1
|
Jia S, Sankaran G, Wang B, Shang H, Tan ST, Yap HM, Shen J, Gutiérrez RA, Fang W, Liu M, Chang VWC, Ng LC, Fang M. Exposure and risk assessment of volatile organic compounds and airborne phthalates in Singapore's Child Care Centers. Chemosphere 2019; 224:85-92. [PMID: 30818198 DOI: 10.1016/j.chemosphere.2019.02.120] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [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: 11/27/2018] [Revised: 02/16/2019] [Accepted: 02/18/2019] [Indexed: 06/09/2023]
Abstract
Infants and children under 6 years old spend most of daily time in Child Care Centers (CCCs), especially in the tropical regions like Singapore. Environmental exposure and associated risk during this early critical developmental stage is of great public concern. In this study, seven representative volatile organic compounds (VOCs) and five typical phthalates were analyzed in the indoor and outdoor air samples collected from 32 Singapore CCCs. The median of total VOC and phthalate concentration in indoor air was 19.03 and 5.41 μg m-3; respectively. For both indoors and outdoors environment, benzene, toluene and xylene were the dominant VOC contributors (more than 68%). For indoor air phthalates, di(2-ethylhexyl) phthalate and di-butyl phthalate (DBP) accounts for 60-76%. The level of both VOCs and phthalates in indoor environment was significantly higher than that in outdoor, with an average indoor/outdoor ratio of 1.24 and 1.45; respectively. A strong correlation (r > 0.50, p < 0.05) was observed between indoor and outdoor air compounds. VOC and phthalate levels have no significant difference between CCCs with split-unit and centrally ventilated air conditioners. Monte Carlo simulation was used to estimate exposure uncertainty and variability for the risk assessment. Overall, the concentrations of VOC were below the healthy reference values from either EPA Integrated Risk Information System (IRIS) or Singapore guideline. However, similar to other countries' report, benzene, DBP, ethylbenzene and naphthalene were at levels that could exceed the stringent standards such as Office of Environmental Health Hazard Assessment (OEHHA) cancer and reproductive health-based benchmarks.
Collapse
Affiliation(s)
- Shenglan Jia
- Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore, 637141, Singapore
| | - Gayatri Sankaran
- Environmental Health Institute NEA, 11 Biopolis Way, Singapore, 138667, Singapore
| | - Bei Wang
- Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore, 637141, Singapore
| | - Hongtao Shang
- Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore, 637141, Singapore
| | - Sze Tat Tan
- Environmental Health Institute NEA, 11 Biopolis Way, Singapore, 138667, Singapore
| | - Hooi Ming Yap
- Environmental Health Institute NEA, 11 Biopolis Way, Singapore, 138667, Singapore
| | - Joanna Shen
- Environmental Health Institute NEA, 11 Biopolis Way, Singapore, 138667, Singapore
| | | | - Wenjuan Fang
- Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore, 637141, Singapore
| | - Min Liu
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Victor Wei-Chung Chang
- Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore, 637141, Singapore; Department of Civil Engineering, Monash University, 23 College Walk, Clayton, Victoria, 3800, Australia.
| | - Lee Ching Ng
- Environmental Health Institute NEA, 11 Biopolis Way, Singapore, 138667, Singapore
| | - Mingliang Fang
- Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore, 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore; Analytics Cluster, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore, 1 Cleantech Loop, CleanTech One, Singapore.
