Impact of frequency of denture cleaning on microbial and clinical parameters - a bench to chairside approach.

Objective: Robust scientific and clinical evidence of how to appropriately manage denture plaque is lacking. This two-part study (i) developed an in vitro model of denture plaque removal, and (ii) assessed effectiveness of these approaches in a randomised clinical trial. Method: (i) a complex denture plaque model was developed using the dominant microbial genera from a recent microbiome analyses. Biofilms formed on polymethylmethacrylate were brushed daily with a wet toothbrush, then either treated daily for 5 days or only on Days 1 and 5 with Polident® denture cleanser tablets (3 min soaking). Quantitative and qualitative microbiological assessments were performed. (ii), an examiner-blind, randomised, crossover study of complete maxillary denture wearers was performed (n = 19). Either once-daily for 7 days or on Day 7 only, participants soaked dentures for 15 min using Corega® denture cleansing tables, then brushed. Denture plaque microbiological assessment used sterilized filter paper discs. Results: The in vitro model showed daily cleaning with denture cleanser plus brushing significantly reduced microbial numbers compared to intermittent denture cleaning with daily brushing (p < 0.001). The clinical component of the study showed a statistically significant reduction in denture plaque microbial numbers in favour of daily versus weekly treatment (aerobic bacteria p = 0.0144). Both in vitro and in vivo studies showed that denture plaque biofilm composition were affected by different treatment arms. Conclusions: This study demonstrated that daily denture cleansing regimens are superior to intermittent denture cleansing, and that cleansing regimens can induce denture plaque compositional changes. Clinicaltrials.gov registration: NCT02780661.

Evaluating Streptococcus mutans Strain Dependent Characteristics in a Polymicrobial Biofilm Community.

Aim: The purpose of this study was to investigate strain dependent differences of the cariogenic biofilm forming Streptococcus mutans within both simple and complex communities. Methods: A mono-species containing representative S. mutans clinical isolates (caries and non-caries), and a multispecies in vitro caries biofilm model containing Lactobacillus casei, Veillonella dispar, Fusobacterium nucleatum and Actinomyces naeslundii, and either of two representative S. mutans clinical isolates (caries and non-caries), was developed as a comparison model. Compositional analysis of total and live bacteria within biofilms, and transcriptional analysis of biofilm associated virulence factors were evaluated by live/dead PCR and quantitative PCR, respectively. Scanning electron microscopy (SEM) was used to analyze the architecture of biofilm. One-way analysis of variance and t-tests were used to investigate significant differences between independent groups of data. Results: Within a mono-species biofilm, different S. mutans strains responded similarly to one another during biofilm formation in different carbohydrate sources, with sucrose showing the highest levels of biofilm biomass and galactose showing the lowest. Within the polymicrobial biofilm system, compositional analysis of the bacteria within the biofilm showed that S. mutans derived from a caries-free patient was preferentially composed of both total and viable L. casei, whereas S. mutans derived from a caries patient was dominated by both total and viable S. mutans (p < 0.001). Normalized gene expression analysis of srtA, gtfB, ftf, spaP, gbpB, and luxS, showed a general upregulation within the S. mutans dominant biofilm. Conclusion: We were able to demonstrate that individual strains derived from different patients exhibited altered biofilm characteristics, which were not obvious within a simple mono-species biofilm model. Influencing the environmental conditions changed the composition and functionality S. mutans within the polymicrobial biofilm. The biofilm model described herein provides a novel and reproducible method of assessing the impact on the biofilm microbiome upon different environmental influences.

The seroprevalence of hepatitis C virus infection among children and their mothers attending for dental care in Glasgow, Scotland, United Kingdom.

This paper describes a voluntary anonymous survey to investigate the seroprevalence of Hepatitis C (HCV) in children in Glasgow, UK attending a Dental Hospital and the proportion of HCV positive mothers who have a child who is HCV seropositive. The study was undertaken among children and accompanying parents and household contacts attending a general anaesthetic assessment clinic at Glasgow Dental Hospital and School. Children were asked to provide an oral fluid specimen for HCV testing. Accompanying adults were asked to provide demographic data on the child and information on familial risk factors for HCV infection using a standardised questionnaire. Birth mothers were also asked to provide an oral fluid specimen. Specimens and questionnaires were linked by a unique anonymous study number. Between June 2009 and December 2011, samples were collected from 2141 children and 1698 mothers. None of the samples from the children were HCV seropositive but 16 (0.9%, 95% CI 0.6-1.5%) of the specimens from mothers were HCV antibody positive. In summary, the prevalence of HCV seropositivity in the birth mothers of the children was similar to that estimated in the general population served by the hospital and showed no evidence of mother-to-child transmission of HCV.

