Subgingival strains of Candida albicans in relation to geographical origin and occurrence of periodontal pathogenic bacteria

In vitro photodynamic inactivation effects of hypocrellin B on azole-sensitive and resistant Candida albicans

BACKGROUND AND AIM

The extensive use of antifungal drugs has led to resistance from Candida albicans. The search for alternative treatment against drug-resistant C. albicans is highly desirable. Antimicrobial photodynamic therapy (aPDT) is an emerging and promising approach for treating localized and superficial C. albicans infections. The aim of this study was to investigate the photodynamic inactivation (PDI) effects of hypocrellin B (HB) on azole-sensitive and resistant C. albicans in vitro.

METHODS

The PDI efficacies of HB on standard C. albicans strain (ATCC 10231), azole-sensitive clinical isolate of C. albicans, and azole-resistant clinical isolate of C. albicans were assessed. The uptake of HB in C. albicans cells was investigated by confocal laser scanning microscopy (CLSM). The PDI effects on cellular structure and surface characteristics were investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM).

RESULTS

HB exhibited no significant dark toxicity, but inactivated the azole-sensitive and resistant C. albicans in a light-dose and PS concentration-dependent manner. CLSM images indicated that PDI treated C. albicans cells showed stronger fluorescence compared to untreated cells. TEM images suggested that significant damage to the cell wall, membrane, and cytoplasm were induced by HB-mediated PDI. SEM analysis revealed that the surface of C. albicans cells became twisted and ruptured after PDI treatment.

CONCLUSIONS

Azole-sensitive and resistant C. albicans could be effectively inactivated by HB in the presence of light, and HB-mediated aPDT shows promise as an antifungal treatment for C. albicans.

Candida spp. Determination and Th1/Th2 Mixed Cytokine Profile in Oral Samples From HIV+ Patients With Chronic Periodontitis

Background: Chronic periodontitis (CP), caused by bacteria and fungi, appears in up to 66% of HIV-patients. The impact and association of HIV-treatment (HAART) and Candida itself has not been properly evaluated in the development and progression of CP. The immunopathogenesis is characterized by CD4⁺ T-cells activation and the balance between the T-helper 1 (Th1) and T-helper 2 (Th2) or a mixed cytokine profile. Currently, the associated causes of an immune response in HIV-patients with CP is controversial. Our aims were the determination of Candida spp. and cytokine profile in oral samples from HIV-positive patients with CP, considering the CD4⁺ T cells levels and HAART use.

Methods: From 500 HIV-positive patients evaluated, 228 patients were enrolled. Patients were separated in groups: (A) n = 53 (≤200 CD4⁺ T-cells on HAART); (B) n = 57 (≤200 CD4⁺ T-cells without HAART); (C) n = 50 (>200 CD4⁺ T-cells without HAART); (D) n = 68 (>200 CD4⁺ T-cells on HAART). Candida spp. were isolated from the oral biofilm and crevicular fluid in CHROMagar and confirmed by endpoint PCR. Cytokine levels were measured by beads-based immunoassay in saliva by flow cytometry.

Results: 147 patients (64.5%) were positive to Candida spp. and 204 strains were isolated; 138 (67.6%) were C. albicans and the remaining C. non-albicans species (C. glabrata>C. tropicalis>C. krusei>C. dubliniensis). In this study, CHROMagar showed good sensitivity (95%) but poor specificity (68%); since of the 152 samples identified as C. albicans, only 131 were confirmed by PCR; from the 10 samples identified as C. glabrata, only six were confirmed. Finally, of the 42 samples detected as C. tropicalis, only five were confirmed. When evaluating Candida spp. presence, group A and D had higher isolation, while group B had the highest species diversity. Whereas, group C had a significant reduction of Candida spp. Despite the presence of Candida and HAART, we found a Th1/Th2 hybrid profile in the saliva of patients with low CD4⁺ T-cell count (group A).

