Rapid detection of Candida species in bronchoalveolar lavage fluid from patients with pulmonary symptoms

Identification and assessment of antifungal susceptibility of Candida species based on bronchoalveolar lavage in immunocompromised and critically ill patients

Background and Objectives

The presence of fungi in the respiratory tract as mycobiome, particularly Candida species (spp.), remains a serious problem due to increasing numbers of immunocompromised patients. The confirmed reliable existence of these pathogens due to frequent colonization is essential. This investigation aimed to recognize Candida spp. among isolates from bronchoalveolar lavage of immunocompromised and critically ill patients and to evaluate their susceptibility to antimycotic drugs.

Materials and Methods

Bronchoalveolar lavage fluid was collected from 161 hospitalized patients presenting with suspected respiratory fungal infection /colonization. The specimens were examined by standard molecular and mycological assays. Candida spp. were recognized with sequence assessment of the D1-D2 section of the large subunit ribosomal DNA. The susceptibility of Candida isolates to common antimycotic drugs was distinguished by standard broth microdilution.

Results

Seventy-one clinical isolates of Candida spp. were recognized. Candida albicans was the most frequent, followed by C. glabrata, C. krusei (Pichia kudriavzevii), C. dubliniensis, C. parapsilosis, and C. tropicalis. We found 5.1% of C. albicans isolates and 8% of C. glabrata isolates to show resistance to fluconazole. The whole of the Candida spp. were sensitive to amphotericin B and caspofungin.

Conclusion

This study demonstrated that C. albicans and C. glabrata are the most common isolates of bronchoalveolar lavage fluid in patients, and the drug susceptibility screening confirmed that amphotericin B and caspofungin are effective against Candida spp. but some C. glabrata and C. albicans isolates showed resistance to fluconazole.

Antifungal activity of three different varieties of Capsicum annuum against clinical isolates of Candida species

OBJECTIVE

Acquired resistance to antifungal agents is rising among Candida species. Herbal extracts including Capsicum annum extracts have biological profits, which can be employed to overcome drug resistance in fungal species. The present study investigated the efficacy of different varieties of C. annum extracts against Candida species.

METHODS

Aqueous and alcoholic extracts of three different varieties of C. annum were prepared using the succulent method. Total values for compound extracts of C. annum var. cayenne, C. annum var. cayenne cultivar sabzevari, and C. annum var. cerasiforme were 43, 42, and 38 g, respectively. The clinical Candida isolates including C. albicans (n = 13), C. dubliniensis (n = 2), C. parapsilosis (n = 2), and C. tropicalis (n = 1); and reference strains of C. albicans (TIMML 1292 and TIMML 183), C. krusei (TIMML 1321), C. parapsilosis (TIMML 2201), and C. tropicalis (TIMML 731) were examined based on the M27-A3 guideline.

RESULTS

Aqueous and alcoholic extracts of Capsicum annum showed a minimum inhibitory concentration (MIC) range of more than 512 µg/ml against clinical and reference strains of Candida. There was no justifiable difference between the effects of these extracts on Candida species.

CONCLUSION

Both aqueous and alcoholic extracts of Capsicum annum could not exert a significant effective impact on clinical and reference strains of Candida. The difference in pepper spiciness did not show a significant role against Candida isolates. However, their possible effects might be different among other yeasts or filamentous fungi.

Diagnostic Value of Metagenomic Next-Generation Sequencing for Multi-Pathogenic Pneumonia in HIV-Infected Patients

Background

To evaluate the value and challenges of real-world clinical application of metagenomic next-generation sequencing (mNGS) for bronchoalveolar lavage fluid (BALF) in HIV-infected patients with suspected multi-pathogenic pneumonia.

Methods

Fifty-seven HIV-infected patients with suspected mixed pneumonia who were agreed to undergo the bronchoscopy were recruited and retrospectively reviewed the results of mNGS and conventional microbiological tests (CMTs) of BALF from July 2020 to June 2022.

Results

54 patients were diagnosed with pneumonia including 49 patients with definite pathogens and five patients with probable pathogens. mNGS exhibited a higher diagnostic accuracy for fungal detection than CMTs in HIV-infected patients with suspected pulmonary infection. The sensitivity of mNGS in diagnosis of pneumonia in HIV-infected patients was much higher than that of CMTs (79.6% vs 61.1%; P < 0.05). Patients with mixed infection had lower CD4 T-cell count and higher symptom duration before admitting to the hospital than those with single infection. The detection rate of mNGS for mixed infection was significantly higher than that of CMTs and more co-pathogens could be identified by mNGS. The most common pattern of mixed infection observed was fungi-virus (11/29, 37.9%), followed by fungi-virus-bacteria (6/29, 20.7%) coinfection in HIV-infected patients with multi-pathogenic pneumonia.

Conclusion

mNGS improved the pathogens detection rate and exhibited advantages in identifying multi-pathogenic pneumonia in HIV-infected patients. Early performance of bronchoscopy and mNGS are recommended in HIV-infected patients with low CD4 T cell counts and long duration of symptoms. The most common pattern of mixed infection observed was fungi-virus, followed by fungi-virus-bacteria coinfection in HIV infected patients with multi-pathogenic pneumonia.

