牙周炎及胃病患者牙菌斑中的幽门螺杆菌

目的 明确牙周炎及胃病患者的牙菌斑中是否存在幽门螺杆菌（Ｈｐ）及Ｈｐ是否为细胞毒素相关基因Ａ阳性。方法 利用尿素酶Ｃ基因和ｃａｇＡ设计引物,通过聚合酶链反应（ＰＣＲ）检测口腔中的Ｈｐ。选择１３例胃病及１０例牙周炎患者,每例患者选６个有牙龈炎症的牙位取龈上、龈下菌斑,共计２７６份样本用于ＰＣＲ检测。结果 胃病组１１例患者和牙周炎组全部病例均少有１份菌斑样本检出Ｈｐ,其中尿素酶Ｃ基因在胃病组的阳性率为     

PCR detection of <Emphasis Type="Italic">Streptococcus mutans</Emphasis> and <Emphasis Type="Italic">Aggregatibacter actinomycetemcomitans</Emphasis> in dental plaque samples from Haitian adolescents

Streptococcus mutans and Aggregatibacter actinomycetemcomitans are oral pathogens associated with dental caries and periodontitis, respectively. The aim of this study was to determine the colonization of these two microorganisms in the dental plaque of a group of Haitian adolescents using two different polymerase chain reaction (PCR) methods, standard PCR, and quantitative real-time PCR (qPCR) assays. Fifty-four pooled supra-gingival plaque samples and 98 pooled sub-gingival plaque samples were obtained from 104 12- to19-year-old rural-dwelling Haitians. The total genomic DNA of bacteria was isolated from these samples, and all participants also received caries and periodontal examinations. Caries prevalence was 42.2%, and the mean decayed, missing, and filled surface (DMFS) was 2.67 ± 5.3. More than half of the adolescents (53.3%) experienced periodontal pockets (Community Periodontal Index score ≥3). S. mutans was detected in 67.3% by qPCR and 38.8% by PCR of the supra-gingival plaque samples (p < 0.01), and 36.6% by qPCR and 8.1% by PCR of the sub-gingival samples (p < 0.01). A. actinomycetemcomitans was detected in 85.1% by qPCR and 44.0% by PCR of the sub-gingival samples (p < 0.01), but the prevalence was similar, 67.3% by qPCR and 59.2% by PCR, in the supra-gingival plaque samples. Neither age nor gender was significantly correlated to the bacterial colonization. The results demonstrated a moderate-to-high prevalence of S. mutans and A. actinomycetemcomitans in the Haitian adolescent population, and qPCR is more sensitive than standard PCR in field conditions. These findings suggest that qPCR should be considered for field oral epidemiologic studies and may be necessary in investigations having major logistic challenges.     

Antifungal susceptibility of <Emphasis Type="Italic">Candida albicans</Emphasis> biofilms on titanium discs with different surface roughness

Although it is well known that fungal biofilms have increased resistance to antimicrobial agents, limited information is available on the formation of candidal biofilms on implant surfaces with different surface roughness and their resistance to conventional antifungal therapy. In the current study, the effect of increasing the surface roughness of titanium discs on the susceptibility of Candida albicans biofilms to amphotericin B was determined. Grade I commercially pure titanium discs were sandblasted with 99.6% aluminium oxide of different grit sizes, producing surface roughness of 0.90, 1.88 and 3.82 μm (Groups A, B and C), respectively (P < 0.001). The antifungal susceptibility of C. albicans biofilm grown on different Ti discs was determined using XTT assay. The 50% reduction in metabolic activity (50% RMA) of planktonic C. albicans (0.5 μg/mL) was much lower than those from Groups A, B and C (2, 16, 2 μg/mL, respectively), while the 50% RMA from Group B was three-fold higher than those from Groups A and C. In conclusion, difference in titanium surface roughness was associated with variations in the antifungal resistance of the candidal biofilm. Group C appeared to have an optimum surface roughness for biofilm resistance.     

