Sjögren's syndrome sufferers have increased oral yeast levels despite regular dental care

Aim:  To investigate the prevalence and quantity of oral yeasts and their association with oral candidiasis in Sjögren's syndrome (SS) patients receiving regular dental care.
Materials and methods:  Yeasts in oral rinse and full-mouth supra-gingival plaque samples from 25 primary SS, 27 secondary SS and 29 control subjects were selectively cultured. All yeasts except single-species isolates were genotyped using pulsed field gel electrophoresis (PFGE).
Results:  Ten (19%) SS sufferers had symptomless candidiasis. SS subjects had a higher prevalence (73% vs 7%) and quantity of yeasts than controls in both oral rinse and plaque samples ( P  < 0.05). The prevalence of yeasts in plaque was associated with candidiasis regardless of denture wearing ( P  ≤ 0.04). Candida albicans was the predominant yeast isolated. PFGE showed 20 (66% of total) C. albicans isolate pairs, i.e. C. albicans species isolated from plaque and oral rinse samples of the same individual, were of closely related genetic clonal types ( P  < 0.01).
Conclusions:  Despite effective oral hygiene, more SS subjects than controls had detectable levels of oral yeasts and their presence in supra-gingival plaque was associated with candidiasis. Candida albicans colonized supra-gingival biofilm even in well-maintained SS individuals, posing a challenge to the control of oral candidiasis.     

A sensitive and a rapid multiplex polymerase chain reaction for the identification of Candida species in concentrated oral rinse specimens in patients with diabetes

Objectives: Oral candidiasis is being frequently recognized in patients with diabetes, and is associated with multiple pathogens including Candida albicans, Candida parapsilosis, Candida glabrata and Candida tropicalis. The aim of this study was to evaluate a usefulness of a Multiplex Polymerase Chain Reaction as a rapid diagnostic tool for identification of four oral Candida pathogens in patients with diabetes.

Materials and methods: A multiplex PCR was optimized to identify four Candida species in concentrated oral rinse samples. Common reverse primer, ITS4 and four species-specific forward primers targeting ITS1 and ITS2 regions of yeast genome were used. Species-specific single amplicon were detected by agarose gel electrophoresis. Performance efficacy of multiplex PCR was compared with phenotypic identification.

Results: Out of 100 oral rinse samples, 72 were culture positive and of these 43 were at risk of oral Candida infection (>600cfu/ml). Multiple Candida species including C. albicans, C. parapsilosis and C. tropicalis were identified in 22 samples which had risk of oral Candida infection. In total, 85 patients were positive for Candida by multiplex PCR and of them 49 had multiple Candida species. All 43 colonized specimens were also positive by multiplex PCR. C. albicans was the most predominant organism (75/85) followed by C. parapsilosis (47/85), C. tropicalis (17/85) and C. glabrata (6/85). In specimens with multiple species, the two most common organisms were C. albicans and C. parapsilosis. Multiplex PCR yielded a sensitivity of 10 Candida cells/ml of oral rinse sample.

Conclusions: Multiplex PCR is found to be rapid, sensitive and specific than phenotypic identification methods in discriminating multiple Candida species in oral rinse specimens.     

Oral distribution of Candida species and presence of oral lesions in Brazilian leprosy patients under multidrug therapy