Time to Positivity Facilitates an Early Differential Diagnosis of Candida tropicalis from Other Candida species

Background

Candidemia caused by Candida tropicalis has more serious adverse consequences and an even higher mortality. Time to positivity (TTP) has been widely used to identify microbial species, resistant microorganisms and distinguish real pathogens and pollutants. However, few studies have demonstrated TTP as a presumptive diagnosis of C. tropicalis in patients with candidemia.

Patients and Methods

A retrospective study of 136 episodes of candidemia and simulated blood cultures with 314 episodes of confirmed Candida strains were applied to explore the role of TTPs in diagnosing C. tropicalis. TTPs were recorded as the shorter one if both aerobic and anaerobic vials were positive. Lastly, relationships were tested between TTPs and resistance and initial inocula concentration.

Results

For the retrospective study, the mean of TTPs for C. tropicalis from 136 patients with candidemia was significantly shorter than other Candida species. The area under the receiver operating characteristics (ROC) curve was 0.8896 ± 0.030 with a sensitivity of 92.86% and a specificity of 77.87%, respectively, indicating TTPs with a cut-off value of <25.50 h had a strong diagnostic power for C. tropicalis in patients with candidemia. Moreover, TTPs from 314 simulated blood cultures showed similar results as the retrospective study, demonstrating TTP is a powerful diagnostic tool in early diagnosing C. tropicalis in patients with candidemia. Additionally, our results showed no statistical significance between TTPs and initial inocula concentration and resistance of Candida species, suggesting initial inocula concentration does not impact TTPs, and TTPs may not be promising in predicting the resistance of all Candida species.

Conclusion

TTP can be employed to early distinguish C. tropicalis from other Candida species in patients with candidemia, which is extremely helpful to initiate empiric antifungal treatments to improve clinical outcomes.

Recombinant polymerase amplification combined with lateral flow strips for the detection of deep-seated Candida krusei infections

The incidence of Candida infections in intensive care units (ICU) has significantly increased in recent years, and these infections have become one of the most serious complications threatening the lives of ICU patients. The proportion of non-Candida albicans infections, such as Candida krusei and Candida glabrata infections, which are resistant to fluconazole, is increasing each year. Early identification of the strains causing Candida infections is important for the timely implementation of targeted treatments to save patients’ lives. However, the current methods of direct microscopy, culture, and histopathology, as well as other diagnostic methods, have many shortcomings, such as their low sensitivity and long assay times; therefore, they cannot meet the needs for early clinical diagnosis. Recombinant polymerase amplification (RPA) is a promising isothermal amplification technique that can be performed without sophisticated instruments and equipment, and is suitable for use in resource-poor areas. RPA combined with lateral flow strips (LFS) can be used to rapidly amplify and visualize target genes within 20 min. In this study, RPA-LFS was used to amplify the internal transcribed spacer 2 (ITS2) region of C. krusei. The primer-probe design was optimized by introduction of base mismatches (probe modification of five bases) to obtain a specific and sensitive primer-probe combination for the detection of clinical specimens. Thirty-five common clinical pathogens were tested with RPA-LFS to determine the specificity of the detection system. The RPA-LFS system specifically detected C. krusei without cross-reaction with other fungi or bacteria. A gradient dilution of the template was tested to explore the lower limit of detection and sensitivity of the assay. The sensitivity was 10 CFU/50 µL per reaction, without interference from genomic DNA of other species. The RPA-LFS and qPCR assays were performed on 189 clinical specimens to evaluate the detection performance of the RPA-LFS system. Seventy-six specimens were identified as C. krusei, indicating a detection rate of 40.2%. The results were consistent with those of qPCR and conventional culture methods. The RPA-LFS system established in our study provides a reliable molecular diagnostic method for the detection of C. krusei, thus meeting the urgent need for rapid, specific, sensitive, and portable clinical field testing.

The role of IL-15 on vulvovaginal candidiasis in mice and related adverse pregnancy outcomes

Vulvovaginal candidiasis (VVC), a major gynecological disease with high recurrence rate, increases the risk of abortion, intrauterine infection, premature rupture of membranes, and premature birth in pregnancy. However, the exact pathogenesis of this disease has yet to be elucidated. To facilitate understanding of the pathogenesis of VVC in pregnancy, this study sought to establish an animal model of vaginal infection with Candida albicans in pregnant mice. Female mice were mated with male mice, and female mice were infected with C. albicans at E4.5 (embryonic day 4.5). The weight and abortion rate of pregnant mice at E0.5, E4.5, E8.5, E11.5, and E18.5 were recorded, respectively, as well as the weights of fetus and placenta on E18.5. Fetal weight at E18.5 and the weight growth rate in the experimental mice was lower than those in the control mice, but the placenta weight at E18.5 and the abortion rate in the experimental mice were increased with those of the control mice. Hematoxylin-eosin (H&E) staining, Gomori-Grocott staining and vaginal lavage culturing were conducted to verify that the experimental mice were infected with C. albicans. Differentially expressed gene IL-15 was screened out by polymerase chain reaction (PCR) array between the two groups. Enzyme-linked immunosorbent assay (ELISA) showed that IL-15 expression in plasma of the mice was decreased in the experimental group compared with the control group. RT-qPCR confirmed that IL-15 mRNA expression was increased in placental tissues, while mRNA expression of IL-15R/JAK1-JAK3/PI3K/PDK1/AKT/P70S6K-mTOR was decreased in placental tissues. In conclusion, this study demonstrated that VVC in BALB/c pregnant mice led to a series of adverse pregnancy outcomes that were related to changes in IL-15 and its downstream signaling pathways, which may indicate a potential therapy for VVC during pregnancy in humans.