| |
Collapse
|
2
|
Yap M, Chau ML, Hartantyo SHP, Oh JQ, Aung KT, Gutiérrez RA, Ng LC. Microbial Quality and Safety of Sushi Prepared with Gloved or Bare Hands: Food Handlers' Impact on Retail Food Hygiene and Safety. J Food Prot 2019; 82:615-622. [PMID: 30907665 DOI: 10.4315/0362-028x.jfp-18-349] [Citation(s) in RCA: 8] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Food handlers play an important role in retail food hygiene and safety. This study was conducted to better understand the impact of food handlers on the microbiological quality and safety of sushi and ingredients handled by gloved and bare hands. At retail premises, food handlers were asked to prepare a batch of sushi with raw fish followed by a batch of sushi with cooked ingredients. Food (sushi and ready-to-eat ingredients), hand, and glove samples were collected for analysis of overall microorganisms (standard plate counts) and targeted foodborne bacteria: Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella, and Listeria monocytogenes. Results suggested that cross-contamination was more prevalent at premises where bare hands were used to prepare sushi. When bare hands were used, significantly higher standard plate counts were obtained from samples of cooked rice (2.3 to 4.9 log CFU/g) and sushi (2.8 to 6.9 log CFU/g) and the prevalence of S. aureus in samples was higher on food (21.7%, 28 of 129 samples) and hands (30%, 18 of 60 samples) ( P < 0.05). Glove changing in combination with hand washing minimized cross-contamination during sushi preparation as indicated by the lower prevalence of S. aureus (0%, 0 of 28 samples) and total targeted foodborne bacteria (3.6%, 1 of 28 samples) on the gloves of food handlers who changed gloves and washed their hands compared with those handlers who did not don new gloves. Repeated use of dishcloths could be a cause of cross-contamination, and the prevalence of total targeted foodborne bacteria was significantly higher on hands dried with dishcloths (64.7%, 11 of 17 samples) than on hands dried with paper towels (12.5%, 1 of 8 samples) ( P < 0.05). The prevalences of B. cereus, L. monocytogenes, and Salmonella in the 356 food samples were 5.1% (18 samples), 0.8% (3 samples), and 0%, respectively. Improvements to hand washing, hand drying, and glove changing practices are needed to lower the occurrence of cross-contamination during sushi preparation.
Collapse
Affiliation(s)
- Min Yap
- 1 Environmental Health Institute, National Environment Agency, 11 Biopolis Way, 04-03/04 Helios Block, Singapore 138667, Singapore
| | - Man Ling Chau
- 1 Environmental Health Institute, National Environment Agency, 11 Biopolis Way, 04-03/04 Helios Block, Singapore 138667, Singapore
| | - Sri Harminda Pahm Hartantyo
- 1 Environmental Health Institute, National Environment Agency, 11 Biopolis Way, 04-03/04 Helios Block, Singapore 138667, Singapore
| | - Jia Quan Oh
- 1 Environmental Health Institute, National Environment Agency, 11 Biopolis Way, 04-03/04 Helios Block, Singapore 138667, Singapore
| | - Kyaw Thu Aung
- 1 Environmental Health Institute, National Environment Agency, 11 Biopolis Way, 04-03/04 Helios Block, Singapore 138667, Singapore
| | - Ramona Alikiiteaga Gutiérrez
- 1 Environmental Health Institute, National Environment Agency, 11 Biopolis Way, 04-03/04 Helios Block, Singapore 138667, Singapore
| | - Lee Ching Ng
- 1 Environmental Health Institute, National Environment Agency, 11 Biopolis Way, 04-03/04 Helios Block, Singapore 138667, Singapore.,2 School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| |
Collapse
|
3
|
Hartantyo SHP, Chau ML, Fillon L, Ariff AZBM, Kang JSL, Aung KT, Gutiérrez RA. Sick pets as potential reservoirs of antibiotic-resistant bacteria in Singapore. Antimicrob Resist Infect Control 2018; 7:106. [PMID: 30186596 PMCID: PMC6117887 DOI: 10.1186/s13756-018-0399-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [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: 07/24/2018] [Accepted: 08/21/2018] [Indexed: 08/25/2023] Open
Abstract
An analysis of 186 diagnostic reports collected from a veterinary clinic in Singapore between 2014 to 2016 showed that sick companion animals can carry bacteria that are of significance to human health. Among the 186 specimens submitted, 82 showed polymicrobial growth (45%, 82/186) and in total, 359 bacteria were isolated. Of the 359 bacteria reported, 45% (162/359) were multi-drug resistant and 18% (66/359) were extended-spectrum-beta-lactamase species. Resistance to broad-spectrum antibiotics were also observed among individual species. Namely, methicillin-resistance among Staphylococcus pseudintermedius (63%, 32/51) and Staphylococcus aureus (50%, 4/8); fluoroquinolone-resistance among Escherichia coli (40%, 17/42) and carbapenem-resistance among Klebsiella pneumoniae (7%, 2/30) were noted. Our analysis suggests that sick pets may contribute to the pool of clinically relevant antibiotic-resistant bacteria and play a role in the spread of antibiotic resistance in Singapore. A more extensive study to better understand the extent of distribution and the factors affecting transmission of antibiotic-resistant bacteria to and from pets is necessary.
