Species diversity of yeast in oral colonization of insulin-treated diabetes mellitus patients

Diversity and Antifungal Susceptibilities of Yeasts from Mangroves in Hong Kong, China-A One Health Aspect

While mangrove ecosystems are rich in biodiversity, they are increasingly impacted by climate change and urban pollutants. The current study provides first insights into the emergence of potentially pathogenic yeasts in Hong Kong's mangroves. Sediment and water samples were collected from ten urban and rural mangroves sites. Initial CHROMagarTM Candida Plus screening, representing the first application of this differential medium for water and soil samples collected from a non-clinical environment, enabled the rapid, preliminary phenotypic identification of yeast isolates from mangroves. Subsequent molecular profiling (ITS and/or 28S nrDNA sequencing) and antifungal drug susceptibility tests were conducted to further elucidate yeast diversity and drug resistance. A diversity of yeasts, including 45 isolates of 18 distinct species across 13 genera/clades, was isolated from sediments and waters from Hong Kong mangroves. Molecular profiling revealed a dominance of the Candida/Lodderomyces clade (44.4%), a group of notorious opportunistic pathogens. The findings also reveal a rich biodiversity of non-Candida/Lodderomyces yeasts in mangroves, including the first reported presence of Apiotrichum domesticum and Crinitomyces flavificans. A potentially novel Yamadazyma species was also discovered. Remarkably, 14.3% of the ubiquitous Candida parapsilosis isolates displayed resistance to multiple antifungal drugs, suggesting that mangroves may be reservoirs of multi-drug resistance. Wildlife, especially migratory birds, may disseminate these hidden threats. With significant knowledge gaps regarding the environmental origins, drug resistance, and public health impacts of pathogenic yeasts, urgent surveillance is needed from a One Health perspective. This study provides an early warning that unrestrained urbanization can unleash resistant pathogens from coastal ecosystems globally. It underscores the necessity for enhanced surveillance studies and interdisciplinary collaboration between clinicians, ornithologists, and environmental microbiologists to effectively monitor and manage this environmental health risk, ensuring the maintenance of 'One Health'.

Microbial Diversity of Periprosthetic Joint Infections in Diabetic and Nondiabetic Patients Following Hip Arthroplasty

BACKGROUND

Periprosthetic joint infection (PJI) is a major complication following hip arthroplasty, leading to prolonged hospital stays, increased health care costs, and major morbidity. Diabetes mellitus is a prevalent comorbidity among hip arthroplasty patients, contributing to an increased risk of surgical complications, including infections. However, limited evidence exists regarding the microbial profiles of PJIs in diabetic patients compared to nondiabetic counterparts.

METHODS

We conducted a retrospective cohort study to investigate the microbial diversity of PJIs in diabetic and nondiabetic patients following hip arthroplasty. Medical records of patients who underwent hip arthroplasty procedures between 1996 and 2021 were reviewed. Patients diagnosed with PJI, based on the international consensus meeting, were included in the study. Microbiological data, including culture results, and risk factors were collected and analyzed. A total of 4,261 culture-positive patients diagnosed with PJI following hip arthroplasty were included in the analysis.

RESULTS

Microbiological analysis revealed a diverse spectrum of microbial pathogens, with Staphylococcus species being the most commonly isolated pathogen. Comparison between diabetic and nondiabetic patients revealed differences in the microbial profiles of PJIs, with diabetic patients more likely to be infected with specific pathogens, including Candida albicans (P = 0.01 odds ratio (OR) 2.8, confidence interval (CI) 1.2 to 6.2), Klebsiella pneumoniae (P = 0.03 OR 2.4, CI 1.0 to 5.6), Staphylococcus aureus (P = 0.04 OR 1.3, CI 1.0 to 1.8), Staphylococcus epidermidis (P < 0.001 (R 1.7, CI 1.4 to 2.2), Polymicrobial infections (P < 0.001 OR 1.5, CI 1.2 to 1.8), and Clostridium perfringens (P = 0.04 OR 5.9, CI 1.0 to 33.1).