Deep Fungal Infections Among General Hospital Inpatients in Southwestern China: A 5-Year Retrospective Study

Background

Deep fungal infection is a type of life-threatening opportunistic infection. Its incidence has been increasing in recent years. This infection can affect the prognosis of patients, prolong hospital stays and raise costs for patients and their families.

Objective

We aimed to understand the current situation of deep fungal infections in the First Affiliated Hospital of Kunming Medical University and to provide a basis for the clinical diagnosis and treatment of deep fungal infections.

Methods

This was a retrospective analysis of 528,743 cases in the hospital from 2015 to 2019, including the epidemiological characteristics, treatment and prognosis of deep fungal infections.

Results

A total of 274 cases (0.05%) with deep fungal infections were identified, accounting for 0.05% of the total number of hospitalizations. The incidence of deep fungal infections in the hospital showed an increasing trend from 2015 to 2019. The most commonly infected site was the respiratory tract (93.07%). Among patients with deep fungal infections, 266 specimens were positive for fungal culture, by which 161 cultured Candida albicans (C. albicans), accounting for 60.53%, the main pathogen causing deep fungal infection. From 2015 to 2019, the percentage of C. albicans cases showed a downward trend, while that of non-C. albicans showed an opposite trend. Antibiotics were the most common predisposing factor for deep fungal infections (97.45%). Among the underlying diseases of patients with deep fungal infections, infectious diseases (59.49%) were the most common. Those with underlying diseases such as renal insufficiency and neurological diseases had a worse prognosis. Indwelling catheters, nervous system disease and tumors were risk factors for a poor prognosis.

Conclusions

We report for the first time the epidemiological data of deep fungal infections in a general hospital in southwestern China from 2015 to 2019. In the past 5 years, the number of patients with deep fungal infections in the First Affiliated Hospital of Kunming Medical University has been increasing. Although the clinical data are limited, these results can provide references for the diagnosis and treatment of deep fungal infections.

Allergic bronchopulmonary candidiasis: A review of the literature and a case report

Background

Allergic bronchopulmonary candidiasis (ABPC) is an uncommon clinical syndrome associated with immune hypersensitivity to Candida species.

Case presentation

The case presentation describes a 58-year-old man with acute respiratory failure and bilateral lung infiltrates. Due to high inflammatory markers and a chest X-ray indicating lung infiltration, he was initially treated for pneumonia with combined antibiotics. Despite comprehensive treatment at the ICU, the patient’s clinical status deteriorated rapidly, and further investigations provided a rare diagnosis of ABPC. After several days of combined corticosteroid and antifungal therapy, we observed rapid clinical improvement and subsequent resolution of the pulmonary infiltrates.

Conclusion

This case report presented a rare case of ABPC mimicking bilateral pneumonia and acute respiratory failure. Our case highlighted the importance of prompt corticosteroid and antifungal treatment initiation as it resulted in rapid clinical improvement and a near complete reversal of the bilateral lung infiltrates.

Pneumocystis Jirovecii Pneumonia Diagnosis via Metagenomic Next-Generation Sequencing

The incidence of non-HIV-infected Pneumocystis Jirovecii Pneumonia (PJP) is increasing. The prognosis for non-HIV PJP is poor and diagnostic tests are of lower sensitivity in non-HIV patients. Metagenomic next-generation sequencing (mNGS) was compared with routine detection assays, including Gomori methenamine silver (GMS) stain and polymerase chain reaction (PCR) technique. Specimens of 4 bronchoalveolar lavages (BAL) and 1 lung tissue samples were obtained from 4 non-HIV patients from our hospitals. Although both GMS and mNGS were positive for P. jirovecii with PCR as positive control, the testing time of mNGS was obviously shorter than GMS. Compared with the traditional GMS method, mNGS has absolute advantages. However, the issue with PJP presentations having atypical symptoms and ambiguous imaging features persists. Hence, the disease can easily be ignored. Secondly, PJP progresses rapidly in non-HIV-infected patients and can cause severe respiratory failure with unfavorable prognosis. This study affirms that mNGS can be used to quickly and accurately diagnose PJP, but a combination of clinical judgement of symptoms, laboratory testing, and imaging examination is required to make a comprehensive judgment along with mNGS test results.

