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Uhrbrand K, Koponen IK, Schultz AC, Madsen AM. Evaluation of air samplers and filter materials for collection and recovery of airborne norovirus. J Appl Microbiol 2017; 124:990-1000. [PMID: 28921812 DOI: 10.1111/jam.13588] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 09/14/2017] [Accepted: 09/14/2017] [Indexed: 11/27/2022]
Abstract
AIMS The aim of this study was to identify the most efficient sampling method for quantitative PCR-based detection of airborne human norovirus (NoV). METHODS AND RESULTS A comparative experiment was conducted in an aerosol chamber using aerosolized murine norovirus (MNV) as a surrogate for NoV. Sampling was performed using a nylon (NY) filter in conjunction with four kinds of personal samplers: Gesamtstaubprobenahme sampler (GSP), Triplex-cyclone sampler (TC), 3-piece closed-faced Millipore cassette (3P) and a 2-stage NIOSH cyclone sampler (NIO). In addition, sampling was performed using the GSP sampler with four different filter types: NY, polycarbonate (PC), polytetrafluoroethylene (PTFE) and gelatine (GEL). The sampling efficiency of MNV was significantly influenced by both sampler and filter type. The GSP sampler was found to give significantly (P < 0·05) higher recovery of aerosolized MNV than 3P and NIO. A higher recovery was also found for GSP compared with TC, albeit not significantly. Finally, recovery of aerosolized MNV was significantly (P < 0·05) higher using NY than PC, PTFE and GEL filters. CONCLUSIONS The GSP sampler combined with a nylon filter was found to be the best method for personal filter-based sampling of airborne NoV. SIGNIFICANCE AND IMPACT OF THE STUDY The identification of a suitable NoV air sampler is an important step towards studying the association between exposure to airborne NoV and infection.
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Affiliation(s)
- K Uhrbrand
- National Research Centre for the Working Environment, Copenhagen Ø, Denmark.,Division of Microbiology and Production, National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - I K Koponen
- National Research Centre for the Working Environment, Copenhagen Ø, Denmark
| | - A C Schultz
- Division of Microbiology and Production, National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - A M Madsen
- National Research Centre for the Working Environment, Copenhagen Ø, Denmark
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Uhrbrand K, Schultz AC, Koivisto AJ, Nielsen U, Madsen AM. Assessment of airborne bacteria and noroviruses in air emission from a new highly-advanced hospital wastewater treatment plant. Water Res 2017; 112:110-119. [PMID: 28153697 DOI: 10.1016/j.watres.2017.01.046] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 12/20/2016] [Accepted: 01/22/2017] [Indexed: 05/21/2023]
Abstract
Exposure to bioaerosols can pose a health risk to workers at wastewater treatment plants (WWTPs) and to habitants of their surroundings. The main objective of this study was to examine the presence of harmful microorganisms in the air emission from a new type of hospital WWTP employing advanced wastewater treatment technologies. Air particle measurements and sampling of inhalable bacteria, endotoxin and noroviruses (NoVs) were performed indoor at the WWTP and outside at the WWTP ventilation air exhaust, downwind of the air exhaust, and upwind of the WWTP. No significant differences were seen in particle and endotoxin concentrations between locations. Bacterial concentrations were comparable or significantly lower in the exhaust air than inside the WWTP and in the upwind reference. Bacterial isolates were identified using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry. In total, 35 different bacterial genera and 64 bacterial species were identified in the air samples. Significantly higher genus and species richness was found with an Andersen Cascade Impactor compared with filter-based sampling. No pathogenic bacteria were found in the exhaust air. Streptomyces was the only bacterium found in the air both inside the WWTP and at the air emission, but not in the upwind reference. NoV genomes were detected in the air inside the WWTP and at the air exhaust, albeit in low concentrations. As only traces of NoV genomes could be detected in the exhaust air they are unlikely to pose a health risk to surroundings. Hence, we assess the risk of airborne exposure to pathogenic bacteria and NoVs from the WWTP air emission to surroundings to be negligible. However, as a slightly higher NoV concentration was detected inside the WWTP, we cannot exclude the possibility that exposure to airborne NoVs can pose a health risk to susceptible to workers inside the WWTP, although the risk may be low.
