1
|
Ng E, Tay JRH, Leung NHL, Seneviratne CJ. Letter to the Editor, "Sources of SARS-CoV-2 and Other Microorganisms in Dental Aerosols". J Dent Res 2021; 101:236. [PMID: 34928742 DOI: 10.1177/00220345211037224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- E Ng
- Department of Restorative Dentistry, National Dental Centre Singapore, Singapore
| | - J R H Tay
- Department of Restorative Dentistry, National Dental Centre Singapore, Singapore
| | - N H L Leung
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - C J Seneviratne
- Oral Health Academic Clinical Programme, Duke-NUS Medical School, Singapore.,Singapore Oral Microbiomics Initiative, National Dental Research Institute Singapore, National Dental Centre Singapore, Singapore
| |
Collapse
|
2
|
Rosa V, Malhotra R, Agarwalla SV, Morin JLP, Luong-Van EK, Han YM, Chew RJJ, Seneviratne CJ, Silikas N, Tan KS, Nijhuis CA, Castro Neto AH. Graphene Nanocoating: High Quality and Stability upon Several Stressors. J Dent Res 2021; 100:1169-1177. [PMID: 34253090 DOI: 10.1177/00220345211024526] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Titanium implants present 2 major drawbacks-namely, the long time needed for osseointegration and the lack of inherent antimicrobial properties. Surface modifications and coatings to improve biomaterials can lose their integrity and biological potential when exposed to stressful microenvironments. Graphene nanocoating (GN) can be deposited onto actual-size dental and orthopedic implants. It has antiadhesive properties and can enhance bone formation in vivo. However, its ability to maintain structural integrity and quality when challenged by biologically relevant stresses remains largely unknown. GN was produced by chemical vapor deposition and transferred to titanium via a polymer-assisted transfer technique. GN has high inertness and did not increase expression of inflammatory markers by macrophages, even in the presence of lipopolysaccharides. It kept high coverage at the top tercile of tapered dental implant collars after installation and removal from bone substitute and pig maxilla. It also resisted microbiologically influenced corrosion, and it maintained very high coverage area and quality after prolonged exposure to biofilms and their removal by different techniques. Our findings show that GN is unresponsive to harsh and inflammatory environments and that it maintains a promising level of structural integrity on the top tercile of dental implant collars, which is the area highly affected by biofilms during the onset of implant diseases. Our findings open the avenues for the clinical studies required for the use of GN in the development of implants that have higher osteogenic potential and are less prone to implant diseases.
Collapse
Affiliation(s)
- V Rosa
- Faculty of Dentistry, National University of Singapore, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore
| | - R Malhotra
- Faculty of Dentistry, National University of Singapore, Singapore
| | - S V Agarwalla
- Faculty of Dentistry, National University of Singapore, Singapore
| | - J L P Morin
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore
| | - E K Luong-Van
- Faculty of Dentistry, National University of Singapore, Singapore
| | - Y M Han
- Department of Chemistry, National University of Singapore, Singapore
| | - R J J Chew
- Faculty of Dentistry, National University of Singapore, Singapore
| | | | - N Silikas
- Division of Dentistry, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
| | - K S Tan
- Faculty of Dentistry, National University of Singapore, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore
| | - C A Nijhuis
- Department of Molecules and Materials, Faculty of Science and Technology, University of Twente, Enschede, Netherlands
| | - A H Castro Neto
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore
| |
Collapse
|
3
|
Ng E, Tay JRH, Ong MMA, Bostanci N, Belibasakis GN, Seneviratne CJ. Probiotic therapy for periodontal and peri-implant health - silver bullet or sham? Benef Microbes 2021; 12:215-230. [PMID: 34057054 DOI: 10.3920/bm2020.0182] [Citation(s) in RCA: 6] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Probiotics are thought to be beneficial microbes that influence health-related outcomes through host immunomodulation and modulation of the bacteriome. Its reported success in the treatment of gastrointestinal disorders has led to further research on its potential applicability within the dental field due to similarities such as a polymicrobial aetiology and disease associated microbial-shifts. Although the literature is replete with studies demonstrating its efficacy, the use of probiotics in dentistry continues to polarise opinion. Here, we explore the evidence for probiotics and its effect on periodontal and peri-implant health. MEDLINE, EMBASE, and CENTRAL were systemically searched from June 2010 to June 2020 based on a formulated search strategy. Of 1,956 potentially relevant articles, we selected 27 double-blinded randomised clinical trials in the areas of gingivitis, periodontitis, residual pockets during supportive periodontal therapy, and peri-implant diseases, and reviewed their efficacy in these clinical situations. We observed substantial variation in treatment results and protocols between studies. Overall, the evidence for probiotic therapy for periodontal and peri-implant health appears unconvincing. The scarcity of trials with adequate power and follow-up precludes any meaningful clinical recommendations. Thus, the routine use of probiotics for these purposes are currently unsubstantiated. Further multi-centre trials encompassing a standardised investigation on the most promising strains and administration methods, with longer observation times are required to confirm the benefits of probiotic therapy for these applications.
