Performance of chromogenic media for Candida in rapid presumptive identification of Candida species from clinical materials

Isolation and identification of Wickerhamiella tropicalis from blood culture by MALDI-MS

Wickerhamiella is a genus of budding yeast that is mainly isolated from environmental samples, and 40 species have been detected. The yeast isolated from human clinical samples usually only contain three species: W. infanticola, W. pararugosa and W. sorbophila. In this study, we isolated W. tropicalis from a blood sample of a six-year-old female with a history of B-cell precursor lymphoblastic leukemia in Japan in 2022. Though the strain was morphologically identified as Candida species by routine microbiological examinations, it was subsequently identified as W. tropicalis by sequencing the internal transcribed spacer (ITS) of ribosomal DNA (rDNA). The isolate had amino acid substitutions in ERG11 and FKS1 associated with azole and echinocandin resistance, respectively, in Candida species and showed intermediate-resistant to fluconazole and micafungin. The patient was successfully treated with micafungin. Furthermore, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) detected three novel peaks that are specific for W. tropicalis, indicating that MALDI-MS analysis is useful for rapid detection of Wickerhamiella species in routine microbiological examinations.

Real-Time PCR Detection of Candida Species in Biopsy Samples from Non-Smokers with Oral Dysplasia and Oral Squamous Cell Cancer: A Retrospective Archive Study

The impact of Candida sp. in the development of oral cancer remains uncertain and requires sensitive analytical approaches for clarification. Given the invasive capabilities of these microorganisms in penetrating and invading host tissues through hyphal invasion, this study sought to detect the presence of five Candida sp. in oral biopsy tissue samples from non-smoker patients. Samples were obtained from patients at varying stages of oral carcinogenesis, including dysplasia, carcinoma in situ, OSCC, and histologically benign lesions, and analyzed using Real-Time PCR. Oral tissue samples from 80 patients (46 males and 34 females) were included. Significantly higher C. albicans presence was detected in the mild/moderate dysplasia group compared to the healthy (p = 0.001), carcinoma in situ (p = 0.031) and OSCC groups (p = 0.000). Similarly, C. tropicalis carriage was higher in tissues with mild/moderate dysplasia compared to healthy (p = 0.004) and carcinoma in situ (p = 0.019). Our results showed a significant increase in the presence of C. albicans and C. tropicalis within the mild/moderate dysplasia group compared to other cohorts. Coexistence of these two microorganisms was observed, suggesting a potential transition from a commensal state to an opportunistic pathogen, which could be particularly linked to the onset of oral neoplasia.

Absence of Oral Opportunistic Infections in Patients with Inflammatory Bowel Disease Receiving Anti-TNF-α and Anti-Integrin-α4β7 Therapy

Biological therapy of inflammatory bowel disease (IBD) carries an increased risk for the development of opportunistic infections due to immunomodulation. The aim of this study was to determine the prevalence and types of oral infections in IBD patients treated with biological (anti-TNF-α and anti-integrin-α4β7) and conventional medication protocols. The study included 20 IBD patients receiving anti-TNF-α therapy, 20 IBD patients receiving anti-integrin-α4β7 therapy and 20 IBD patients without immunomodulatory therapy. Participants completed questionnaires on medical information, oral lesions and symptoms. For each patient, clinical examination and a salivary flow rate test were performed, followed by a swab of the oral mucosa. The swab samples were cultured to identify Candida spp. and oral bacteria. No bacterial opportunistic infections were detected. Candidiasis was detected in four participants, with no significant difference between groups (p = 0.765). Hyposalivation was most common in the anti-TNF-α group, with a significant difference between groups (p = 0.036). There were no significant differences between groups in self-reported oral mucosal lesions and symptoms (p > 0.05), or in the distribution of oral mucosal lesions (p > 0.05). This study suggests that IBD patients receiving biological therapy are at no greater risk of developing oral opportunistic infections than IBD patients not receiving immunomodulatory therapy.