Antifungal Activity of Curcuminoids and Difluorinated Curcumin Against Clinical Isolates of Candida Species

BACKGROUND

Acquired resistance to antifungals is rising particularly among Candida species. Herbal ingredients have biological and pharmacological activities, which make them potential fungicidal agents. The present study investigated the effects of curcumin (CUR) and difluorinated curcumin (CDF) on Candida species.

MATERIAL AND METHOD

CUR and CDF were examined against Candida isolates obtained from patients candidemia due to C. albicans (n = 13), C. dubliniensis (n = 2), C. parapsilosis (n = 2), and C. tropicalis (n = 1); and laboratory strains of C. albicans (TIMML 1292 and TIMML 183), C. krusei (TIMML 1321), C. parapsilosis (TIMML 2201), and C. tropicalis (TIMML 731) based on the M27-A3 guideline.

RESULTS

At the concentrations of 1-512μg/mL, none of the CDF and CUR showed a significant minimum inhibitory concentration (MIC) range against Candida isolates. There was no significant difference between the effects of CUR and CDF against Candida species.

CONCLUSION

The CUR and CDF did not exert any inhibitory effect on the growth of Candida strains. Any possible effect on other yeast and filamentous fungi needs to be further investigated.

Expression of anti-fungal peptide, β-defensin 118 in oral fibroblasts induced by C. albicans β-glucan-containing particles

Objective:

Methodology:

Results:

Conclusion:

Case Report: Next-Generation Sequencing in Diagnosis of Pneumonia Due to Pneumocystis jirovecii and Cytomegalovirus in a Patient With HIV Infection

Background: Pulmonary infections remain a significant cause of morbidity and mortality in immunocompromised patients. The pathogens spectrum of pulmonary infection that can affect patients with human immunodeficiency virus (HIV) is wide such as bacterial, fungal, viral, parasitic organisms, and so on. The risk of multi-pathogenic pneumonia is higher in HIV-infected patients. However, the fast and accurate diagnosis of multi-pathogenic pneumonia is challenging because of the limitations of current conventional tests. Case Presentation: Here, we report a case of pneumonia due to Pneumocystis jirovecii and cytomegalovirus (CMV) in a 22-year-old male with newly diagnosed HIV infection. Blood tests revealed a low CD4 count, a chest computed tomography (CT) scan showed extensive ground-glass opacities in the bilateral lung with multiple cavity lesions in the left upper lung. Microscopic examination of stained sputum and bronchoalveolar lavage fluid (BALF) smear specimens did not find any pathogens. There was also no evidence of pathogens known to cause pneumonia in bacteria and fungi culture tests and virus antibodies such as EBV, CMV, and COVID-19. The nucleic acid of CMV in blood was reported by quantitative PCR. Next-generation sequencing (NGS) analysis of BALF specimens identified a large number of P. jirovecii and CMV reads, and confirmed the diagnosis of pneumonia due to P. jirovecii and CMV. Following the patient's treatment with anti-PCP and anti-CMV, the patient was cured and discharged. Conclusions: This case highlights the combined application of NGS in the clinical diagnosis of multi-pathogenic pneumonia in an HIV-infected patient. NGS is proposed as an important adjunctive diagnostic approach for identifying pathogens of multi-pathogenic pneumonia in HIV-infected patients.

The Effects of Different Fungi on the IL-1β Expression in Mouse Dendritic Cells

Background: Invasive fungal infection received more and more attention because of its high mortality, Candida albicans and Aspergillus fumigatus is the most common pathogenic fungus for systematic fungal infection, A. lentulus was isolated and identified recently and named as a sister of A. fumigatus. Objectives: The current study aimed to explore the concentration and time-dependent relationships of the virulence of fungi due to the change in the Interleukin-1 beta (IL-1β) level. Methods: Candida albicans, A. fumigatus, and A. lentulus suspensions with a multiplicity of infection = 0, 1, 5, 10, and 20 units were used to treat mouse dendritic cells. The IL-β level was measured by enzyme-linked immunosorbent assay (ELISA) at 2, 6, 12, 24, and 48 hours after the treatment was administered. Results: The main effects and interactions between the multiplicity of infection, intervention duration, and the dependent variable of IL-1β were significant. Besides, there were statistically significant differences. Only C. albicans and A. lentulus could induce IL-1β 48 hours after administration. Furthermore, the production of IL-1β induced by A. fumigatus was higher than that induced by A. lentulus and C. albicans. Conclusions: This study demonstrated concentration- and time-dependent relationships in IL-1β production by dendritic cells induced by three types of fungi. Candida albicans and A. lentulus exhibited a slow phase-in in vitro inflammation induction. The inflammatory response induced by A. fumigatusin vitro has the characteristics of a short action time and a strong toxic effect. Finally, A. lentulus is less virulent than A. fumigatus, and its inflammation-inducing time is relatively longer.