Collapse
Affiliation(s)
- E Ng
- Department of Restorative Dentistry, National Dental Centre Singapore, 5 Second Hospital Ave, 168938, Singapore
| | - J R H Tay
- Department of Restorative Dentistry, National Dental Centre Singapore, 5 Second Hospital Ave, 168938, Singapore
| | - M M A Ong
- Department of Restorative Dentistry, National Dental Centre Singapore, 5 Second Hospital Ave, 168938, Singapore.,Oral Health Academic Clinical Programme, Duke-NUS Medical School, 8 College Road, 169857, Singapore
| | - N Bostanci
- Division of Oral Diseases, Department of Dental Medicine, Karolinska Institutet, P.O. Box 4064, 14104 Huddinge, Sweden
| | - G N Belibasakis
- Division of Oral Diseases, Department of Dental Medicine, Karolinska Institutet, P.O. Box 4064, 14104 Huddinge, Sweden
| | - C J Seneviratne
- Oral Health Academic Clinical Programme, Duke-NUS Medical School, 8 College Road, 169857, Singapore.,Singapore Oral Microbiomics Initiative, National Dental Research Institute Singapore, National Dental Centre Singapore, Second Hospital Ave, 168938, Singapore
| |
Collapse
|
4
|
Balan P, Brandt BW, Chong YS, Crielaard W, Wong ML, Lopez V, He HG, Seneviratne CJ. Subgingival Microbiota during Healthy Pregnancy and Pregnancy Gingivitis. JDR Clin Trans Res 2020; 6:343-351. [PMID: 32777190 DOI: 10.1177/2380084420948779] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 11/17/2022] Open
Abstract
INTRODUCTION Previous studies have largely explored the microbial composition and pathogenesis of pregnancy gingivitis. However, the patterns of microbial colonization during pregnancy in the absence of pregnancy gingivitis have rarely been studied. Characterization of the oral microbiome in pregnant women with healthy gingiva is an important initial step in understanding the role of the microbiome in progression to pregnancy gingivitis. OBJECTIVES In this study, we compared the oral microbiome of pregnant women without gingivitis (healthy pregnancy) with pregnant women having gingivitis and nonpregnant healthy women to understand how pregnancy modifies the oral microbiome and induces progression to pregnancy gingivitis. METHODS Subgingival plaque samples were collected from Chinese pregnant women with gingivitis (n = 10), healthy pregnant women (n = 10), and nonpregnant healthy women (n = 10). The Illumina MiSeq platform was used to perform 16S rRNA gene sequencing targeting the V4 region. RESULTS The alpha and beta diversity was significantly different between pregnant and nonpregnant women, but minimal differences were observed between pregnant women with and without gingivitis. Interestingly, the oral bacterial community showed higher abundance of pathogenic taxa during healthy pregnancy as compared with nonpregnant women despite similar gingival and plaque index scores. However, when compared with overt pregnancy gingivitis, pathogenic taxa were less abundant during healthy pregnancy. PICRUSt analysis (phylogenetic investigation of communities by reconstruction of unobserved states) also suggested no difference in the functional capabilities of the microbiome during pregnancy, irrespective of gingival disease status. However, metabolic pathways related to amino acid metabolism were significantly increased in healthy pregnant women as compared with nonpregnant women. CONCLUSION The presence of pathogenic taxa in healthy pregnancy and pregnancy gingivitis suggests that bacteria may be necessary for initiating disease development but progression to gingivitis may be influenced by the host environmental factors. More efforts are required to plan interventions aimed at sustaining health before the appearance of overt gingivitis. KNOWLEDGE TRANSFER STATEMENT The results of this study draw attention to the importance of oral health maintenance during pregnancy, as women without any prenatal oral conditions are predisposed to the risk of developing pregnancy gingivitis. Hence, it is important to incorporate comprehensive assessment of oral health in the prenatal health care schedules. Pregnant woman should be screened for oral risks, counseled on proper oral hygiene and expected oral changes, and referred for dental treatment, when necessary.