Conclusion: Abundance and diversity of the Candida spp. detected in HIV-patients with CP could be related to HAART and low CD4⁺ T-cells levels. Also, the immunosuppression might promote a local Th1/Th2 hybrid cytokine profile.

Oral Candida spp carriage and periodontal diseases in HIV-infected patients in Ribeirão Preto, Brazil

The majority of HIV-infected patients develop Candida spp-associated clinical oral lesions. Studies have shown that asymptomatic oral colonization of Candida spp may lead to oral lesions or become a source of disseminated infections. The aim of this study was to verify the effects of periodontal conditions on Candida spp prevalence and Candida spp carriage in the oral cavity of HIV-infected patients compared to non-infected patients. Twenty-five patients not infected with HIV and 48 HIV-infected patients were classified according to periodontal conditions as being periodontal healthy or with periodontal disease. Candida spp carriage and classification were performed in oral rinse samples. Viral load and CD4+ T lymphocyte (CD4+L) counts were performed in blood samples from HIV-infected patients. No differences in Candida spp prevalence related to HIV status or periodontal condition were detected. However, Candida spp carriage was increased in periodontally affected HIV-infected patients when compared to periodontally healthy HIV-infected patients (p= 0.04). Periodontally healthy HIV-infected patients presented Candida spp carriage in similar levels as healthy or periodontally affected non-HIV-infected patients. Candida spp carriage was correlated with CD4+L counting in HIV-infected patients. We concluded that periodontal disease is associated with increased Candida spp carriage in HIV-infected patients and may be a predisposing factor to clinical manifestations of candidiasis.

Photodynamic inactivation of Candida albicans by hematoporphyrin monomethyl ether

AIM

To evaluate the capacity of hematoporphyrin monomethyl ether (HMME) in the presence of light to cause photodynamic inactivation (PDI) of Candida albicans.

MATERIALS & METHODS

HMME photoactivity was evaluated against azole-susceptible and -resistant C. albicans. The mechanisms by which PDI of C. albicans occurred were also investigated.

RESULTS

HMME-mediated PACT caused a dose-dependent inactivation of azole-susceptible and -resistant C. albicans. Incubation with 10 μM HMME and irradiation with 72 J cm(-2) light decreased the viability of C. albicans by 7 log10, induced damage of genomic DNA, led to loss of cellular proteins and damaged the cell wall, membrane and intracellular targets.

CONCLUSION

Candida albicans can be effectively inactivated by HMME in the presence of light, and HMME-mediated PACT shows its potential as an antifungal treatment.

Oral Candida Carriage and Morphotype Differentiation in Chronic Periodontitis Patients with and without Diabetes in the Indian Sub-Continent

The aim of this study was to assess the oral Candida carriage and morphotype differentiation of Candida species in chronic periodontitis patients, with and without diabetes mellitus. This cross sectional study included 30 subjects in the age range of 40–60 years, who were divided into two groups: 15 chronic periodontitis only (CP) patients, and 15 chronic periodontitis patients with diabetes (CPD). Clinical measurements included plaque index (PI), gingival index (GI), probing depth (PD), clinical attachment level (CAL), and fasting blood sugar level (FBS). The unstimulated whole saliva samples were collected for fungal analysis. Candida carriage was analyzed by measuring colony forming units (CFU) following the culture of samples. Qualitative morphotype differentiation of Candida species from yeast to hyphal form was analyzed using Periodic acid-Schiff (PAS) staining. There was no statistically significant difference between CP and CPD groups for the periodontal parameters. However, a significantly higher Candida species CFU count was found in CPD (0.33 ± 0.23) as compared to CP (0.05 ± 0.04) group. This pilot study suggests that the occurrence of Candida species is higher in the saliva of chronic periodontitis patients with diabetes as compared to patients with chronic periodontitis alone.