Collapse
Affiliation(s)
- Sri Harminda Pahm Hartantyo
- 1Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04/05, Helios Block, Singapore, 138667 Singapore
| | - Man Ling Chau
- 1Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04/05, Helios Block, Singapore, 138667 Singapore
| | - Laurent Fillon
- Veterinary Emergency and Specialty Hospital Pte Ltd, 2-14 Rochdale Road, Singapore, 535815 Singapore
| | - Ahmad Zhafir Bin Mohamad Ariff
- 1Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04/05, Helios Block, Singapore, 138667 Singapore
| | - Joanne Su Lin Kang
- 1Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04/05, Helios Block, Singapore, 138667 Singapore
| | - Kyaw Thu Aung
- 1Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04/05, Helios Block, Singapore, 138667 Singapore.,3School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore, 637459 Singapore
| | - Ramona Alikiiteaga Gutiérrez
- 1Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04/05, Helios Block, Singapore, 138667 Singapore
| |
Collapse
|
4
|
Zwe YH, Tang VCY, Aung KT, Gutiérrez RA, Ng LC, Yuk HG. Prevalence, sequence types, antibiotic resistance and, gyrA mutations of Salmonella isolated from retail fresh chicken meat in Singapore. Food Control 2018. [DOI: 10.1016/j.foodcont.2018.03.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
5
|
Chuang L, Aung KT, Kang JS, Lim M, Kang C, Gutiérrez RA, Yap JH. A Case Note on Legionnaires' Disease Caused by Serogroup 1, Sequence Type ST496 in Singapore. Ann Acad Med Singap 2018; 47:194-195. [PMID: 29911737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Affiliation(s)
- Leyland Chuang
- Department of Medicine, Ng Teng Fong General Hospital, Singapore
| | | | | | | | | | | | | |
Collapse
|
6
|
Chau ML, Aung KT, Hapuarachchi HC, Lee PSV, Lim PY, Kang JSL, Ng Y, Yap HM, Yuk HG, Gutiérrez RA, Ng LC. Microbial survey of ready-to-eat salad ingredients sold at retail reveals the occurrence and the persistence of Listeria monocytogenes Sequence Types 2 and 87 in pre-packed smoked salmon. BMC Microbiol 2017; 17:46. [PMID: 28245788 PMCID: PMC5331722 DOI: 10.1186/s12866-017-0956-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 02/14/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND As the preparation of salads involves extensive handling and the use of uncooked ingredients, they are particularly vulnerable to microbial contamination. This study aimed to determine the microbial safety and quality of pre-packed salads and salad bar ingredients sold in Singapore, so as to identify public health risks that could arise from consuming salads and to determine areas for improvement in the management of food safety. RESULTS The most frequently encountered organism in pre-packed salad samples was B. cereus, particularly in pasta salads (33.3%, 10/30). The most commonly detected organism in salad bar ingredients was L. monocytogenes, in particular seafood ingredients (44.1%, 15/34), largely due to contaminated smoked salmon. Further investigation showed that 21.6% (37/171) of the pre-packed smoked salmon sold in supermarkets contained L. monocytogenes. Significantly higher prevalence of L. monocytogenes and higher Standard Plate Count were detected in smoked salmon at salad bars compared to pre-packed smoked salmon in supermarkets, which suggested multiplication of the organism as the products move down the supply chain. Further molecular analysis revealed that L. monocytogenes Sequence Type (ST) 2 and ST87 were present in a particular brand of pre-packed salmon products over a 4-year period, implying a potential persistent contamination problem at the manufacturing level. CONCLUSIONS Our findings highlighted a need to improve manufacturing and retail hygiene processes as well as to educate vulnerable populations to avoid consuming food prone to L. monocytogenes contamination.