Collapse
Affiliation(s)
- P Balan
- Singapore Oral Microbiomics Inititative, National Dental Research Institute Singapore, SingHealth, Singapore.,Oral Health ACP, Duke NUS Medical School, Singapore
| | - B W Brandt
- Department of Preventive Dentistry, Academic Centre for Dentistry, Amsterdam, the Netherlands
| | - Y S Chong
- Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University Hospital, Singapore
| | - W Crielaard
- Department of Preventive Dentistry, Academic Centre for Dentistry, Amsterdam, the Netherlands
| | - M L Wong
- Discipline of Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore
| | - V Lopez
- School of Nursing, Hubei University of Medicine, Shiyan City, China
| | - H G He
- Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - C J Seneviratne
- Singapore Oral Microbiomics Inititative, National Dental Research Institute Singapore, SingHealth, Singapore.,Oral Health ACP, Duke NUS Medical School, Singapore
| |
Collapse
|
5
|
Ellepola K, Truong T, Liu Y, Lin Q, Lim TK, Lee YM, Cao T, Koo H, Seneviratne CJ. Multi-omics Analyses Reveal Synergistic Carbohydrate Metabolism in Streptococcus mutans-Candida albicans Mixed-Species Biofilms. Infect Immun 2019; 87:e00339-19. [PMID: 31383746 PMCID: PMC6759298 DOI: 10.1128/iai.00339-19] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [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: 04/29/2019] [Accepted: 07/26/2019] [Indexed: 12/25/2022] Open
Abstract
Candida albicans, a major opportunistic fungal pathogen, is frequently found together with Streptococcus mutans in dental biofilms associated with severe childhood caries (tooth decay), a prevalent pediatric oral disease. However, the impact of this cross-kingdom relationship on C. albicans remains largely uncharacterized. Here, we employed a novel quantitative proteomics approach in conjunction with transcriptomic profiling to unravel molecular pathways of C. albicans when cocultured with S. mutans in mixed biofilms. RNA sequencing and iTRAQ (isobaric tags for relative and absolute quantitation)-based quantitative proteomics revealed that C. albicans genes and proteins associated with carbohydrate metabolism were significantly enhanced, including sugar transport, aerobic respiration, pyruvate breakdown, and the glyoxylate cycle. Other C. albicans genes and proteins directly and indirectly related to cell morphogenesis and cell wall components such as mannan and glucan were also upregulated, indicating enhanced fungal activity in mixed-species biofilm. Further analyses revealed that S. mutans-derived exoenzyme glucosyltransferase B (GtfB), which binds to the fungal cell surface to promote coadhesion, can break down sucrose into glucose and fructose that can be readily metabolized by C. albicans, enhancing growth and acid production. Altogether, we identified key pathways used by C. albicans in the mixed biofilm, indicating an active fungal role in the sugar metabolism and environmental acidification (key virulence traits associated with caries onset) when interacting with S. mutans, and a new cross-feeding mechanism mediated by GtfB that enhances C. albicans carbohydrate utilization. In addition, we demonstrate that comprehensive transcriptomics and quantitative proteomics can be powerful tools to study microbial contributions which remain underexplored in cross-kingdom biofilms.
Collapse
Affiliation(s)
- K Ellepola
- Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore
- Center of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - T Truong
- Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore
| | - Y Liu
- Biofilm Research Labs, Levy Center for Oral Health, Department of Orthodontics and Divisions of Pediatric Dentistry & Community Oral Health, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Q Lin
- Protein and Proteomic Centre, Department of Biological Sciences, National University of Singapore, Singapore
| | - T K Lim
- Protein and Proteomic Centre, Department of Biological Sciences, National University of Singapore, Singapore
| | - Y M Lee
- Protein and Proteomic Centre, Department of Biological Sciences, National University of Singapore, Singapore
| | - T Cao
- Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore
| | - H Koo
- Biofilm Research Labs, Levy Center for Oral Health, Department of Orthodontics and Divisions of Pediatric Dentistry & Community Oral Health, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - C J Seneviratne
- National Dental Centre Singapore, Oral Health ACP, SingHealth Duke NUS, Singapore
| |
Collapse
|
6
|
Pereira D, Seneviratne CJ, Koga-Ito CY, Samaranayake LP. Is the oral fungal pathogen Candida albicans a cariogen? Oral Dis 2017; 24:518-526. [PMID: 28513096 DOI: 10.1111/odi.12691] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/13/2017] [Accepted: 04/27/2017] [Indexed: 12/31/2022]
Abstract
Pathobiology of dental caries is complex. Data from recent molecular microbiologic studies have further redefined the role of the oral microbiome in the etiology of dental caries. This new information challenges the conventional view on the hegemony of classic cariogenic prokaryotes such as Streptococcus mutans in caries etiology, and raises the intriguing possibility of the participation of the eukaryotic oral fungal pathogen Candida in the caries process. The virulence attributes of Candida species such as their acidogenicity and aciduric nature, the ability to develop profuse biofilms, ferment and assimilate dietary sugars, and produce collagenolytic proteinases are all indicative of their latent cariogenic potential. Based on the above, oral candidal counts have been used by some as a caries risk indicator. On the contrary, other studies suggest that Candida is merely a passenger extant in an acidic cariogenic milieu, and not a true pathogen. In this review, we critically examine the varying roles of Candida, and traditionally accepted cariogens such as the mutans group of streptococci in the pathobiology of dental caries. The weight of available data tends to imply that Candida may play a pivotal role as a secondary agent perpetuating the carious process, especially in dentinal caries.