Photodynamic inactivation of Candida albicans mediated by a low density of light energy

Shorter times and lower energies of application of light sources are desirable to use photodynamic antimicrobial chemotherapy (PACT) to the clinical control of candidiasis, especially among babies and children. Light energies ranging from 39.5 to 100 J/cm(2) were previously applied to kill Candida albicans by PACT. The present study evaluated the efficacy of a combination of 0.05 mg/mL toluidine blue O (TBO) and a short time of application (60 s) and a low density of light energy (18 J/cm(2)) of a red light-emitting diode (LED) in killing C. albicans planktonic cells. Standard suspensions of C. albicans were randomly assigned for four treatment groups: control (L-P-), LED alone (L+P-), TBO alone (L-P+), and PACT (L+P+). After treatments, serial dilutions of suspensions were prepared and streaked on Sabouraud dextrose agar to determine colony-forming units of C. albicans per milliliter (CFU/mL). The results were analyzed by ANOVA and Tukey's post-hoc test (P < 0.05). PACT significantly reduced CFUs of C. albicans in comparison to other three treatments. Our results demonstrated a fungicidal effect of PACT mediated by a shorter time of application of LED on C. albicans planktonic cells. Further in vivo studies are needed to elucidate the efficacy of PACT to treat human fungal infections.

Genetic and phenotypic evaluation of Candida albicans strains isolated from subgingival biofilm of diabetic patients with chronic periodontitis

Candida spp. are commensal microorganisms that are part of the microflora of different sites within the oral cavity. In healthy subjects, who have an unaltered immunological status, these yeasts do not cause disease. However, in immunosuppressed individuals whose condition may have been caused by diabetes mellitus, Candida spp. can express different virulence factors and may consequently become pathogenic. Studies have detected the presence of Candida spp. in periodontal sites of patients with chronic periodontitis, especially those that are immunologically compromised. However, the role of these microorganisms in the pathogenesis of periodontal disease is still unknown. The objectives of this study were: (1) to isolate and identify Candida albicans strains from subgingival sites of diabetic patients with chronic periodontitis; (2) to evaluate the following virulence factors; colony morphology, proteinase, phospholipase and hemolysin activities and cell surface hydrophobicity (CSH) under different atmospheric conditions; and (3) to determine the genetic patterns of these C. albicans isolates. Microbial samples were collected from subgingival sites and seeded on CHROMagar for subsequent identification of C. albicans by polymerase chain reaction (PCR). For the phenotypic tests, all strains of C. albicans were grown under reduced oxygen (RO) and anaerobiosis (ANA) conditions. Genotypes were defined by the identification through PCR of the transposable introns in the 25S rDNA. The results obtained relative to virulence factors were analyzed according to the atmospheric condition or genetic group, using Chi-square and Wilcoxon non-parametric tests. In this study, 128 strains were identified as C. albicans and of these, 51.6% were genotype B, 48.4% were genotype A and Genotype C was not found. Most of the strains were alpha-hemolytic in both atmospheric conditions, without a statistical difference. However, when comparing the genotypes, 46.1% of the genotype A strains were beta-hemolytic. In relation to colony morphology, 100% of the strains under ANA showed rough colonies, which were especially prevalent in genotype A isolates. In contrast, most of the colonies were smooth under RO. C. albicans strains did not produce proteinase and phospholipase activity in the total absence of oxygen. In RO, most strains had high proteinase activity and were positive by phospholipase tests (P < 0.05). Hydrophobicity was higher in anaerobiosis and was noted mainly for genotype A isolates. In conclusion, environmental oxygen concentration influenced the virulence factors of C. albicans strains isolated from subgingival sites of diabetic and periodontal patients. In addition, genotype A seems to be more virulent based on the phenotypic tests evaluated in this study.