Collapse
Affiliation(s)
- Man Ling Chau
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667 Singapore
| | - Kyaw Thu Aung
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667 Singapore
| | | | - Pei Sze Valarie Lee
- Department of Chemistry, Food Science and Technology Programme, National University of Singapore, 3 Science Drive 3, Singapore, 117543 Singapore
| | - Pei Ying Lim
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551 Singapore
| | - Joanne Su Lin Kang
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667 Singapore
| | - Youming Ng
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667 Singapore
| | - Hooi Ming Yap
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667 Singapore
| | - Hyun-Gyun Yuk
- Department of Chemistry, Food Science and Technology Programme, National University of Singapore, 3 Science Drive 3, Singapore, 117543 Singapore
| | - Ramona Alikiiteaga Gutiérrez
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667 Singapore
| | - Lee Ching Ng
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667 Singapore
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551 Singapore
| |
Collapse
|
7
|
Aung KT, Lo JACY, Chau ML, Kang JSL, Yap HM, Gutiérrez RA, Yuk HG, Ng LC. MICROBIOLOGICAL SAFETY ASSESSMENT AND RISK MITIGATION OF INDIAN ROJAK (DEEP FRIED READYTO-EAT FOOD) IN SINGAPORE. Southeast Asian J Trop Med Public Health 2016; 47:1231-1245. [PMID: 29634190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We conducted a microbiological assessment of Indian Rojak, a popular deep fried food in Singapore to evaluate its overall microbial quality, assess the effectiveness of reheating and identify key food items that could contribute to the microbial load of the dish. In 2009, an outbreak of foodborne illness associated with this food led to 154 reported cases of acute gastroenteritis, 48 were hospitalized and 2 died. Vibrio parahaemolyticus was isolated from the patients. We evaluated 455 Indian Rojak ingredients from 35 stalls; no Salmonella spp, Vibrio cholerae/parahaemolyticus or Escherichia coli O157:H7 were recovered from the studied samples. The reheating by the food handlers significantly reduced the overall median Standard Plate Count (SPC) of food from 4.5 to 2.7 log colony forming units (CFU)/g (p<0.05). The cooked ingredients with the highest microbial loads were tofu and fish cake, with those purchased from wet markets having significantly higher bacterial loads than those purchased from supermarkets (p<0.05). The Rojak gravy had the lowest median bacterial load (1.9 log CFU/g). Raw, ready-to-eat vegetables, namely green chillis, cucumbers and onions had higher levels ranging from 5.9 to 6.1 log CFU/g. Contamination with E. coli, Staphylococcus aureus, and Bacillus cereus was seen with some of the ready-to-eat raw vegetables. Repeated education of food handlers with emphasis on good hygiene practices should be conducted to reduce the risk of foodborne illnesses.
Collapse
|
8
|
Chau ML, Hartantyo SHP, Yap M, Kang JSL, Aung KT, Gutiérrez RA, Ng LC, Tam CC, Barkham T. Diarrheagenic pathogens in adults attending a hospital in Singapore. BMC Infect Dis 2016; 16:32. [PMID: 26822615 PMCID: PMC4730775 DOI: 10.1186/s12879-016-1354-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 01/18/2016] [Indexed: 11/10/2022] Open
Abstract
Background Singapore’s diarrhoeal notification system is based on specific pathogens. Official data may thus be skewed towards notifiable diseases. Limited information is available on the profiles of aetiological agents responsible for acute gastroenteritis (AGE) cases, especially among the adult population. To understand the frequency and distribution of potential causative agents of diarrheal disease in Singapore, we screened adults’ stool samples collected from a large public hospital. Methods The stool samples were screened for 18 diarrheagenic pathogens using a combination of commercial multiplex polymerase chain reaction (PCR), in-house singleplex PCR and immunochromatographic assays. One hundred adult faecal samples that were collected from October 2013 to January 2014 for routine diagnostic purposes and submitted for culture at Tan Tock Seng Hospital, Singapore were used. Results Pathogens were detected in 32 % of the samples. The predominant organisms encountered were norovirus genogroup II (11 %), Aeromonas spp. (9 %) and Campylobacter spp. (5 %). One sample was positive for both verocytotoxigenic E. coli (VTEC) and E. coli O157:H7. Two other samples were positive for VTEC only, and one other sample was positive for E. coli O157:H7 only. Astrovirus, C. perfringens, Shigella spp. and toxigenic C. difficile were each detected in 2 % of the samples. Cryptosporidium parvum, Giardia lamblia, group A rotavirus, Salmonella spp. and Vibrio spp. were each detected in 1 % of the samples. No L. monocytogenes, Y. enterocolitica, enteric adenovirus, or norovirus genogroup I were detected. Conclusion Our preliminary findings suggest that pathogens causing non-notifiable diseases might have contributed considerably to the adult hospitalised AGE cases. However, as the samples were from an adult hospital, the data obtained may not be representative of the whole community. Thus, a larger study to collect clinical samples and risk exposure data from primary healthcare clinics and children hospital is planned for, to gain a more holistic perspective on the epidemiology of AGE in Singapore. A larger study may also offer valuable insights for improving the approach of microbiological surveillance of food, as well as strategizing inspection efforts along the food supply chain by public health authorities.
