14 results on '"van Leeuwen AE"'
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2. Detectie van legionella in water met een amoebekweekmethode
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LZO, cib, Schalk JAC, Docters van Leeuwen AE, Lodder WJ, Euser SM, den Boer JW, de Roda Husman AM, LZO, cib, Schalk JAC, Docters van Leeuwen AE, Lodder WJ, Euser SM, den Boer JW, and de Roda Husman AM
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RIVM rapport:Het RIVM heeft in opdracht van de Inspectie Leefomgeving en Transport een methode ontwikkeld om levensvatbare legionellabacteriën in water beter te kunnen aantonen, de zogeheten amoebekweekmethode. Het is een aanvulling op de bestaande kweekmethode op agarplaten, die vermoedelijk niet alle ziekmakende legionellabacteriën in watermonsters opspoort. De nieuwe kweekmethode is vooral veel geschikter voor monsters die veel andersoortige bacteriën bevatten, zoals monsters van rioolwaterzuiveringsinstallaties. Bij de bestaande kweek wordt het watermonster op platen met agar gebracht, dat voedingsmiddelen bevat waarop legionellabacteriën zich optimaal in koloniën kunnen ontwikkelen. Deze methode heeft als nadeel dat andere, niet-legionellabacteriën er ook op groeien. Deze andere bacteriën kunnen de groei van de legionellabacteriën op de agarplaten belemmeren, zodat deze moeilijker op te sporen zijn. Bovendien zijn hiermee legionellabacteriën in een bepaald stadium ('levend, maar niet kweekbaar') niet aan te tonen. Bij de amoebekweekmethode worden watermonsters eerst aangebracht op amoeben. Deze eencelligen zijn de natuurlijke gastheer van legionellabacteriën, waarin legionella zich kan vermenigvuldigen. Dit heeft als voordeel dat vooral de groei van de legionellabacterie wordt gestimuleerd en niet die van andere bacteriën. Door deze verrijkingsstap zijn de legionellabacteriën vervolgens wel aan te tonen op agarplaten. In Nederland wordt bij drinkwaterinstallaties en koeltorens regelmatig gecontroleerd of er legionella aanwezig is. Dit wordt gedaan om voorkomen dat mensen worden blootgesteld aan deze bacterie. Legionellabesmetting kan leiden tot een ernstige vorm van longontsteking. Daarnaast wordt bij een besmetting de bron gezocht in de omgeving van degenen die er ziek van zijn geworden, om verdere blootstelling te voorkomen. Legionella wordt dan aangetoond met de kweekmethode op agarplaten. De amoebekweek kan hierop een aanvulling zijn. Dit geldt vooral voor monsters die, On the authority of the Netherlands VROM-Inspectorate, the RIVM has developed a new method for detecting live Legionella bacteria in water. The method known as the amoebal co-culture method can be used in addition to the regular culture method using agar plates, which probably does not detect all harmful Legionella bacteria in water samples. The co-culture method is particularly suitable for samples that contain a lot of other bacteria, like samples from sewage treatment plants. With the regular culture methods, water samples are applied to agar plates that contain specific nutrients on which Legionella can grow and be seen as colonies. Other, non-Legionella, bacteria can also grow on the agar plates and inhibit the growth of Legionella so that they are hard to detect. Moreover, Legionella bacteria at a certain stage (viable-but-not-culturable) cannot grow on agar plates. With the amoebal co-culture method, water samples are placed on amoebae. These single-celled organisms are the natural host for Legionella, in which the bacteria can multiply. This has the advantage of stimulating the growth of Legionella and not other bacteria. This process of enrichment allows Legionella bacteria to subsequently be detected by plating on agar plates. In the Netherlands, in-premise plumbing and cooling towers are checked regularly for Legionella in order to prevent human exposure to Legionella. A Legionella infection can lead to a severe form of pneumonia. When people have incurred a Legionella infection, it is important to track down and eradicate the source of the bacteria to prevent further exposure. Legionella is detected with the regular culture method on agar plates. The amoebal co-culture method can now also be used for detecting the bacteria, especially for samples where the bacteria is difficult to detect.