New antimicrobial therapies used against fungi present in subgingival sites--a brief review

Although the main reservoir of Candida spp. is believed to be the buccal mucosa, these microorganisms can coaggregate with bacteria in subgingival biofilm and adhere to epithelial cells. The treatment of periodontal disease includes scaling and root planning (SRP) associated with proper oral hygiene. However, some patients may have negative responses to different therapeutic procedures, with a continuous loss of insertion, so the use of antimicrobials is needed as an adjuvant to SRP treatment. The use of a broad-spectrum antibiotic, such as tetracycline and metronidazole, as an aid in periodontal treatment has also been a factor for the development of superinfections by resistant bacteria and Candida species, even in patients with HIV. In the dental practice, the most commonly used antifungals are nystatin and fluconazole. However, the introduction of new drugs like the next generation of azoles is essential before the onset of emergent species in periodontal disease. Plants are good options for obtaining a wide variety of drugs. This alternative could benefit a large population that uses plants as a first treatment option. Plants have been used in medicine for a long time and are extensively used in folk medicine, because they represent an economic alternative, are easily accessible and are applicable to various diseases. Herein, we briefly review the literature pertaining the presence of Candida sp. in periodontal pockets, the conventional antifungal resistance and new therapies that include natural antifungal agents are reviewed.

Periodontal conditions and prevalence of putative periodontopathogens and Candida spp. in insulin-dependent type 2 diabetic and non-diabetic patients with chronic periodontitis--a pilot study

OBJECTIVES

The aims of this study were to evaluate periodontal conditions and identify the presence of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythia, and four different species of Candida (C. albicans, C. dubliniensis, C. glabrata and C. tropicalis) in periodontal pockets and furcation sites of insulin-dependent type 2 diabetic and non-diabetic patients with generalised chronic periodontitis.

DESIGN

Clinical parameters, including oral status assessed using plaque index, gingival index, probing depth, gingival recession and clinical attachment level and systemic conditions with fasting glucose level or glycosylated haemoglobin were measured in diabetic and non-diabetic patients with chronic periodontitis. Samples of subgingival biofilm were obtained from the periodontal pockets and furcation sites and submitted to phenol-chloroform DNA extraction and PCR analysis using specific primers.

RESULTS

Clinical conditions of diabetic and non-diabetic patients were similar, without statistical differences in both periodontal indexes and glucose levels (p>0.05). Diabetics had a higher prevalence of Candida spp., mainly C. albicans and C. dubliniensis, and a lower frequency of T. forsythia, when compared to non-diabetic patients, for both periodontal sites. C. glabrata and C. tropicalis were not found in periodontal pockets and furcation sites of non-diabetic patients.

CONCLUSION

The results demonstrated a strong colonisation of Candida spp. in the periodontal sites of diabetic patients that have generalised chronic periodontitis with a higher prevalence of C. dubliniensis followed by C. albicans.

Recovery of Candida dubliniensis and other Candida species from the oral cavity of subjects with periodontitis who had well-controlled and poorly controlled type 2 diabetes: a pilot study

The goal of this study was to determine the prevalence of Candida dubliniensis and other Candida species from saliva samples and from subgingival plaque samples at periodontally healthy and periodontally diseased sites in subjects who had type 2 diabetes and periodontitis. Saliva and subgingival samples were obtained from 30 subjects with periodontitis: 15 with poorly controlled and 15 with well-controlled type 2 diabetes. Samples were analyzed for the presence of C. dubliniensis and other Candida species. Among subjects with poorly controlled diabetes, 53% were positive for C. albicans, 20% for C. glabrata, 6% for C. tropicalis, and 6% for C. parapsilosis. Among well-controlled subjects, 33% were positive for C. albicans and 13% for C. glabrata; none had C. tropicalis or C. parapsilosis. No samples were positive for C. dubliniensis in either group of subjects.