Objective:  The aim of this study was to evaluate the prevalence of Candida spp. and presence of oral lesions in Brazilian leprosy patients under multidrug therapy (MDT).
Methods:  Thirty-eight individuals (18 males and 20 females, median age 53 years) clinically and microbiologically diagnosed as leprosy (lepromatous variant), and under MDT for at least 45 days were studied. The control group constituted by 38 healthy individuals (median age 53.5), matched to the test group in relation to age, gender and oral conditions. Oral rinses were collected and the Candida identification was performed by phenotypic tests. The existence of Candida dubliniensis among the isolates was analyzed using a validated multiplex PCR assay. Twenty-nine leprosy patients were examined intra-orally for the presence of lesions. Data were analyzed by z- and Mann–Whitney tests (α = 5%).
Results:  Yeast carriage rate between leprosy patients (65.8%) and controls (47.4%) was similar ( P  = 0.099), and no significant difference between yeast counts was observed ( P  = 0.1004). Candida albicans was the most frequently isolated species in both groups. In the leprosy group, Candida tropicalis and Candida parapsilosis were also identified. In the control group, we additionally identified Candida tropicalis , Candida glabrata and Candida kefyr. Candida dubliniensis was not detected. No leprosy-related oral lesion was registered.
Conclusion:  Within the limits of the study, we concluded that Brazilian leprosy patients under MDT showed similar levels of carriage and Candida species distribution in relation to the controls.     

Identification of oral species of the genus Veillonella by polymerase chain reaction

Introduction:  Members of the genus Veillonella cannot be reliably distinguished by their biochemical characteristics and phenotypic features. Moreover, DNA–DNA hybridization and sequence analyses of the 16S ribosomal RNA gene including random fragment length polymorphism analysis, are complex and time-consuming procedures that are not well-suited to identifying oral species of Veillonella : Veillonella atypica , Veillonella denticariosi , Veillonella dispar , Veillonella parvula , and Veillonella rogosae .
Methods:  In this study, five forward primers and a reverse primer were designed for polymerase chain reaction (PCR) according to the partial sequences of the rpoB genes of these oral Veillonella species.
Results:  The forward primers were species-specific for these five Veillonella species, and could produce specific amplicons when used together with reverse primer and individual DNA templates of these species in PCR. These primer pairs were also found to discriminate between the respective species, and the Veillonella strains isolated from human oral cavities were successfully assigned to one of the five oral species of the genus Veillonella based on their specific products by PCR.
Conclusion:  A simple two-step PCR procedure using the five sets of primer pairs developed in the present study is a rapid and reliable method for the identification of the recognized oral Veillonella species.     

Oral Candida infection and colonization in solid organ transplant recipients

Introduction:  Oral Candida carriage and infection have been reported to be associated with a greater risk for systemic infection in transplant recipients; however, a systematic analysis of the oral Candida titers and species has not been previously conducted. The objectives of this study were to determine the prevalence of oropharyngeal candidiasis, the oral carrier status, Candida titers and species in this population.
Methods:  Ninety kidney and heart transplant subjects and 72 age-matched healthy controls were included. Swabs from the oral mucosa and a standardized amount of unstimulated saliva were plated on Chromagar™ Candida , and colony-forming units per millilitre were calculated. Initial speciation was based on colony color and was confirmed by standard germ tube, biotyping, or polymerase chain reaction assays.
Results:  Infection with C. albicans was detected in seven transplant subjects and none of the controls. The transplant group had significantly higher oral Candida titers than the control group. There were no statistically significant relationships between the dose or type of immunosuppressants and oral Candida titers or infection. A significantly higher percentage of transplant subjects were colonized by more than one species, compared with control subjects. The most frequent species combination in transplant subjects was C. albicans and C. glabrata . C. glabrata was isolated from 13.5% of transplant carriers and none of the controls.
Conclusions:  Increased oral Candida infection and carriage titers were found in the transplant population. Although the majority of transplant patients were colonized by C. albicans , C. glabrata appears to emerge as the second most prevalent species.     

Sj?gren's syndrome sufferers have increased oral yeast levels despite regular dental care.