Adherence of <Emphasis Type="Italic">Candida albicans</Emphasis> to denture base acrylics and silicone-based resilient liner materials with different surface finishes

This study evaluated the surface roughness and Candida albicans adherence on denture base acrylic resins and silicone-based resilient liners with different surface finishes. Four commercial denture base acrylic resins (three heat polymerized and one room temperature polymerized) and five silicone-based liner materials (two heat polymerized and three room temperature polymerized) (10 × 10 × 2 mm) were tested in this study. The materials were processed against glass or plaster or finished with a tungsten carbide bur. Surface roughness measurements were made using a profilometer with an optical scanner probe. All specimens were ultrasonically cleaned in water for 15 s, autoclave sterilized, and contaminated with C. albicans solution for adherence assay evaluation. The materials processed against the glass surface showed significantly lower surface roughness values (0.11 ± 0.1–1.66 ± 1.1 μm) than those of the materials processed against the dental plaster (2.61 ± 0.2–6.12 ± 2.8 μm) or roughening with a bur (1.48 ± 0.2–7.05 ± 1.2 μm; p < 0.05, one- or two-way analysis of variance). Also, the materials processed against the glass surface showed lower C. albicans adhesion (mean ranks 120.36) than those of the materials processed against the dental plaster (mean ranks 139.77) or roughening with a bur (mean ranks 143.06), but the differences were not statistically significant (p > 0.05, Kruskal–Wallis and Mann–Whitney). In all types of surface finishes, C. albicans adhesion on denture base acrylics was significantly less (mean ranks 90.18–90.40) than those of silicone liners (mean ranks 119.38–205.18; p < 0.01, Kruskal–Wallis).     

Adhesion of<Emphasis Type="Italic"> Porphyromonas gingivalis</Emphasis> to cultured pocket epithelium: mono- and multi-layered

Adhesion of bacteria to epithelial cells might be influenced by the degree of cell differentiation, as observed in the multi-layering process of epithelial cells. In the present study, the adhesion of a large group of clinical Porphyromonas gingivalis strains (n=11) to in vitro cultured mono- and multi-layers of epithelial cells was examined and compared. The tissue samples originated from 6 patients with chronic adult periodontitis. Porphyromonas gingivalis bacteria adhered more to mono-layers as opposed to the more differentiated multi-layers. Differences between the clinical P. gingivalis strains, however, became obvious only on multi-layers. These partially differentiated cells may also better represent the individual subject variations. Mono-layer cultures, which are simpler to obtain, seem to be less precise. The importance of cell differentiation on bacterial adhesion needs more attention.     

<Emphasis Type="Italic">Tannerella forsythia</Emphasis> and the <Emphasis Type="Italic">HLA-DQB1</Emphasis> allele are associated with susceptibility to periodontal disease in Japanese adolescents

Periodontal disease is a multiple factor disease caused by genetic factors, environmental factors, and periodontal bacteria (periodontal pathogens). The present study aimed to elucidate the risk factors for periodontal disease in Japanese adolescents. Subjects (11–16 years old) were classified into three groups: localized aggressive periodontitis (LAP), periodontal attachment loss (PAL), and periodontally healthy (PH) groups. Genomic DNA isolated from the buccal mucosa was used for single-nucleotide polymorphism analyses of the candidate genes (interleukin-1α-889; interleukin-1α +4845; interleukin-1β +3954; an immunoglobulin G Fc gamma receptor, FcγRIIa-R/H131; and a human leukocyte antigen class II allele, HLA-DQB1) of aggressive periodontitis. Subgingival plaque samples obtained from the same subjects were used for 16S rRNAbased polymerase chain reaction analysis of five important periodontal pathogens (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola, and Tannerella forsythia). Tannerella forsythia was detected in the deepest periodontal pockets in all subjects in the LAP and PAL groups. The prevalence of an atypical BamHI restriction site in HLA-DQB1 of the LAP group was significantly higher than that in the PH and PAL groups. Furthermore, all subjects who had the atypical BamHI restriction site in HLA-DQB1 had T. forsythia infection. These results suggested that T. forsythia is associated with periodontal disease in Japanese adolescents and also suggested that HLA-DQB1 is related to LAP and is associated with T. forsythia infection.     