Collapse
Affiliation(s)
- Dfa Pereira
- São José dos Campos Institute of Science and Technology, Universidade Estadual Paulista/UNESP, São José dos Campos, Brazil
| | - C J Seneviratne
- Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore
| | - C Y Koga-Ito
- São José dos Campos Institute of Science and Technology, Universidade Estadual Paulista/UNESP, São José dos Campos, Brazil
| | - L P Samaranayake
- Department of Bioclinical Sciences, Kuwait University, Kuwait.,School of Dentistry, The University of Queensland, Australia
| |
Collapse
|
7
|
Ellepola K, Liu Y, Cao T, Koo H, Seneviratne CJ. Bacterial GtfB Augments Candida albicans Accumulation in Cross-Kingdom Biofilms. J Dent Res 2017; 96:1129-1135. [PMID: 28605597 DOI: 10.1177/0022034517714414] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Streptococcus mutans is a biofilm-forming oral pathogen commonly associated with dental caries. Clinical studies have shown that S. mutans is often detected with Candida albicans in early childhood caries. Although the C. albicans presence has been shown to enhance bacterial accumulation in biofilms, the influence of S. mutans on fungal biology in this mixed-species relationship remains largely uncharacterized. Therefore, we aimed to investigate how the presence of S. mutans influences C. albicans biofilm development and coexistence. Using a newly established haploid biofilm model of C. albicans, we found that S. mutans augmented haploid C. albicans accumulation in mixed-species biofilms. Similarly, diploid C. albicans also showed enhanced biofilm formation in the presence of S. mutans. Surprisingly, the presence of S. mutans restored the biofilm-forming ability of C. albicans bcr1Δ mutant and bcr1Δ/Δ mutant, which is known to be severely defective in biofilm formation when grown as single species. Moreover, C. albicans hyphal growth factor HWP1 as well as ALS1 and ALS3, which are also involved in fungal biofilm formation, were upregulated in the presence of S. mutans. Subsequently, we found that S. mutans-derived glucosyltransferase B (GtfB) itself can promote C. albicans biofilm development. Interestingly, GtfB was able to increase the expression of HWP1, ALS1, and ALS3 genes in the C. albicans diploid wild-type SC5314 and bcr1Δ/Δ, leading to enhanced fungal biofilms. Hence, the present study demonstrates that a bacterial exoenzyme (GtfB) augments the C. albicans counterpart in mixed-species biofilms through a BCR1-independent mechanism. This novel finding may explain the mutualistic role of S. mutans and C. albicans in cariogenic biofilms.
Collapse
Affiliation(s)
- K Ellepola
- 1 Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore
| | - Y Liu
- 2 Biofilm Research Labs, Levy Center for Oral Health, Department of Orthodontics and Divisions of Pediatric Dentistry & Community Oral Health, School of Dental Medicine, University of Pennsylvania, PA, USA
| | - T Cao
- 1 Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore
| | - H Koo
- 2 Biofilm Research Labs, Levy Center for Oral Health, Department of Orthodontics and Divisions of Pediatric Dentistry & Community Oral Health, School of Dental Medicine, University of Pennsylvania, PA, USA
| | - C J Seneviratne
- 1 Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore
| |
Collapse
|
8
|
Seneviratne CJ, Samaranayake LP, Ohshima T, Maeda N, Jin LJ. Identification of antifungal molecules from novel probiotic Lactobacillus bacteria for control of Candida infection. Hong Kong Med J 2016; 22 Suppl 7:34-36. [PMID: 29941691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023] Open
Affiliation(s)
| | | | - T Ohshima
- School of Dental Medicine, Tsurumi University, Japan
| | - N Maeda
- School of Dental Medicine, Tsurumi University, Japan
| | - L J Jin
- Faculty of Dentistry, The University of Hong Kong
| |
Collapse
|
9
|
Seneviratne CJ, Yip JWY, Chang JWW, Zhang CF, Samaranayake LP. Effect of culture media and nutrients on biofilm growth kinetics of laboratory and clinical strains of Enterococcus faecalis. Arch Oral Biol 2013; 58:1327-34. [PMID: 23880095 DOI: 10.1016/j.archoralbio.2013.06.017] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [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: 11/21/2012] [Revised: 05/31/2013] [Accepted: 06/20/2013] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Enterococcus faecalis is a bacterial pathogen that is often associated with endodontic infections. Biofilm formation is a key virulence attribute in the pathogenicity of E. faecalis. In the present study, we comprehensively examined the effect of various culture media and nutrients on the development of E. faecalis biofilms. DESIGN A reference strain and a clinical isolate of E. faecalis were used in all experiments for comparison. Commonly used liquid culture media with different nutrient compositions were used to support the development of E. faecalis biofilms in a time-dependent assay. E. faecalis biofilms were quantified by colony forming unit (CFU) and crystal violet (CV) assays. Biofilm architecture and cellular viability were evaluated by scanning electron microscopy and confocal laser scanning microscopy. RESULTS Growth kinetics evaluated by CFU and CV assays and by microscopy showed that E. faecalis biofilms reached maturity at 72h. "Pg broth" (Tryptic Soy Broth with yeast extract, hemen and vitamin K) promoted E. faecalis biofilm formation more than Brain Heart Infusion broth or Tryptic Soy Broth. Addition of 2% glucose enhanced biofilm formation. Thus, it seems that nutrients such as hemen, vitamin K and glucose are important for E. faecalis for the formation of biofilms. CONCLUSION The present study demonstrated that nutrient-rich media containing glucose enhances the formation of E. faecalis biofilms, which exhibit maturation at 72h.