Human Papilloma Virus (HPV) Oral Prevalence in Scotland (HOPSCOTCH): A Feasibility Study in Dental Settings.

The purpose of this study was to test the feasibility of undertaking a full population investigation into the prevalence, incidence, and persistence of oral Human Papilloma Virus (HPV) in Scotland via dental settings. Male and female patients aged 16-69 years were recruited by Research Nurses in 3 primary care and dental outreach teaching centres and 2 General Dental Practices (GDPs), and by Dental Care Teams in 2 further GDPs. Participants completed a questionnaire (via an online tablet computer or paper) with socioeconomic, lifestyle, and sexual history items; and were followed up at 6-months for further questionnaire through appointment or post/online. Saline oral gargle/rinse samples, collected at baseline and follow-up, were subject to molecular HPV genotyping centrally. 1213 dental patients were approached and 402 individuals consented (participation rate 33.1%). 390 completed the baseline questionnaire and 380 provided a baseline oral specimen. Follow-up rate was 61.6% at 6 months. While recruitment was no different in Research Nurse vs Dental Care Team models the Nurse model ensured more rapid recruitment. There were relatively few missing responses in the questionnaire and high levels of disclosure of risk behaviours (99% answered some of the sexual history questions). Data linkage of participant data to routine health records including HPV vaccination data was successful with 99.1% matching. Oral rinse/gargle sample collection and subsequent HPV testing was feasible. Preliminary analyses found over 95% of samples to be valid for molecular HPV detection prevalence of oral HPV infection of 5.5% (95%CI 3.7, 8.3). It is feasible to recruit and follow-up dental patients largely representative / reflective of the wider population, suggesting it would be possible to undertake a study to investigate the prevalence, incidence, and determinants of oral HPV infection in dental settings.

Dentures are a Reservoir for Respiratory Pathogens.

PURPOSE: Recent studies have established a relationship between dental plaque and pulmonary infection, particularly in elderly individuals. Given that approximately one in five adults in the UK currently wears a denture, there remains a gap in our understanding of the direct implications of denture plaque on systemic health. The aim of this study was to undertake a comprehensive evaluation of putative respiratory pathogens residing upon dentures using a targeted quantitative molecular approach. MATERIALS AND METHODS: One hundred and thirty patients' dentures were sonicated to remove denture plaque biofilm from the surface. DNA was extracted from the samples and was assessed for the presence of respiratory pathogens by quantitative polymerase chain reaction (qPCR). Ct values were then used to approximate the number of corresponding colony forming equivalents (CFEs) based on standard curves. RESULTS: Of the dentures, 64.6% were colonized by known respiratory pathogens. Six species were identified: Streptococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, Haemophilus influenzae B, Streptococcus pyogenes, and Moraxella catarrhalis. P. aeruginosa was the most abundant species followed by S. pneumoniae and S. aureus in terms of average CFE and overall proportion of denture plaque. Of the participants, 37% suffered from denture stomatitis; however, there were no significant differences in the prevalence of respiratory pathogens on dentures between healthy and inflamed mouths. CONCLUSIONS: Our findings indicate that dentures can act as a reservoir for potential respiratory pathogens in the oral cavity, thus increasing the theoretical risk of developing aspiration pneumonia. Implementation of routine denture hygiene practices could help to reduce the risk of respiratory infection among the elderly population.

The Francis Report--Why it Matters to the Dental Team.

The Francis Report into the deaths at Mid-Staffordshire NHS Trust highlighted the problems facing the NHS when patients, families, clinicians and nurses are not heard, and where the management, leadership and ensuing culture are focused on the system's business, not patient care. This paper, the first in a series based on the implications of the Francis Report, provides the background and context for the subsequent 'perspective' articles from a range of relevant stakeholders and care-providers. The overriding message is that in all areas of healthcare, dentistry included, the quality of patient care, especially patient safety, must be placed above all other aims. Clinical Relevance: The overriding importance of patient-centredness and quality of care, above all other aims, is the key message of clinical relevance from the Francis Report.

Summary of: general dental practitioners' perceptions of antimicrobial use and resistance: a qualitative interview study.

