http://hdl.handle.net/10400.18/91 Wed, 19 Jun 2013 09:50:43 GMT 2013-06-19T09:50:43Z http://hdl.handle.net/10400.18/1184 Title: Microbiological monitoring of water for control of Legionella Authors: Coelho, Carla; Pizarro, Cristina; Reinas, Alcina; Rebelo, Helena Abstract: Legionellosis is a collection of infections that are caused by Legionella pneumophila and related Legionella bacteria. The severity of legionellosis varies from mild febrile illness (Pontiac fever) to a potentially fatal form of pneumonia (Legionnaires’ disease) that can affect anyone, but principally affects those who are susceptible due to age, illness, immunosuppression or other risk factors, such as smoking. Legionella spp. are heterotrophic bacteria found in a wide range of water environments and proliferate at temperatures between 25°C and 45°C. These bacteria are members of the natural flora of many freshwater environments, such as rivers, streams and impoundments, where they occur in relatively low numbers. Bacteria of the genus Legionella are ubiquitous, they can proliferate in certain human-made water environments, such as water cooling devices associated with air conditioning systems, hot water, spas, distribution systems, on the inside surfaces of shower heads especially in warm waters. Legionellae can be ingested by certain amoebae which play an important role in their persistence in water environments. Devices that support multiplication of Legionella have been associated with outbreaks of Legionnaires’disease. Nosocomial cases usually make up a small proportion of reported cases of legionellosis. However, the proportion of cases that are fatal tends to be much higher with nosocomial infections than with community-acquired infections. Health-care facilities may include environments that support the proliferation and dissemination of Legionella and must be monitored. In Portugal only exists legislation for air conditioning systems and thermal waters. It is important to be aware of the need to develop specific rules for the detection of Legionella in water intended for human consumption in order to act more for the prevention of the disease than to act only in the monitoring of an outbreak. In recent years there has been an increasing incidence of disease caused by this bacterium, atypical pneumonia, and a large variety of water systems are different sources of contamination. Fri, 01 Jun 2012 00:00:00 GMT http://hdl.handle.net/10400.18/1184 2012-06-01T00:00:00Z http://hdl.handle.net/10400.18/1171 Title: Evaluation of phylogenetic markers suitable for Planktothrix spp. discrimination Authors: Menezes, Carina; Churro, Catarina; Pereira, Paulo; Vasconcelos, Vitor; Valério, Elisabete Abstract: In Portugal, potentially toxic cyanobacteria from Planktothrix genus have become frequently observed in freshwater reservoirs. Identification of Planktothrix species through optical microscopy is complicated due to limited morphological differences among them. The aim of this work was to determine the most suitable phylogenetic markers that could be used for the molecular identification of Planktothrix species. In order to do so, several genes of interest were selected: rpoB, rpoC1, cpcA, cpcB, rbcX, 16S rRNA genes and 16S rRNA–tRNAIle–tRNAAla-23S rRNA internal transcribed spacer (ITS), and their sequences retrieved from public databases. Phylogenetic analysis showed that 16S rRNA, cpcA, rbcX genes and ITS region trees do not allow a clear discrimination of Planktothrix species, however cpcB and rpoB seemed putative suitable phylogenetic markers for Planktothrix species identification. The applicability of these markers was then evaluated in 20 Planktothrix isolates, isolated over the years from several Portuguese freshwater reservoirs and maintained in the Estela Sousa e Silva Algae Culture Collection (ESSACC). The selected genes, cpcB and rpoB, were amplified by PCR and sequenced and the resulting trees compared with the phylogenetic clustering obtained with our previously characterized rpoC1 phylogenies. The phylogenetic analyses, based on the three gene regions, revealed that Planktothrix isolates analyzed in this study could be phylogenetically resolved into their corresponding species. This work contributes for the discussion of the appropriate genes that can be used in phylogenetic identification of Planktothrix species. Tue, 07 Aug 2012 00:00:00 GMT http://hdl.handle.net/10400.18/1171 2012-08-07T00:00:00Z http://hdl.handle.net/10400.18/1102 Title: Toxic cyanobacteria blooms in Portuguese freshwaters – a summarized overview Authors: Paulino, Sérgio; Faria, Natália; Valério, Elisabete; Pereira, Paulo; Tavares, António Abstract: Toxic cyanobacteria are common in Portuguese freshwaters and are a cause of concern, given that exposure to subacute levels of cyanobacterial toxins through drinking and recreational water might have deleterious effects on human health. Since 1996 several laboratories have been involved in the screening of cyanotoxins in different freshwater bodies, some on regularly basis and others more sporadically. Here we summarized the main data obtained by our laboratory during the last years, in order to give a simplified overview of the quality and diversity of our freshwater resources in terms of cyanobacteria occurrence. Sat, 01 Nov 2008 00:00:00 GMT http://hdl.handle.net/10400.18/1102 2008-11-01T00:00:00Z http://hdl.handle.net/10400.18/796 Title: Air Quality in a children Day Care Centres - Pilot Study Authors: Cano, M.; Aguiar, F.; Almeida, G.; Proença, C. Abstract: 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. Sat, 01 Oct 2011 00:00:00 GMT http://hdl.handle.net/10400.18/796 2011-10-01T00:00:00Z