Collapse
Affiliation(s)
- Man Ling Chau
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667, Singapore.
| | - Sri Harminda Pahm Hartantyo
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667, Singapore.
| | - Min Yap
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667, Singapore.
| | - Joanne Su Lin Kang
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667, Singapore.
| | - Kyaw Thu Aung
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667, Singapore.
| | - Ramona Alikiiteaga Gutiérrez
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667, Singapore.
| | - Lee Ching Ng
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #04-03/04, Helios Block, Singapore, 138667, Singapore.
| | - Clarence C Tam
- Saw Swee Hock School of Public Health, National University of Singapore, Tahir Foundation Building, 12 Science Drive 2, #10-01, Singapore, 117549, Singapore. .,London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | - Timothy Barkham
- Department of Laboratory Medicine, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore.
| |
Collapse
|
9
|
Goh V, Yap HM, Gutiérrez RA, Ng LC, Vesper SS. DNA-based analyses of molds in Singapore public buildings results in a proposed Singapore Environmental Relative Moldiness Index. Trop Biomed 2014; 31:663-669. [PMID: 25776591] [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: 06/04/2023]
Abstract
Dust samples (n=75) were collected from shopping malls, hotels and libraries in Singapore and then analyzed using Mold Specific Quantitative Polymerase Chain Reaction (MSQPCR) for the 36 molds that make up the Environmental Relative Moldiness Index (ERMI). Most of these molds (23/36) occur at similar rates in Singapore and the United States. A Singapore Environmental Relative Moldiness Index (SERMI) is proposed which might be divided into low (<18), medium (18 to 28) and high (>28) mold burden categories but more samples will help to refine these categories.
Collapse
Affiliation(s)
- V Goh
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #06-05/08 Helios Block, Singapore 138667
| | - H M Yap
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #06-05/08 Helios Block, Singapore 138667
| | - R A Gutiérrez
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #06-05/08 Helios Block, Singapore 138667
| | - L C Ng
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, #06-05/08 Helios Block, Singapore 138667
| | - S S Vesper
- US Environmental Protection Agency, National Exposure Research Laboratory, Cincinnati, OH USA
| |
Collapse
|
10
|
Gutiérrez RA, Sorn S, Nicholls JM, Buchy P. Eurasian Tree Sparrows, risk for H5N1 virus spread and human contamination through Buddhist ritual: an experimental approach. PLoS One 2011; 6:e28609. [PMID: 22164310 PMCID: PMC3229601 DOI: 10.1371/journal.pone.0028609] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 11/11/2011] [Indexed: 01/13/2023] Open
Abstract
Background The Highly Pathogenic Avian Influenza H5N1 virus has dramatically spread throughout Southeast Asia since its first detection in 1997. Merit Release Birds, such as the Eurasian Tree Sparrow, are believed to increase one's positive karma when kissed and released during Buddhist rituals. Since these birds are often in close contact with both poultry and humans, we investigated their potential role in the spread of H5N1 virus. Methodology/Principal Findings Seven series of experiments were conducted in order to investigate the possible interactions between inoculated and exposed birds, including sparrow/sparrow, sparrow/chicken, duck/sparrow. Daily and post-mortem samples collected were tested for H5N1 virus by real-time RT-PCR and egg inoculation. When directly inoculated, Eurasian Tree Sparrows were highly susceptible to the H5N1 virus, with a fatality rate approaching 100% within 5 days post-inoculation. Although transmission of fatal infection between sparrows did not occur, seroconversion of the exposed birds was observed. Up to 100% chickens exposed to inoculated sparrows died of H5N1 infection, depending on the caging conditions of the birds, while a fatality rate of 50% was observed on sparrows exposed to infected ducks. Large quantities of H5N1 virus were detected in the sparrows, particularly in their feathers, from which infectious particles were recovered. Conclusions/Significance Our study indicates that under experimental conditions, Eurasian Tree Sparrows are susceptible to H5N1 infection, either by direct inoculation or by contact with infected poultry. Their ability to transmit H5N1 infection to other birds is also demonstrated, suggesting that the sparrows may play a role in the dissemination of the virus. Finally, the presence of significant quantities of H5N1 virus on sparrows' feathers, including infectious particles, would suggest that Merit Release Birds represent a risk for human contamination in countries where avian influenza virus is circulating and where this religious ritual is practiced.