CONCLUSIONS

Our study provides valuable insights into the microbial diversity of PJIs in diabetic and nondiabetic patients following hip arthroplasty. The identification of a tendency to different microbial profiles in diabetic patients underscores the need for tailored approaches to infection prevention and management in this high-risk population. Further research is needed to elucidate the underlying mechanisms and develop targeted interventions to improve patient outcomes.

Candida albicans skin infection in diabetic patients: An updated review of pathogenesis and management

Candida species, commensal residents of human skin, are recognized as the cause of cutaneous candidiasis across various body surfaces. Individuals with weakened immune systems, particularly those with immunosuppressive conditions, are significantly more susceptible to this infection. Diabetes mellitus, a major metabolic disorder, has emerged as a critical factor inducing immunosuppression, thereby facilitating Candida colonization and subsequent skin infections. This comprehensive review examines the prevalence of different types of Candida albicans-induced cutaneous candidiasis in diabetic patients. It explores the underlying mechanisms of pathogenicity and offers insights into recommended preventive measures and treatment strategies. Diabetes notably increases vulnerability to oral and oesophageal candidiasis. Additionally, it can precipitate vulvovaginal candidiasis in females, Candida balanitis in males, and diaper candidiasis in young children with diabetes. Diabetic individuals may also experience candidal infections on their nails, hands and feet. Notably, diabetes appears to be a risk factor for intertrigo syndrome in obese individuals and periodontal disorders in denture wearers. In conclusion, the intricate relationship between diabetes and cutaneous candidiasis necessitates a comprehensive understanding to strategize effective management planning. Further investigation and interdisciplinary collaborative efforts are crucial to address this multifaceted challenge and uncover novel approaches for the treatment, management and prevention of both health conditions, including the development of safer and more effective antifungal agents.

Exploring the diversity of uncommon oral yeast species and associated risk factors among substance abusers in southwestern Iran

Yeast species are a group of coexistent microorganisms in the oral cavity that can cause opportunistic infections in vulnerable individuals, including addicts. This study aimed to identify the yeast species profile responsible for oral yeast colonization (OYC) and the associated risk factors in patients with substance use disorder (SUD) in Ahvaz, Iran. Oral samples were collected from drug users hospitalized in 12 addiction treatment centers, and the related clinical information was mined. Oral yeast species were identified using 21-plex PCR and sequencing of the internal transcribed spacer region (ITS1-5.8S-ITS2). A total of 244 yeast strains were identified from 245 individuals with substance abuse. Candida albicans was the most common species (37.7%) and non-albicans Candida was responsible for 57.7% of OYC, primarily C. dubliniensis (33.2%) and C. glabrata (11.9%). Moreover, uncommon oral yeasts constituted 5.3% of species, including Saccharomyces cerevisiae, Clavispora lusitaniae, Pichia kluyveri, Geotrichum candidum, Magnusiomyces capitatus, Hanseniospora opuntiae, Wickerhamomyces subpelliculosus, Trichosporon asahii, and Aureobasidium pullulans. Importantly, OYC exhibited associations with such factors as duration of drug use, daily drug consumption rate, opioid utilization, oral drug administration, and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) score. The present study is the pioneering investigation revealing the prevalence and diversity of oral yeast species, along with associated risk factors, in individuals with SUD in southwestern Iran. Furthermore, it underscores the importance of developing efficient and cost-effective diagnostic methods tailored for resource-constrained settings.

Meyerozyma guilliermondii species complex: review of current epidemiology, antifungal resistance, and mechanisms

Meyerozyma guilliermondii has been accepted as a complex composed of Meyerozyma guilliermondii, Meyerozyma carpophila, and Meyerozyma caribbica. M. guilliermondii is a saprophyte detected on human mucosa and skin. It can lead to serious infections in patients with risk factors like chemotherapy, immunodeficiency, gastrointestinal or cardiovascular surgery, and oncology disorders. Most deaths related to M. guilliermondii infections occur in individuals with malignancy. In recent decades, incidence of M. guilliermondii infections is increased. Sensitivity of this microorganism to conventional antifungals (e.g., amphotericin B, fluconazole, micafungin and anidulafungin) was reduced. Prophylactic and empirical uses of these drugs are linked to elevated minimal inhibitory concentrations (MICs) of M. guilliermondii. Drug resistance has concerned many researchers across the world. They are attempting to discover appropriate solution to combat this challenge. This study reviews the most important mechanisms of resistance to antifungals developed by in M. guilliermondii species complex.

