus, de uma forma aparentemente dependente da dose de extrato aplicada. O S. aureus é uma bacteria Gram-positiva, frequentemente associada a uma vasta gama de patologias, desde simples infeções na pele, até infeções graves como pneumonia e meningite. Assim, revela-se do maior interesse explorar as propriedades antibacterianas de cianobactérias, designadamente do género Planktothrix, contribuindo, desta forma, para um dos desafios atuais da ciência: a identificação de novos antibióticos de origem natural.
- 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.
- Adequacy of the standardised in vitro mammalian cell Micronucleus (MN) test for nanomaterials genotoxicity testingPublication . Fernández-Bertólez, Natalia; Rodríguez-Fernández, R.; Lema-Arranz, C.; Pásaro, E.; Brandão, Fátima; Teixeira, João Paulo; Costa, Carla; Valdiglesias, Vanessa; Laffon, BlancaAbout adequacy of the standardised in vitro mammalian cell Micronucleus (MN) test for nanomaterials genotoxicity testing.
- Air microbiology – external quality assurance programPublication . Cano, Manuela; Rosa, Nuno; Correia, Helena; Faria, Ana PaulaThe Regulation on Energy Heating and Cooling Systems in Buildings (Decreto-Lei 79/2006, April 4th) imposed efficiency rules for Heating Ventilation and Air Conditioning Systems (HVAC) in buildings, established reference concentrations for chemical and microbiological pollutants and compelled the execution of regular audits to indoor air quality in order to guarantee healthy indoor environments in existing commercial buildings with large HVAC systems. Given the significant increase in indoor air quality audits it became necessary to harmonize sampling and analysis procedures for microbiological pollutants in order to obtain comparable results. The Air and Occupational Health Unit (UASO) implemented the required procedures for accreditation of the assay “Determination of airborne culturable microorganisms” according to the International Standard ISO/IEC 17025 [1], unequivocal indicator of technical proficiency. In the absence of external quality assessment programs (EQA), a requirement of the standard, the UASO Unit in collaboration with the National Program for External Quality Assessment, organized the EQA program - Air Microbiology that consists on the bacteriological and fungal enumeration in air samples collected following the EN 13998 Standard methodology [2]. The EQA program allowed the comparability of results between participant Laboratories leading also to the harmonization of procedures, improving the traceability of measurements, result validation and improving the whole process leading to accreditation. At the end of each year the organizers of the EQA Program present the results and organize training courses in the areas identified as sensitive. The most debated topics have been the equipment calibration, estimation of uncertainty, the acceptance criteria of duplicate samples and control laboratory test conditions. The aim of this study is the assessment of the results of the EQA program - Air Microbiology (2010-2015).
- Air pollution in urban environments: implications for citizens´healthPublication . Slezakova, Klara; Madureira, Joana; Teixeira, João Paulo; Pereira, Maria do CarmoCurrently, 54% of worldwide population lives in urban areas. While growing urbanization causes environmental pollution and energy demand, it has also adverse implications on health, living conditions and lifestyle habits of the respective citizens. To protect human health, numerous organizations have implemented guidelines to limit environmental pollution, or even proposed recommendation on human activity, but how do these translate to the exposure and risks of the respective population? This work aimed to explore how urban development, using time series data from 2015 to 2018, might influence air quality and potential health risks of citizens living in these zones.