Collapse
Affiliation(s)
| | - San Sorn
- National Veterinary Institute, Ministry of Agriculture Forestry and Fisheries, Phnom Penh, Cambodia
| | - John M. Nicholls
- Department of Pathology, University of Hong Kong, Pok Fu Lam, Hong Kong, People's Republic of China
| | - Philippe Buchy
- Virology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
- * E-mail:
| |
Collapse
|
11
|
Horm SV, Gutiérrez RA, Ly S, Vong S, Buchy P. Environmental contamination during influenza A (H5N1) outbreaks in Cambodia. BMC Proc 2011. [PMCID: PMC3019493 DOI: 10.1186/1753-6561-5-s1-p65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
12
|
Gutiérrez RA, Viari A, Godelle B, Frutos R, Buchy P. Biased mutational pattern and quasispecies hypothesis in H5N1 virus. Infect Genet Evol 2011; 15:69-76. [PMID: 22063822 PMCID: PMC7106232 DOI: 10.1016/j.meegid.2011.10.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 10/12/2011] [Accepted: 10/19/2011] [Indexed: 12/14/2022]
Abstract
Like other RNA viruses, influenza viruses are subject to high mutation rates. Carrying segmented RNA genomes, their genetic variability is even higher. We aimed at analyzing the mutational events occurring during the infection of chickens by the Highly Pathogenic Avian Influenza (HPAI) H5N1 virus. We therefore studied the different sequences of two surface proteins, hemagglutinin (HA) and neuraminidase (NA), as well as two internal proteins, PB2 and NS. Three organs (lung, spleen, brain) were obtained from a chicken, experimentally infected with a lethal dose of HPAI H5N1 virus. Cloning these PCR fragments enabled us to investigate the mutations undergone by the virus after several replicative cycles. The first outcome is the presence of a strong mutational bias, resembling host-driven ADAR1 adenosine deamination, which is responsible for 81% of all mutations. Whereas the frequency of RNA dependent RNA polymerase-related mutations is compatible with the survival of the virus, the ADAR1-like activity usually strongly increases the mutation frequency into a level of “error catastrophe” in theory incompatible with virus survival. Nevertheless, the virus was successfully infective. HPAI H5N1 virus displayed traits in agreement with the quasispecies theory. The role of this quasispecies structure in successful infection and the superposition with the ADAR1-like response is discussed.
Collapse
Affiliation(s)
- Ramona Alikiiteaga Gutiérrez
- Virology Unit, Institut Pasteur in Cambodia, Réseau International des Instituts Pasteur, 5 Monivong blvd, PO Box 983, Phnom Penh, Cambodia
| | | | | | | | | |
Collapse
|
13
|
Ding H, Tsai C, Gutiérrez RA, Zhou F, Buchy P, Deubel V, Zhou P. Superior neutralizing antibody response and protection in mice vaccinated with heterologous DNA prime and virus like particle boost against HPAI H5N1 virus. PLoS One 2011; 6:e16563. [PMID: 21305045 PMCID: PMC3030595 DOI: 10.1371/journal.pone.0016563] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Accepted: 01/05/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Although DNA plasmid and virus-like particle (VLP) vaccines have been individually tested against highly pathogenic avian influenza (HPAI) H5N1 viruses, the combination of both vaccines into a heterologous prime-boost strategy against HPAI H5N1 viruses has not been reported before. METHODOLOGY/PRINCIPAL FINDINGS We constructed DNA plasmid encoding H5HA (A/Shenzhen/406H/06, subclade 2.3.4) and generated VLP expressing the same H5HA and N1NA. We then compared neutralizing antibody responses and immune protection elicited with heterologous DNA-VLP, homologous DNA-DNA and VLP-VLP prime-boost strategies against HPAI H5N1 viruses in mice. We demonstrate that DNA-VLP elicits the highest neutralizing antibody titers among the three prime-boost strategies, whereas DNA-DNA elicits higher neutralizing antibody titers than VLP-VLP. We show that although all three prime-boost strategies protect mice from death caused by 10 MLD(50) of homologous and heterologous H5N1 challenge, only DNA-VLP and DNA-DNA protect mice from infection as manifested by no weight loss and no lung pathology. In addition, we show that although DNA-VLP and DNA-DNA protect mice from death caused by 1,000 MLD(50) of homologous H5N1 challenge, only DNA-VLP protects mice from infection. Moreover, we show that after 1,000 MLD(50) of heterologous H5N1 challenge, while all mice in PBS, VLP-VLP and DNA-DNA died, 3 of 6 mice in DNA-VLP actually survived. Finally, we show that DNA-VLP completely protects mice from infection after 1,000 MLD(50) of homologous H5N1 challenge even when the challenge was administrated at 60 days post the boost. CONCLUSIONS/SIGNIFICANCE These results provide strong support for clinical evaluation of heterologous DNA-VLP prime-boost strategy as a public health intervention against a possible H5N1 pandemic.