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- 2012
3. Prevalence of antibiotic resistant bacteria in the rivers Meuse, Rhine and New Meuse
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LZO, cib, Blaak H, van Rooijen SR, Schuijt MS, Docters van Leeuwen AE, Italiaander R, van den Berg HHJL, Lodder-Verschoor F, Schets FM, de Roda Husman AM, LZO, cib, Blaak H, van Rooijen SR, Schuijt MS, Docters van Leeuwen AE, Italiaander R, van den Berg HHJL, Lodder-Verschoor F, Schets FM, and de Roda Husman AM
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RIVM rapport:In de grote Nederlandse rivieren de Maas, de Rijn en de Nieuwe Maas komen bacteriën voor waarvan hoge percentages resistent zijn tegen een of meer soorten antibiotica. Dit blijkt uit verkennend onderzoek van het RIVM. Blootstelling via oppervlaktewater: Als mensen aan verontreinigd oppervlaktewater blootgesteld worden, kunnen zij antibioticaresistente bacteriën binnenkrijgen. Dit kan bijvoorbeeld via recreatiewater of via water dat gebruikt worden om gewassen te besproeien. Dergelijk contact kan risico's voor de volksgezondheid met zich meebrengen, omdat deze antibiotica nodig zijn om infecties te behandelen. Antibioticaresistente bacteriën kunnen op meerdere manieren in oppervlaktewater terechtkomen, bijvoorbeeld doordat mest van dieren die met antibiotica zijn behandeld, afspoelt naar het oppervlaktewater. Een andere oorzaak kan zijn dat gedeeltelijk gezuiverd of ongezuiverd afvalwater in oppervlaktewater wordt geloosd, bijvoorbeeld afkomstig van ziekenhuizen waar mensen zijn behandeld met antibiotica. In totaal waren gemiddeld eenderde tot de helft van alle Escherichia coli en van de intesintale enterococcen resistent tegen een of meer soorten antibiotica. In sommige van de monsters werden antibioticaresistente stammen van Staphylococcus aureus, Campylobacter en Salmonella aangetoond. De meeste van deze bacteriën zijn darmbacteriën; Staphylococcus aureus komt vooral voor op de huid, en in de neus en keel van mensen. Diverse risico's: De risico's kunnen zich op verschillende manieren manifesteren. Op de eerste plaats kunnen mensen die aan antibioticaresistente bacteriën worden blootgesteld, daarvan ziek worden en vervolgens problemen krijgen bij de behandeling ervan. Daarnaast is het mogelijk dat mensen die worden blootgesteld aan de resistente bacteriën zelf niet ziek worden, maar deze overdragen aan mensen met verminderde weerstand, zoals ziekenhuispatiënten en ouderen. Deze groep mensen kan vervolgens wel ziek worden door deze bacteriën. Ten slotte is er het ri, A high percentage of bacteria in large Dutch rivers is resistant to one or more antibiotics. This was demonstrated in an exploratory study performed at the RIVM. Exposure through surface water: If people come into contact with contaminated surface water, they risk exposure to bacteria that are resistant to one or more antibiotics. This may occur for instance during recreation in surface water or through water used for irrigation of crops. Because antibiotics are needed for treatment of infections, such contact may involve public health risks. Antibiotic resistant bacteria can end up in surface water by different routes, for example through run off of manure from animals treated with antibiotics to surface water. Another source may be the discharge of partially treated or untreated waste water, for instance derived from hospitals where people are treated with antibiotics. Overall, one third to half of all Escherichia coli and intestinal enterococci were resistant to one or more antibiotics. In some of the samples antibiotic resistant strains of Staphylococcus aureus, Campylobacter and Salmonella were detected. Most of these bacteria are gut bacteria; Staphylococcus aureus is predominantly present on people's skin and in their noses and throats. Diverse risks: The risks can manifest themselves in different ways. Firstly, after exposure to antibiotic resistant bacteria people may develop disease caused by these bacteria, which may therefore be hard to treat. Additionally, people may not become ill themselves, but transfer the resistant bacteria to people who are more vulnerable, such as hospital patients and the elderly. Subsequently, this category of people can develop disease. Finally, there is a risk that the antibiotic resistant bacteria establish themselves in the gut and transfer resistance genes to disease-causing bacteria if these are subsequently ingested Further research on public health risks: Data on the prevalence of antibiotic resistant bacteria in surfac
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- 2012
4. Longitudinale studie naar de aanwezigheid van legionella en amoeben in drinkwaterinstallaties
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LZO, cib, Schalk JAC, Redeker S, Docters van Leeuwen AE, Lodder WJ, de Roda Husman AM, LZO, cib, Schalk JAC, Redeker S, Docters van Leeuwen AE, Lodder WJ, and de Roda Husman AM
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RIVM rapport:In Nederland wordt bij prioritaire instellingen met collectieve leidingwaterinstallaties, zoals ziekenhuizen en verzorgingstehuizen, twee keer per jaar gecontroleerd of legionella in de waterleidingen aanwezig is. De concentratie legionellabacteriën in het water moet wettelijk lager zijn dan 100 kolonievormende eenheden per liter. De eigenaren van dergelijke collectieve installaties zijn verplicht om maatregelen te nemen om legionella-infecties te voorkomen. Oudere mensen of mensen die verzwakt zijn, zijn namelijk gevoeliger om ziek te worden van een infectie met legionella. Uit onderzoek van het RIVM blijkt dat de concentratie van legionellabacteriën in korte tijd sterk kan variëren, tot een factor 50. Beheerders van prioritaire collectieve drinkwaterinstallaties wordt daarom aanbevolen om eventuele maatregelen niet alleen op basis van de resultaten van een controle te nemen. Het is minstens zo belangrijk om ervoor te zorgen dat de drinkwaterinstallaties goed worden geïnstalleerd en onderhouden. Zo moeten temperaturen waarbij legionella goed kan groeien, worden voorkomen en mag het water in de leidingen niet te lang stilstaan. De studie is uitgevoerd in opdracht van de Inspectie voor Leefomgeving en Transport (ILT). In het onderzoek zijn de koudwaterleidingen van drie drinkwaterinstallaties gedurende tien maanden onderzocht op legionella. Bij deze drinkwaterinstallaties is in het verleden meerdere malen legionella aangetroffen. Dit keer werden in de watermonsters twee soorten legionellabacteriën aangetroffen, de Legionella anisa of Legionella gormanii. De Legionella pneumophila, de legionellasoort die verantwoordelijk is voor het merendeel van de ziektegevallen in Nederland, is niet aangetroffen., In the Netherlands, the collective drinking water installations of institutes such as hospitals and nursing homes, should be checked twice a year for the presence of Legionella bacteria. The Legionella concentration should be lower than 100 colony-forming units (cfu) per litre. The owners of these collective drinking water installations are obliged to take measures for the prevention of Legionella infections. Elderly people or people who are weak or vulnerable are at risk of becoming ill if they are infected with Legionella. In the current study, carried out by the RIVM, it was found that the concentration of Legionella bacteria in drinking water installations can vary over a short period by a factor of fifty. Owners of collective drinking water installations are therefore advised not to take measures that are based only on the results of the periodic controls. It is equally important to ensure the correct installation and maintenance of drinking water installations. For example, temperatures at which Legionella grows easily must be prevented and water in the pipes should not be stationary for too long. This study was commissioned by the Dutch Human Environment and Transport Inspectorate (ILT). In the study, the cold water pipes of three drinking water installations were examined over a period of ten months for the presence of Legionella. This concerned water installations in which Legionella had been detected several times in the past. On examination, two species of Legionella were found in the water samples, Legionella anisa and Legionella gormanii. Legionella pneumophila, the Legionella species that is responsible for most of the cases of Legionella pneumonia in the Netherlands, was not found in this study.