Aspartyl Proteinase and Phospholipase Activities of Candida albicans Isolated From Oropharyngeal Candidiasis in Head and Neck Cancer Patients

Background: Candida albicans is one of the most important members of the human normal flora that can cause opportunistic fungal infections. Hydrolytic enzymes are one of the main virulence factors in the pathogenesis of Candida species. Objectives: This study was carried out to determine proteolytic activities, and their related gene expressions in C. albicans isolates obtained from oropharyngeal candidiasis in head and neck cancer patients. Methods: Thirty-two C. albicans clinical isolates were included in this study. Secreted aspartyl protease and phospholipase activities were analyzed by appropriate agar media and precipitation zones. The expression levels of SAP1, 3 and PLB1, 2 genes were evaluated by real-time PCR. Results: All the 32 isolates exhibited proteinase activity while 28 of them showed phospholipase activity. All the strains possessed all SAPs genes; however, PLBs genes were not expressed in four isolates. Conclusions: Our findings demonstrated that the clinical strains of C. albicans had strong proteolytic activity and high expression levels of the pertaining genes.

Antifungal Susceptibility of Non-albicans Candida Species in A Tertiary Care Hospital, Bulgaria

Background: Emerging non-albicans Candida (NAC) species are a major threat because of their intrinsic or acquired resistance to routinely applied antifungal agents. Objectives: The purpose of our study was to reveal in vitro activity of nine antifungal agents against NAC isolates. Methods: A total of 67 NAC (27 Candida glabrata, 10 C. tropicalis, 6 C. krusei, 6 C. parapsilosis, 4 C. lusitaniae, 4 C. lipolytica, etc.) were identified and tested. The antifungal susceptibility was estimated on the basis of minimum inhibitory concentrations (MIC). Results: Overall, 13 species were determined, of which C. glabrata was the most common (40.3%), followed by C. tropicalis (14.9%), C. krusei, and C. parapsilosis (8.9 % each). Forty-nine NAC isolates (73.13%) demonstrated decreased susceptibility to one or more antifungals, and 18 of them were resistant to all azoles. Out of 27 C. glabrata, 12 (44.4%) were resistant to fluconazole with MICs: 32 - >128 µg/mL and 15 (55.6%) were intermediate with MICs: 8 - 16 µg/mL Non-albicans Candida revealed a good susceptibility to echinocandins. Amphotericin B resistance was found in 5.97% of the isolates. Of particular interest was the detection of 6 (8.95%) multidrug-resistant NAC, which expressed resistance to azoles and echinocandins and/or amphotericin B. Conclusions: About one-fourth of the studied NAC were resistant to all azoles. These findings as well as the detection of several multidrug-resistant isolates determine the necessity of susceptibility testing of clinically important yeast isolates and control of the antifungal drugs in our hospital.

Genotyping of Candida albicans Strains Obtained from Oropharyngeal Candidiasis Patients Based on ABC and RPS Typing Systems

Background: Candida albicanss has been introduced as one of the most common causes of nosocomial infections. Molecular typing methods are powerful tools in epidemiology to investigate the infection source of candidiasis, identify the transmission routes, and control the measures. Objectives: This study aimed for genotyping C. albicans species isolated from oral cavities of the non-HIV patients who suffer from oropharyngeal candidiasis via combined ABC and repeat sequences (RPS) typing systems. Methods: In this study, 31 DNA samples of clinical isolates of C. albicans were evaluated in terms of 25s ribosomal DNA region sequence or ABC typing, and ALT repeats numbers within RPS. DNA was amplified in two separate reactions, and the PCR products were electrophoresed to identify the genotypes of the isolates. Based on the band's pattern, phylogenetic analysis was conducted by UPGMA, and the discriminatory power of ABC and RPS typing was measured by Simpson’s index of diversity. Results: Genotype A with (14 isolates, 45.2%) were the most frequent and followed by genotype B (10 isolates, 32.3%) and Genotype C (7 isolates, 22.6%), respectively. In addition, genotype 3 with 25 isolates (80.6%) were the most prevalent, followed by genotype 2/3 (4 isolates, 12.9%) and genotype 3/4 (2 isolates, 6.5%) respectively. No significant relationship was found between the obtained genotypes and drug-resistant isolates (P < 0.05). Conclusions: This study showed that 25s rDNA and RPS typing is a quick, simple, and cost-effective method with average discriminatory power and good reproducibility for C. albicans genotyping. It can be used for the epidemiology of C. albicans infections.

Low prevalence of antifungal resistant Candida africana, in the C. albicans complex causing vulvovaginal candidiasis

The Candida (C.) albicans complex includes C. albicans, C. dubliniensis, C. stellatoidea, and C. africana, with the last mentioned as an important emerging agent of vulvovaginal candidiasis (VVC). The aim of the study was to identify C. africana and C. dubliniensis and assess their drug susceptibility in vaginitis. One-hundred Candida isolates of the C. albicans complex from women diagnosed with vaginitis and from vaginal samples in the culture collection of a medical mycology laboratory were examined. Species of the C. albicans complex were identified with conventional and molecular methods using polymerase chain reaction (PCR) for amplification and sequencing of the internal transcribed spacer (ITS) region, PCR for partial amplification of hyphal wall protein 1 (HWP1) gene and duplex PCR. The effects of antifungal drugs were evaluated according to standard broth microdilution protocols.