- Air Quality in a children Day Care Centres - Pilot StudyPublication . Cano, M.; Aguiar, F.; Almeida, G.; Proença, C.The negative impact of a poor indoor air quality in children’s health is well recognized and the establishment of a relation between air quality, ventilation and children’s health is crucial to correct the actual situation. Levels of carbon dioxide usually exceed recommended values and are often associated with the raise of many other indoor pollutants accumulated in consequence of poor ventilation rates. This paper describes field measurements of chemical and biological indoor contaminants in order to investigate indoor air quality in a children day care center (CDCC). Objective The aim of this pilot study was to point out the need for indoor air quality investigations in CDCC in order to control ventilation rates and prevent children respiratory diseases. Material and Methods The monitoring tasks were carried out in a CDCC in Lisbon with the evaluation of suspended particulate matter, carbon dioxide, carbon monoxide, total volatile organic compounds (TVOC’s), bacteria and fungi. Relevant measurements of chemical and biological parameters were also conducted outdoors. The studied CDCC had mixed ventilation with extraction in toilets and openable windows. Carbon monoxide, carbon dioxide and TVOC’s were monitored using a Photoacoustic Multigas Monitor Type 1312, INNOVA, Air Tech Instruments. Particulate matter was collected by active sampling into PVC filters using pumps operating at 2 L/min airflow, followed by gravimetric analysis. Samples of viable microorganisms were collected using the MAS-100 sampler with Malt Extract Agar (MEA) plates supplemented with chloranphenicol, Trypticase Soy Agar (TSA) and MacConkey agar as collecting media for fungi, total bacteria and gram-negative bacteria respectively. Field campaign was conducted in March 2008, during routine school activities (10:00-17:00). Results TVOC’s concentrations exceed recommended limits in one of the ten studied rooms, being also one of the rooms with CO2 concentration above the recommended value (2200 mg/m3). CO concentrations ranged from 0,064 mg/m3 to 0,361 mg/m3 never exceeding 12,5 mg/m3. The mean CO2 concentration indoors exceeds 1800 mg/m3 in 7 of the 10 studied rooms, with a maximum concentration of 3750 mg/m3, a minimum of 1630 mg/m3 and an outdoor level of 773 mg/m3. The results obtained show a relation between CO2 and bacterial concentrations, being also observed a predominance of gram-positive bacteria. Fungal spore concentrations ranged from 116 to 476 ufc/m3 and the outdoor level (582 ufc/m3) was never exceeded. The maximum total suspended particulate matter concentration obtained was 0,162 mg/m3 with an outdoor level of 0,062 mg/m3, the minimum level was obtained in the nursery (0,051 mg/m3). Conclusion This pilot study provides evidence that ventilation in the monitored CDCC is clearly insufficient to maintain an acceptable indoor air quality. Being the human occupancy the major source of CO2 and bacteria, it is possible to predict the accumulation of other infectious agents, such as human origin viruses and also of chemical contaminants from indoor sources, as a consequence of poor ventilation. These results are in accordance with previous studies that report an increased risk of infectious diseases of children attending day care centers compared with those cared for at home. Further research is needed with an enlarged number of CDCC in order to develop guidelines to create healthy environments for children.
- Antibiotic resistance in freshwater cyanobacteria and associated bacteriaPublication . Dias, Elsa; Dias, Daniela; Ferreira, Eugénia; Manageiro, Vera; Vasconcelos, Vitor; Pereira, Paulo; Caniça, ManuelaObjectives: Cyanobacteria are ubiquitous prokaryotes in aquatic ecosystems and although they can be exposed to antibiotics, their role on water resistome was never investigated. Thus, this work aimed to evaluate the antibiotic susceptibility patterns and resistance mechanisms of cyanobacteria and co-occurring bacteria in order to assess their contribution to the global pool of resistance determinants in freshwater. Methods: We investigated 4 cyanobacterial genera (Microcystis, Aphanizomenon, Anabaena and Planktothrix), previously isolated from freshwater reservoirs, and several bacteria isolated from those cyanobacterial cultures. Antibiotic susceptibility of cyanobacteria was evaluated by microdilution method, under specific culturing conditions, against beta-lactams, aminoglycosides, quinolones, sulfonamides