BACKGROUND: Dentists are responsible for 9-10% of all antibiotics dispensed in primary care in the UK, many of which may be provided contrary to clinical guidelines. Since antibiotic consumption has been identified as a major cause of antibiotic resistance, dental prescribing may be a significant contributor to this important public health problem. OBJECTIVE: This study aims to explore general dental practitioners' (GDPs) perceptions and attitudes towards antibiotic use and resistance. METHOD: Qualitative interview study with 19 purposively sampled GDPs working in Wales. A set of open-ended questions were developed and amended during semi-structured telephone interviews. Interviews were recorded, transcribed verbatim and codes were developed using thematic analysis. RESULTS: Perceptions of antibiotic use and resistance varied widely between practitioners, particularly with respect to the prevalence and impact of resistant strains on the management of dentoalveolar infection, and the impact of dental prescribing on the emergence of resistance. GDPs reported that their antibiotic prescribing decisions were driven by both clinical pressures and wider public health considerations. CONCLUSIONS: Interventions to enhance the quality of antibiotic prescribing in primary care dentistry should address issues associated with inappropriate prescribing as well as providing education about the causes, prevalence and impact of antibiotic resistance.

Antifungal, cytotoxic, and immunomodulatory properties of tea tree oil and its derivative components: potential role in management of oral candidosis in cancer patients.

Candida albicans forms oral biofilms that cause disease and are difficult to treat with conventional antifungal agents. Tea tree oil (TTO) is a natural compound with reported antimicrobial and immunomodulatory activities. The aims of the study were to evaluate the antifungal efficacy of TTO and key derivatives against C. albicans biofilms, to assess the toxicological effects of TTO on a clinically relevant oral cell line, and to investigate its impact on inflammation. TTO and its derivatives were examined against 100 clinical strains of C. albicans. Planktonic minimum inhibitory concentrations (MICs) were determined using the CLSI M-27A broth microdilution method. Sessile MICs were determined using an XTT reduction assay. Inhibition, time-kill, and mode of action studies were performed. OKF6-TERT2 epithelial cells were used for cytotoxicity and cytokine expression assays. Planktonic C. albicans isolates were susceptible to TTO, terpinen-4-ol (T-4-ol), and α-terpineol, with an MIC(50) of 0.5, 0.25, and 0.25%, respectively. These three compounds also displayed potent activity against the 69 biofilm-forming strains, of which T-4-ol and α-terpineol displayed rapid kill kinetics. For all three compounds, 1 × MIC(50) effectively inhibited biofilm growth when C. albicans were treated at 0, 1, and 2 h post adhesion. By scanning electron microscopy analysis and PI uptake, TTO and derivative components were shown to be cell membrane active. TTO and T-4-ol were cytotoxic at 1 × MIC(50), whereas at 0.5 × MIC(50) T-4-ol displayed no significant toxicity. Transcript and protein analysis showed a reduction of IL-8 when treated with TTO and T-4-ol. These data provide further in vitro evidence that TTO and its derivative components, specifically T-4-ol, exhibit strong antimicrobial properties against fungal biofilms. T-4-ol has safety advantages over the complete essential oil and may be suitable for prophylaxis and treatment of established oropharyngeal candidosis. A clinical trial of T-4-ol is worthy of consideration.

Carbohydrate Derived Fulvic Acid: An in vitro Investigation of a Novel Membrane Active Antiseptic Agent Against Candida albicans Biofilms.

Carbohydrate derived fulvic acid (CHD-FA) is a heat stable low molecular weight, water soluble, cationic, colloidal material with proposed therapeutic properties. The aim of this study was to evaluate the antifungal activity of CHD-FA against Candida albicans, and to characterize its mode of action. A panel of C. albicans isolates (n = 50) derived from a range of clinical specimens were grown planktonically and as biofilms, and the minimum inhibitory concentrations determined. Scanning electron microscopy was performed to examine ultrastructural changes and different cell membrane assays were used to determine its mode of action. In addition, the role of C. albicans biofilm resistance mechanisms were investigated to determine their effects on CHD-FA activity. CHD-FA was active against planktonic and sessile C. albicans at concentrations 0.125 and 0.25% respectively, and was shown to be fungicidal, acting through disruption of the cell membrane activity. Resistance mechanisms, including matrix, efflux, and stress, had a limited role upon CHD-FA activity. Overall, based on the promising in vitro spectrum of activity and minimal biofilm resistance of the natural and cheap antiseptic CHD-FA, further studies are required to determine its applicability for clinical use.