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- 2012
5. Emerging pathogenen in oppervlaktewater
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LZO, cib, Blaak H, van den Berg HHJL, Docters van Leeuwen AE, Italiaander R, Schalk JAC, Rutjes SA, Schets FM, de Roda Husman AM, LZO, cib, Blaak H, van den Berg HHJL, Docters van Leeuwen AE, Italiaander R, Schalk JAC, Rutjes SA, Schets FM, and de Roda Husman AM
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RIVM rapport:In grote Nederlandse rivieren zijn twee virussen en een bacteriesoort aangetroffen die schadelijk kunnen zijn voor de gezondheid van de mens. Het betreft het hepatitis E virus (HEV), het humaan parechovirus (HPeV) en de methicilline-resistente Staphylococcus aureus (MRSA) bacterie. Dit blijkt uit verkennend onderzoek van het RIVM. Deze ziekteverwekkende micro-organismen worden 'emerging' pathogenen genoemd. Het gaat daarbij om nieuwe ziekteverwekkers (MRSA) en ziekteverwekkers waarvan het bestaan pas relatief kort bekend is (HEV en HPeV). De aanwezigheid van emerging pathogenen in oppervlaktewater kan schadelijk zijn als mensen aan dit water worden blootgesteld, bijvoorbeeld door recreatie. Om in te kunnen schatten in welke mate dit schadelijk is, is onderzoek nodig naar deze pathogenen op dergelijke recreatielocaties. Het RIVM heeft het onderzoek in samenwerking met Rijkswaterstaat Waterdienst uitgevoerd voor het VROM-Inspectie-project 'Emerging substances and pathogens'. Hiervoor zijn van mei 2008 tot en met mei 2009 drie meetlocaties onderzocht, te weten de Rijn bij Lobith, de Maas bij Eijsden en de Nieuwe Maas bij Brienenoord. In deze wateren is elke vier weken gekeken of HPeV, HEV en MRSA aanwezig waren. HEV en HPeV zijn in de Maas, de Rijn, en de Nieuwe Maas aangetroffen. Beide virussen zijn vooral in de Maas en het minst vaak in de Nieuwe Maas gevonden. HPeV werd vaker gevonden dan HEV. MRSA is in de Maas en de Rijn maar niet in de Nieuwe Maas gevonden., In large Dutch rivers, two virus species and a bacterial species were detected that can be detrimental to public health. It concerns hepatitis E virus (HEV), human parechovirus (HPeV) and the bacterium methicillin-resistent Staphylococcus aureus (MRSA). This was demonstrated in an exploratory study performed at the RIVM. These pathogenic micro-organisms are called emerging pathogens. This can be newly evolved human pathogens (MRSA) or pathogens that have just recently been identified (HEV en HPeV). The presence of these pathogens in surface water can be harmful when people get exposed to these waters, for instance during recreation. To be able to estimate the magnitude of the health risk, the prevalence of these pathogens needs to be investigated in specific surface waters, such as those used for recreation. The research was performed in collaboration with 'Rijkswaterstaat Waterdienst' as part of the project 'Emerging substances and pathogens' for the VROM-Inspectorate. For this purpose, three locations have been sampled from May 2008 to May 2009: the Rhine at Lobith, the Meuse at Eijsden, and the New Meuse at Brienenoord. Every four weeks these waters were screened for the presence of HPeV, HEV en MRSA. HEV en HPeV were detected in the Meuse, Rhine and New Meuse. Both viruses were most often detected in the Meuse, and least in the New Meuse. Overall, HPeV was found more frequently than HEV. MRSA was observed in the Meuse and the Rhine, but not in the New Meuse.