AIM: To investigate the prevalence and quantity of oral yeasts and their association with oral candidiasis in Sj?gren's syndrome (SS) patients receiving regular dental care. MATERIALS AND METHODS: Yeasts in oral rinse and full-mouth supra-gingival plaque samples from 25 primary SS, 27 secondary SS and 29 control subjects were selectively cultured. All yeasts except single-species isolates were genotyped using pulsed field gel electrophoresis (PFGE). RESULTS: Ten (19%) SS sufferers had symptomless candidiasis. SS subjects had a higher prevalence (73%vs 7%) and quantity of yeasts than controls in both oral rinse and plaque samples (P < 0.05). The prevalence of yeasts in plaque was associated with candidiasis regardless of denture wearing (P < or = 0.04). Candida albicans was the predominant yeast isolated. PFGE showed 20 (66% of total) C. albicans isolate pairs, i.e. C. albicans species isolated from plaque and oral rinse samples of the same individual, were of closely related genetic clonal types (P < 0.01). CONCLUSIONS: Despite effective oral hygiene, more SS subjects than controls had detectable levels of oral yeasts and their presence in supra-gingival plaque was associated with candidiasis. Candida albicans colonized supra-gingival biofilm even in well-maintained SS individuals, posing a challenge to the control of oral candidiasis.     

基质辅助激光解析电离飞行时间质谱用于口腔念珠菌菌株鉴定的准确性研究

目的： 探讨基质辅助激光解析电离飞行时间质谱（matrix assisted laser desorption ionization-time of flight mass spectrometry, MALDI-TOF MS）用于口腔念珠菌菌株鉴定的准确性。方法： 本研究分为2部分,第一部分采集170例口腔念珠菌病患者唾液,使用沙保弱琼脂培养基培养48 h,MALDI-TOF MS进行菌种鉴定,以PCR检测结果为金标准,评价MALDI-TOF MS诊断的灵敏度、特异度等诊断学指标。第二部分采集42例口腔念珠菌病患者含漱液,使用液体培养基培养, MALDI-TOF MS鉴定,评价诊断准确性。采用SPSS 18.0软件包对数据进行统计学分析。结果： 纳入212例患者,分离临床菌株230株。PCR检测结果显示,白色念珠菌为最常见的口腔念珠菌（65.65%,151/230）,其次为光滑念珠菌（11.74%,27/230）。第一部分中,MALDI-TOF MS诊断白色念珠菌的灵敏度为93.33%,特异度为92.73%;诊断非白色念珠菌的灵敏度为83.64%,特异度为89.17%;对所有念珠菌菌株的诊断准确率为90.29%。第二部分结果显示,沙保弱液体培养基培养24 h,MALDI-TOF MS诊断准确率最高（78.42%）。结论： 白色念珠菌是口腔念珠菌病最常见的致病菌。MALDI-TOF MS可用于沙保弱固体培养基培养的口腔念珠菌菌种的快速鉴定,诊断准确性高于液体培养基。     

Mixed Candida albicans and Candida glabrata populations associated with the pathogenesis of denture stomatitis

Introduction:  Oral yeasts are an important component of the resident microbial ecology of the oral cavity, but they are also associated with various forms of oral candidosis, such as denture stomatitis. Although Candida albicans is the predominant oral fungal pathogen, other species may also play an integral role in pathogenesis. The aim of this study was to examine the mycological ecology in patients with denture stomatitis, using an improved sampling technique, to determine whether species diversity and species quantity were related to oral pathology.
Methods:  Thirty-seven patients attending the Glasgow Dental Hospital were enrolled in this study following informed consent. A full clinical history was obtained, including details of their oral hygiene practices and the levels of erythema based on Newton's classification scale. Oral rinse, denture sonicate, and swab samples were taken, which were processed for quantitative and qualitative analysis of oral yeasts.
Results:  The proportion of patients with no inflammation or Newton's Types I, II, and III were 31, 33, 25, and 14%, respectively. Denture sonication was a superior sampling procedure, with statistically greater quantities of yeasts isolated using this methodology ( P  < 0.01). The predominant oral yeasts isolated were C. albicans (75%) and Candida glabrata (30%), which were isolated in higher proportions in patients with the highest grades of inflammation (100 and 80%), and in combination from 80% of these patients.
Conclusions:  This study has demonstrated that mixed C. albicans and C. glabrata biofilms may play an important role in the pathogenesis associated with severe inflammation in denture wearers.     