Collapse
Affiliation(s)
- C J Seneviratne
- Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore.
| | | | | | | | | |
Collapse
|
10
|
Li X, Zhu XF, Zhang CF, Cathro P, Seneviratne CJ, Shen S. Endodontic bacteria from primary and persistent endodontic lesions in Chinese patients as identified by cloning and 16S ribosomal DNA gene sequencing. Chin Med J (Engl) 2013; 126:634-639. [PMID: 23422180] [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: 06/01/2023] Open
Abstract
BACKGROUND Few literatures pertain to the 16S ribosomal DNA (16S rDNA) analysis of bacteria contributing to primary and persistent endodontic lesions, with no information available for the Chinese population. As such, we investigated endodontic bacteria associated with primary and persistent endodontic lesions in adult Chinese patients living in Beijing, China using 16S rDNA gene sequencing techniques. METHODS Endodontic microbial samples were obtained from fourteen adult Chinese patients and subjected to DNA extraction. Pllymerase chain reaction (PCR) products were cloned and 100 clones from each generated library were randomly selected. Purified plasmid DNA with 16S rDNA gene inserts was sequenced, and the sequences were searched against GenBank databases using the BLASTN algorithm. Only significant identification with the highest-scored BLAST result and 99% minimum similarity was considered for phylotyping. RESULTS More than 150 taxa were obtained. Primary endodontic infection was mainly associated with Burkholderia cepacia, Actinomyces, Aranicola spp. and Streptococcus sanguinis, whilst Burkholderia cepacia was predominant in the persistent endodontic infections. CONCLUSION There is a difference in the species profile associated with endodontic infections of Chinese patients living in Beijing in comparison to other geographical or ethnic reports.
Collapse
Affiliation(s)
- Xin Li
- Faculty of Dentistry, Peking University Third Hospital, Beijing, 100191, China
| | | | | | | | | | | |
Collapse
|
11
|
Leung CY, Chan YC, Samaranayake LP, Seneviratne CJ. Biocide resistance of Candida and Escherichia coli biofilms is associated with higher antioxidative capacities. J Hosp Infect 2012; 81:79-86. [PMID: 22595316 DOI: 10.1016/j.jhin.2011.09.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 09/25/2011] [Indexed: 11/27/2022]
Abstract
BACKGROUND Most clinical guidelines for the use of biocides have been developed for planktonic micro-organisms, but in nature, most micro-organisms live as surface-adherent communities or biofilms. AIM To evaluate the effectiveness of commonly used biocides against Escherichia coli and Candida spp. in three distinct growth phases: planktonic, adhesion and biofilm. METHODS Ultrastructural, architectural and cellular viability changes following a 5 min exposure to biocide were monitored by scanning electron microscopy and confocal laser scanning microscopy using fluorescent dyes. Comparative transcript expression of the antioxidants SOD1 and CAT1 in the planktonic and biofilm phases was evaluated using quantitative real-time polymerase chain reaction. FINDINGS E. coli and Candida spp. in the planktonic phase were susceptible to all the tested biocides at the recommended concentrations. However, early adhesion and late biofilm phases of both were less susceptible to the biocides, and exceeded the recommended concentrations on several occasions. A short period of biocide exposure failed to fully eradicate the adherent microbial cells, and they recovered from the biocide challenge, forming biofilm on the biocide-treated surfaces. The biofilm phase showed higher expression of SOD1 and CAT1. CONCLUSION The recommended concentrations of biocides for clinical disinfection in the hospital setting may not fully eradicate the adhesion or biofilm phases of E. coli and Candida spp. Higher antioxidative capacities in microbial biofilms may be responsible for the resistance of biofilms against clinical biocides.