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- 2010
6. Detectie van infectieuze enterovirussen met celkweek-PCR voor de in Nederland wettelijk vereiste infectierisicoschatting voor drinkwater
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LZO, Schalk JAC, Rutjes SA, Docters van Leeuwen AE, de Roda Husman AM, LZO, Schalk JAC, Rutjes SA, Docters van Leeuwen AE, and de Roda Husman AM
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RIVM rapport:Het RIVM heeft een snelle methode ontwikkeld waarmee lage concentraties levende enterovirussen in een relatief grote hoeveelheid water kunnen worden aangetoond. De verwachting is bovendien dat met deze nieuwe celkweek-polymerase chain reaction-methode (cel culture PCR) veel verschillende typen enterovirus kunnen worden aangetoond. Hierdoor ontstaat een betrouwbaarder beeld van de in het water aanwezige enterovirussen. Dit rapport beschrijft hoe de nieuwe methode is ontwikkeld. Ze moet nog worden gevalideerd. Enterovirussen komen via ontlasting in oppervlaktewater en kunnen onder andere bloedvergiftiging en hersenvliesontsteking veroorzaken. Enterovirusbepalingen worden gedaan op oppervlaktewater voor drinkwaterproductie. De bepalingen zijn in Nederland wettelijk vereist om het risico te kunnen schatten dat mensen met het virus geinfecteerd raken nadat zij ongekookt drinkwater hebben geconsumeerd. De cc-PCR combineert specifieke vormen van celkweek met de PCR. Eerst wordt een watermonster aangebracht op een laag cellen. Hierna kunnen de eventueel aanwezige virussen de cellen infecteren en kan het virus zich in de cellen vermeerderen. Vervolgens worden deze vermeerderde virussen aangetoond met PCR. De methode is uitgevoerd met verschillende soorten cellen om te achterhalen welke het beste in staat zijn om een breed scala aan enterovirussen aan te tonen. De menselijke darmkankercel HT-29 bleek het meest geschikt., The National Institute for Public Health and the Environment (RIVM) has developed a fast method for detecting low concentrations of live enteroviruses in relatively large amounts of water. It is expected that many different types of enterovirus will be detected when this new cell culture-PCR (polymerase chain reaction) is used. This will enable accurate estimates of the enteroviruses present in water to be made. The current report describes how the method, which still needs to be validated, has been developed. Enteroviruses find their way into surface water via faecal contamination and can cause septicaemia and meningitis. Testing for enteroviruses takes place on surface water collected for the production of drinking water. The measurements are required by law in order to estimate the risk of people becoming infected with a virus after consumption of unboiled drinking water. The cell culture-PCR method combines specific forms of cell culture with PCR. First a water sample is applied to a layer of cells. Subsequently, any viruses present can infect the cells which leads to the viruses multiplying in the cells. These multiplied viruses can then be detected by PCR. The method has been performed with different kinds of cells in order to detect which cells are more susceptible to harbouring a broad range of enteroviruses. The human cell for colon carcinoma HT-29 proved to be the best cell for this purpose.
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- 2010
7. Pathogene micro-organismen in zwemwater in relatie tot indicatoren voor fecale verontreiniging
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MGB, Schets FM, Berg HHJL van den, Lodder WJ, Docters van Leeuwen AE, Roda Husman AM de, MGB, Schets FM, Berg HHJL van den, Lodder WJ, Docters van Leeuwen AE, and Roda Husman AM de
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RIVM rapport:Micro-organisms possibly causing infectious diseases such as gastroenteritis or inflammation of the ear were detected in bathing water that complied with the current European Bathing Water Directive 76/160/EEG. On the basis of the stricter guidelines in the revised Bathing Water Directive 2006/7/EC, the quality of these bathing waters was assessed as being less favourable. In this study, the presence of pathogenic micro-organisms was related to the current and revised European bathing water guidelines at two official bathing sites in the Netherlands, Katwijk-Noord and Vinkeveenseplassen (island 1). Indicator parameters in the revised Bathing Water Directive were analysed by using two different (permitted) detection methods. The (potentially) pathogenic micro-organisms Staphylococcus aureus, Pseudomonas aeruginosa, Vibrio, Cryptosporidium and Giardia were detected at both sampling sites. Campylobacter was not found at Katwijk-Noord, but was detected at Vinkeveenseplassen. Salmonella, norovirus and enterovirus were not detected at either site, whereas rotavirus was detected once at Katwijk-Noord and adenovirus once at Vinkeveenseplassen. According to the current Bathing Water Directive, water quality was 'excellent' at Katwijk-Noord and 'good' at Vinkeveenseplassen. The use of different methods for detecting the revised Bathing Water Directive parameters resulted in deviant assessments of water quality. Based on membrane filtration results, water quality at Katwijk-Noord was rated 'good', whereas on the basis of MPN results it was 'acceptable'. Bathing water quality at Vinkeveenseplassen was assessed 'poor' by either method. The assessment of bathing water quality at Dutch bathing sites was, according to the revised Bathing Water Directive, indicated as being dependent on the detection method used for faecal indicators. Compliance with the European bathing water guidelines does not guarantee the absence of human pathogenic micro-organisms in water., In zwemwater wat voldeed