Gene targeting demonstrates that inducible nitric oxide synthase is not essential for resistance to oral candidiasis in mice, or for killing of Candida albicans by macrophages in vitro

Introduction:  Oral candidiasis is caused by opportunistic infections with the yeast Candida albicans . Previous studies have demonstrated important roles for innate immunity and T helper type 1-mediated inflammatory reactions in recovery from infection, with macrophages and neutrophils as key effector cells. Both effector cell types use the inducible isoform of nitric oxide synthase (iNOS) to generate candidacidal molecules, but it is not clear whether nitric oxide (NO) is an absolute requirement for candidacidal effector activity.
Methods:  In this study we directly investigated the role of iNOS-derived NO in resistance to murine experimental oral candidiasis, using iNOS knockout mice.
Results:  Knockout mice were no more susceptible to oral candidiasis than wild-type controls. Bone marrow-derived macrophages from the knockout mice killed C. albicans yeasts efficiently in vitro , and were still able to produce nitrites in an iNOS-independent manner, albeit less efficiently than wild-type controls. There were no significant differences in local mucosal production of interleukins 6, 12, 17A, or 23, interferon-γ, or transforming growth factor-β 24 h after oral challenge with C. albicans .
Conclusion:  These data suggest that iNOS-derived NO is not required for resistance to oral candidiasis in vivo , and that bone marrow-derived macrophages may have iNOS-independent means of generating reactive nitrogen species.     

HIV感染者口腔念珠菌负荷及生物型研究

目的调查人类免疫缺陷病毒（human immunodeficiency virus，HIV）感染者口腔中念珠菌负荷状况、生物分型及与口腔念珠菌病临床表现的关系。方法采取漱口法对64例HIV感染者和42名健康对照者进行口腔念珠菌的定量分离培养，并综合利用革兰染色、厚壁孢子生成实验、CHROMagar显色培养和API 20C AUX酵母菌鉴定系统对分离株进行生物型鉴定。结果64例HIV感染者中，52例中可分离出念珠菌74株，阳性分离率为81．3％，而42名健康对照者口腔念珠菌阳性分离率仅为16．7％（P〈0．001）。通过对74株念珠菌的生物型进行鉴定，发现有39株白色念珠菌，15株热带念珠菌及其他6个生物型20株。健康对照组中，分离出5株白色念珠菌和其他裂2株。结论HIV感染者口腔念珠菌感染率明显增加，其口腔念珠菌的检出率和负荷量亦明显增加，白色念珠菌和热带念珠菌为其主要分离菌；与健康对照组相比，HIV感染者的口腔念珠菌分离株生物类型旱现多样化。     

Prevalence of oral Candida carriage in Thai adolescents

Aim: Oral candidiasis is among the most common AIDS‐associated opportunistic infections. Adolescents remain at the highest risk of HIV infection and could suffer from oral candidiasis. However, information on oral Candida carriage in this population is limited. This study aims to evaluate the prevalence of oral Candida in Thai adolescents. Methods: Oral rinse samples from 80 healthy Thais (age: 15–17 years) were collected and analyzed for the prevalence of Candida species using culture‐based and polymerase chain reaction assays. Results: Twenty six adolescents (32.5%) carried Candida in the oral cavity. Candida albicans was detected in 28.75% (23/80). Non‐albicans Candida species were detected in 6.25% (5/80). The majority (92.3%, 24/26) of adolescents with Candida carried a single species. Two carried two species: one with Candida glabrata and Candida albicans, and the other with Candida parapsilosis and Candida albicans. Three adolescents harbored only non‐albicans species, with one carrying Candida tropicalis and two carrying Candida parapsilosis. Candida dubliniensis was not detected in this population. Most adolescents carried Candida at a low level (<500 c.f.u./mL). Conclusions: Oral Candida was present in approximately one‐third of adolescents. Candida albicans was the most prevalent (88.5%), and non‐albicans species were present in 19.2% of those with oral Candida.     