In vitro Candida albicans biofilm induced proteinase activity and SAP8 expression correlates with in vivo denture stomatitis severity.

Denture stomatitis is a common inflammatory disorder of the palatal mucosa amongst denture wearers. The pathological changes are induced by Candida albicans biofilm on the fitting surface of the upper denture, and different individuals experience different levels of disease. C. albicans is known to produce secreted aspartyl proteinases (SAPs) to aid adhesion, invasion and tissue destruction. We hypothesised that differential expression and activity of SAPs from denture stomatitis isolates results in different levels of disease amongst denture wearers. We selected C. albicans isolates from asymptomatic controls and three different severities of disease [Newton's type (NT) 0, I, II and III]. We assessed biofilm formation and proteinase activity for each biofilm and investigated the transcriptional profile of SAPs 1, 2, 5, 6 and 8 from early (12 h) and mature (24 h) biofilms. There were no significant differences between isolates with respect to biofilm formation, whereas proteinase activity normalised to biofilm growth was significantly increased in the diseased groups (p < 0.0001). Proteinase activity correlated strongly with SAP expression (p < 0.0001). SAP8 expression was the greatest, followed by SAP5, 6, 2 and 1. The diseased groups showed the greatest levels of SAP expression, with significant differences also observed between the groups (p < 0.005). All SAPs except SAP5 were expressed in greater amounts in the mature biofilms compared to early biofilms. Overall, this study suggests that SAP activity in biofilms determined in vitro may help to explain differences in disease severity. SAP8 has been shown for the first time to play a prominent role in biofilms.

Commercial mouthwashes are more effective than azole antifungals against Candida albicans biofilms in vitro.

OBJECTIVE: The aim of this study was to evaluate and compare the activity of prescription and over-the-counter antimicrobial compounds against planktonic and biofilm forms of Candida albicans isolated from cases of oral candidiasis in vitro. STUDY DESIGN: The efficacy of azoles, polyenes, an echinocandin, and 4 over-the-counter mouthwashes were tested against C. albicans-derived planktonic and biofilm cells. RESULTS: Planktonic cells were shown to be highly sensitive to all of the antifungal agents tested. Sessile cells were highly resistant to azoles (≥128 mg/L) but equally sensitive to caspofungin and short treatments with Corsodyl, Listerine, and Oraldene. CONCLUSIONS: Although C. albicans is sensitive to azole antifungal agents in planktonic form, it is highly resistant within the biofilm. The good efficacy of the over-the-counter mouthwashes against candidal biofilms in vitro suggests that clinical trials should now be designed to establish their role in the clinical management of oral candidal infections.

Molecular detection of transcriptionally active bacteria from failed prosthetic hip joints removed during revision arthroplasty.

The purpose of this study was to use microbiological culture and bacterial 16S rRNA gene sequencing methods to detect transcriptionally active bacteria present on the surface of failed prosthetic hip joints removed during revision arthroplasty. Five failed prosthetic hip joints were sonicated to dislodge adherent bacteria and subjected to microbiological culture. Bacterial RNA was extracted from each sonicate, cDNA prepared by reverse transcription and the 16S rRNA gene amplified using universal primers. Polymerase chain reaction (PCR) products were cloned, assigned to distinct groups by restriction fragment length polymorphism (RFLP) analysis and one representative clone from each group was sequenced. Bacteria were identified by comparison of the obtained 16S rRNA gene sequences with those deposited in public access sequence databases. All five specimens were positive for the presence of bacteria by both culture and PCR. Culture methods identified species from eight genera. Molecular detection of transcriptionally active bacteria identified a wider range of species. A total of 42 phylotypes were identified, of which Lysobacter gummosus was the most abundant (31.6%). Thirty-four clones (14.5%) represented uncultivable phylotypes. No potentially novel species were identified. It is concluded that a diverse range of transcriptionally active bacterial species are present within biofilms on the surface of failed prosthetic hip joints.

Reducing the incidence of denture stomatitis: are denture cleansers sufficient?