Collapse
Affiliation(s)
- C Y Leung
- Oral Biosciences, Faculty of Dentistry, University of Hong Kong, Hong Kong
| | | | | | | |
Collapse
|
12
|
Herath TDK, Wang Y, Seneviratne CJ, Darveau RP, Wang CY, Jin LJ. Heterogeneous LPS of Porphyromonas gingivalis differentially modulate the innate immune response of human gingiva. BMC Proc 2011. [DOI: 10.1186/1753-6561-5-s1-p86] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
13
|
Watamoto T, Samaranayake LP, Egusa H, Yatani H, Seneviratne CJ. Transcriptional regulation of drug-resistance genes in Candida albicans biofilms in response to antifungals. J Med Microbiol 2011; 60:1241-1247. [DOI: 10.1099/jmm.0.030692-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- T. Watamoto
- Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry, Osaka, Japan
- Oral Biosciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR
| | - L. P. Samaranayake
- Oral Biosciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR
| | - H. Egusa
- Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - H. Yatani
- Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - C. J. Seneviratne
- Oral Biosciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR
| |
Collapse
|
14
|
Seneviratne CJ, Wong SSW, Yuen KY, Meurman JH, Pärnänen P, Vaara M, Samaranayake LP. Antifungal Susceptibility and Virulence Attributes of Bloodstream Isolates of Candida from Hong Kong and Finland. Mycopathologia 2011; 172:389-95. [DOI: 10.1007/s11046-011-9444-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 06/28/2011] [Indexed: 11/27/2022]
|
15
|
Herath TDK, Wang Y, Seneviratne CJ, Darveau RP, Wang CY, Jin LJ. Heterogeneous LPS of Porphyromonas gingivalis differentially modulate the innate immune response of human gingiva. BMC Proc 2011. [PMCID: PMC3019516] [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: 11/04/2022] Open
Affiliation(s)
- TDK Herath
- The University of Hong Kong, Hong Kong SAR
| | - Y Wang
- The University of Hong Kong, Hong Kong SAR
| | | | | | - CY Wang
- UCLA School of Dentistry, Los Angeles, USA
| | - LJ Jin
- The University of Hong Kong, Hong Kong SAR
| |
Collapse
|
16
|
Low B, Lee W, Seneviratne CJ, Samaranayake LP, Hagg U. Ultrastructure and morphology of biofilms on thermoplastic orthodontic appliances in 'fast' and 'slow' plaque formers. Eur J Orthod 2010; 33:577-83. [DOI: 10.1093/ejo/cjq126] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
17
|
|
18
|
Seneviratne CJ, Silva WJ, Jin LJ, Samaranayake YH, Samaranayake LP. Architectural analysis, viability assessment and growth kinetics of Candida albicans and Candida glabrata biofilms. Arch Oral Biol 2009; 54:1052-60. [PMID: 19712926 DOI: 10.1016/j.archoralbio.2009.08.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 02/18/2009] [Accepted: 08/01/2009] [Indexed: 11/25/2022]
Abstract
The human fungal pathogen Candida is able to form biofilms in almost all the medical devices in current use. Indeed, biofilm formation is a major virulence attribute of microorganisms and account for a majority of human infections. Therefore, understanding processes appertaining to biofilm development is an important prerequisite for devising new strategies to prevent or eradicate biofilm-related infections. In the present study we used an array of both conventional and novel analytical tools to obtain a comprehensive view of Candida biofilm development. Enumeration of colony forming units, colorimetric (XTT) assay, Scanning Electron Microscopy (SEM) and novel Confocal Laser Scanning Microscopy (CLSM) coupled with COMSTAT software analyses were utilised to evaluate growth kinetics; architecture and viability of biofilms of a reference (ATCC) and a clinical strain each of two Candida species, C. albicans and C. glabrata. Biofilm growth kinetics on a polystyrene substrate was evaluated from the initial adhesion step (1.5 h) up to 72 h. These analyses revealed substantial inter- and intra-species differences in temporal organisation of Candida biofilm architecture, spatiality and cellular viability, while reaching maturity within a period of 48 h, on a polystyrene substrate. There were substantial differences in the growth kinetics upon methodology, although general trend seemed to be the same. Detailed architectural analysis provided by COMSTAT software corroborated the SEM and CSLM views. These analyses may provide a strong foundation for down stream molecular work of fungal biofilms.