Hyposalivation, xerostomia and oral health status of HIV-infected subjects in Thailand before HAART era

J Oral Pathol Med (2010) 39 : 28–34
Background:  The aims of this study were to determine hyposalivation, xerostomia, and oral health status of HIV-subjects in Thailand before highly active antiretroviral therapy era.
Methods:  Oral examination and measurement of saliva flow rate of both unstimulated and wax-stimulated whole saliva were performed in 135 subjects (56 HIV-subjects, mean age: 34.5 years, and 79 non-HIV controls, mean age: 29.5 years). Presence of oral candidiasis, cervical root caries, and number of existing teeth were recorded. Microbiological investigation of oral Candida was conducted using oral rinse technique. Risk factors associated with hyposalivation and xerostomia were analysed.
Results:  The unstimulated flow rates in HIV-subjects and non-HIV controls were 0.19 and 0.33 ml/min ( P  = 0.0024). For stimulated flow rates, the corresponding figures were 1.45 and 1.62 ml/min ( P  = 0.31). The unstimulated flow rate was significantly higher in the asymptomatic HIV-subjects: 0.17 ml/min, when compared with the symptomatic/AIDS group 0.11 ml/min ( P  = 0.003). No significant difference between the groups could be found with respect to stimulated flow rate. Hyposalivation was significantly associated with the colony forming unit of Candida . Smoking and alcohol consumption were significantly associated with hyposalivation, but not xerostomia. The following factors were significantly associated with both hyposalivation and xerostomia; sex, stage of HIV infection, risk group of HIV infection, systemic disease, and medication use.
Conclusions:  Salivary flow rate of HIV-subjects in Thailand was affected by HIV infection. The rate was significantly decreased with advanced stage of the disease. Various factors including medication use were associated with hyposalivation and xerostomia among the subjects.     

Oral yeast carriage in patients with advanced cancer

The aim of this study was to investigate oral yeast carriage amongst patients with advanced cancer. Oral rinse samples were obtained from 120 subjects. Yeasts were isolated using Sabouraud's dextrose agar and CHROMagar Candida, and were identified using a combination of the API 20 C AUX yeast identification system, species-specific PCR and 26S rDNA gene sequencing. Oral yeast carriage was present in 66% of subjects. The frequency of isolation of individual species was: Candida albicans, 46%; Candida glabrata, 18%; Candida dubliniensis, 5%; others, < 5%. The increasing isolation of non-Candida albicans species is clinically important, since these species are often more resistant to antifungal drugs. Oral yeast carriage was associated with denture wearing (P = 0.006), and low stimulated whole salivary flow rate (P = 0.009). Identification of these risk factors offers new strategies for the prevention of oral candidosis in this group of patients.     

Occurrence of two newly named oral treponemes - Treponema parvum and Treponema putidum - in primary endodontic infections

Background/aims:  Recent evidence from molecular genetic studies has revealed that oral Treponema species are involved in infections of endodontic origin. This study assessed the occurrence of two newly named oral treponemes −  Treponema parvum and Treponema putidum –  in primary endodontic infections using a culture-independent identification technique.
Methods:  Genomic DNA was isolated directly from clinical samples, and a 16S rRNA gene-based nested polymerase chain reaction (PCR) assay was used to determine the presence of T. parvum and T. putidum . Species-specific primer pairs were developed by aligning closely related 16S rRNA gene sequences. The specificity for each primer pair was validated by running PCR against a panel of oral bacteria and by sequence analysis of PCR products from positive clinical samples.
Results:  T. parvum was detected in 52% of the root canals associated with chronic apical periodontitis, in 20% of the cases diagnosed as acute apical periodontitis, and in no abscessed case. In general, T. parvum was detected in 26% of the samples from primary endodontic infections. T. putidum was found in only one case of acute apical periodontitis (2% of the total number of cases investigated).
Conclusions:  The devised nested PCR protocol was able to identify both T. parvum and T. putidum directly in clinical samples and demonstrated that these two treponemes can take part in endodontic infections.     