Fungal infections diagnosis - Past, present and future

Despite the scientific advances observed in the recent decades and the emergence of new methodologies, the diagnosis of systemic fungal infections persists as a problematic issue. Fungal cultivation, the standard method that allows a proven diagnosis, has numerous disadvantages, as low sensitivity (only 50% of the patients present positive fungal cultures), and long growth time. These are factors that delay the patient's treatment and, consequently, lead to higher hospital costs. To improve the accuracy and quickness of fungal infections diagnosis, several new methodologies attempt to be implemented in clinical microbiology laboratories. Most of these innovative methods are independent of pathogen isolation, which means that the diagnosis goes from being considered proven to probable. In spite of the advantage of being culture-independent, the majority of the methods lack standardization. PCR-based methods are becoming more and more commonly used, which has earned them an important place in hospital laboratories. This can be perceived now, as PCR-based methodologies have proved to be an essential tool fighting against the COVID-19 pandemic. This review aims to go through the main steps of the diagnosis for systemic fungal infection, from diagnostic classifications, through methodologies considered as "gold standard", to the molecular methods currently used, and finally mentioning some of the more futuristic approaches.

The burden of serious fungal infections in Azerbaijan

Background:

Azerbaijan is an upper middle-income country in South Caucasus with an area of 86,600 km² and a total population of 10 million people and gross domestic product of US $4480 per capita. The aim of this research is to estimate fungal infection burden and highlight the problem at national and international levels.

Methods:

Fungal infection burden was estimated using data from epidemiological papers and population at risk and LIFE (Leading International Fungal Education) modelling.

Results:

The number of people living with human immunodeficiency virus (PLHIV) in 2018 was 6193, 29% of them not receiving antiretroviral therapy. Based on 90% and 20% rates of oral and oesophageal candidiasis in patients with CD4 cell count <200 µl^–1 we estimate 808 and 579 patients with oral and oesophageal candidiasis, respectively. The annual incidences of cryptococcal meningitis and Pneumocystis pneumonia are 5 and 55 cases, respectively. We estimated 2307 cases of chronic pulmonary aspergillosis (CPA), 4927 patients with allergic bronchopulmonary aspergillosis (ABPA), and 6504 with severe asthma with fungal sensitization (SAFS). Using data on chronic obstructive pulmonary diseases (COPD), lung cancer, acute myeloid leukaemia rates, and number of transplantations, we estimated 693 cases of invasive aspergillosis following these conditions. Using a low-European rate for invasive candidiasis, we estimated 499 and 75 patients with candidemia and intra-abdominal candidiasis respectively. The number of adult women (15–55 years) in Azerbaijan is ~2,658,000, so it was estimated that 159,490 women suffer from recurrent vulvovaginal candidiasis (rVVC).

Discussion:

In total, the estimated number of people suffering from fungal diseases in Azerbaijan is 225,974 (2.3% of the population). However, the fungal rate is underestimated due to lack of epidemiological data. The most imminent need is improvement in diagnostic capabilities. This aim should be achieved via establishing a reference laboratory and equipping major clinical centers with essential diagnostics assays.

High Biofilm Formation of Non-Smooth Candida parapsilosis Correlates with Increased Incorporation of GPI-Modified Wall Adhesins

Candida parapsilosis is among the most frequent causes of candidiasis. Clinical isolates of this species show large variations in colony morphotype, ranging from round and smooth to a variety of non-smooth irregular colony shapes. A non-smooth appearance is related to increased formation of pseudohyphae, higher capacity to form biofilms on abiotic surfaces, and invading agar. Here, we present a comprehensive study of the cell wall proteome of C. parapsilosis reference strain CDC317 and seven clinical isolates under planktonic and sessile conditions. This analysis resulted in the identification of 40 wall proteins, most of them homologs of known Candida albicans cell wall proteins, such as Gas, Crh, Bgl2, Cht2, Ecm33, Sap, Sod, Plb, Pir, Pga30, Pga59, and adhesin family members. Comparative analysis of exponentially growing and stationary phase planktonic cultures of CDC317 at 30 °C and 37 °C revealed only minor variations. However, comparison of smooth isolates to non-smooth isolates with high biofilm formation capacity showed an increase in abundance and diversity of putative wall adhesins from Als, Iff/Hyr, and Hwp families in the latter. This difference depended more strongly on strain phenotype than on the growth conditions, as it was observed in planktonic as well as biofilm cells. Thus, in the set of isolates analyzed, the high biofilm formation capacity of non-smooth C. parapsilosis isolates with elongated cellular phenotypes correlates with the increased surface expression of putative wall adhesins in accordance with their proposed cellular function.