PURPOSE: Candida albicans is the predominant oral yeast associated with denture stomatitis. With an increasing population of denture wearers, the incidence of denture stomatitis is increasing. Effective management of these patients will alleviate the morbidity associated with this disease. The aim of this study was to examine the capacity of four denture cleansers to efficiently decontaminate and sterilize surfaces covered by C. albicans biofilms. MATERIALS AND METHODS: Sixteen C. albicans strains isolated from denture stomatitis patients and strain ATCC 90028 were grown as mature confluent biofilms on a 96-well format and immersed in Dentural, Medical Interporous, Steradent Active Plus, and Boots Smile denture cleansers according to the manufacturers' instructions or overnight. The metabolic activity and biomass of the biofilms were then quantified, and scanning electron microscopy (SEM) used to examine treated biofilms. RESULTS: Dentural was the most effective denture cleanser, reducing the biomass by greater than 90% after 20 minutes. Steradent Active plus was significantly more effective following 10-minute immersion than overnight (p < 0.001). All cleansers reduced the metabolic activity by greater than 80% following overnight immersion; however, Boots Smile exhibited significantly reduced metabolic activity following only a 15-minute immersion (p < 0.001). SEM revealed residual C. albicans material following Dentural treatment. CONCLUSIONS: This study showed that denture cleansers exhibit effective anti-C. albicans biofilm activity, both in terms of removal and disinfection; however, residual biofilm retention that could lead to regrowth and denture colonization was observed. Therefore, alternative mechanical disruptive methods are required to enhance biofilm removal.

Attachment of Candida albicans to denture base acrylic resin processed by three different methods.

Denture stomatitis is a debilitating disease associated with the presence of adherent Candida albicans. This study compared the attachment capacity of C. albicans to three different acrylic resin materials (self-curing [SC], conventional pressure-packed [CPP], and injection-molded [IM]) to determine whether the physical properties of the materials influenced candidal attachment. No significant differences in attachment between the isolates were observed for each acrylic resin. However, a comparison of the mean of all isolates showed significantly less attachment to SC than to CPP (P < .05). These data indicate that choice of denture acrylic resin material may influence the capacity for developing denture stomatitis.

Factors Contributing to the Spread of Odontogenic Infections: A prospective pilot study.

OBJECTIVES: Spreading odontogenic infections (SOI) are the commonest type of serious infections encountered in the orofacial region. A prospective multi-centre study was conducted in the West of Scotland to investigate the contributing role of social, systemic and microbial factors in the pathogenesis of SOI. METHODS: Twenty-five patients with severe odontogenic infections were recruited over a period of six months. At admission, clinical assessment included temperature rise, haematological and biochemical investigations. Demographic data, social and past medical histories were obtained. Microbiology samples were collected to identify causative microorganisms and the clinical management of each infection was recorded. RESULTS: Most infections were associated with teeth or roots. Eighty percent of the patients were tobacco smokers and 72% came from deprived areas. Five patients were intravenous drug users, four admitted chronic alcohol abuse, six had underlying systemic disorders and two were at high risk of malnutrition. A raised C-reactive protein at admission was a useful indicator of the severity of infection. Inappropriate prior antibiotic treatment in the absence of surgical drainage was common. Microbiology results showed a predominance of strict anaerobes, notably anaerobic streptococci, Prevotella and Fusobacterium species. CONCLUSION: SOIs remain surprisingly common and our present pilot study showed a particular association with social deprivation and tobacco smoking. Further elucidation of the role of malnutrition in SOI would be of interest. Molecular characterisation of the microflora associated with SOI may help to highlight whether bacterial factors play a role in converting a localised dentoalveolar abscess into a serious, spreading odontogenic infection.

Risk factors for chest infection in acute stroke: a prospective cohort study.