Comparative analysis of putative periodontopathic bacteria by multiplex polymerase chain reaction

Background and Objective:  The polymerase chain reaction (PCR) has been applied for the rapid and specific detection of periodontopathic bacteria in subgingival plaque and is potentially of clinical benefit in the diagnosis and treatment of periodontitis subjects. However, several technical points need to be modified before the conventional PCR detection system can be used by clinicians.
Material and Methods:  To develop a PCR-based technique more applicable for clinical use than conventional PCR, we established a multiplex PCR for five putative periodontopathic ( Treponema denticola , Porphyromonas gingivalis , Aggregatibacter actinomycetemcomitans , Prevotella intermedia and Tannerella forsythia ) and two nonperiodontopathic ( Streptococcus sanguinis and Streptococcus salivarius ) species of bacteria using whole-plaque suspension as templates, and detected bacteria in subgingival plaque taken from 85 subjects at the supportive periodontal therapy stage after active periodontal treatments.
Results:  Among putative periodontopathic bacteria, the detection frequency of T. denticola and P. gingivalis was elevated in parallel with higher probing pocket depth and clinical attachment loss, and had 4.2–14.1 times increasing odds of the clinical parameters tested. Detection of any of the five species of putative periodontopathic bacteria markedly increased the odds ratio of a higher probing pocket depth, clinical attachment loss and bleeding on probing.
Conclusion:  The multiplex PCR system developed in this study enabled the detection of all the bacteria under investigation in one reaction tube in a less time- and labor-intensive manner than conventional PCR. These results support the potential clinical use of multiplex PCR for detecting periodontopathic bacteria and for evaluating therapeutic strategies and predicting the prognosis for each subject.     

免疫抑制剂对口腔白色念珠菌的分布及基因分型的影响

目的:研究服用免疫抑制剂患者口腔中白色念珠菌的分布及基因分型。方法:含漱液浓缩法取样,CHROM agar Cand ida鉴定培养基分离鉴定,PCR方法鉴定白色念珠菌和基因分型,PCR结果测序验证。结果:实验组白色念珠菌的检出率为20%,对照组7.69%,差异有显著性,实验组中多种念珠菌共存的现象多见。对照组白色念珠菌基因型以A型为主,实验组白色念珠菌基因型呈多态性。结论:长期服用免疫抑制剂影响口腔念珠菌及不同基因型白色念珠菌的检出。     

Prevalence of Candida species in AIDS patients and HIV-free subjects in Thailand

Teanpaisan R, Nittayananta W: Prevalence of Candida species in AIDS patients and HIV-free subjects in Thailand. J Oral Pathol Med 1998; 27: 4–7. © Munksgaard, 1998.
The purpose of this study was to examine the prevalence of Candida species among groups of HIV-infected and HIV-free subjects in Thailand and to ascertain whether particular Candida species were associated with HIV infection. Oral rinse specimens were collected from 45 AIDS patients (CDC stage IV), 74 HIV-free healthy subjects, and 42 HIV-free patients who had clinical candidiasis. Yeasts recovered in culture were identified and quantified. The mean ages of the cohorts were 30.75 ± 8.19 years (AIDS group), 28.50 ± 7.98 (HIV-free healthy group) and 41.83 ± 12.25 years (HIV-free candidiasis group). Yeasts were isolated from 30/45 (66.66%, range 6.6 ± 10²-5.7 × 10⁶ CFU/ml) of the AIDS group, 8/74 (10.81%, range 8.0 × 10¹-3.5 × 10⁴ CFU/ml) of the HIV-free healthy group, and 24/42 (57.14%, range l.0 × 10 10²-1.1 × 10⁵ CFU/ml) of the HIV-free candidiasis group. There were statistically significant differences in the Candida colony counts between the AIDS group without oral candidiasis and the healthy group ( P =0.0078) and between the AIDS group with candidiasis and the HIV-free, oral candidiasis group ( P = 0.0003). Candida albicans was the most common species recovered from AIDS patients (29 out of 30; 96.66%).     