Collapse
Affiliation(s)
- Heng Ding
- Unit of Anti-Viral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Cheguo Tsai
- Unit of Anti-Viral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | | | - Fan Zhou
- Unit of Anti-Viral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | | | | | - Paul Zhou
- Unit of Anti-Viral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
- * E-mail:
| |
Collapse
|
14
|
Gutiérrez RA, Buchy P. The Merit Release Birds: Buddhist ritual and implications in the H5N1 virus contamination cycle. BMC Proc 2011. [PMCID: PMC3019492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
15
|
|
16
|
Pasaye EH, Gutiérrez RA, Alcauter S, Mercadillo RE, Aguilar-Castañeda E, De Iturbe M, Romero-Romo J, Barrios FA. Event-Related Functional Magnetic Resonance Images during the Perception of Phantom Limb. A Brushing Task. Neuroradiol J 2010; 23:665-70. [PMID: 24148719 DOI: 10.1177/197140091002300604] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 08/13/2010] [Indexed: 11/17/2022] Open
Abstract
The phantom limb phenomenon has been used in amputee patients as a paradigm to study plasticity, mainly of the sensorimotor cortex. Nevertheless, most functional studies have been done in upper limb amputee patients using magnetoencephalography and functional magnetic resonance image imaging (fMRI). In addition, the actual experience of phantom limb sensation has not been widely used to study the neural mechanism of the human brain as a conscious knowledge of the phantom limb perception like the integration of the body image in amputee patients. fMRI studies of patients with lower limb amputation have recently been published, but none of these used an event-related design to try to observe only the stimulus application, correlating images with the subject's indication of phantom perception and discarding images with no phantom perception. In this work, we used the event-related fMRI design in two right-handed patients with identical right, transfemoral amputations, performing the same sensitive stimulation in a 3.0 T MR scanner. For comparison, we applied the same paradigm to six control subjects to compare the resulting functional maps. We found areas with statistical significance in the sensorimotor cortex contralateral to the site of stimulation, in the parietal lobe in Brodmann areas 3 in both cases (Patients and Control Subjects), but we also found activation in the Brodmann areas 6, 40, and 5 with stimulation of the stump. We observed a specific activation of the frontoparietal circuit during phantom limb perception in both amputee patients.
Collapse
Affiliation(s)
- E H Pasaye
- Institute of Neurobiology, National University of Mexico; Queretaro, Mexico - National Institute of Neurology and Neurosurgery; Mexico DF, Mexico -
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Romero-Romo JI, Bauer CCC, Pasaye EH, Gutiérrez RA, Favila R, Barrios FA. Abnormal functioning of the thalamocortical system underlies the conscious awareness of the phantom limb phenomenon. Neuroradiol J 2010; 23:671-9. [PMID: 24148720 DOI: 10.1177/197140091002300605] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 10/07/2010] [Indexed: 11/15/2022] Open
Abstract
Phantom limb (PL), a phenomenon experienced by most patients after amputation, has mostly served as a paradigm to study experiences that appear to be associated with neural plasticity within the CNS. However, the subjective nature of PL experiences has had no definitive means of reliable assessment other than using patients' direct reports, nor was there a way to study the neural mechanisms involved in the conscious awareness of this mental phenomenon. Here we obtained patients' indirect responses to PL experiences for an objective evaluation using functional magnetic resonance imaging (fMRI). Six control subjects and six lower limb (LL) amputees participated in a motor imagery task for both the intact and the particular phantom toes. While all subjects shared neural processing of distinctive regional cerebral activations during motor imagery of the intact toes (prefrontal (PF), supplementary motor area (SMA), primary motor cortex (M1), superior temporal gyrus (STG)), it was only during motor imagery of the amputated toes in amputees that we observed an increased blood oxygen level-dependent (BOLD) signal in the contralateral basal ganglia at the medial globus pallidus (MGP), substantia nigra (SN), and thalamus. This increased BOLD signal in the basal ganglia-thalamus-cortex pathway during imaginary movement of the phantom toes may reflect an abnormal open loop functioning of the thalamocortical system underlying the conscious awareness of the phantom phenomenon. We suggest that the reduction in afferent information contributes to and coalesces with the higher-level reorganization resulting in the subjective conscious awareness of the phantom limb.