aan de normen voor microbiologische kwaliteit uit de huidige Zwemwaterrichtlijn 76/160/EEG werden micro-organismen aangetroffen die infectieziekten zoals gastro-enteritis of oorontsteking kunnen veroorzaken. Op basis van de strengere normen uit de herziene Zwemwaterrichtlijn 2006/7/EC werd de kwaliteit van dit zwemwater minder gunstig beoordeeld. Op twee officiele Nederlandse zwemlocaties, Katwijk-Noord en Vinkeveenseplassen (bij eiland 1), is de aanwezigheid van (potentieel) pathogene micro-organismen onderzocht en gerelateerd aan de huidige en de herziene Europese zwemwaternormen; voor de parameters uit de herziene Zwemwaterrichtlijn werden twee verschillende (toegestane) detectiemethoden toegepast. De ziekteverwekkende micro-organismen Staphylococcus aureus, Pseudomonas aeruginosa, Vibrio, Cryptosporidium en Giardia werden op beide locaties aangetroffen. Campylobacter werd niet gevonden bij Katwijk-Noord, maar wel in de Vinkeveenseplassen. Salmonella, norovirus en enterovirus werden op geen van beide locaties aangetroffen, terwijl rotavirus eenmaal bij Katwijk-Noord en adenovirus eenmaal in de Vinkeveenseplassen werd aangetoond. Volgens de huidige Zwemwaterrichtlijn was de waterkwaliteit bij Katwijk-Noord 'uitstekend' en in de Vinkeveenseplassen 'goed'. Voor de parameters uit de herziene Zwemwaterrichtlijn bestond er verschil in beoordeling bij gebruik van de verschillende methoden: op basis van membraanfiltratie was de waterkwaliteit bij Katwijk-Noord 'goed', terwijl deze op basis van MPN resultaten 'aanvaardbaar' was. De zwemwaterkwaliteit in de Vinkeveenseplassen werd op basis van beide methoden als 'slecht' beoordeeld. Er zijn aanwijzingen verkregen dat de beoordeling van de waterkwaliteit op Nederlandse zwemlocaties volgens de herziene Zwemwaterrichtlijn afhankelijk is van de toegepaste detectiemethode (membraanfiltratie of MPN). Het voldoen aan de Europese Zwemwaterrichtlijn garandeert niet de afwezigheid van voor de mens ziekteverw
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- 2006
8. De microbiologische kwaliteit van hemelwater toegepast voor toiletspoeling, schoonmaken en tuinsproeien - inventariserend onderzoek 2005
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MGB, Schets FM, van den Berg HHJL, Lodder WJ, Docters van Leeuwen AE, in 't Veld S, de Roda Husman AM, MGB, Schets FM, van den Berg HHJL, Lodder WJ, Docters van Leeuwen AE, in 't Veld S, and de Roda Husman AM
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RIVM rapport:Regenwater opgevangen in reservoirs en toegepast voor onder andere toiletspoeling is vaak fecaal verontreinigd en bevat soms ziekteverwekkende bacterien. Om het infectierisico bij toepassing van dit water te kunnen schatten is aanvullend onderzoek nodig waarbij ziekteverwekkers worden gekwantificeerd en getypeerd en waarbij onderzocht wordt in welke mate gebruikers worden blootgesteld aan het besmette water.Regenwater is aanvankelijk onbesmet, maar bij afstromen langs oppervlakken en tijdens opslag in reservoirs kan besmetting optreden met micro-organismen die ziekte bij de mens kunnen veroorzaken. Dit kan gebeuren wanneer bijvoorbeeld vogelfeces van het dak wordt gespoeld of ratten of andere dieren toegang hebben tot het reservoir of open leidingen. Onderzoek van opgevangen hemelwater op vier verschillende locaties in Nederland toonde de aanwezigheid van de indicatoren voor fecale verontreiniging, bacterien van de coligroep, E. coli en enterococcen, in respectievelijk 28, 27 en 27 van de 28 onderzochte monsters aan. De potentieel ziekteverwekkende bacterien Campylobacter en Legionella pneumophila werden elk een maal op een locatie aangetroffen. Aeromonas en Clostridium perfringens, die ook ziekte bij de mens kunnen veroorzaken, werden in respectievelijk 20 en 23 van de 28 monsters gevonden. Salmonella en Vibrio werden op geen van de locaties aangetroffen. De aanwezigheid van ziekteverwekkende micro-organismen in regenwater toegepast voor toiletspoeling kan negatieve gevolgen voor de volksgezondheid hebben. Op basis van de verkregen resultaten is het nog niet mogelijk om het risico op het oplopen van een infectie bij blootstelling aan dit water te schatten omdat daarvoor nog aanvullende typerings- en blootstellingsgegevens nodig zijn., Rainwater collected in reservoirs and used for toilet flushing, for example, is often fecally contaminated and sometimes contains pathogenic bacteria. Estimating risk of infection caused by use of this water, will require additional research for enumerating and typing pathogens and for determining exposure to the contaminated water. Rainwater at the source is not contaminated with potential human pathogenic micro-organisms, but may become so at surface run-off and during storage in containers. This may occur when bird faeces runs off roofs, or rats or other animals have access to rainwater reservoirs or open mains. Examination of collected rainwater at four different sites in the Netherlands showed the presence of faecal indicator bacteria as total coliforms, E. coli and intestinal enterococci in 28, 27 and 27, respectively, of the 28 samples examined. Each of the potential human pathogenic bacteria, Campylobacter and Legionella pneumophila, was detected once at one sampling site. Aeromonas and Clostridium perfringens, which may also cause disease in humans, were detected in 20 and 23 of the 28 tested samples, respectively. Salmonella and Vibrio were not detected in any of the samples. The presence of potential pathogenic micro-organisms in rainwater used for toilet flushing may have adverse health effects. However, on the basis of the above results, and because additional typing and exposure data are required, it is not yet possible to estimate the risk of infection at exposure to this water.
