Molecular identification and antifungal susceptibility pattern of Candida species isolated from HIV infected Patients with candisiasis

Antifungal susceptibility profile of Candida species and uncommon yeasts from drug abusers with oral candidiasis

In Iran, there is limited information regarding the species distribution and antifungal susceptibility profiles of yeast isolates from drug addicts suffering from oral candidiasis (OC). In this study, 104 yeast isolates, including 98 Candida species and 6 uncommon yeasts, were collected from 71 drug abusers with OC. The susceptibility profiles of Candida spp. and uncommon yeasts to amphotericin B (AMB), itraconazole (ITC), nystatin (NYC), fluconazole (FLC), and caspofungin (CAS) were evaluated using the CLSI broth microdilution method. The prevalence of OC in the sampled population was found to be 29%. The susceptibility profile of Candida spp. revealed remarkable sensitivity, with 100% and 99% of isolates susceptible to NYC and AMB, respectively. However, concerning levels of resistance or non-wild-type minimum inhibitory concentrations (MICs) were observed, with 13.2% of Candida isolates showing resistance to FLC, 13.2% to ITC, and 16.3% to CAS. Notably, 35.2% of patients showed mixed yeast species, while 5.1% of Candida isolates exhibited multidrug resistance. The analysis of the uncommon yeast species showed that the overall frequencies of the highest MICs were observed for CAS. Furthermore, within the six non-Candida species identified, Hanseniaspora opuntiae and one isolate of Pichia kluyveri exhibited resistance to FLC and ITC, respectively, while all non-Candida species were susceptible to AMB and NYC. Additionally, one isolate of Pichia kluyveri exhibited simultaneously high MICs to two drugs ITC and CAS. Furthermore, the Hanseniaspora opuntiae isolate showed high MICs to CAS and FLC. The findings from the present study suggest that AMB and NYC can be suitable choices for empiric treatment of both common Candida species and uncommon yeast infections in substance abuse patients.

EpiCandIn: An open online resource for epidemiology of Candida infections in India

Background & objectives Candida spp. cause candidiasis in humans under conditions disrupting the host defence. While Candida albicans is the most reported cause of candidiasis, there is a surge in the incidence of infections by non-albicans Candida species (NACs), such as C. tropicalis, C. glabrata and C. auris. These species can infect all organs of the human body. To effectively manage these outbreaks, it is important to track the epidemiology of candidiasis. A consolidated resource describing the landscape of candidiasis in India is absent. Methods To address this gap, we have developed an online resource named Epidemiology of Candida Infections in India (EpiCandIn) by manually curating published literature on Candida infections in the Indian population obtained from PubMed and ScienceDirect databases. Results EpiCandIn contains data available since 1972 from 51 sites across 16 States and four Union Territories of India. It provides information on geographical location, Candida species, niche affected, disease characteristics and drug therapy details extracted from the publications. This resource is integrated with visualization tools. Interpretation & conclusions EpiCandIn will be useful for public health researchers and policymakers as it will help them gain insights into the emerging trends and management of Candida infections in India. It can be accessed at epicandin.bicnirrh.res.in.

Marine Ascomycetes Extract Antifungal Susceptibility against Candida spp. Isolates from Oral Candidiasis HIV/AIDS Patient: An In Vitro Study

OBJECTIVE

 The etiology of oral candidiasis (OC) was Candida albicans, C. krusei, C. dubliniensis, C. tropicalis that are frequently found in human immunodeficiency virus/ acquired immunodeficiency syndrome (HIV/AIDS) patients. Marine ascomycetes (MA) have been widely reported as an important producer of various antibiotic compounds. However, there is limited study of antifungal compounds from MA against Candida species. The aim of this study was to investigate the antifungal susceptibility of MA against Candida spp. isolates from OC HIV/AIDS patient.