and tetracyclines. Minimum inhibitory concentrations (MIC) were determined according to cyanobacterial cell dentisty (DO, 450nm) and microscopic examination of cultures integrity. Bacteria were identified by 16S sequencing and their susceptibility patterns were determined by disk diffusion, according to SFM 2012 non-specific breakpoints, against the same antibiotics. All strains were subjected to the search of class 1, 2 and 3 integrons and antibiotic resistance genes according to the phenotype. Results: Overall, we observed a great diversity of susceptibility to the tested antibiotics, among the distinct strains. Microcystis showed the lowest susceptibility regarding beta-lactams. Conversely, Microcystis was more susceptible to quinolones, while Planktothrix showed higher MIC values. Bacteria from cyanobacterial cultures were identified as Hydrogenophaga atypica, Limnobacter thioxidans, Rhizobium radiobacter, Sphingobium sp. and Brevundimonas lenta. Even though no known antibiotic resistance genes were yet identified, bacteria from different species and showing distinct phenotypes exhibited class 1 and 2 integrons. L. thioxidans, for example, revealed to be resistant to aminoglycosides and harbored a class 2 integron. Conclusions: Although no known antibiotic resistance genes were found in cyanobacteria and co-occurring bacteria, the presence of integrons and the susceptibility to antibiotics, suggest that they may play a role on freshwater resistome and eventually contribute to the dissemination of antibiotic resistance. These results may also be helpful to define guidelines and breakpoints to access cyanobacteria antibiotic susceptibility.
- Antibiotic-resistant bacteria from air samples collected in nursing homesPublication . Salgueiro, Vanessa; Manageiro, Vera; Jones-Dias, Daniela; Cano, Manuela; Ferreira, Eugénia; Caniça, ManuelaIntroduction: Antibiotic resistance is currently a worldwide public health problem that can include diverse mechanisms and bacterial species. The understanding and monitoring of such phenomena is essential to avoid further dissemination. The main aim of this study was the characterization of antibiotic resistance mechanisms in bacterial strains collected in air samples from nursing homes and compare them with clinical samples isolated from the same geographic area. Materials and methods: Air samples were collected from bedrooms, living rooms and outdoor of 4 nursing homes located in Lisbon, Portugal. Screening of antimicrobial susceptibility of 18 Gram-negative (5 Acinetobacter spp., 1 Klebsiella oxytoca, 4 Pantoea spp., 7 Pseudomonas spp., 1 Sphingomonas paucimobilis) and 12 Gram-positive (3 Micrococcus luteus, 3 Staphylococcus spp.) isolates was performed by disk diffusion method. Different antibiotic resistant genes were searched by PCR. PFGE was used to evaluate clonality between K. oxytoca isolated from the air environment and other strains from clinical origin. Results and discussion: The majority of strains were susceptible to all antibiotics tested. Among beta-lactam antibiotics, reduced susceptibility to cefoxitin was detected in Staphylococcus capitis, through expression of the mecA gene, and to ampicillin, piperacillin and piperacillin-tazobactam in 1 K. oxytoca expressing a blaOXY-5-type beta-lactamase. Nonsusceptibility to meropenem and piperacillin-tazobactam was observed in 2 Pseudomonas putida however no antibiotic resistance gene was detected. Regarding quinolones, non-susceptibility was found in 1 S S. capitis, 2 Staphylococcus haemolyticus, and 1 K. oxytoca. The molecular characterization of the mecA-positive S. capitis from the nursing homes and from a hospital within the same region suggests a potential dissemination of strains between these two environments. The genetic relatedness of K. oxytoca from nursing homes (n=1) and clinical isolates (n=9) recovered within the same region, allowed to conclude that they were not genetically related. Conclusions: Globally, nursing homes environments may act as complementary reservoirs of antibiotic resistant bacteria and antibiotic resistance genes. Thus, a better understanding of the antibiotic resistance mechanisms and dissemination pathways in other reservoirs than human is essential to control its emergence and spread.
- Application of chemometric methods to assess the impact of intensive horticulture practices on groundwater content of nitrates, sodium, potassium and pesticidesPublication . Pinto, E.; Melo, A.; Aguiar, A.; Mansilha, C.; Pinho, O.; Ferreira, I.