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- 2006
9. BluePrint molecular subtypes predict response to neoadjuvant pertuzumab in HER2-positive breast cancer.
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Liefaard MC, van der Voort A, van Ramshorst MS, Sanders J, Vonk S, Horlings HM, Siesling S, de Munck L, van Leeuwen AE, Kleijn M, Mittempergher L, Kuilman MM, Glas AM, Wesseling J, Lips EH, and Sonke GS
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- Humans, Female, Neoadjuvant Therapy, Receptor, ErbB-2 metabolism, Trastuzumab therapeutic use, Antineoplastic Combined Chemotherapy Protocols adverse effects, Breast Neoplasms drug therapy, Breast Neoplasms genetics, Breast Neoplasms pathology
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Background: The introduction of pertuzumab has greatly improved pathological complete response (pCR) rates in HER2-positive breast cancer, yet effects on long-term survival have been limited and it is uncertain which patients derive most benefit. In this study, we determine the prognostic value of BluePrint subtyping in HER2-positive breast cancer. Additionally, we evaluate its use as a biomarker for predicting response to trastuzumab-containing neoadjuvant chemotherapy with or without pertuzumab., Methods: From a cohort of patients with stage II-III HER2-positive breast cancer who were treated with neoadjuvant chemotherapy and trastuzumab with or without pertuzumab, 836 patients were selected for microarray gene expression analysis, followed by readout of BluePrint standard (HER2, Basal and Luminal) and dual subtypes (HER2-single, Basal-single, Luminal-single, HER2-Basal, Luminal-HER2, Luminal-HER2-Basal). The associations between subtypes and pathological complete response (pCR), overall survival (OS) and breast cancer-specific survival (BCSS) were assessed, and pertuzumab benefit was evaluated within the BluePrint subgroups., Results: BluePrint results were available for 719 patients. In patients with HER2-type tumors, the pCR rate was 71.9% in patients who received pertuzumab versus 43.5% in patients who did not (adjusted Odds Ratio 3.43, 95% CI 2.36-4.96). Additionally, a significantly decreased hazard was observed for both OS (adjusted hazard ratio [aHR] 0.45, 95% CI 0.25-0.80) and BCSS (aHR 0.46, 95% CI 0.24-0.86) with pertuzumab treatment. Findings were similar in the HER2-single subgroup. No significant benefit of pertuzumab was seen in other subtypes., Conclusions: In patients with HER2-type or HER2-single-type tumors, pertuzumab significantly improved the pCR rate and decreased the risk of breast cancer mortality, which was not observed in other subtypes. BluePrint subtyping may be valuable in future studies to identify patients that are likely to be highly sensitive to HER2-targeting agents., (© 2023. The Author(s).)
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- 2023
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10. De-escalation of radiotherapy after primary chemotherapy in cT1-2N1 breast cancer (RAPCHEM; BOOG 2010-03): 5-year follow-up results of a Dutch, prospective, registry study.
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de Wild SR, de Munck L, Simons JM, Verloop J, van Dalen T, Elkhuizen PHM, Houben RMA, van Leeuwen AE, Linn SC, Pijnappel RM, Poortmans PMP, Strobbe LJA, Wesseling J, Voogd AC, and Boersma LJ
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- Female, Follow-Up Studies, Humans, Mastectomy, Neoplasm Recurrence, Local pathology, Radiotherapy, Adjuvant, Registries, Breast Neoplasms drug therapy, Breast Neoplasms radiotherapy, Radiation Oncology
- Abstract
Background: Primary chemotherapy in breast cancer poses a dilemma with regard to adjuvant locoregional radiotherapy, as guidelines for locoregional radiotherapy were originally based on pathology results of primary surgery. We aimed to evaluate the oncological safety of de-escalated locoregional radiotherapy in patients with cT1-2N1 breast cancer treated with primary chemotherapy, according to a predefined, consensus-based study guideline., Methods: In this prospective registry study (RAPCHEM, BOOG 2010-03), patients referred to one of 17 participating radiation oncology centres in the Netherlands between Jan 1, 2011, and Jan 1, 2015, with cT1-2N1 breast cancer (one to three suspicious nodes on imaging before primary chemotherapy, of which at least one had been pathologically confirmed), and who were treated with primary chemotherapy and surgery of the breast and axilla were included in the study. The study guideline comprised three risk groups for locoregional recurrence, with corresponding locoregional radiotherapy recommendations: no chest wall radiotherapy and no regional radiotherapy in the low-risk group, only local radiotherapy in the intermediate-risk group, and locoregional radiotherapy in the high-risk group. Radiotherapy consisted of a biologically equivalent dose of 25 fractions of 2 Gy, with or without a boost. During the study period, the generally applied radiotherapy technique in the Netherlands was forward-planned or inverse-planned intensity modulated radiotherapy. 