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Affiliation(s)
- K Uhrbrand
- The National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark; National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, 2860 Søborg, Denmark.
| | - A C Schultz
- National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, 2860 Søborg, Denmark
| | - A J Koivisto
- The National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark
| | - U Nielsen
- DHI, Agern Allé 5, 2970 Hørsholm, Denmark
| | - A M Madsen
- The National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark
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Ibfelt T, Frandsen T, Permin A, Andersen LP, Schultz AC. Test and validation of methods to sample and detect human virus from environmental surfaces using norovirus as a model virus. J Hosp Infect 2016; 92:378-84. [PMID: 26905662 DOI: 10.1016/j.jhin.2016.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 01/06/2016] [Indexed: 10/22/2022]
Abstract
BACKGROUND Viruses cause a major proportion of human infections, especially gastroenteritis and respiratory infections in children and adults. Indirect transmission between humans via environmental surfaces may play a role in infections, but methods to investigate this have been sparse. AIM To validate and test efficient and reliable procedures to detect multiple human pathogenic viruses on surfaces. METHODS The study was divided into two parts. In Part A, six combinations of three different swabs (consisting of cotton, foamed cotton, or polyester head) and two different elution methods (direct lysis or immersion in alkaline glycine buffer before lysis) were tested for efficient recovery of human norovirus GII.7 and mengovirus from artificially contaminated surfaces. In Part B we determined the detection limit for norovirus GI.1 and GII.3 using the best procedure found in Part A linked with a commercial multiplex real-time quantitative polymerase chain reaction detection assay. FINDINGS Combining the polyester swab with direct lysis allowed recovery down to 100 and 10 genome copies/cm(2) of norovirus GI.1 and GII.3, respectively. This procedure resulted in the significant highest recovery of both norovirus and mengovirus, whereas no differences in amplification efficiencies were observed between the different procedures. CONCLUSION The results indicate that it is possible to detect low concentrations of virus on environmental surfaces. We therefore suggest that a polyester swab, followed by direct lysis, combined with a multiplex qPCR detection assay is an efficient screening tool that merits study of different respiratory and gastrointestinal viruses on environment surfaces.
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Affiliation(s)
- T Ibfelt
- Departments of Infection Control 6901 and Clinical Microbiology 9301, Copenhagen University Hospital (Rigshospitalet), Denmark.
| | - T Frandsen
- Departments of Infection Control 6901 and Clinical Microbiology 9301, Copenhagen University Hospital (Rigshospitalet), Denmark
| | - A Permin
- National Food Institute, Technical University of Denmark, DTU, Denmark
| | - L P Andersen
- Departments of Infection Control 6901 and Clinical Microbiology 9301, Copenhagen University Hospital (Rigshospitalet), Denmark
| | - A C Schultz
- National Food Institute, Technical University of Denmark, DTU, Denmark
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Ibfelt T, Engelund EH, Schultz AC, Andersen LP. Effect of cleaning and disinfection of toys on infectious diseases and micro-organisms in daycare nurseries. J Hosp Infect 2014; 89:109-15. [PMID: 25549827 PMCID: PMC7114571 DOI: 10.1016/j.jhin.2014.10.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 10/21/2014] [Indexed: 11/24/2022]
Abstract
Background The rising number of children in daycare nurseries increases opportunities for the transmission of infectious diseases. Pathogens may be transmitted directly from child to child via sneezing, coughing and touching, or indirectly via the environment. Toys are among the fomites with the highest pathogen load, but their role in disease transmission is unknown. Aim To determine if washing and disinfection of toys can reduce sickness absence and microbial pathogen load in the nursery environment. Methods Twelve nurseries (caring for 587 children) were randomized to intervention and control groups. The intervention consisted of washing and disinfection of toys and linen every two weeks for three months by a commercial cleaning company. The extent and causes of sickness absence among the children were recorded in both groups before and after introduction of the intervention. Ten sampling points in each nursery were examined for bacteria and respiratory viruses. Results The presence of respiratory virus DNA/RNA was widespread, but very few pathogenic bacteria were found in the environment. The intervention reduced the presence of adenovirus [odds ratio (OR) 2.4, 95% confidence interval (CI) 1.1–5.0], rhinovirus (OR 5.3, 95% CI 2.3–12.4) and respiratory syncytial virus (OR 4.1, 95% CI 1.5–11.2) compared with the control group, but the intervention had no effect on sickness absence or disease patterns in the nurseries. Conclusion Although cleaning and disinfection of toys every two weeks can decrease the microbial load in nurseries, it does not appear to reduce sickness absence among nursery children.