Collapse
Affiliation(s)
- C J Seneviratne
- Oral Bio-Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong.
| | | | | | | | | |
Collapse
|
19
|
Watamoto T, Samaranayake LP, Jayatilake JAMS, Egusa H, Yatani H, Seneviratne CJ. Effect of filamentation and mode of growth on antifungal susceptibility of Candida albicans. Int J Antimicrob Agents 2009; 34:333-9. [PMID: 19376687 DOI: 10.1016/j.ijantimicag.2009.03.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 03/03/2009] [Accepted: 03/04/2009] [Indexed: 11/29/2022]
Abstract
Biofilm formation involving profuse hyphal growth is a major characteristic of Candida spp. and confers higher antifungal resistance than its planktonic mode of growth. We investigated the antifungal susceptibility of Candida albicans and its hyphal mutants (Delta efg1/efg1, Delta cph1/cph1 and DeltaDelta cph1/cph1 efg1/efg1) to commonly used antifungals during planktonic, adhesion and biofilm modes of growth. The minimum inhibitory concentration (MIC) of each antifungal agent was determined for a lower inoculum (1x10(3) cells/mL) and higher inoculum (1x10(7) cells/mL) of planktonic Candida. Furthermore, MICs of C. albicans biofilms and adhesion modes of growth were determined with a standard XTT assay. Candida albicans in adhesion and biofilm modes of growth, but not in planktonic mode, were resistant to all five antifungal agents tested. Although Delta efg1/efg1 and DeltaDelta cph1/cph1 efg1/efg1 mutants formed less biofilm than wild-type C. albicans SC5314, they were similarly resistant to caspofungin. However, these mutants were more sensitive to amphotericin B and nystatin than the wild-type. Adhesion per se confers increased resistance to antifungal agents, which is further pronounced in the biofilm mode of Candida. Filamentation does not appear to be a major determinant of the antifungal resistance in Candida biofilms.
Collapse
Affiliation(s)
- T Watamoto
- Oral BioSciences, Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, 34 Hospital Road, Pokfulam, Hong Kong, China
| | | | | | | | | | | |
Collapse
|
20
|
Abstract
Photodynamic therapy is a treatment that combines the use of three non-toxic components, viz. photosensitiser, light and oxygen to cause localised oxidative photodamage. In the present study, the antifungal effect of the photosensitiser, BAM-SiPc, an unsymmetrical bisamino phthalocyanine, was investigated. BAM-SiPc was effective in photo-inactivating Candida albicans in a dose-dependent manner. The cell viability as determined by the clonogenic assay was reduced to c. 10% at 0.02 micromol l(-1) BAM-SiPc with a total fluence of 12 J cm(-2) at a cell density of 10(7) cells ml(-1). A short incubation time of 5-15 min was sufficient to allow the photosensitiser to exert its optimal antifungal activity. Microscopical analysis showed that BAM-SiPc was effectively internalised by the fungal cells. Photodynamic treatment led to an increase in the intracellular reactive oxygen species level and disturbed the membrane integrity of the fungal cells.
Collapse
Affiliation(s)
- Cheung-Wai So
- Department of Biochemistry, The Chinese University of Hong Kong, Hong Kong, China
| | | | | | | | | | | |
Collapse
|
21
|
Abstract
Candida is the major fungal pathogen of humans causing a variety of afflictions ranging from superficial mucosal diseases to deep seated mycoses. Biofilm formation is a major virulence factor in the pathogenicity of Candida, and Candida biofilms are difficult to eradicate especially because of their very high antifungal resistance. Consequently, research into the pathogenicity of Candida has focused on the prevention and management of biofilm development, their architecture, and antifungal resistance. Although studies have shed some light, molecular mechanisms that govern biofilm formation and pathogenicity still await full clarification. This review outlines the key features of what is currently known of Candida biofilm development, regulation and antifungal resistance and, their proteomics.
Collapse
Affiliation(s)
- C J Seneviratne
- Oral Bio-Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong
| | | | | |
Collapse
|
22
|
Abstract
BACKGROUND South Asian migrants have a higher cardiovascular mortality than the indigenous population. Contributory factors may include a lower rate of cardiovascular risk assessment uptake and compliance. AIM To compare rates of lipid testing, follow-up and patterns of dyslipidaemia in South Asian and non-South-Asian populations in Manchester. DESIGN Retrospective cross-sectional survey. METHODS Lipid requests from 14 general practices were analysed, using name recognition software to assign ethnicity. RESULTS Compared with non-South-Asians, the age-standardized rate of lipid testing in South Asians was similar in men at 12.1% (95%CI 11.6-12.6) vs. 11.2% (9.5-13.0), but higher in women at 18.6% (15.9-21.2) vs. 13.2% (12.6-13.7). Trends of cholesterol with repeat testing were similar in the two populations. However, South Asian women had lower mean levels of total cholesterol (5.50 vs. 5.68 mmol/l, p = 0.021), lower levels of HDL (1.20 vs. 1.46 mmol/l, p < 0.001), an excess of hypertriglyceridaemia (1.62 vs. 1.45 mmol/l, p = 0.035) and a greater proportion with cholesterol > 5.2 mmol/l combined with low HDL (43.1% vs. 20.2%, p = 0.002). South Asian men had lower levels of total cholesterol (5.17 vs. 5.37 mmol/l, p = 0.048) and lower levels of HDL (1.07 vs. 1.64 mmol/l, p < 0.001). There was no difference in the proportion of South Asians men and women with cholesterol < 5.2 mmol/l combined with low HDL. DISCUSSION The rate of lipid testing and change in cholesterol levels with repeated testing did not differ between South Asian and non-South-Asian groups. The pattern of dyslipidaemia seen in this South Asian population, especially women, was different from that of the non-South-Asian population, with possible implications for cardiovascular risk assessment.