Effects of low-concentrated chlorhexidine on growth of<Emphasis Type="Italic"> Streptococcus sobrinus</Emphasis> and primary human gingival fibroblasts

The aim of this study was to investigate the in vitro effects of low concentrations of chlorhexidine (CHX) on the proliferation of Streptococcus sobrinus (ATCC 33478) and primary human gingival fibroblasts (HGF). Liquid cultures of bacteria or human gingival fibroblasts were exposed to CHX concentrations ranging from 0.07 to 40 M in microtiter plates at 37°C for 24 h. Bacteria or cells grown without CHX served as controls. The effects of CHX were determined either by measurements of the optical density (OD) of bacterial cultures or by evaluation of cell growth with the DNA-intercalating fluorescent stain H33342 in comparison to untreated controls. Results were evaluated calculating means and standard deviations. Data were statistically analyzed by an ANOVA using Post Hoc tests (p<0.005). No growth inhibition of S. sobrinus was found at concentrations between 0.07 and 0.15 M CHX, whereas 0.3 M CHX led to an elongated (2 h more) lag phase and 0.6 M CHX induced a lag phase of 4 h more and a minor inclination of the curve in the log phase. Concentrations of CHX1.25 M completely inhibited growth of S. sobrinus. On the contrary, CHX showed no significant effect on growth of HGF at concentrations 5 M. A slight growth inhibition was only observed at a concentration of 5 M. CHX-concentrations of 10 and 20 M reduced cell growth to 88 or 75% of control assays. Data analysis showed that overall treatment effects were highly significant (p<0.005). Our data reveal that chlorhexidine inhibits proliferation of S. sobrinus even at very low concentrations while concentrations of CHX5 M are not cytotoxic to human gingival fibroblasts.     

Absence of Helicobacter pylori in the oral cavity of 10 non‐dyspeptic subjects demonstrated by real‐time polymerase chain reaction

Helicobacter pylori plays a significant role in gastric disease. However, the presence of this bacterium in the oral cavity remains controversial. The aim of the present study was to detect and quantify H. pylori in 29 different sites of the oral cavity in non‐dyspeptic subjects by means of real‐time polymerase chain reactions (PCR). Ten subjects without gastric symptoms were studied. Samples from unstimulated saliva, three sites of the tongue, oral mucosa, and 12 sites of both supragingival and subgingival plaque were collected from each subject. DNA was extracted from the oral samples and analysed for the presence of H. pylori by real‐time PCR (LightCycler^®) using JW23/22 primers which targeted the 16S rRNA gene. DNA from H. pylori DSM 4867 was used as a positive control. Amplification efficiency for the LightCycler^® 2.0 runs ranged from 1.8 to 2.4. Melting curve analysis identified all the positive control capillaries, which contained H. pylori reference DNA, as a single and narrow peak at a melting temperature between 84.5 and 84.9°C. All the negative control capillaries with no template control and the 29 oral samples from each subject showed either no melting peaks or broad melting peaks below 80°C, which were considered as primer dimers. Therefore, H. pylori was not detected from any of the 290 oral samples. As a conclusion, H. pylori seems not to be permanently present in the oral cavity of a non‐dyspeptic population.     

Clinical effects of scaling and root planing in adults infected with<Emphasis Type="Italic"> Actinobacillus actinomycetemcomitans</Emphasis>

The periodontal pathogen Actinobacillus actinomycetemcomitans can frequently be isolated from subgingival plaque of adults with chronic inflammatory periodontal disease and individuals with plaque-induced gingivitis. Problems with the persistence of the organism after thorough debridement of root surfaces have been reported. In the present study clinical effects of the hygienic phase of periodontal therapy in ten adult patients with moderate or advanced periodontitis harbouring A. actinomycetemcomitans were analysed. Since proper analysis of highly correlated data within a given patient is crucial for appropriate interpretation, a major objective of this study was to compare the results of different models derived from logistic regression of clinical and microbiological factors on gain or loss of clinical attachment under different assumptions. Subgingival samples from every tooth present were obtained before and 6 weeks after thorough subgingival scaling, and selectively cultivated for the organism. A relevant gain of clinical attachment of 2 mm or more was observed at a total of 36% of periodontitis sites after scaling. Overall, loss of attachment of 2 mm or more was observed at 8% sites. Most loss occurred at sites with gingival enlargement (15%), whereas 3% periodontitis sites lost 2 mm or more. In multivariate analyses erroneously assuming either independence of data or correctly considering the correlated structure of observations attachment gain was mainly associated with deep probing depths at the outset. Presence or absence of A. actinomycetemcomitans before or after therapy was not included into the periodontitis models. Also, loss of attachment of 2 mm or more after subgingival scaling was not influenced by the organism. A direct comparison of the results obtained with both approaches of logistic regression may be helpful in the assessment of the influence of the magnitude of correlation of the data on the regression coefficients.     