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Affiliation(s)
- T Ibfelt
- Departments of Infection Control 6901 and Clinical Microbiology 9301, Copenhagen University Hospital (Rigshospitalet), Denmark.
| | | | - A C Schultz
- National Food Institute, DTU FOOD, Division of Food Microbiology, Søborg, Denmark
| | - L P Andersen
- Departments of Infection Control 6901 and Clinical Microbiology 9301, Copenhagen University Hospital (Rigshospitalet), Denmark
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Ethelberg S, Lisby M, Bottiger B, Schultz AC, Villif A, Jensen T, Olsen KE, Scheutz F, Kjelso C, Muller L. Outbreaks of gastroenteritis linked to lettuce, Denmark, January 2010. Euro Surveill 2010; 15:19484. [PMID: 20158982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023] Open
Abstract
At least 11 linked outbreaks of gastroenteritis with a total of 260 cases have occurred in Denmark in mid January 2010. Investigations showed that the outbreaks were caused by norovirus of several genotypes and by enterotoxigenic Escherichia coli. Lettuce of the lollo bionda type grown in France was found to be the vehicle.
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Affiliation(s)
- S Ethelberg
- Department of Epidemiology, Statens Serum Institut, Copenhagen, Denmark.
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Ethelberg S, Lisby M, Böttiger B, Schultz AC, Villif A, Jensen T, Olsen KE, Scheutz F, Kjelsø C, Muller L. Outbreaks of gastroenteritis linked to lettuce, Denmark, January 2010. Euro Surveill 2010. [DOI: 10.2807/ese.15.06.19484-en] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
At least 11 linked outbreaks of gastroenteritis with a total of 260 cases have occurred in Denmark in mid January 2010. Investigations showed that the outbreaks were caused by norovirus of several genotypes and by enterotoxigenic Escherichia coli. Lettuce of the lollo bionda type grown in France was found to be the vehicle.
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Affiliation(s)
- S Ethelberg
- Department of Microbiological Surveillance and Research, Statens Serum Institut, Copenhagen, Denmark
- Department of Epidemiology, Statens Serum Institut, Copenhagen, Denmark
| | - M Lisby
- Regional Veterinary and Food Control Authority East, Ringsted, Denmark
| | - B Böttiger
- Department of Virology, Statens Serum Institut, Copenhagen, Denmark
| | - A C Schultz
- National Food Institute, Technical University, Copenhagen, Denmark
| | - A Villif
- Regional Veterinary and Food Control Authority East, Ringsted, Denmark
| | - T Jensen
- Danish Veterinary and Food Administration, Copenhagen, Denmark
| | - K E Olsen
- Department of Microbiological Diagnostics, Statens Serum Institut, Copenhagen, Denmark
- Department of Microbiological Surveillance and Research, Statens Serum Institut, Copenhagen, Denmark
| | - F Scheutz
- Department of Microbiological Surveillance and Research, Statens Serum Institut, Copenhagen, Denmark
| | - C Kjelsø
- Department of Epidemiology, Statens Serum Institut, Copenhagen, Denmark
| | - L Muller
- Department of Epidemiology, Statens Serum Institut, Copenhagen, Denmark
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Russell RA, Schultz AC, Warrener RN, Tiekink RT. Crystal structure of dimethyl (1α,2β,3α,4β,7β,8α,9β,10α)-13-isopropylidene- pentacyclo[8.2.1.14,7.02,9.03,8]tetradeca-5,11-diene-2,9-dicarboxylate, C21H24O4. Z KRIST-NEW CRYST ST 2002. [DOI: 10.1524/ncrs.2002.217.1.211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Russell RA, Schultz AC, Warrener RN, Tiekink RT. Crystal structure of dimethyl (1α,2β,3α,4β,7β,8α,9β,10α)-13-isopropylidene- pentacyclo[8.2.1.14,7.02,9.03,8]tetradeca-5,11-diene-2,9-dicarboxylate, C21H24O4. Z KRIST-NEW CRYST ST 2002. [DOI: 10.1524/ncrs.2002.217.jg.211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Russell RA, Schultz AC, Warrener RN, Tiekink ERT. Crystal structure of dimethyl (1α,2β,3α,4β,7β,8α,9β,10α)-13-isopropylidene- pentacyclo[8.2.1.14,7.02,9.03,8]tetradeca-5,11-diene-2,9-dicarboxylate, C21H24O4. Z KRIST-NEW CRYST ST 2002. [DOI: 10.1524/ncrs.2002.217.2.211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Schultz AC, Nygaard P, Saxild HH. Functional analysis of 14 genes that constitute the purine catabolic