5-year follow-up was assessed, taking into account adherence to the study guideline, with locoregional recurrence rate as primary endpoint. We hypothesised that 5-year locoregional recurrence rate would be less than 4% (upper-limit 95% CI 7·8%). This study was registered at ClinicalTrials.gov, NCT01279304, and is completed., Findings: 838 patients were eligible for 5-year follow-up analyses: 291 in the low-risk group, 370 in the intermediate-risk group, and 177 in the high-risk group. The 5-year locoregional recurrence rate in all patients was 2·2% (95% CI 1·4-3·4). The 5-year locoregional recurrence rate was 2·1% (0·9-4·3) in the low-risk group, 2·2% (1·0-4·1) in the intermediate-risk group, and 2·3% (0·8-5·5) in the high-risk group. If the study guideline was followed, the locoregional recurrence rate was 2·3% (0·8-5·3) for the low-risk group, 1·0% (0·2-3·4) for the intermediate-risk group, and 1·4% (0·3-4·5) for the high-risk group., Interpretation: In this study, the 5-year locoregional recurrence rate was less than 4%, which supports our hypothesis that it is oncologically safe to de-escalate locoregional radiotherapy based on locoregional recurrence risk, in selected patients with cT1-2N1 breast cancer treated with primary chemotherapy, according to this predefined, consensus-based study guideline., Funding: Dutch Cancer Society., Translation: For the Dutch translation of the abstract see Supplementary Materials section., Competing Interests: Declaration of interests For data management of the RAPCHEM study, LJB received a grant from Dutch Cancer Society (grant number 2010-4679). SCL reports grants from AstraZeneca, Eurocept Plaza, Roche, Genentech, Gilead Sciences, Tesaro, Novartis, Dutch Cancer Society, ZonMw, and A Sister's Hope; consulting fees from AstraZeneca, European Research Council (ERC), and NWO (Dutch Research Council); other financial support (eg, for attending meetings or travel) from Daiichi Sankyo, ESMO, ERC, and NWO; and non-financial support (ie, drugs, and gene expression tests) from Genentech, Roche, Gilead Sciences, Novartis, Agendia, and AstraZeneca, outside the submitted work. SCL has a patent (UN23A01/P-EP) pending. SCL is Chair of the Trial Steering Committee of the PIONEER trial (NCT03306472), and member of the Health Council of the Netherlands. All other authors declare no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)
- Published
- 2022
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11. Radiotherapy after primary CHEMotherapy (RAPCHEM): Practice variation in a Dutch registration study (BOOG 2010-03).
- Author
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Boersma LJ, Verloop J, Voogd AC, Elkhuizen PHM, Houben R, van Leeuwen AE, Linn S, de Munck L, Pijnappel R, Strobbe L, van Dalen T, Wesseling J, and Poortmans P
- Subjects
- Humans, Lymphatic Metastasis, Mastectomy, Neoplasm Staging, Netherlands, Prospective Studies, Radiotherapy, Adjuvant, Breast Neoplasms drug therapy, Breast Neoplasms pathology
- Abstract
Background: We conducted a prospective cohort study in the Netherlands (RAPCHEM: NCT01279304, BOOG 2010-03) in breast cancer (BC) patients treated with primary systemic therapy (PST), followed by surgery and post-operative radiation therapy (RT) according to a predefined consensus-based study-guideline (SG). The aim of the current analysis is to evaluate adherence to the SG., Methods: From January 2011 to January 2015, patients with cT1-2N1 BC treated in 17 Dutch RT Centres were included. Patients with four or more suspicious nodes at imaging were excluded. SG recommended whole breast RT for patients treated with breast conserving therapy. SG on loco(-regional) RT were defined for three risk groups based on the ypN status: (1) ypN0 (low-risk): RT breast and no RT after mastectomy; (2) ypN1 (intermediate-risk): RT breast or chest wall; (3) ypN2 (high-risk): RT breast or chest wall, including regional lymph nodes., Results: We included 848 patients: 292 in the low-risk group; 374 in the intermediate-risk group; 182 in the high-risk group. Overall, 64% of the patients was treated according to the SG; 11% received less RT than the predefined target volumes and 25% received more extensive RT than according to the SG. The largest variation was seen in the intermediate risk group, where only 54% was treated according to the SG., Conclusion: Substantial deviation from the SG for post-operative RT was observed after PST, especially in patients with an intermediate-risk. Future analyses will evaluate outcome of these patients in relation to risk factors and the actual RT given., (Copyright © 2020 Elsevier B.V. All rights reserved.)
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- 2020
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12. Viable Legionella pneumophila bacteria in natural soil and rainwater puddles.