Ninety-seven C. albicans (97%) and three C. africana (3%) isolates were identified. Results of susceptibility testing revealed one isolate of C. africana to be resistant to both clotrimazole and fluconazole, and one showed reduced susceptibility to itraconazole.

Identification of Candida species especially C. africana in vaginitis is crucial, there are varying levels of resistance to antifungal drugs.

Recurrent Vulvovaginal Candidiasis: The Causative Agents, Clinical Signs and Susceptibility to Fluconazole in Gonabad City, Northeast Iran

Background:

Recurrent vulvovaginal candidiasis (RVVC) is the second most common cause of genital tract infection in females. Excessive use of fluconazole and other azoles is likely to cause the emergence of the resistant species of Candida.

Objective :

The purpose of this research was to identify Candida isolates from RVVC and the antifungal effect of fluconazole against them.

Methods :

In this study, 152 patients with vulvovaginal candidiasis were evaluated for the RVVC form. The Candida isolates were purified using CHROMagar Candida and identified based on the nuclear ribosomal internal transcribed spacer (ITS1-ITS2 rDNA) sequence analysis by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The antifungal susceptibility of C. albicans isolates against fluconazole was determined according to document M27-A3.

Results:

Out of 152 patients, 20 cases (13.2%) were identified as recurrent form. The frequencies of the Candida species among the patients with RVVC were C. albicans (n = 16, 80%), C. parapsilosis (n = 3, 15%) and C. tropicalis (n = 1, 5%). The most common clinical sign was vaginal discharge (60%). The mean minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of fluconazole against Candida isolates were 32 µg/mL and 64 µg/mL, respectively.

Conclusion:

C. albicans was the dominant cause of RVVC. The Candida isolates showed relatively high resistance to fluconazole in vitro. Vaginal discharge was the most common clinical sign among patients with RVVC.

UPLC-MS-ESI-QTOF Analysis and Antifungal Activity of the Spondias tuberosa Arruda Leaf and Root Hydroalcoholic Extracts

The aim of this study was to identify and evaluate the chemical compositions and effects of the S. tuberosa leaf and root hydroalcoholic extracts (HELST and HERST) against different strains of Candida. Chemical analysis was performed by Ultra-Performance Liquid Chromatography Coupled to Quadrupole/Time of Flight System (UPLC-MS-ESI-QTOF). The Inhibitory Concentration of 50% of the growth (IC₅₀₎ as well as the intrinsic and combined action of the extracts with the antifungal fluconazole (FCZ) were determined by the microdilution method while the minimum fungicidal concentrations (MFCs) and the effect on fungal morphological transitions were analyzed by subculture and in humid chambers, respectively. From the preliminary phytochemical analysis, the phenols and flavonoids were the most abundant. The intrinsic IC₅₀ values for HELST ranged from 5716.3 to 7805.8 µg/mL and from 6175.4 to 51070.9 µg/mL for the HERST, whereas the combination of the extracts with fluconazole presented IC₅₀ values from 2.65 to 278.41 µg/mL. The MFC of the extracts, individually, for all the tested strains was ≥16384 µg/mL. When fluconazole was combined with each extract, the MFC against CA URM 5974 was reduced (HELST: 2048 and HERST: 4096 µg/mL). Synergism was observed against standard C. albicans (CA) and C. tropicalis (CT) strains and with the root extract against the CT isolate. The leaf extract inhibited the morphological transition of all strains while the root extract inhibited only CT strains.

Identification of Candida Species from Clinical Samples in a Honduran Tertiary Hospital

Candida species are one of the most important causes of human infections, especially in hospitals and among immunocompromised patients. The correct and rapid etiological identification of yeast infections is important to provide adequate therapy, reduce mortality, and control outbreaks. In this study, Candida species were identified in patients with suspected fungal infection, and phenotypic and genotypic identification methods were compared. A total of 167 axenic fungal cultures and 46 clinical samples were analyzed by HardyCHROM^®, MicroScan^®(Omron Microscan Systems Inc, Renton, WA, USA), and PCR-RFLP (Restriction Fragment Length Polymorphisms). The species of the C. albicans complex were the most frequent, followed by C. tropicalis and C. glabrata. Less common but clinically relevant species of Candida were also isolated. The comparison between the three methods was concordant, especially for the most common Candida species. Fungal DNA amplification was successful in all clinical samples.

In vitro activities of nine antifungal agents against rare pathogenic fungi

Purpose. To assess in vitro activities of nine antifungal agents (amphotericin B, fluconazole, voriconazole, itraconazole, posaconazole, caspofungin, micafungin, terbinafine and 5-flucytosine) against 93 strains of rare pathogenic fungi and the combined effects of drug combinations against several multidrug-resistant fungi.Methodology. The broth microdilution method M38-A3 and M27-A4 from the Clinical and Laboratory Standards Institute and the checkerboard method were performed in this study.Results. Low MICs for fluconazole were observed in moulds including Tritirachium oryzae, Exophiala attenuata and yeasts. MICs for amphotericin B>2 µg ml^-1 were found among Aspergillus nidulans, Fusarium napiforme, Trichoderma longibrachiatum, Tritirachium oryzae, Cunninghamella bertholletiae, Cunninghamella phaeospora, Conidiobolus coronatus, Exophiala attenuata, Ochroconis mirabilis and Rhinocladiella basitona. Multidrug resistance was observed in Microascus spp., Lomentospora prolificans and Pythium insidiosum.Conclusion. Our study illustrated in vitro drug susceptibilities of some rare pathogenic fungi, which provide data to guide clinical treatment of fungal infections.