BACKGROUND AND PURPOSE: Pneumonia is a major cause of morbidity and mortality after stroke. We aimed to determine key characteristics that would allow prediction of those patients who are at highest risk for poststroke pneumonia. METHODS: We studied a series of consecutive patients with acute stroke who were admitted to hospital. Detailed evaluation included the modified National Institutes of Health Stroke Scale; the Abbreviated Mental Test; and measures of swallow, respiratory, and oral health status. Pneumonia was diagnosed by set criteria. Patients were followed up at 3 months after stroke. RESULTS: We studied 412 patients, 391 (94.9%) with ischemic stroke and 21 (5.1%) with hemorrhagic stroke; 78 (18.9%) met the study criteria for pneumonia. Subjects who developed pneumonia were older (mean+/-SD age, 75.9+/-11.4 vs 64.9+/-13.9 years), had higher modified National Institutes of Health Stroke Scale scores, a history of chronic obstructive pulmonary disease, lower Abbreviated Mental Test scores, and a higher oral cavity score, and a greater proportion tested positive for bacterial cultures from oral swabs. In binary logistic-regression analysis, independent predictors (P<0.05) of pneumonia were age >65 years, dysarthria or no speech due to aphasia, a modified Rankin Scale score > or =4, an Abbreviated Mental Test score <8, and failure on the water swallow test. The presence of 2 or more of these risk factors carried 90.9% sensitivity and 75.6% specificity for the development of pneumonia. CONCLUSIONS: Pneumonia after stroke is associated with older age, dysarthria/no speech due to aphasia, severity of poststroke disability, cognitive impairment, and an abnormal water swallow test result. Simple assessment of these variables could be used to identify patients at high risk of developing pneumonia after stroke.

Identification of bacteria on the surface of clinically infected and non-infected prosthetic hip joints removed during revision arthroplasties by 16S rRNA gene sequencing and by microbiological culture.

It has been postulated that bacteria attached to the surface of prosthetic hip joints can cause localised inflammation, resulting in failure of the replacement joint. However, diagnosis of infection is difficult with traditional microbiological culture methods, and evidence exists that highly fastidious or non-cultivable organisms have a role in implant infections. The purpose of this study was to use culture and culture-independent methods to detect the bacteria present on the surface of prosthetic hip joints removed during revision arthroplasties. Ten consecutive revisions were performed by two surgeons, which were all clinically and radiologically loose. Five of the hip replacement revision surgeries were performed because of clinical infections and five because of aseptic loosening. Preoperative and perioperative specimens were obtained from each patient and subjected to routine microbiological culture. The prostheses removed from each patient were subjected to mild ultrasonication to dislodge adherent bacteria, followed by aerobic and anaerobic microbiological culture. Bacterial DNA was extracted from each sonicate and the 16S rRNA gene was amplified with the universal primer pair 27f/1387r. All 10 specimens were positive for the presence of bacteria by both culture and PCR. PCR products were then cloned, organised into groups by RFLP analysis and one clone from each group was sequenced. Bacteria were identified by comparison of the 16S rRNA gene sequences obtained with those deposited in public access sequence databases. A total of 512 clones were analysed by RFLP analysis, of which 118 were sequenced. Culture methods identified species from the genera Leifsonia (54.3%), Staphylococcus (21.7%), Proteus (8.7%), Brevundimonas (6.5%), Salibacillus (4.3%), Methylobacterium (2.2%) and Zimmermannella (2.2%). Molecular detection methods identified a more diverse microflora. The predominant genus detected was Lysobacter, representing 312 (60.9%) of 512 clones analysed. In all, 28 phylotypes were identified: Lysobacter enzymogenes was the most abundant phylotype (31.4%), followed by Lysobacter sp. C3 (28.3%), gamma proteobacterium N4-7 (6.6%), Methylobacterium SM4 (4.7%) and Staphylococcus epidermidis (4.7%); 36 clones (7.0%) represented uncultivable phylotypes. We conclude that a diverse range of bacterial species are found within biofilms on the surface of clinically infected and non-infected prosthetic hip joints removed during revision arthroplasties.

Identification of bacteria associated with spreading odontogenic infections by 16S rRNA gene sequencing.

OBJECTIVE: To determine the bacterial species associated with spreading odontogenic infections (SOIs). STUDY DESIGN: Pus samples from 4 cases of SOI were analyzed by microbiological culture methods for the presence of bacteria, and by polymerase chain reaction (PCR) amplification, cloning, and sequencing of bacterial 16S rRNA genes. RESULTS: Culture methods identified species from the genera Prevotella, Streptococcus, and Fusobacterium, as well as anaerobic streptococci. Molecular detection methods identified a far more diverse microflora. The predominant genus detected was Prevotella, representing 102 (50.2%) of 203 clones analyzed. Prevotella oris was the most abundant species identified, representing 45 (22.2%) of 203 clones analyzed. Twelve clones (5.9%) represented uncultivable species, namely Prevotella PUS9.180, an uncultured Peptostreptococcus species, and an uncultured bacterium belonging to the Bacteroidetes phylum. CONCLUSIONS: Prevotella species may play an important role in SOIs, and further work to examine in more detail the pathogenicity determinants of these organisms and associated host responses is warranted.