Oral microbiota associated with gingiva of healthy, gingivitis and periodontitis cases

Oral microbes coexist with each other in a symbiotic relationship or as commensals in healthy body. Teeth and oral cavity harbor diverse community of fungi and bacteria. This study focused on bacterial and fungal component of gingiva, where the last occupy little attention. In addition to study the antimicrobial activity of toothpastes, mouth washes and natural oils against microorganisms. Sixty swabs from outer surfaces of gingiva in healthy persons, as well as patients complaining of gingivitis and periodontitis were collected for fungal and bacterial analyses. Sensitivity of the isolated microorganisms to some pharmaceutical preparations and natural oils was also performed. Ten fungal and 9 bacterial species were identified. There is a highly significant variation in the frequency of Klebsiella pneumonia among healthy, gingivitis and periodontitis. Also, Candida tropicalis and cocci bacteria showed significant diversity among the three tested groups. Among pharmaceutical preparations (toothpastes and mouth washes) and natural oils, Paradontax, Hexitol and clove oil showed the best antimicrobial activity against tested fungal and bacterial strains. Although, minimum inhibition concentrations (MICs) of clove oil were high compared to Paradontax and Hexitol, nevertheless, it is highly recommended as both antifungal and antibacterial agent against oral pathogenic microorganisms, because it is a natural compound and nearly devoid of side effects.

State of Evidence on Oral Health Problems in Diabetic Patients: A Critical Review of the Literature

Diabetes mellitus (DM) is a global health problem, having recognized that in the next 20 years the number of diabetic patients in the world will increase to 642 million. DM exerts enormous repercussions on general health diabetic (especially derived from vascular, cardiac, renal, ocular, or neurological affectation). It entails in addition a high number of deaths directly related to the disease, as well as a high health care cost, estimated at $673 billion annually. Oral cavity is found among all the organs and systems affected in the course of DM. Important pathologies are developed with higher prevalence, such as periodontitis (PD), alterations in salivary flow, fungal infections, oral cancer, and oral potentially malignant disorders (OPMD). It has been proven that PD hinders the metabolic control of DM and that the presence of PD increases the possibility for developing diabetes. Despite the relevance of these oral pathologies, the knowledge of primary care physicians and diabetes specialists about the importance of oral health in diabetics, as well as the knowledge of dentists about the importance of DM for oral health of patients is scarce or non-existent. It is accepted that the correct management of diabetic patients requires interdisciplinary teams, including dentists. In this critical review, the existing knowledge and evidence-degree on the preventive, clinical, diagnosis, prognosis, and therapeutic aspects of oral diseases that occur with a significant frequency in the diabetic population are developed in extension.

State of Evidence on Oral Health Problems in Diabetic Patients: A Critical Review of the Literature

Diabetes mellitus (DM) is a global health problem, having recognized that in the next 20 years the number of diabetic patients in the world will increase to 642 million. DM exerts enormous repercussions on general health diabetic (especially derived from vascular, cardiac, renal, ocular, or neurological affectation). It entails in addition a high number of deaths directly related to the disease, as well as a high health care cost, estimated at $673 billion annually. Oral cavity is found among all the organs and systems affected in the course of DM. Important pathologies are developed with higher prevalence, such as periodontitis (PD), alterations in salivary flow, fungal infections, oral cancer, and oral potentially malignant disorders (OPMD). It has been proven that PD hinders the metabolic control of DM and that the presence of PD increases the possibility for developing diabetes. Despite the relevance of these oral pathologies, the knowledge of primary care physicians and diabetes specialists about the importance of oral health in diabetics, as well as the knowledge of dentists about the importance of DM for oral health of patients is scarce or non-existent. It is accepted that the correct management of diabetic patients requires interdisciplinary teams, including dentists. In this critical review, the existing knowledge and evidence-degree on the preventive, clinical, diagnosis, prognosis, and therapeutic aspects of oral diseases that occur with a significant frequency in the diabetic population are developed in extension.