Candida spp. in periodontal disease: a brief review

Although the main reservoir of Candida spp. is believed to be the buccal mucosa, these microorganisms can coaggregate with bacteria in subgingival biofilm and adhere to epithelial cells. Such interactions are associated with the capacity of Candida spp. to invade gingival conjunctive tissue, and may be important in the microbial colonization that contributes to progression of oral alterations caused by diabetes mellitus, some medications, and immunosuppressive diseases such as AIDS. In addition, immune deficiency can result in proliferation of Candida spp. and germination of forms that are more virulent and have a higher capacity to adhere to and penetrate cells in host tissues. The virulence factors of Candida spp. increase host susceptibility to proliferation of these microorganisms and are likely to be important in the study of periodontal disease. Herein, we briefly review the literature pertaining to the role of Candida spp. in periodontal disease, and consider the main virulence factors, the host immune response to these microorganisms, and the effect of concomitant immunosuppressive conditions.

Yeast diversity in the oral microbiota of subjects with periodontitis: Candida albicans and Candida dubliniensis colonize the periodontal pockets

The term periodontitis encompasses several polymicrobial infectious diseases, of multifactorial etiology, with chronic and aggressive forms. In spite of the etiopathogenic differences between these two forms of the disease, few studies have analyzed the subgingival colonization by yeast. The objective of this investigation was to analyze the composition of the yeast microbiota present in the mucosa and subgingival sites of healthy individuals and patients with aggressive and chronic periodontitis. For this, samples were recovered from these two locations and the yeast recovered identified by phenotypic and genotypic methods. Patients with chronic periodontitis showed significant differences in relation to the other groups with respect to carrier status (69.2% versus 35.7% of healthy individuals; [chi(i)(2) test; p=0.014]), the total number of isolated colony forming units or CFU (mean and ranges 281.6 (0-6048) [K-W(2)=6.998; p=0.03]), the Simpson diversity index (I) in site b (I(b)=0.344 versus healthy subjet and aggresive periodontitis where I=0 [multiple t-test comparisons with the Bonferronni correction, p<0.05]), and the species profile. Interestingly, in spite of the varied profiles of the species present in the mucosa of the three groups analyzed we noted that only C. albicans and C. dubliniensis were capable of colonizing the periodontal pockets in patients with chronic periodontitis, while only C. albicans was identified in the subgingiva of healthy individuals and patients with aggressive periodontitis.

Genetic diversity and exoenzyme activities of Candida albicans and Candida dubliniensis isolated from the oral cavity of Brazilian periodontal patients

OBJECTIVE

Mucosal surfaces are the primary oral reservoirs of Candida species, but these species can also be found in subgingival biofilm. The present study investigated the genetic diversity and production of exoenzymes of C. albicans and C. dubliniensis isolated from the oral cavity of systemically healthy patients with periodontitis.

DESIGN

Fifty-three patients were analysed. Samples were collected from three oral cavity sites (periodontal pocket, gingival sulci and oral mucosa), plated and, after isolation, suspect strains of C. albicans and C. dubliniensis were identified by PCR. The genetic diversity of the isolates was evaluated by RAPD and the activities of the secreted aspartyl proteinases and phospholipases were evaluated by the agar plate method.

RESULTS

Twenty-one patients showed positive results for Candida spp. There were no statistically significant differences between genders, or between sites. C. albicans was the most frequently found specie, while C. dubliniensis was isolated from the periodontal pocket of only one patient. Sixteen genotypes were detected among the C. albicans isolates, and one among the C. dubliniensis isolates. The similarity coefficient (S(SM)) values among the C. albicans genotypes ranged from 0.684 to 1.0 with an average of 0.905+/-0.074. All isolates produced high levels of Saps and most of them produced high levels of phospholipases. No relationship was found between the genotypes and the pattern of enzymatic production. There was no association between specific genotypes and their site of isolation.

CONCLUSIONS

The results of the present study suggest that genetically homogeneous strains of C. albicans are present in the oral cavity of patients with periodontitis and that these strains are capable of producing high levels of exoenzyme.