MATERIALS AND METHODS

 Trichoderma sp. is a sponge-associated fungus collected from Karimunjawa National Park, Central Java, Indonesia. The validation of C. albicans, C. krusei, C. dubliniensis, C. tropicalis. was done by ChromAgar. This study was true experimental with post-test only control group design; the sample was four replications for each group. Nystatin administration (K +), the golden standard antifungal drug, was used. The minimum fungicidal concentration (MFC), minimum inhibitory concentration (MIC), and diffusion zone methods were done. Analysis of variance difference test, and post-hoc Tukey's honest significant different were done to analyze the significant different between groups (p ≤ 0.05).

RESULTS

 The MFC and MIC of MA against C. albicans, C. krusei, C. dubliniensis, and C. tropicalis were found at 12.5%. In addition, the greatest diffusion zone of MA against C. albicans, C. krusei, C. dubliniensis, and C. tropicalis was found at 12.5%. There is no appreciable difference in antifungal activity between K + and 12.5% of MA extract (p ≥ 0.05).

CONCLUSION

 Concentration of 12.5% MA extract has antifungal susceptibility against Candida spp. isolates from OC HIV/AIDS patient.

Detection of Candida DNA in peritoneal fluids by PCR assay optimizing the diagnosis and treatment for intra-abdominal candidiasis in high-risk ICU patients: A prospective cohort study

Background

Intra-abdominal candidiasis (IAC) is the predominant type of invasive candidiasis with high mortality in critically ill patients. This study aimed to investigate whether the polymerase chain reaction (PCR) assay for detecting Candida DNA in peritoneal fluids (PF) is useful in diagnosing and management of IAC in high-risk patients in intensive care unit (ICU).

Methods

A prospective single-center cohort study of surgical patients at high risk for IAC was conducted in the ICU. PF was collected from the abdominal drainage tubes (within 24 h) or by percutaneous puncture. Direct PF smear microscopy, PF culture, blood culture, and serum (1-3)-β-D-glucan were performed in all patients. For Candida PCR assay, the ITS1/ITS4 primers that targeted the ITS1-5.8 s-ITS2 regions were used for PCR, and sequencing analysis was used to identify the pathogen at the species level. IAC was defined according to the 2013 European consensus criteria.

Results

Among 83 patients at high risk for IAC, the IAC criteria were present in 17 (20.5%). The sensitivity and specificity of the Candida PCR assay were 64.7 and 89.4%, respectively, and the area under the receiver operating characteristic curve was 0.77 (95% CI: 0.63-0.91). In this cohort, the positive predictive value and negative predictive value were 90.8% (95% CI: 80.3-96.2%) and 61.1% (95% CI: 36.1-81.7%), respectively. Diagnostic consistency was moderate (kappa 0.529, p < 0.001) according to the 2013 European consensus criteria.

Conclusion

Detection of Candida DNA in PF using PCR can be considered an adjunct to existing routine diagnostic tools which may optimize the diagnosis and antifungal treatment of IAC in high-risk patients in the ICU.

Extensive Diversity and Prevalent Fluconazole Resistance among Environmental Yeasts from Tropical China

Yeasts play important roles in both the environment and in human welfare. While some environmental yeasts positively contribute to nutrient cycling and food production, a significant number of yeast species are opportunistic human pathogens, including several that are tolerant/resistant to commonly used antifungal drugs. At present, most of our understanding of environmental yeasts has come from a few terrestrial environments in selected geographic regions. Relatively little is known about yeast diversity in tropical environments and their potential impacts on human health. Here, we characterize culturable yeasts in 968 environmental samples from eight regions in tropical China. Among the 516 soil, 273 freshwater, and 179 seawater samples, 71.5%, 85.7%, and 43.6% contained yeasts, respectively. A total of 984 yeast isolates were analyzed for their DNA barcode sequences and their susceptibilities to fluconazole. DNA sequence comparisons revealed that the 984 yeast isolates likely belonged to 144 species, including 106 known species and 38 putative novel species. About 38% of the 984 isolates belonged to known human pathogens and the most common species was Candida tropicalis, accounting for 21% (207/984) of all isolates. Further analyses based on multi-locus sequence typing revealed that some of these environmental C. tropicalis shared identical genotypes with clinical isolates previously reported from tropical China and elsewhere. Importantly, 374 of the 984 (38%) yeast isolates showed intermediate susceptibility or resistance to fluconazole. Our results suggest that these environmental yeasts could have significant negative impacts on human health.