State of Evidence on Oral Health Problems in Diabetic Patients: A Critical Review of the Literature

Diabetes mellitus (DM) is a global health problem, having recognized that in the next 20 years the number of diabetic patients in the world will increase to 642 million. DM exerts enormous repercussions on general health diabetic (especially derived from vascular, cardiac, renal, ocular, or neurological affectation). It entails in addition a high number of deaths directly related to the disease, as well as a high health care cost, estimated at $673 billion annually. Oral cavity is found among all the organs and systems affected in the course of DM. Important pathologies are developed with higher prevalence, such as periodontitis (PD), alterations in salivary flow, fungal infections, oral cancer, and oral potentially malignant disorders (OPMD). It has been proven that PD hinders the metabolic control of DM and that the presence of PD increases the possibility for developing diabetes. Despite the relevance of these oral pathologies, the knowledge of primary care physicians and diabetes specialists about the importance of oral health in diabetics, as well as the knowledge of dentists about the importance of DM for oral health of patients is scarce or non-existent. It is accepted that the correct management of diabetic patients requires interdisciplinary teams, including dentists. In this critical review, the existing knowledge and evidence-degree on the preventive, clinical, diagnosis, prognosis, and therapeutic aspects of oral diseases that occur with a significant frequency in the diabetic population are developed in extension.

Candida sp. Infections in Patients with Diabetes Mellitus

Candidiasis has increased substantially worldwide over recent decades and is a significant cause of morbidity and mortality, especially among critically ill patients. Diabetes mellitus (DM) is a metabolic disorder that predisposes individuals to fungal infections, including those related to Candida sp., due to a immunosuppressive effect on the patient. This review aims to discuss the latest studies regarding the occurrence of candidiasis on DM patients and the pathophysiology and etiology associated with these co-morbidities. A comprehensive review of the literature was undertaken. PubMed, Scopus, Elsevier’s ScienceDirect, and Springer’s SpringerLink databases were searched using well-defined search terms. Predefined inclusion and exclusion criteria were applied to classify relevant manuscripts. Results of the review show that DM patients have an increased susceptibility to Candida sp. infections which aggravates in the cases of uncontrolled hyperglycemia. The conclusion is that, for these patients, the hospitalization periods have increased and are commonly associated with the prolonged use of indwelling medical devices, which also increase the costs associated with disease management.

White Piedra: Clinical, Mycological, and Therapeutic Experience of Fourteen Cases

Background

White piedra (WP) is an asymptomatic superficial mycosis that affects the hair stems, forming whitish nodules caused by various species of the genus Trichosporon.

Objective

To present a case series of WP of the head, its epidemiological data, as well as clinical, mycological, and therapeutic experience.

Methods

We conducted a 12-year retrospective and observational study of WP cases tested by dermoscopy, mycological study, and the identification of species through morphology, biochemistry, and proteomics (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry). The treatment was based on ketoco-nazole shampoo as well as keratolytics.

Results

We included 14 cases of WP, all located in the head and 1 case with both head and scrotum affected. Nine cases (64.3%) presented in children aged < 15 years. The majority of the cases (13/14, 92.8%) were women. Two cases were associated with hyperkeratosis and intertrigo. Most patients had long hair and excessive moisture. In all cases hair nodules were observed and Trichosporon inkin (11/14, 78.6%) was usually isolated. Eleven cases (78.6%) were cured by administering 2% ketoconazole shampoo.

Conclusion

WP was observed in school-age girls. The diagnosis was based on the observation of hair nodules and its main etiologic agent was T. inkin, with good response to treatment in most cases.