Evaluation of divergent yeast genera for fermentation-associated stresses and identification of a robust sugarcane distillery waste isolate Saccharomyces cerevisiae NGY10 for lignocellulosic ethanol production in SHF and SSF

BACKGROUND

Lignocellulosic hydrolysates contain a mixture of hexose (C6)/pentose (C5) sugars and pretreatment-generated inhibitors (furans, weak acids and phenolics). Therefore, robust yeast isolates with characteristics of C6/C5 fermentation and tolerance to pretreatment-derived inhibitors are pre-requisite for efficient lignocellulosic material based biorefineries. Moreover, use of thermotolerant yeast isolates will further reduce cooling cost, contamination during fermentation, and required for developing simultaneous saccharification and fermentation (SSF), simultaneous saccharification and co-fermentation (SScF), and consolidated bio-processing (CBP) strategies.

RESULTS

In this study, we evaluated thirty-five yeast isolates (belonging to six genera including Saccharomyces, Kluyveromyces, Candida, Scheffersomyces, Ogatea and Wickerhamomyces) for pretreatment-generated inhibitors {furfural, 5-hydroxymethyl furfural (5-HMF) and acetic acid} and thermotolerant phenotypes along with the fermentation performances at 40 °C. Among them, a sugarcane distillery waste isolate, Saccharomyces cerevisiae NGY10 produced maximum 49.77 ± 0.34 g/l and 46.81 ± 21.98 g/l ethanol with the efficiency of 97.39% and 93.54% at 30 °C and 40 °C, respectively, in 24 h using glucose as a carbon source. Furthermore, isolate NGY10 produced 12.25 ± 0.09 g/l and 7.18 ± 0.14 g/l of ethanol with 92.81% and 91.58% efficiency via SHF, and 30.22 g/l and 25.77 g/l ethanol with 86.43% and 73.29% efficiency via SSF using acid- and alkali-pretreated rice straw as carbon sources, respectively, at 40 °C. In addition, isolate NGY10 also produced 92.31 ± 3.39 g/l (11.7% v/v) and 33.66 ± 1.04 g/l (4.26% v/v) ethanol at 40 °C with the yields of 81.49% and 73.87% in the presence of 30% w/v glucose or 4× concentrated acid-pretreated rice straw hydrolysate, respectively. Moreover, isolate NGY10 displayed furfural- (1.5 g/l), 5-HMF (3.0 g/l), acetic acid- (0.2% v/v) and ethanol-(10.0% v/v) tolerant phenotypes.

CONCLUSION

A sugarcane distillery waste isolate NGY10 demonstrated high potential for ethanol production, C5 metabolic engineering and developing strategies for SSF, SScF and CBP.

Oral Candida colonization in patients with chronic periodontitis. Is there any relationship?

BACKGROUND

Candida can be implicated in the pathology of chronic periodontitis.

AIMS

To analyze the oral Candida carriage in patients suffering from chronic periodontitis (CP) and its correlation with the severity of this condition.

METHODS

Microbiological samples were taken from 155 patients using the oral rinse (OR) technique and by using paper points in the periodontal pockets (GPP). These patients were divided into 3 groups: 89 patients without CP (control), 47 with moderate CP, and 19 with severe CP. Samples were cultured in a Candida chromogenic agar for Candida. Species were identified by microbiological and molecular methods.