Impact of <Emphasis Type="Italic">Streptococcus mutans</Emphasis> on the generation of fluorescence from artificially induced enamel and dentin carious lesions in vitro

The purpose of this study was to examine whether Streptococcus mutans is implicated in the generation of fluorescence detected in carious lesions. Enamel surfaces and dentin cavities of extracted human teeth were subjected to artificial caries generation by exposing them either to a culture medium containing S. mutans or to a lactic acid buffer for 2 weeks. Fluorescence from the lesions was detected with confocal laser scanning microscopy or fluorescence microscopy at various excitation wavelengths, and maximum fluorescence radiance was computed using imageanalyzing software. Culture media of S. mutans were also examined for fluorescence generation. The results demonstrated that S. mutans-induced enamel and dentin lesions exhibited increased fluorescence in the red and green spectral regions, with the signal stronger in the red region. In the blue region, however, fluorescence signals in the corresponding area were below the background level. Significantly weaker or virtually no fluorescence was detected in lactic acid-demineralized lesions at all excitation wavelengths. Neither bacterial cells nor culture media generated any fluorescence. These results indicate that, although the presence of S. mutans may be a prerequisite for the emission of fluorescence from carious lesions, some interaction of S. mutans with exposed tooth matrix elements may also be required for the generation or unmasking of fluorophores.     

Dental caries experience in relation to salivary findings and molecular identification of <Emphasis Type="Italic">S. mutans</Emphasis> and <Emphasis Type="Italic">S. sobrinus</Emphasis> in subjects with Down syndrome

This study investigated the association between clinical and salivary or molecular parameters in Down syndrome subjects. Sixty individuals (1- to 48-year old) were clinically examined using DMFT/DMFS. Stimulated saliva was collected; salivary flow was calculated (mL/min), buffering capacity was measured using a standard pH tape. In addition, 25 μL of saliva was diluted using 10-fold-dilution method and then placed on Mitis-Salivarius-Bacitracin agar to count colony forming units (CFU/mL) of mutans streptococci. Polymerase chain reaction analysis identified species. Caries indexes were 0.65–13.5 (DMFT) and 0.65–26.0 (DMFS) according to groups. Ninety-four percent of subjects had low flow rate (0.7–1.0 mL/min) and 44% had low buffering capacity (pH < 4). Besides, 60% had more than 1 × 10⁶ CFU/mL, 60% had S. mutans, and 41.4% had S. sobrinus. Caries indexes did not significantly correlate with flow rate, buffering capacity, CFU/mL by Pearson’s correlation (p > 0.05), and showed no significant association with prevalence of species by Chi-square (p > 0.05). There is no association between clinical picture and salivary or molecular parameters in Down syndrome subjects.     

Three-dimensional analysis of tooth dimensions in the <Emphasis Type="Italic">MSX1</Emphasis>-missense mutation

Objectives

A novel, 3D technique to measure the differences in tooth crown morphology between the MSX1 cases and non-affected controls was designed to get a better understanding of dental phenotype-genotype associations.

Materials and methods

Eight Dutch subjects from a single family with tooth agenesis, all with an established nonsense mutation c.332 C > A, p. Ser 111 Stop in exon 1 of MSX1, were compared with unaffected controls regarding several aspects of tooth crown morphology of incisor and molar teeth. A novel method of quantitative three-dimensional analysis was used to detect differences.

Results

Statistically significant shape differences were observed for the maxillary incisor in the MSX1 family compared with the controls on the following parameters: surface area, buccolingual dimension, squareness, and crown volume (P?≤?0.002). Molar crown shape was unaffected.

Conclusions

A better understanding of dental phenotype-genotype associations may contribute to earlier diagnosis of some multiple-anomaly congenital syndromes involving dental anomalies.

Clinical relevance

A “shape database” that includes associated gene mutations resulting from developmental syndromes may facilitate the genetic identification of hypodontia cases.