Mining the oral mycobiome: Methods, components, and meaning

Research on oral fungi has centered on Candida. However, recent internal transcribed spacer (ITS)-based studies revealed a vast number of fungal taxa as potential oral residents. We review DNA-based studies of the oral mycobiome and contrast them with cultivation-based surveys, showing that most genera encountered by cultivation have also been detected molecularly. Some taxa such as Malassezia, however, appear in high prevalence and abundance in molecular studies but have not been cultivated. Important technical and bioinformatic challenges to ITS-based oral mycobiome studies are discussed. These include optimization of sample lysis, variability in length of ITS amplicons, high intra-species ITS sequence variability, high inter-species variability in ITS copy number and challenges in nomenclature and maintenance of curated reference databases. Molecular surveys are powerful first steps to characterize the oral mycobiome but further research is needed to unravel which fungi detected by DNA are true oral residents and what role they play in oral homeostasis.

Prevalence of oral Candida colonization in patients with diabetes mellitus

OBJECTIVES OF THE STUDY

We aimed to assess the prevalence of oral Candida colonization in patients with diabetes and its relationship with factors such as Candida species, serum glucose level, and the susceptibility rate of isolated yeasts to antifungals.

PATIENTS

Random samples were obtained from 113 patients with type 2 diabetes, 24 patients with type 1 diabetes, and 105 healthy controls.

MATERIALS AND METHODS

The samples were taken by swabbing the oral mucosa of patients with diabetes mellitus and healthy individuals. Afterwards the samples were inoculated onto CHROMagar-Candida. The growing colonies were counted, and the isolated yeasts were identified by PCR-RFLP and RapID methods. Various isolated species of Candida were also subjected to susceptibility testing of antibiotic drugs. Blood samples were taken to evaluate glycosylated hemoglobin (HbA1c).

RESULTS

Although the Candida carriage rate and density were statistically higher in diabetics than healthy individuals, no direct association was found between having high Candida-burden and glycosylated hemoglobin. The most commonly isolated species in both diabetics and controls was Candida albicans. Of the tested antifungal drugs, the highest rate of resistance was found against itraconazole, followed in frequency by ketoconazole and fluconazole.

CONCLUSIONS

This study identified a significant association between the poor glycemic control and the higher prevalence rates of Candida carriage and density in diabetic patients. In addition, a high prevalence of C. dubliniensis in diabetic patients was found, which might be misdiagnosed with its morphologically related species, C. albicans.

Use of denaturing gradient gel electrophoresis for the identification of mixed oral yeasts in human saliva

A PCR-denaturing gradient gel electrophoresis (DGGE) method was established for the simultaneous presumptive identification of multiple yeast species commonly present in the oral cavity. Published primer sets targeting different regions of the Saccharomyces cerevisiae 26-28S rRNA gene (denoted primer sets N and U) and the 18S rRNA gene (primer set E) were evaluated with ten Candida and four non-Candida yeast species, and twenty Candida albicans isolates. Optimized PCR-DGGE conditions using primer set N were applied to presumptively identify, by band matching, yeasts in the saliva of 25 individuals. Identities were confirmed by DNA sequencing and compared with those using CHROMagar Candida culture. All primer sets yielded detectable DGGE bands for all species tested. Primer set N yielded mainly single bands and could distinguish all species examined, including differentiating Candida dubliniensis from C. albicans. Primer set U was less discriminatory among species but yielded multiple bands that distinguished subspecies groups within C. albicans. Primer set E gave poor yeast discrimination. DGGE analysis identified yeasts in 17 of the 25 saliva samples. Six saliva samples contained two yeast species: three contained C. albicans and three C. dubliniensis. C. dubliniensis was present alone in one saliva sample (total prevalence 16 %). CHROMagar culture detected yeasts in 16 of the yeast-containing saliva samples and did not enable identification of 7 yeast species identified by DGGE. In conclusion, DGGE identification of oral yeast species with primer set N is a relatively fast and reliable method for the simultaneous presumptive identification of mixed yeasts in oral saliva samples.