Efficacy of chlorhexidine gluconate rinse for treatment and prevention of oral candidiasis in HIV-infected children: a pilot study

PURPOSE: We evaluated the effect of chlorhexidine (CHX) 0.12% rinses on the clinical and microbiologic manifestations of oral candidiasis in HIV-infected children. STUDY DESIGN: This was a cross-sectional, clinical intervention study of 38 HIV-positive children. Inclusion in the study was based on oral examination and positive oral culture for Candida. At baseline, subjects with no clinical lesions but who were culture-positive for Candida (N = 9) were placed on preventive therapy of CHX q.d. for 90 days. Subjects with clinical oral candidiasis (N = 9) were placed on therapeutic CHX b.i.d. All 38 subjects received oral exams at monthly intervals. At 90 days oral mucosal samples were again taken for Candida. Colony-forming units (CFU) were determined before and after CHX treatment. RESULTS: Of 18 culture-positive subjects, 12 were included in the CFU analyses. After 3 months of CHX oral rinse therapy, Candida was undetectable in 3 children; another 8 showed an average 2-fold reduction in CFU. In 1 child the number of CFU increased modestly. Overall, the average pre- and posttreatment mean CFU was 6.18 +/- 2.19 and 2.73 +/- 3.15, respectively (P = .009). Five patients with clinical oral candidiasis at baseline, including all 3 who had pseudomembranous candidiasis, were free of signs of disease at the end of the study. CONCLUSIONS: This study suggests that the topical disinfectant CHX may be a promising agent for treating and preventing oral candidiasis in HIV-infected children.     

Molecular analyses of bacterial DNA in extirpated heart valves from patients with infective endocarditis

Background/aims:  Infective endocarditis (IE) is caused by a microbial infection of the endothelial surface of the heart. Although blood culture examinations are commonly used to determine the associated bacterial species, molecular techniques, which enable rapid identification of targeted bacterial species, have recently been applied in clinical cases.
Methods:  Nine heart valve specimens from IE patients (six subacute cases and three acute cases) were extirpated and collected, then bacterial DNA was extracted. Bacterial species in the specimens were determined by two different molecular methods and the results were compared with those from a conventional blood culture technique. In addition, a comparison between the two molecular methods was carried out using known numbers of six streptococcal species.
Results:  The conventional blood culture method revealed the bacterial species in eight cases, while one was found to be negative. Multiple species were identified in most of the cases by both molecular methods; however, those specified by one method were not always consistent with those specified by the other. Furthermore, the species determined by the blood culture technique were not always identified by the molecular methods. We also found that the two molecular methods used in the present study were extremely sensitive to detect from 1 to 100 cells of individual oral streptococcal species.
Conclusion:  Our results suggest that species specified by molecular methods may have disseminated incidentally into the bloodstream, so interpretation of such results should be carefully undertaken in clinical situations.     

Molecular characterization of Candida spp. isolated from the oral cavities of patients from diverse clinical settings

Infections by Candida spp. have increased in medical importance over the past few decades. Our understanding of species identification, commensalisms, pathogenicity, person-to-person spread, and the development of antifungal resistance within specific strains has been greatly enhanced by the utilization of molecular epidemiological methodology. The aim of the current research was to assess the quantity, species and molecular characterization of oral yeast isolates from well-defined cohorts of immunocompetent patients from a diverse range of clinical settings. Oral rinse samples were assessed for the growth of yeast and degree of colonization. Isolates were defined to the species level by both phenotypic and molecular methods and strains were further genotypically subtyped. Significant variation was shown to exist in the number, species and genotypic subgroups of yeast isolated from the oral cavity in different patient groups. This variation could be attributed to the local oral conditions unique to these patient groups.