Unexpected Diversity of Yeast Species in Esophageal Mycosis of Waterfowls

This study was performed to evaluate the diversity and prevalence of yeasts associated with esophageal mycosis in domestic ducks and geese. Fungi were isolated from esophageal lesions of dead animals sent for microbiologic laboratory diagnosis. Species identification using a culture-dependent method was carried out by sequencing of the internal transcribed spacer (ITS)1-5.8S rRNA-ITS2 region. The most frequently isolated yeast was Candida albicans (43.1%) followed by Saccharomyces cerevisiae (17.6%), Candida kefyr (11.7%), Kazachstania bovina (11.7%), Candida lambica (3.9%), and single isolates (1.9%) representing Candida inconspicua, Candida rugosa, Candida pelliculosa, Candida krusei, Magnusiomyces capitatus, and Trichosporon asahii. Our results indicate that a number of potentially pathogenic yeast species can be isolated from esophageal mycosis of waterfowls, but additional studies are needed to make conclusions regarding their possible etiologic role in disease.

Species Diversity and Antifungal Susceptibilities of Oral Yeasts from Patients with Head and Neck Cancer

Purpose

To investigate the colonization and susceptibility to antifungal drugs of oral yeasts in head and neck cancer patients in Hainan, China.

Methods

Oral mucosa samples from 211 head and neck cancer patients were collected. Oral yeasts were isolated and identified to species by rDNA ITS sequencing. The susceptibilities of all yeasts to amphotericin B, fluconazole, fluorocytosine, itraconazole, and ketoconazole were determined.

Results

Yeasts were isolated from 124 of the 211 oral swabs. The 124 yeast isolates were classified into following 10 species, from the most frequent to the least frequent, Candida albicans (53.2%), Candida tropicalis (22.6%), Candida krusei (6.5%), Kodamaea ohmeri (5.6%), Candida parapsilosis (4.8%), Hanseniaspora opuntiae (2.4%), Candida metapsilosis (1.6%), Pichia terricola (1.6%), Pichia norvegensis (0.8%), and Trichosporon asahii (0.8%). The overall frequencies of resistance among the yeasts to amphotericin B, fluconazole, flucytosine, itraconazole, and ketoconazole were 4.8%, 8.1%, 16.1%, 9.7%, and 9.7%, respectively. One C. albicans strain and one C. tropicalis strain were tolerant/resistant to all five drugs.

Conclusion

Given the high prevalence of oral yeast colonization in head and neck cancer patients and the observed resistance of certain yeast isolates to the five antifungal drugs, our results suggest that rapid identification and susceptibility testing should be implemented before antifungal treatment is applied among patients with head and neck cancer in Hainan.

Identification of Fungi Isolated from Oral Cavity of Patients with HIV Using MALDI-TOF MS

BACKGROUND

A growing incidence of invasive fungal infections, especially among immunocompromised patients, has given increased significance to microbiological diagnostics of yeast-like fungi. More accurate and faster fungi identification methods that can compete with classical methods are being searched for. In this paper, classical microbiological methods are compared to MALDI-TOF MS (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry).

METHODS

The diagnostic material was collected from buccal mucosa from 98 adults, including 69 with HIV. Only positive cultures were included in the study.

RESULTS

Matching results were obtained in 45 samples, and there were nonmatching results in 35 samples, with the majority of these in the study group, constituting 50% of identifications within this group. A particularly common mistake resulting from the use of classical methods is the false identification of C. dubliniensis as C. albicans. Additionally, C. tropicalis proves to be difficult to identify.