Candida albicans serotype B strains synthesize a serotype-specific phospholipomannan overexpressing a beta-1,2-linked mannotriose

Candida albicans strains consist of serotypes A and B depending on the presence of terminal beta-1,2-linked mannose residues in the acid-stable part of serotype A phosphopeptidomannan (PPM). The distribution of C. albicans serotypes varies according to country and human host genetic and infectious backgrounds. However, these epidemiological traits have not yet been related to a phenotypically stable molecule as cell surface expression of the serotype A epitope depends on the growth conditions. We have shown that C. albicans serotype A associates beta-mannose residues with another molecule, phospholipomannan (PLM), which is a member of the mannoseinositolphosphoceramide family. In this study, PLM from serotype B strains was analysed in order to provide structural bases for the differences in molecular mass and antigenicity observed between PLMs from both serotypes. Through these analyses, carbon 10 was shown to be the location of a second hydroxylation of fatty acids previously unknown in fungal sphingolipids. Minor differences observed in the ceramide moiety appeared to be strain-dependent. More constant features of PLM from serotype B strains were the incorporation of greater amounts of phytosphingosine C20, a twofold reduced glycosylation of PLM and overexpression of a beta-1,2 mannotriose, the epitope of protective antibodies. This specific beta-mannosylation was observed even when growth conditions altered serotype A PPM-specific epitopes, confirming the potential of PLM as a phenotypically stable molecule for serotyping. This study also suggests that the regulation of beta-mannosyltransferases, which define specific immunomodulatory adhesins whose activity depends on the mannosyl chain length, are part of the genetic background that differentiates serotypes.

The effect of calcium chelating or binding agents on Candida albicans

OBJECTIVE

The aim of this study was to evaluate antifungal effects of calcium-chelating or -binding agents on Candida albicans comparing with conventional antifungal agents.

STUDY DESIGN

Two clinical oral isolates and 1 standard strain of C albicans were included in the study. Test solutions were ethylenediamine-tetraacetic acid (EDTA), ethyleneglycol-tetraacetic acid (EGTA), sodium fluoride (NaF), titanium tetrafluoride (TiF4), nystatin, and ketoconazole. Minimum inhibitory and fungicidal concentrations of the solutions were determined. The results were analyzed statistically using Friedman's nonparametric 2-way ANOVA and Mann-Whitney U tests.

RESULTS

All isolates demonstrated similar susceptibility patterns (P>.05). Except ketoconazole, EDTA had the highest antifungal and fungicidal activity, followed by TiF4. EGTA and NaF were the weakest agents against C albicans among all test solutions.

CONCLUSION

EDTA and TiF4 may be recommended as an alternative irrigating solution particularly in persistent root canal infections and in root canals of patients having a high incidence of oral candidosis.

Point prevalence, microbiology and antifungal susceptibility patterns of oral Candida isolates colonizing or infecting Mexican HIV/AIDS patients and healthy persons

We have conducted a longitudinal study over a 3-year period to address the point prevalence, microbiological characteristics and antifungal susceptibility patterns of yeast isolates colonizing or infecting the oral cavities of 111 HIV-infected (51 adults, 60 children) and 201 non HIV-infected (109 adults, 92 children) Mexican persons. Regarding the epidemiology of oral candidiasis, Candida albicans was the most frequent species isolated. Seventy-one out of 85 isolates from colonized persons were C. albicans (83.5%), 27 isolates of them were from HIV-infected children and 44 from non HIV-infected patients. Sixty-two isolates belonged to serotype A which was the most prevalent serotype of C. albicans. Non-albicans species (Candida glabrata, Candida tropicalis and Candida parapsilosis, and Saccharomyces cerevisiae) were isolated from 16.5% of colonized patients and from 38.5% patients with candidiasis or Candida-related lesions. There were nine episodes of infection or colonization by at least 2 different yeast species. In the case of HIV/AIDS patients, it was determined that yeast carriage was not associated with the number of CD4+ cells or the viral load, but HAART reduced the prevalence of oral candidiasis. Overall, most patients harbored strains in vitro susceptible to fluconazole, however 10.8% of the yeasts were resistant to one or more azole antifungal agents and 29% were intermediate susceptible to them. On the contrary, 5-fluorocytosine was very active against all isolates tested, and amphotericin B was active against 97.9% of them.