Oral Candida colonization in HIV-positive women: associated factors and changes following antiretroviral therapy

There is a paucity of information about the factors associated with oral colonization with Candida species and the changes associated with antiretroviral (ARV) therapy. This study investigated the role of ARV therapy and other factors in a study population. Relevant clinical and laboratory information was obtained and oral rinse specimens were tested for yeast identification. The findings were compared with previous data from the same clinic before ARV therapy was available. Of 197 patients, 117 (59.4 %) were colonized. Candida albicans was the dominant species (71 %) and Candida dubliniensis was the most frequent non-albicans Candida. The colonized group had a higher rate of concurrent tuberculosis (TB) infection (77.4 % compared with 56 % in the non-colonized patients, P = 0.03) and a lower median CD4(+) count (346.5 cells mm(-3)) compared with the non-colonized group (418 cells mm(-3)). Participants not on ARV therapy and those having oral prosthesis were all colonized (P = 0.003 and P = 0.022, respectively). The oral Candida count was negatively correlated with the CD4(+) count in participants on ARV therapy (P = 0.006). Associated factors using logistic regression were dental caries (odds ratio = 1.30; 95 % confidence interval = 1.07-1.60] and diabetes mellitus (odds ratio = 5.52; 95 % confidence interval = 1.68-18.12). The colonization rate was higher (81.3 %) as well as the yeast count before ARV therapy was available, while the prevalence of C. dubliniensis was found to have increased from 6.3 to 11 %. Dental caries, diabetes mellitus, oral prostheses and TB infection were associated with oral colonization. The colonization rate, variety and yeast counts declined with ARV therapy.

Wild-type Drosophila melanogaster as an alternative model system for investigating the pathogenicity of Candida albicans

Candida spp. are opportunistic pathogens in humans, and their systemic infections display upwards of 30% mortality in immunocompromised patients. Current mammalian model systems have certain disadvantages in that obtaining results is time consuming owing to the relatively long life spans and these results have low statistical resolution because sample sizes are usually small. We have therefore evaluated the potential of Drosophila melanogaster as an additional model system with which to dissect the host-pathogen interactions that occur during Candida albicans systemic infection. To do this, we monitored the survival of wild-type flies infected with various C. albicans clinical isolates that were previously ranked for murine virulence. From our lifetime data we computed two metrics of virulence for each isolate. These correlated significantly with murine survival, and were also used to group the isolates, and this grouping made relevant predictions regarding their murine virulence. Notably, differences in virulence were not predictably resolvable using immune-deficient spz^−/− flies, suggesting that Toll signalling might actually be required to predictably differentiate virulence. Our analysis reveals wild-type D. melanogaster as a sensitive and relevant model system; one that offers immense genetic tractability (having an extensive RNA interference library that enables tissue-specific gene silencing), and that is easy to manipulate and culture. Undoubtedly, it will prove to be a valuable addition to the model systems currently used to study C. albicans infection.

Oral geotrichosis: report of 12 cases

Oral geotrichosis is an uncommon opportunistic infection caused by Geotrichum candidum, a habitual contaminant and component of the flora of various parts of the body. This communication reports both a 20-year retrospective study of clinically and mycologically proven cases of oral geotrichosis, and a prospective study of fungal oral flora in 200 individuals divided into two groups: normal individuals and individuals with associated conditions. Twelve patients with proven oral geotrichosis were included: 9 females and 3 males, with a mean age of 48.5 years; the associated conditions were diabetes mellitus (66.6%), leukemia, Hodgkin's lymphoma and HIV/AIDS infection. The oral geotrichoses showed three clinical varieties: pseudomembranous (75%), hyperplastic, and palatine ulcer. G. candidum was isolated in 11 cases and G. capitatum in one. Positive fungal cultures were obtained from the two groups, and 48% and 78% of cultures were positive, respectively, for Candida spp. In 2.8% and 6.33% of the cases, G. candidum was isolated, respectively, together with one strain of G. capitatum. Oral geotrichosis is an exceptional infection that clinically presents, and is treated, as oral candidiasis. G. candidum may be isolated from the oral flora of a small proportion of patients, either normal individuals or those with associated conditions.