     

Detection of salivary antibodies to crude antigens of <Emphasis Type="Italic">Opisthorchis viverrini</Emphasis> in opisthorchiasis and cholangiocarcinoma patients

Opisthorchis viverrini (O. viverrini; known as human liver fluke) is a major health problem in the northeastern region of Thailand. Infection with O. viverrini is the cause of hepatobiliary disease and cholangiocarcinoma (CCA). Previous studies demonstrated specific antibodies to crude O. viverrini antigens in serum from O. viverrini-infected patients. However, no studies have measured specific antibodies to O. viverrini antigens in saliva from patients with opisthorchiasis and CCA. The objective of the study was to detect specific antibodies to crude O. viverrini antigens in saliva from patients with opisthorchiasis and CCA, and to evaluate their use for diagnosis of O. viverrini infection. Saliva samples from 23 control subjects, 30 opisthorchiasis patients, and 38 CCA patients were collected. ELISA was established for detection of salivary IgA and IgG to crude O. viverrini antigens. ANOVA was used to compare salivary IgA and IgG levels among groups. Salivary IgA to crude O. viverrini antigens in CCA patients was significantly higher than controls (p = 0.007). Salivary IgG in CCA patients was significantly higher than opisthorchiasis patients and controls (p = 0.010 and p < 0.001, respectively). The cut-off value from salivary IgG test demonstrated higher accuracy for positivity of O. viverrini infection than salivary IgA. In conclusion, specific antibodies to crude O. viverrini antigens were detected in saliva of patients with opisthorchiasis and CCA. Salivary antibodies reflect serum immune response to O. viverrini infection, and salivary IgG tends to be a good candidate for diagnosis of O. viverrini infection.     

Contribution of phosphoglucosamine mutase to determination of bacterial cell morphology in <Emphasis Type="Italic">Streptococcus gordonii</Emphasis>

Phosphoglucosamine mutase (GlmM; EC 5.4.2.10) catalyzes the interconversion of glucosamine-6-phosphate to glucosamine-1-phosphate, an essential step in the biosynthetic pathway leading to the formation of the peptidoglycan precursor uridine 5′-diphospho-N-acetylglucosamine. We have recently identified the gene (glmM) encoding the enzyme of Streptococcus gordonii, an early colonizer on the human tooth and an important cause of infective endocarditis, and indicated that the glmM mutation in S. gordonii appears to influence bacterial cell growth, morphology, and sensitivity to penicillins. Moreover, the glmM mutation results in increased sensitivity to polymorphonuclear leukocyte (PMN)-dependent killing. In the present study, we observed similarities in the utilization of sugar between the wild-type strain and the glmM mutant of S. gordonii when cultivated with medium containing 0.2% glucose, fructose, lactose, or sucrose. Morphological analyses clearly indicated that the glmM mutation causes marked elongation of the streptococcal chains, enlargement of bacterial cells, increased distortion of the bacterial cell surface, and defects in cell separation. These results suggest that mutations in glmM appear to influence bacterial cell growth and morphology, independent of the carbon source.     

<Emphasis Type="Italic">Susuks</Emphasis> (charm needles) in the craniofacial region

Objectives  We conducted a study to determine the numbers of susuks (charm needles) and their distribution in the craniofacial region of susuk wearers, and the sex, racial affiliation, and age of the wearers. In addition, we sought to determine whether the presence of susuks posed any potential hazard to patients undergoing magnetic resonance imaging (MRI). Methods  We studied various radiographs of 33 susuk wearers (age range, 33–69 years) and investigated the most common sites of insertion in the craniofacial region. A susuk was also suspended inside a 1.5-T MRI machine to determined whether it was attracted by the machine’s magnet. Results  The largest number of susuks that we observed in the craniofacial region was 39 pins, and susuks were particularly numerous in Malay Muslim women. Other sites with susuks were the maxillofacial region (except the temporomandibular region) and the forehead. The susuks showed no ferromagnetic characteristics. Conclusions  As susuks are made from gold, they are generally biocompatible with human tissue and do not cause problems to their wearers. Gold and the other minor metal constituents found in susuks have no ferromagnetic characteristics and therefore pose no hazard to patients undergoing MRI.     

Effect of mouthrinses on <Emphasis Type="Italic">Aggregatibacter actinomycetemcomitans</Emphasis> biofilms in a hydrodynamic model

The aim of the study was to evaluate the effects of Listerine®, Meridol®, and Perioaid® on the viability and total number of bacteria in established biofilms using an in vitro model under hydrodynamic conditions. Biofilms of Aggregatibacter actinomycetemcomitans were placed in a modified Robbins device and rinsed twice daily during 4 days. Bacteria were quantified by culture and quantitative polymerase chain reaction. Visualization of the samples was performed by scanning electron and confocal laser scanning microscopy, combined with a fluorescent vital staining. All three mouthrinses caused a significant reduction in the number of cultivable A. actinomycetemcomitans in a biofilm. Perioaid® was significantly the most powerful in killing the biofilm-protected bacteria and also in counteracting the development of thick dense microbial communities. The total amount of bacteria was not significantly affected by Listerine® and Meridol®.     