pathway in Bacillus subtilis and evidence for a novel regulon controlled by the PucR transcription activator. J Bacteriol 2001; 183:3293-302. [PMID: 11344136 PMCID: PMC99626 DOI: 10.1128/jb.183.11.3293-3302.2001] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The soil bacterium Bacillus subtilis has developed a highly controlled system for the utilization of a diverse array of low-molecular-weight compounds as a nitrogen source when the preferred nitrogen sources, e.g., glutamate plus ammonia, are exhausted. We have identified such a system for the utilization of purines as nitrogen source in B. subtilis. Based on growth studies of strains with knockout mutations in genes, complemented with enzyme analysis, we could ascribe functions to 14 genes encoding enzymes or proteins of the purine degradation pathway. A functional xanthine dehydrogenase requires expression of five genes (pucA, pucB, pucC, pucD, and pucE). Uricase activity is encoded by the pucL and pucM genes, and a uric acid transport system is encoded by pucJ and pucK. Allantoinase is encoded by the pucH gene, and allantoin permease is encoded by the pucI gene. Allantoate amidohydrolase is encoded by pucF. In a pucR mutant, the level of expression was low for all genes tested, indicating that PucR is a positive regulator of puc gene expression. All 14 genes except pucI are located in a gene cluster at 284 to 285 degrees on the chromosome and are contained in six transcription units, which are expressed when cells are grown with glutamate as the nitrogen source (limiting conditions), but not when grown on glutamate plus ammonia (excess conditions). Our data suggest that the 14 genes and the gde gene, encoding guanine deaminase, constitute a regulon controlled by the pucR gene product. Allantoic acid, allantoin, and uric acid were all found to function as effector molecules for PucR-dependent regulation of puc gene expression. When cells were grown in the presence of glutamate plus allantoin, a 3- to 10-fold increase in expression was seen for most of the genes. However, expression of the pucABCDE unit was decreased 16-fold, while expression of pucR was decreased 4-fold in the presence of allantoin. We have identified genes of the purine degradation pathway in B. subtilis and showed that their expression is subject to both general nitrogen catabolite control and pathway-specific control.
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Affiliation(s)
- A C Schultz
- Section for Molecular Microbiology, BioCentrum-DTU, Technical University of Denmark, 2800 Lyngby, Denmark
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Abstract
There are two distinct approaches to solving reinforcement learning problems, namely, searching in value function space and searching in policy space. Temporal difference methods and evolutionary algorithms are well-known examples of these approaches. Kaelbling, Littman and Moore recently provided an informative survey of temporal difference methods. This article focuses on the application of evolutionary algorithms to the reinforcement learning problem, emphasizing alternative policy representations, credit assignment methods, and problem-specific genetic operators. Strengths and weaknesses of the evolutionary approach to reinforcement learning are presented, along with a survey of representative applications.
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Abstract
The composition of pancreatic calculi in patients with tropical pancreatitis is unknown. At present, except for malnutrition, there are no known etiologic factors for chronic calcific pancreatitis in the tropics. We report the results of an x-ray diffraction study of 41 stones from 26 patients obtained at autopsy in the Kerala state in India. Calcite was present in all stones, vaterite in 12%, and a central amorphous material in 30%. The latter may be analogous to the protein plugs as nuclei for stones described by Sarles et al in patients with alcoholic pancreatitis.
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Schultz AC. Ask before you buy--planned gifts software questions. Fund Raising Manage 1986; 16:40-2. [PMID: 10278386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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