Collapse
Affiliation(s)
- M W France
- Department of Clinical Biochemistry, Manchester Royal Infirmary, Barlow Medical Centre, Manchester, UK.
| | | | | | | |
Collapse
|
23
|
Fay H, Seneviratne CJ. Alan Hadfield Gowenlock. West J Med 2001. [DOI: 10.1136/bmj.323.7325.1371c] [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: 11/03/2022]
|
24
|
Herren KR, Mackway-Jones K, Richards CR, Seneviratne CJ, France MW, Cotter L. Is it possible to exclude a diagnosis of myocardial damage within six hours of admission to an emergency department? Diagnostic cohort study. BMJ 2001; 323:372. [PMID: 11509427 PMCID: PMC37396 DOI: 10.1136/bmj.323.7309.372] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To assess the clinical efficacy and accuracy of an emergency department based six hour rule-out protocol for myocardial damage. DESIGN Diagnostic cohort study. SETTING Emergency department of an inner city university hospital. PARTICIPANTS 383 consecutive patients aged over 25 years with chest pain of less than 12 hours' duration who were at low to moderate risk of acute myocardial infarction. INTERVENTION Serial measurements of creatine kinase MB mass and continuous ST segment monitoring for six hours with 12 leads. MAIN OUTCOME MEASURE Performance of the diagnostic test against a gold standard consisting of either a 48 hour measurement of troponin T concentration or screening for myocardial infarction according to the World Health Organization's criteria. RESULTS Outcome of the gold standard test was available for 292 patients. On the diagnostic test for the protocol, 53 patients had positive results and 239 patients had negative results. There were 18 false positive results and one false negative result. Sensitivity was 97.2% (95% confidence interval 95.0% to 99.0%), specificity 93.0% (90.0% to 96.0%), the negative predictive value 99.6%, and the positive predictive value 66.0%. The positive likelihood ratio was 13.9 and the negative likelihood ratio 0.03. CONCLUSIONS The six hour rule-out protocol for myocardial infarction is accurate and efficacious. It can be used in patients presenting to emergency departments with chest pain indicating a low to moderate risk of myocardial infarction.
Collapse
Affiliation(s)
- K R Herren
- Department of Emergency Medicine, Manchester Royal Infirmary, Manchester M13 9WL
| | | | | | | | | | | |
Collapse
|
25
|
France MW, Seneviratne CJ. Authors' Reply. Ann Clin Biochem 1998. [DOI: 10.1177/000456329803500238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- M W France
- Department of Clinical Biochemistry, Central Manchester Healthcare Trust, Oxford Road, Manchester M13 9WL, UK
| | - C J Seneviratne
- Department of Clinical Biochemistry, Central Manchester Healthcare Trust, Oxford Road, Manchester M13 9WL, UK
| |
Collapse
|
26
|
Affiliation(s)
- M W France
- Department of Clinical Biochemistry, Manchester Royal Infirmary, UK
| | | |
Collapse
|
27
|
Mallick NP, Dosa S, Acheson EJ, Delamore IW, McFarlane H, Seneviratne CJ, Williams G. Detection, significance and treatment of paraprotein in patients presenting with 'idiopathic' proteinuria without myeloma. Q J Med 1978; 47:145-75. [PMID: 684153] [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: 12/24/2022]
Abstract
This paper describes the detection of a paraprotein in blood or urine in 12 of 260 patients with 'idiopathic' proteinuria, most of whom presented with the nephrotic syndrome. None had myeloma at presentation and only two have developed it. Initial clinical and biochemical findings did not suggest paraprotein-associated disease, total serum globulins and individual immunoglobulin levels usually being in the normal range. In seven of the 12 cases the paraprotein was detected only after repeated analysis of serum and urine specimens over months or years. Renal histopathology varied from case to case and is described in detail; amyloid deposition did not occur in patients who excreted kappa chain Bence Jones protein and was extensive in only three. One of these eventually developed myeloma. Patients were aged 27--69 years at onset and were observed without specific therapy for up to 56 months. Glomerular filtration rate tended to decline and proteinuria persisted. All patients have now been treated by a chemotherapeutic regimen consisting of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), cyclophosphamide, melphalan, and prednisolone, in repeated short courses. In some patients, particularly those who had kappa Bence Jones protein, there was striking improvement. Overall survival is good, eight patients being alive 17--90 months after the onset of symptoms. The importance of repeated search for paraprotein in apparently idiopathic renal disease in adults is emphasized.
Collapse
|