The <Emphasis Type="Italic">Candida</Emphasis> species that are important for the development of atrophic glossitis in xerostomia patients

Background

The purpose of this study was to clarify the species of Candida that are important for the development of atrophic glossitis in xerostomia patients.

Methods

A total of 231 patients with subjective dry mouth were enrolled in the present study. Logistic regression analysis was performed to clarify the contribution of each Candida species and other variables to the development of atrophic glossitis. The dependent variable was the absence/presence of atrophic glossitis. The Candida colony-forming units (CFU) of C. albicans, C. glabrata, C. tropicalis, and C. krusei, as well as age, gender, resting (RSFR) and stimulated (SSFR) whole salivary flow rate, and denture-wearing status, were treated as explanatory variables.

Results

Logistic regression analysis showed that two factors were closely associated with the presence of atrophic glossitis: an increase in C. albicans CFU and a decrease in the SSFR.

Conclusions

C. albicans, but not non-albicans Candida, was associated with atrophic glossitis in xerostomia patients who had no systemic predisposing factors, indicating that C. albicans remains a treatment target for Candida-related atrophic glossitis.

     

A fast Look–Locker method for <Emphasis Type="Italic">T</Emphasis><Subscript>1</Subscript> mapping of the head and neck region

Objective  A sequence for T ₁ relaxation time measurements that allows a high-resolution image to be obtained within a short acquisition time is described. Its application to the orofacial region is investigated. Methods  The sequence is based on the Look–Locker (LL) method and employs a magnetization-preparation pulse prior to data acquisition, with either a turbo-field echo (TFE) or turbo-field echo echo-planar imaging (TFEPI) sequence. We applied the multiple LL sequence by synchronizing the data acquisition with the virtual electrocardiogram. T ₁ results from the LL sequence were compared with those from the inversion recovery (IR) sequence. In an in vitro study, we evaluated the T ₁ maps of contrast medium at different concentrations. In an in vivo study, we evaluated the T ₁ maps in seven volunteers. Results  In the in vitro study, the correlation between the T ₁ values obtained from the LL sequence and those from the IR sequence was high, with an R ² of more than 0.99. For T ₁ values between 200 and 1,500 ms, the difference between the two methods was less than 7%. In the in vivo study, a high correlation was observed between the T ₁ values from the IR sequence and those from the LL sequence. The scan duration for the LL sequence was less than 3 min. Conclusion  Our method, based on the LL sequence, was found to be clinically useful for producing a T ₁ map.     

Occurrence of oral <Emphasis Type="Italic">Candida</Emphasis> colonization and its risk factors among patients with malignancies in China

Objectives

Oral colonization of Candida could lead to later development of oropharyngeal candidiasis or candidemia among the immunocompromised patients. This study aims to describe the occurrence and risk factors of oral Candida colonization in patients with malignancies.

Materials and methods

From October 2012 to March 2013, 78 patients with pulmonary cancer (group I), 101 patients with gastrointestinal tract tumor (group II), 79 patients with hematopoietic system malignant tumor (group III), and 101 healthy controls were consecutively recruited in a hospital in Beijing, China. The oral rinse samples were taken and Candida species were identified; the enzymes activities were tested.

Results

In total, 110 and 27 Candida strains were isolated from 91 patients and 26 controls, respectively. The oral colonization rate with Candida albicans in group III (12.7 %) was significant lower than that in group I (30.8 %), group II (33.7 %), and control group (25.7 %). The oral colonization rates with non-albicans Candida species in group I, group II, and group III were 15.4, 10.9, and 12.7 %, respectively, while only one non-albicans Candida strain was identified in control group. The non-albicans Candida species exhibited a lower virulence than C. albicans. Age was an independent risk factor for Candida colonization in patients with pulmonary cancer and digestive tract malignant tumor, “Teeth brush <1 time/day” was an independent risk factor for Candida colonization in patients with hematopoietic system tumor.

Conclusions

The differences of risk factors for oral Candida colonization in patients with different cancers require different strategies for the prevention and control of Candida infection.

Clinical relevance

Old aged patients with pulmonary cancer and digestive tract malignant tumor are high-risk population for Candida colonization. Increasing frequency of teeth brush might be helpful for preventing Candida colonization.