Kinetics of antifungal activity of home-generated ozonated water on Candida albicans

Background and Purpose:

Candida-associated denture stomatitis is one of the most common forms of oral candidiasis among denture wearers. Regarding this, the aim of the present study was to evaluate the antifungal effects of home-generated ozonated water on the adhesion of the C. albicans attached to the surface of the denture base acrylic resins.

Materials and Methods:

For the purpose of the study, different concentrations of C. albicans were added to the tubes containing acrylic resin blocks, and then incubated for 2 h at 35°C. The samples were assigned into three groups, each of which contained 42 samples, including normal saline (NS) solution as the negative control, nystatin (N) solution as the positive control, and ozonated water as the test group. The samples were washed and placed in an ultrasonic bath. Subsequently, the saline solution was cultured on Sabouraud dextrose agar. The concentrations of Candida were evaluated during the contact times.

Results:

The test group (i.e., ozonated water) with 114 colony-forming units (CFU) showed a significant reduction of Candida colonies, compared to the NS group with 2,172 CFU. The 120- and 1-minute incubation with ozonated water showed the highest and lowest effects on the viability of Candida adhered to the acrylic resin, respectively.

Conclusion:

Based on the findings, home-generated ozonated water can be applied to remove the Candida attached to the surface of the denture plates.

In Vitro Antifungal Susceptibility of Candida Species Isolated from Iranian Patients with Denture Stomatitis

Background

Candida-associated denture stomatitis (CADS) is a common fungal infection in people who wear dentures. The main objective of this study was to make molecular identification of causative agents of CADS and in vitro antifungal susceptibility testing (AFST) in the Iranian patients with denture stomatitis.

Methods

A total of 134 Candida spp. were obtained from patients with denture stomatitis. The Candida spp. were identified using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) involving the universal internal transcribed spacer (ITS1 and ITS4) primers, which were subjected to digestion with MspI and BlnI restriction enzymes. The in vitro antifungal susceptibility of Candida spp. to fluconazole (FLC), terbinafine (TRB), itraconazole (ITC), voriconazole (VRC), posaconazole (POS), ketoconazole (KET), amphotericin B (AMB), and caspofungin (CAS) was evaluated using the Clinical and Laboratory Standards Institute M27-A3 and M27-S4 guidelines.

Results

Overall, C. albicans was the most commonly isolated species (n = 84; 62.6%), followed by C. glabrata (n = 23; 17.2%), C. tropicalis (n = 16; 12%), and C. parapsilosis (n = 11; 8.2%). Posaconazole had the lowest geometric mean minimum inhibitory concentration (MIC) (0.03 μg/ml), followed by AMB (0.05 μg/ml), ITC (0.08 μg/ml), VRC (0.11 μg/ml), CAS (0.12 μg/ml), KET (0.15 μg/ml), and FLC (0.26 μg/ml).

Discussion

Our study showed that C. albicans was most prevalent in Iranian patients with CADS and was susceptible to both azoles and amphotericin B. In addition, POS could be an appropriate alternative to the current antifungal agents used for the treatment of CADS, as well as in the treatment of recurrent candidiasis.

High prevalence of candiduria due to non-albicans Candida species among diabetic patients: A matter of concern?

BACKGROUND

Among the fungal pathogens, Candida species are the most common cause of urinary tract infection (UTI). Some predisposing factors such as diabetes mellitus, urinary retention, urinary stasis, renal transplantation, and hospitalization can increase the risk of candiduria. The aim of this cross-sectional study was to evaluate candiduria among type 2 diabetic patients and identification of the Candida isolates.

METHOD

Four hundred clean-catch midstream urine specimens were obtained from patients with type 2 diabetes mellitus. The specimens were centrifuged and the sediments were examined by direct examination and cultured on Sabouraud dextrose agar. The plates were incubated for 2-3 days at 35°C. The Candida colonies were counted and purified using CHROMagar Candida. The isolates were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) system.

RESULTS

Of the 400 urine specimens, 40 (10%) had positive cultures for Candida species with a colony count of ≥1 × 10³ colony forming units (CFU)/mL. The frequencies of the Candida species were as follows: C. albicans (n = 19, 47.5%), C. glabrata (n = 15, 37.5%), C. kefyer (n = 4, 10%) and C. krusei (n = 2, 5%). Seventy-three (88%) of the patients with candiduria had hemoglobin A1c (HbA1c) levels above 7%.

CONCLUSION

The rate of candiduria was relatively high in type 2 diabetic patients and they were also suffering from a lack of proper blood glucose control. Although the frequency of non-albicans Candida species had not significantly higher than C. albicans, however, they obtained more from those with symptomatic candiduria.