Collapse
|
18
|
Gutiérrez RA, Naughtin MJ, Horm SV, San S, Buchy P. A(H5N1) Virus Evolution in South East Asia. Viruses 2009; 1:335-61. [PMID: 21994553 PMCID: PMC3185531 DOI: 10.3390/v1030335] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [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: 07/06/2009] [Revised: 09/02/2009] [Accepted: 10/02/2009] [Indexed: 12/15/2022] Open
Abstract
Highly Pathogenic Avian Influenza (HPAI) H5N1 virus is an ongoing public health and socio-economic challenge, particularly in South East Asia. H5N1 is now endemic in poultry in many countries, and represents a major pandemic threat. Here, we describe the evolution of H5N1 virus in South East Asia, the reassortment events leading to high genetic diversity in the region, and factors responsible for virus spread. The virus has evolved with genetic variations affecting virulence, drug-resistance, and adaptation to new host species. The constant surveillance of these changes is of primary importance in the global efforts of the scientific community.
Collapse
Affiliation(s)
- Ramona Alikiiteaga Gutiérrez
- Institut Pasteur du Cambodge, Virology Unit, 5 Monivong boulevard, PO Box 983, Phnom Penh, Cambodia; E-Mails: (M.J.N.); (S.V.H.)
| | - Monica Jane Naughtin
- Institut Pasteur du Cambodge, Virology Unit, 5 Monivong boulevard, PO Box 983, Phnom Penh, Cambodia; E-Mails: (M.J.N.); (S.V.H.)
| | - Srey Viseth Horm
- Institut Pasteur du Cambodge, Virology Unit, 5 Monivong boulevard, PO Box 983, Phnom Penh, Cambodia; E-Mails: (M.J.N.); (S.V.H.)
| | - Sorn San
- National Veterinary Research Institute (NaVRI)/ Phum Trea, Sals Street # 371, Phnom Penh, Cambodia; E-Mail: (S.S.)
| | - Philippe Buchy
- Institut Pasteur du Cambodge, Virology Unit, 5 Monivong boulevard, PO Box 983, Phnom Penh, Cambodia; E-Mails: (M.J.N.); (S.V.H.)
- Author to whom correspondence should be addressed; E-mail: (P.B.); Tel.: +855-23-426-009, Fax: +855-23-725-606
| |
Collapse
|
19
|
Gutiérrez RA, MacIntosh GC, Green PJ. Current perspectives on mRNA stability in plants: multiple levels and mechanisms of control. Trends Plant Sci 1999; 4:429-438. [PMID: 10529824 DOI: 10.1016/s1360-1385(99)01484-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The control of mRNA stability plays a fundamental role in the regulation of gene expression in plants and other eukaryotes. This control can be influenced by the basal mRNA decay machinery, sequence-specific decay components, and regulatory factors that respond to various stimuli. Important progress has been made towards the identification of some of these elements over the past several years. This is true particularly with respect to cis-acting sequences that control mRNA stability, the identification of which has been the focus of much of the initial work in the field. Characterization of mRNA fragments associated with post-transcriptional gene silencing and two plant transcripts that give rise to detectable decay intermediates have provided insight into the mRNA decay pathways. These, and other studies, are indicative of similarities, as well as of interesting differences between mRNA decay mechanisms in plants and yeast - the system that has been used for most of the pioneering work. Future studies in this area, particularly when enhanced by emerging genetic and genomic approaches, have tremendous potential to provide additional knowledge that is unique to plants or of broad significance.
Collapse
Affiliation(s)
- RA Gutiérrez
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824-1312, USA
| | | | | |
Collapse
|
20
|
Borghelli RF, Policicchio JE, Chuchurru JA, Gaig HD, Gutiérrez RA, Sforza RR. [History of oral aphthae and smoking in university students]. Rev Asoc Odontol Argent 1987; 75:24-6. [PMID: 3507731] [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: 01/06/2023]
|