- Author
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van Heijnsbergen E, de Roda Husman AM, Lodder WJ, Bouwknegt M, Docters van Leeuwen AE, Bruin JP, Euser SM, den Boer JW, and Schalk JA
- Subjects
- Legionella pneumophila classification, Legionella pneumophila genetics, Microbial Viability, Rain, Legionella pneumophila isolation & purification, Soil Microbiology, Water Microbiology
- Abstract
Aims: For the majority of sporadic Legionnaires' disease cases the source of infection remains unknown. Infection may possible result from exposure to Legionella bacteria in sources that are not yet considered in outbreak investigations. Therefore, potential sources of pathogenic Legionella bacteria--natural soil and rainwater puddles on roads--were studied in 2012., Methods and Results: Legionella bacteria were detected in 30% (6/20) of soils and 3·9% (3/77) of rainwater puddles by amoebal coculture. Legionella pneumophila was isolated from two out of six Legionella positive soil samples and two out of three Legionella positive rainwater samples. Several other species were found including the pathogenic Leg. gormanii and Leg. longbeachae. Sequence types (ST) could be assigned to two Leg. pneumophila strains isolated from soil, ST710 and ST477, and one strain isolated from rainwater, ST1064. These sequence types were previously associated with Legionnaires' disease patients., Conclusions: Rainwater and soil may be alternative sources for Legionella., Significance and Impact of the Study: The detection of clinically relevant strains indicates that rainwater and soil are potential sources of Legionella bacteria and future research should assess the public health implication of the presence of Leg. pneumophila in rainwater puddles and natural soil., (© 2014 The Authors. Journal of Applied Microbiology published by John Wiley & Sons Ltd on behalf of the Society for Applied Microbiology.)
- Published
- 2014
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13. Extended spectrum ß-lactamase- and constitutively AmpC-producing Enterobacteriaceae on fresh produce and in the agricultural environment.
- Author
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Blaak H, van Hoek AH, Veenman C, Docters van Leeuwen AE, Lynch G, van Overbeek WM, and de Roda Husman AM
- Subjects
- Anti-Bacterial Agents pharmacology, Cefotaxime pharmacology, Cluster Analysis, Enterobacteriaceae drug effects, Enterobacteriaceae enzymology, Enterobacteriaceae genetics, Humans, Netherlands, RNA, Ribosomal, 16S genetics, Soil Microbiology, beta-Lactamases genetics, Agriculture, Enterobacteriaceae metabolism, Environment, Food Microbiology, Vegetables microbiology
- Abstract
The attribution of fresh produce to the overall community-associated exposure of humans to ESBL- or AmpC-producing bacteria is currently unknown. To address this issue, the prevalence of ESBL- and AmpC-producing Enterobacteriaceae on fresh produce produced in the Netherlands was determined. Seven vegetable types that are consumed raw were selected: blanched celery, bunched carrots, chicory, endive, iceberg lettuce, mushrooms, and radish. The vegetables were mostly obtained from supermarkets. To determine whether the agricultural environment is the source of ESBL-producing Enterobacteriaceae on fresh produce, iceberg lettuce was also obtained directly from three farms, in conjunction with soil and irrigation water. ESBL-producing Enterobacteriaceae isolated from vegetables and environment were all environmental species: Rahnella aquatilis (n = 119), Serratia fonticola (n = 45) and Pantoea agglomerans (n = 1). ESBL genes of R. aquatilis and S. fonticola were identified as blaRAHN-1 and blaRAHN-2 and blaFONA-1, blaFONA-2, blaFONA-3/6 and blaFONA-5, respectively. For R. aquatilis and S. fonticola, different prevalence numbers were observed using different isolation methods, which could at least partially be explained by an inverse correlation between the level of cefotaxime resistance of these species and incubation temperature. R. aquatilis was isolated from 0 to 46% of soil samples and 11 to 83% of vegetable samples, and S. fonticola from 2 to 60% of soil samples and 0 to 1.3% of vegetable samples. Third generation cephalosporin-resistant faecal Enterobacteriaceae were isolated from 2.7%, 1.3% and 1.1% of supermarket vegetables, iceberg lettuce from farms, and agricultural soil respectively. Faecal Enterobacteriaceae were all identified as Citrobacter and Enterobacter species and, with the exception of one Citrobacter koseri strain, all had phenotypes indicative of constitutive AmpC production. Comparison of fresh produce and its agricultural environment indicates that the Enterobacteriaceae population on fresh produce reflects that of the soil it is grown in. Public health risks associated with exposure to ESBL- and AmpC-producing bacteria through consumption of uncooked fresh produce are diverse. They range from occasional ingestion of 3GC-resistant opportunistic pathogens which may result in difficult-to-treat infections, to frequent ingestion of relatively harmless ESBL-producing environmental bacteria that may therewith constitute a continuously replenished intestinal reservoir facilitating dissemination of ESBL genes to (opportunistic) pathogens., (© 2013.)
- Published
- 2014
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14. Isolation of Legionella pneumophila from pluvial floods by amoebal coculture.
- Author
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Schalk JA, Docters van Leeuwen AE, Lodder WJ, de Man H, Euser S, den Boer JW, and de Roda Husman AM
- Subjects
- Floods, Humans, Legionella pneumophila classification, Molecular Typing, Serotyping, Amoeba growth & development, Amoeba microbiology, Bacteriological Techniques methods, Legionella pneumophila growth & development, Legionella pneumophila isolation & purification, Water Microbiology
- Abstract
Viable Legionella pneumophila bacteria were isolated by amoebal coculture from pluvial floods after intense rainfall and from water collected at sewage treatment plants. Several isolated L. pneumophila strains belonged to sequence types that have been previously identified in patients.
- Published
- 2012
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