RESULTS

Candida was isolated in the OR of 45 (50.6%), 21 (44.7%), and 11 (57.9%) patients, respectively, and in the GPP of 32 (36%), 14 (29.2%), and 10 (42.6%) patients from the control, moderate CP and severe CP groups, respectively. Candida was isolated more frequently and in a greater burden in OR than in GPP (p<0.01). Candida albicans was the most prevalent species. GPP of patients with CP had poor fungal biodiversity (p<0.01).

CONCLUSIONS

Colonization by Candida was present in the samples of patients without CP, and with both moderate and severe CP. Nonetheless, patients with severe CP had a higher rate of Candida colonization, especially by C. albicans.

Prevalence of vulvovaginal candidiasis in pregnancy at three health centers in Burkina Faso

INTRODUCTION

Pregnant women are more susceptible to vaginal colonization and infection by yeast. The role of Candida colonization in the occurrence of preterm birth is well established. The knowledge of local epidemiology and identification of risk factors for preterm birth is important for the prevention and management strategies. The purpose of the study was to determine the prevalence of Candida sp. in vaginal swabs of pregnant women.

METHODS

Pregnant women attending routine antenatal visits in three primary health centres in Bobo-Dioulasso (Burkina Faso) were enrolled into a cross-sectional study carried out from February to April 2015. Vaginal swabs samples were taken from participants after obtaining oral consent. The swabs were inoculated into Sabouraud's glucose agar supplemented with chloramphenicol and incubated at 37°C for 24 to 48hours under aerobic conditions in order to perform fungal culture. The identification of the Candida species was done by culture on HiCrome Candida Differential Agar at 35°C for 48h for production of species-specific colors.

RESULTS

A total of 229 pregnant women were included. The prevalence of vulvovaginal candidiasis (VVC) was 22.71%, (95% CI [17.45-28.69]). Candida albicans accounted for 40.39% and non-Candida albicans species for 59.61% of the isolates, with mainly C. glabrata (32.69%), C. tropicalis (15.38%) and C. krusei (11.54%).

CONCLUSIONS

This study revealed a high prevalence of non-C. albicans species. The syndromic management guidelines for VVC in Burkina Faso will be revised to include a specific protocol for pregnant women.

In Vitro Antifungal Susceptibility of Oral Candida Isolates from Patients Suffering from Caries and Chronic Periodontitis

Caries and chronic periodontitis are common oral diseases where a higher Candida colonization is reported. Antifungal agents could be adjuvant drugs for the therapy of both clinical conditions. The aim of the current study has been to evaluate the in vitro activities of conventional and new antifungal drugs against oral Candida isolates from patients suffering from caries and/or chronic periodontitis. In vitro activities of amphotericin B, fluconazole, itraconazole, miconazole, nystatin, posaconazole and voriconazole against 126 oral Candida isolates (75 Candida albicans, 18 Candida parapsilosis, 11 Candida dubliniensis, six Candida guilliermondii, five Candida lipolytica, five Candida glabrata, four Candida tropicalis and two Candida krusei) from 61 patients were tested by the CLSI M27-A3 method. Most antifungal drugs were highly active, and resistance was observed in less than 5% of tested isolates. Miconazole was the most active antifungal drug, being more than 98% of isolates susceptible. Fluconazole, itraconazole, and the new triazoles, posaconazole and voriconazole, were also very active. Miconazole, fluconazole and voriconazole have excellent in vitro activities against all Candida isolates and could represent suitable treatment for a hypothetically adjunctive therapy of caries and chronic periodontitis.

Usefulness of CHROMagar Candida Medium, Biochemical Methods--API ID32C and VITEK 2 Compact and Two MALDI-TOF MS Systems for Candida spp. Identification

This study was conducted to compare of the yeasts identification results obtained with two new systems using the MALDI-TOF MS technique with the ones obtained using the routine identification methods of Candida spp. in clinical microbiology laboratories. All 124 Candida spp. isolates were recovered from the routine examination of clinical specimens in microbiological laboratories and collected in the Centre of Quality Control in Microbiology in Warsaw (Poland). Our findings confirm the high agreement (98%) of fungal identification using the standard, biochemistry laboratory methods and mass spectrometry technique.