Differential recovery of Candida species from subgingival sites in human immunodeficiency virus-positive and healthy children from Rio de Janeiro, Brazil

The prevalence of subgingival Candida species was studied in 52 human immunodeficiency virus (HIV)-positive and 42 HIV-negative children. Candida was cultured from 22 (42.3%) and 3 (7.1%) HIV-infected and control children, respectively. C. albicans was the most common Candida species isolated from HIV-infected children, followed by C. dubliniensis, C. glabrata, and C. tropicalis. In the HIV-positive group, the prevalence of Candida isolation was significantly higher in children who presented with low CD4(+)-T-lymphocyte counts, elevated viral loads, and gingivitis.

Yeasts in apical periodontitis

Microbiological reports of apical periodontitis have revealed that yeasts can be isolated from approximately 5-20% of infected root canals. They occur either in pure cultures or together with bacteria. Almost all isolated yeasts belong to the genus Candida, and the predominant species is C. albicans. Pheno- and genotypic profiles of C. albicans isolates show heterogeneity comparable with those of isolates from other oral sites. C. albicans expresses several virulence factors that are capable of infecting the dentin-pulp complex, including dentinal tubules. This causes, consequentially, an inflammatory response around the root apex, which suggests a pathogenic role for this organism in apical periodontitis. Yeasts are particularly associated with persistent root canal infections that do not respond favorably to conservative root canal therapy. This may be due to the resistance of all oral Candida species against a commonly used topical medicament, calcium hydroxide. However, other antimicrobial agents may offer alternative therapeutic approaches and improve the treatment of these persistent cases of apical periodontitis.

Subgingival microflora in Turkish patients with periodontitis

BACKGROUND

No information exists on periodontitis-associated subgingival microbiota from Turkey. We determined the occurrence, interspecies relationships, and clonal characteristics for a group of periodontal bacteria in a Turkish study population.

METHODS

Subgingival microbial samples were obtained from patients with localized (LAgP, N = 18) or generalized (GAgP, N = 17) types of aggressive periodontitis, generalized chronic periodontitis (GCP, N = 14), and non-periodontitis subjects (N = 20). Culture methods were used to recover 6 periodontal bacterial species and yeasts, and a polymerase chain reaction technique was used to detect Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. Intraspecies characterization of A. actinomycetemcomitans was carried out by serotyping and genotyping.

RESULTS

All species, except for Micromonas micros (formerly Peptostreptococcus micros) occurred more frequently (P < 0.05) in periodontitis than non-periodontitis subjects. Detection frequencies for Tannerella forsythensis (formerly Bacteroides forsythus) and Campylobacter rectus differed among the periodontitis subgroups; the lowest frequency occurred in LAgP. The mean proportions of A. actinomycetemcomitans, P. gingivalis, and C. rectus were higher (P < 0.008) in GAgP than in non-periodontitis subjects. Significant positive associations were seen between 7 of the 22 possible combinations (P < 0.05). A. actinomycetemcomitans serotype c (34%) and non-serotypeable isolates (34%) were the most common antigenic types among the 305 strains analyzed. Eleven arbitrarily primed (AP)-PCR genotypes were distinguished among 273 isolates from 29 subjects. Yeasts were found in 23% of the 69 subjects.

CONCLUSIONS

The results on the Turkish study population were generally in line with earlier reports on the occurrence and interspecies relationships of certain bacteria in periodontitis. However, A. actinomycetemcomitans was not overrepresented in LAgP, and the serotype distribution resembled that reported from the East. The high frequency of non-serotypeable isolates suggests local characteristics of the species.

Beta-1,2-mannosylation of Candida albicans mannoproteins and glycolipids differs with growth temperature and serotype

Increasing the growth temperature from 28 to 37 degrees C reduced the expression of beta-1,2-oligomannoside epitopes on mannoproteins of Candida albicans serotypes A and B. In contrast, beta-1,2-mannosylation of phospholipomannan (PLM) remained constant despite a slight decrease in the relative molecular weight (M(r)) of this compound. At all growth temperatures investigated, serotype A PLM displayed an M(r) and an antigenicity different from those of serotype B PLM when they were tested with a panel of monoclonal antibodies.