Isolation of Candida Species from Gastroesophageal Lesions among Pediatrics in Isfahan, Iran: Identification and Antifungal Susceptibility Testing of Clinical Isolates by E-test

Background:

Candida species can become opportunistic pathogens causing local or systemic invasive infections. Gastroesophageal candidiasis may depend on the Candida colonization and local damage of the mucosal barrier. Risk factors are gastric acid suppression, diabetes mellitus, chronic debilitating states such as carcinomas, and the use of systemic antibiotics and corticosteroids. The aim of this study is collection and molecular identification of Candida species from gastroesophageal lesions among pediatrics in Isfahan, and determination of minimum inhibitory concentration (MIC) ranges for clinical isolates.

Materials and Methods:

A total of 200 patients underwent endoscopy (130 specimens from gastritis and 70 samples from esophagitis) were included in this study between April 2015 and November 2015. All specimens were subcultured on sabouraud dextrose agar, and genomic DNA of all strains was extracted using boiling method. Polymerase chain reaction and DNA sequencing of the ITS1-5.8SrDNA-ITS2 region were used for the identification of all Candida strains. MIC ranges were determined for itraconazole (ITC), amphotericin B (AmB), and fluconazole (FLU) by E-test.

Results:

Twenty of 200 suspected patients (10%) were positive by direct microscopy and culture. Candida albicans was the most common species (60%) followed by Candida glabrata (30%), Candida parapsilosis (5%), and Candida kefyr (5%). MIC ranges were determined for FLU (0.125–8 μg/mL), ITC (0.008–0.75 μg/mL), and AmB (0.008–0.75 μg/mL), respectively.

Conclusion:

Every colonization of Candida species should be considered as a potentially factor of mucocutaneous candidiasis and should be treated with antifungal drugs.

Isolation and molecular characterization of Cryptococcus species isolated from pigeon nests and Eucalyptus trees

Background and Purpose:

Cryptococcus species are pathogenic and non-pathogenic basidiomycete yeasts that are found widely in the environment. Based on phenotypic methods, this genus has many species; however, its taxonomy is presently being re-evaluated by modern techniques. The Cryptococcus species complex includes two sibling taxa of Cryptococcus neoformans and Cryptococcus gattii. We aimed to investigate the possible distribution of Cryptococcus species in pigeon nests and Eucalyptus trees in Ilam, Iran, using molecular techniques.

Materials and Methods:

Two hundred and seventy-four specimens were collected from pigeon nests and Eucalyptus trees during 2016-2017. All the specimens were sub-cultured on Sabouraud Glucose Agar with chloramphenicol and bird seed agar. For molecular identification, the ITS15.8SITS2 rDNA region was amplified using the first and fourth internal transcribed spacer (ITS1 and ITS4, respectively) primers. The purified products were applied for cycle sequencing reactions in forward direction with ITS1 primer. The obtained results were analyzed with Chromas 2.3.

Results:

Thirty-three out of 186 cultures (17.7%) and 11 out of 88 cultures (12.5%) were positive among pigeon nest and Eucalyptus tree specimens, respectively. Cryptococcus albidus (17.2%), C. albidus var. kuetzingii (3.4%), C. adeliensis (3.4%), C. uzbekistanensis (3.4%), and C. neoformans var. grubii (3.4%) were isolated from pigeon nests, and Cryptococcusadeliensis (25%) was the only Cryptococcus species isolated from Eucalyptus trees.

Conclusion:

The presence of pigeons and Eucalyptus trees in the vicinity of some particular places such as rest homes and hospitals should be considered as a risk factor for the immunocompromised population.

First case of superficial infection due to Naganishia albida (formerly Cryptococcus albidus) in Iran: A review of the literature

Background and Purpose:

Naganishia albida (formerly Cryptococcus albidus) is a non-neoformans cryptococcal species rarely isolated as a human pathogen.

Case report:

Herein, we present the case of a 26-year-old Iranian man with a superficial cutaneous lesion in the axilla. The initial treatment for pityriasis versicolor by clotrimazole was unsuccessful. We performed skin sampling based on the standard protocol and conducted further investigations by the conventional laboratory tests and molecular analysis of the skin samples. All the mentioned analyses revealed N.albida as the causative agent of infection. The minimum inhibitory concentration (MIC) analysis was carried out for the isolated agent, and the patient was treated using 100 mg daily of oral itraconazole.

Conclusion:

N. albida can be the causative agent of some superficial infections. This is the first report on the successful detection and treatment of a superficial skin infection due to N. albida by oral itraconazole.

The significance of Candida in the human respiratory tract: our evolving understanding

Candida is an opportunistic pathogen and the most commonly isolated fungal genus in humans. Though Candida is often detected in respiratory specimens from humans with and without lung disease, its significance remains undetermined. While historically considered a commensal organism with low virulence potential, the status of Candida as an innocent bystander has recently been called into question by both clinical observations and animal experimentation. We here review what is currently known and yet to be determined about the clinical, microbiological and pathophysiological significance of the detection of Candida spp. in the human respiratory tract.