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.

Normal human gingival epithelial cells sense C. parapsilosis by toll-like receptors and module its pathogenesis through antimicrobial peptides and proinflammatory cytokines

This study was designed to investigate the interaction between C. parapsilosis and human epithelial cells using monolayer cultures and an engineered human oral mucosa (EHOM). C. parapsilosis was able to adhere to gingival epithelial cells and to adopt the hyphal form in the presence of serum. Interestingly, when cultured onto the engineered human oral mucosa (EHOM), C. parapsilosis formed small biofilm and invaded the connective tissue. Following contact with C. parapsilosis, normal human gingival epithelial cells expressed high levels of Toll-like receptors (TLR)-2, -4, and -6, but not TLR-9 mRNA. The upregulation of TLRs was paralleled by an increase of IL-1β, TNFα, and IFNγ mRNA expression, suggesting the involvement of these cytokines in the defense against infection with C. parapsilosis. The active role of epithelial cells in the innate immunity against C. parapsilosis infection was enhanced by their capacity to express high levels of human beta-defensin-1, -2, and -3. The upregulation of proinflammatory cytokines and antimicrobial peptide expression may explain the growth inhibition of C. parapsilosis by the gingival epithelial cells. Overall results provide additional evidence of the involvement of epithelial cells in the innate immunity against C. parapsilosis infections.

Oral Candida carriage of patients attending a dental clinic in Braga, Portugal

BACKGROUND

The ability of the Candida species to colonize surfaces can be considered as a risk factor for oral infection.

AIMS

To establish oral Candida carriage in patients attending a dental clinic in Braga, Portugal.

METHODS

A total of 97 patients were analysed. Swab samples were collected and directly cultured onto CHROMagar Candida. Representative yeasts were identified by polymerase chain reaction.

RESULTS

From the samples analysed 54.6% (n=53) were Candida positive, and Candida albicans was the most frequently isolated species, accounting for 79% of all the species identified. Non-C. albicans Candida (NCAC) species recovered included Candida parapsilosis, Candida glabrata, Candida tropicalis, and Candida guilliermondii. There was a lack of association between the presence of C. albicans or NCAC species, and age, gender, or prostheses wearing in this population. In 17% of the cases (n=9), polymicrobial cultures, with two different Candida species, were identified.

CONCLUSIONS

This study shows a high Candida carriage rate among this population, thus pointing to the relevance of an accurate diagnostic approach in Candida species identification.

Candidal colonization, strain diversity, and antifungal susceptibility among adult diabetic patients

BACKGROUND AND OBJECTIVES

Candidal colonization in diabetics is a matter of debate. The aim of this study is to investigate oral candidal colonization, strain diversity, antifungal susceptibility, and the influence of local and systemic host factors on candidal colonization in adult diabetics.

METHODS

We conducted a case-control study that compared 150 diabetics (49 type 1, 101 type 2) with 50 healthy controls. Two salivary samples were collected, using the oral rinse sampling method: one for salivary flow rate and pH determination, and the other for candidal colonization assessment. The candidal isolates were identified and tested in vitro for antifungal susceptibility using the commercial kit, Candifast. The relationship between specific host factors and candidal colonization was also investigated.

RESULTS

Diabetics had a higher candidal carriage rate compared to controls, but not density. Candida albicans was the most frequently isolated species, but diabetics had a variety of other candidal species present. None of the control samples were resistant to any tested antifungal, while the diabetic samples had differing resistances to azole antifungals. Although there was a significant positive correlation between glycemic control and candidal colonization in type 2 diabetics, there was a negative correlation between salivary pH and candidal carriage in the controls versus density in type 2 diabetics.

CONCLUSIONS

Diabetic patients not only had a higher candidal carriage rate, but also a variety of candidal species that were resistant to azole antifungals. Oral candidal colonization was significantly associated with glycemic control, type of diabetes, and salivary pH.