Genotyping and antifungal susceptibility of human subgingival Candida albicans isolates

Subgingival colonization by Candida albicans has been described in human immunodeficiency virus (HIV)-infected individuals, but subgingival isolates have scarcely been characterized, particularly with respect to genotype and antifungal susceptibility. A series of 29 subgingival strains of C. albicans isolated from nine HIV-infected individuals was typed by electrophoretic karyotyping and tested for susceptibility to fluconazole, itraconazole, the new investigational triazole posaconazole and amphotericin B. DNA typing showed genetic heterogeneity within subgingival isolates, as almost every individual harbored his/her own specific isolate. Genetic identity was usually demonstrated within oral and subgingival isolates simultaneously collected from the same individual, but a number of DNA types were found to be unique to subgingival strains. These findings suggest that colonization is not just the result of Candida spreading from oral surfaces, and that subgingivally adapted strains could be involved. All isolates were susceptible to all the triazole drugs tested and amphotericin B. Additional studies on subgingival Candida colonization and further characterization of subgingival isolates are now required to clarify the role of Candida as opportunistic periodontal pathogen.

Prevalence of yeast among children in Nigeria and the United States

Fungal infections have gained considerable importance over the last decade as a result of significant increase in the incidence of opportunistic and systemic candidosis. Although Candida albicans is the predominant causative agent of candidosis, particularly oral disease, recently an epidemiological trend has been observed where other less pathogenic species of Candida, including the newly characterized species Candida dubliniensis, are emerging as significant opportunistic pathogens. The present study aimed to screen for the presence of C. dubliniensis and to compare the recovery of yeast species from 30 seemingly healthy and 30 HIV-positive children in the United States, as well as from 64 malnourished Nigerian children. Oral samples were cultured for fungal growth, and all germ tube and chlamydospore positive isolates were tested for ability to grow at 45 degrees C to differentiate between C. albicans and C. dubliniensis. All isolates were speciated based on colony color production on CHROMagar medium and sugar assimilation profiles. Among the 30 HIV-positive children, 15 (50%) were positive for fungus; 12 were positive for C. albicans, with one of the latter also positive for Candida glabrata, and three were found to harbor C. dubliniensis. Among the 30 non-HIV-positive children, five C. albicans and four C. dubliniensis isolates were recovered. No C. dubliniensis isolates were recovered from the Nigerian group. However, eight other different yeast species were recovered from 31 (48.4%) of the 64 Nigerian children sampled, with six of them growing a combination of species. In comparing the data from the Nigerian and United States children, the frequency of yeasts in the malnourished Nigerian group was considerably higher. The most striking difference between the two groups was in the variety of the usually less encountered and less pathogenic yeast species recovered from the Nigerian population. The findings support previously reported observations that there may be intrinsic differences between different populations sampled and that malnutrition might favor the presence of yeast species other than C. albicans.

Recovery of Candida dubliniensis and other yeasts from human immunodeficiency virus-associated periodontal lesions

Oral and subgingival samples from periodontal lesions were collected from 54 human immunodeficiency virus (HIV)-positive and 20 HIV-negative patients and cultured for yeast species. Of the 54 samples cultured from HIV-positive patients, 44 (82%) were positive for yeast species, of which 29 (66%) were subgingival. A total of 19 (48%) patients were positive for Candida dubliniensis, of which 15 (79%) were colonized in subgingival sites. Seven isolates of Candida glabrata, two isolates of Candida parapsilosis, and one isolate of Saccharomyces cerevisiae were recovered. This study reports for the first time the recovery of C. dubliniensis from subgingival intraoral sites and confirms the presence of Candida species in sites of periodontal disease associated with HIV.