CONCLUSIONS

Our results and literature data suggest that MALDI-TOF MS should be considered an effective alternative to classical methods in terms of fungi identification, especially among HIV-positive patients, due to the different morphology of fungal colonies.

Genetic diversity and antifungal susceptibility of Candida albicans isolates from Iranian HIV-infected patients with oral candidiasis

Objective

The objectives of this study were to investigate the antifungal susceptibility and genetic diversity of Candida albicans isolated from HIV⁺ patients with oropharyngeal candidiasis. A total of 50 C. albicans isolates were cultured on Sabouraud glucose agar containing chloramophenicol. The antifungal susceptibility of the isolates against fluconazole, clotrimazole, nystatin, amphotericin B, ketoconazole and flucytosine was assessed using disc diffusion method. The genetic diversity of C. albicans isolates was determined using random amplified polymorphic DNA marker.

Results

The inhibition zones ranged from 4 ± 1.8 to 40 ± 3.8 mm for fluconazole, 7 ± 1.0 to 37 ± 1.8 mm for ketoconazole, 14 ± 0.8 to24 ± 0.8 mm for amphotericin B, 25 ± 0.0 to 33 ± 0.0 mm for nystatin and 7 ± 4.2 to 40 ± 0.0 mm for clotrimazole. At 90% similarity, three distinct groups were observed. The smallest cluster composed of 3 isolates, whereas the largest one composed of 17 isolates. 32% (16/50), 28% (14/50) and 14% (7/50) were resistant to fluconazole, ketoconazole and clotrimazole, respectively.

Interactions between invasive fungi and symbiotic bacteria

Infection rates and mortality associated with the invasive fungi Candida, Aspergillus, and Cryptococcus are increasing rapidly in prevalence. Meanwhile, screening pressure brought about by traditional antifungal drugs has induced an increase in drug resistance of invasive fungi, which creates a great challenge for the preservation of physical health. Development of new drugs and novel strategies are therefore important to meet these growing challenges. Recent studies have confirmed that the dynamic balance of microorganisms in the body is correlated with the occurrence of infectious diseases. This discovery of interactions between bacteria and fungi provides innovative insight for the treatment of invasive fungal infections. However, different invasive fungi and symbiotic bacteria interact with each other through various ways and targets, leading to different effects on their growth, morphology, and virulence. And the mechanism and implication of these interactions remains largely unknown. The present review aims to summarize the research progress into the interaction between invasive fungi and symbiotic bacteria with a focus on the anti-fungal mechanisms of symbiotic bacteria, providing a new strategy against drug-resistant fungal infections.

An alarming rise of non-albicans Candida species and uncommon yeasts in the clinical samples; a combination of various molecular techniques for identification of etiologic agents

OBJECTIVE

Yeasts are unicellular microorganisms may cause systemic infection in immunocompromised patients. The aim of this study was to identify yeast strains isolated from clinical specimens using molecular techniques.

RESULTS

A total of 202 yeast strains isolated from 341 clinical samples between February 2017 and May 2019. All clinical isolates were identified using phenotypic and molecular tests including PCR-RFLP, duplex-PCR, multiplex-PCR, and PCR-sequencing. The most yeast fungal isolates were obtained from urine (66.8%), nail (9.4%), skin lesion (7.9%), bronchoalveolar lavage (5.9%), and blood (3.9%). One hundred and twenty-one Candida species were identified as non-albicans versus 76 Candida albicans. Trichosporon asahii, and Pichia terricola were uncommon non-Candida yeasts isolated from urine samples. For the first time, we isolated P. terricola as etiological agent of urinary tract infection in a pregnant female. Since Candida species show different levels of resistance to antifungal agents, precise identification of clinical isolates is critical for better treatment of infection.