Erythematous oral candidiasis in patients with controlled type II diabetes mellitus and complete dentures

Diabetes mellitus (DM) is a systemic condition characterized by a deficient sugar metabolism, which affects the immune system and favors the development of yeasts. The aim of the present study was to perform biochemical, morphological, exoenzyme analyses of Candida species and the molecular identification (DNA) of C. albicans in patients with type II diabetes mellitus. The exoenzyme quantification was compared to non-diabetic patients as controls. Two hundred and seventy-four patients who make use of complete dentures were evaluated, 28 of whom had diabetes and erythematous oral candidiasis. Other thirty patients presented the same clinical feature but without diabetes. Samples were isolated for biochemical identification (auxonogram), morphological identification (production of germ tubes) and PCR molecular identification (DNA). The capability of the Candida samples in producing phospholipases and proteinases was also determined. The diabetic patients had a greater diversity of Candida species (Fischer's exact test, P = 0.04). The production of proteinases by C. albicans in patients with diabetes was greater than in the control group (unpaired "t" test P < 0.003). However, there was no difference between groups for phospholipase production (unpaired "t" test P > 0.05). It was concluded that patients with controlled DM exhibited systemic conditions predisposing C. albicans proteinase increased production.

Infections caused by Candida krusei in five transplant and two surgical patients

BACKGROUND

Candida krusei (Ck) may cause severe infections in immunocompromised hosts and is innately resistant to fluconazole.

PATIENTS AND METHODS

During an 18-month period, seven patients with Ck infection were identified at our center. All were treated in the transplant intensive care unit. Candida isolates were grown on Sabouraud agar, and chromosomal DNA was extracted; clonality was investigated using random amplified polymorphic DNA-polymerase chain reaction with primers M13, OPA-18, and OPE-18.

RESULTS

Among the patients with Ck infection, there were three pancreas recipients with intra-abdominal infection, one liver recipient with cholangitis, one lung recipient with pleural empyema, one patient with pleural empyema after esophageal perforation, and one case of pneumonia in a patient with a ventricular assist device. Treatment consisted of caspofungin (n = 3), voriconazole (n = 1), or a combination of the two (n = 2) together with surgery (n = 3) or pigtail catheter drainage (n = 3). One patient underwent drainage without antifungal treatment, and one patient did not have drainage. The infection was controlled in all cases. The patient with the assist device died from multiple organ dysfunction, the lung recipient died after four months from graft failure, and one pancreas graft was lost. Four patients (57%) harbored the same Ck strain.

CONCLUSION

Solid organ recipients seem to be at particular risk for Ck infections; clonal outbreaks may occur in intensive care units.

Genetic relatedness of commensal strains of Candida albicans carried in the oral cavity of patients' dental prosthesis users in Brazil

The aim of this study is to describe the degree of yeast-colonization in diabetic and hemodialysed-users of dental prostheses. Individuals (306) were examined using an oral rinse technique in order to evaluate the incidence of yeast-carriage, and genotype of C. albicans. Yeasts were isolated from 68.4% (91/133) individual's dental prostheses users. Dental prostheses were found to be a significant factor for the yeast colonization (P < 0.05). Overall, the intensity of carriage was higher in diabetic patients as compared with health and hemodialysed individuals (P < 0.05). The isolation rates were: C. albicans (51.7%), C. parapsilosis (20.9%), C. tropicalis (14.3%), C. glabrata (6.6%), C. krusei (3.3%), C. rugosa (1.1%), and Pichia (Pichia ohmeri, 2.2%). Ready-To-Go RAPD Analysis Beads were used and primer OPJ 6 distinguished the C. albicans isolates found in prostheses users. All the isolates were grouped into 11 RAPD profiles in four main clusters and, the average S (AB) for the entire collection of 47 C. albicans isolates were 0.779 +/- 0.178. Over 85% of isolates had a similarity level higher than or equal to 0.8 reinforcing the idea that the use of dental prostheses, independently of the host's clinical condition, probably provides the necessary conditions for these strains to gain a growth-specific advantage over others.