Relative frequency of albicans and the various non-albicans Candida spp among candidemia isolates from inpatients in various parts of the world: a systematic review

Identification and antifungal susceptibility profile of uncommon yeast species at Fattouma Bourguiba University Hospital in Tunisia

Despite the severe impact of uncommon yeast fungal infections and the pressing need for more research on the topic, there are still few studies available on the identification, epidemiology, and susceptibility profile of those pathogens. The aims of the current study were to define the profile of uncommon yeast species at Fattouma Bourguiba University Hospital using phenotypic, molecular, and proteomic methods and to study their antifungal susceptibility profile. Pre-identified uncommon yeast species were collected from 2018 to 2021. These isolates were further identified using phenotypic methods (ID32C® system and Vitek2® YST), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), and sequencing. The antifungal susceptibility profile was studied using the reference CLSI broth microdilution method. In total, 30 strains were collected during the study period. Referring to the sequencing, the most isolated uncommon species were Saprochaete capitata, Candida lusitaniae, Candida kefyr, Candida inconspicua, and Candida guilliermondii. A total of 90% of isolates were correctly identified by MALDI-TOF MS compared to 76.7% and 63.3% by ID32® C and VITEK® 2 YST, respectively. The isolated species showed variable responses to antifungals. Candida guilliermondii showed increased azole minimum inhibitory concentrations. Misidentification of uncommon yeast species was common using commercial phenotypic methods. The high percentage of concordance of MALDI-TOF results with sequencing highlights its high performance and usefulness as a routine diagnosis tool.

Factors influencing outcomes in candidemia: A retrospective study of patients in a Swedish county

BACKGROUND

Candidemia is a diverse condition and associated with a broad spectrum of clinical presentation. As mortality is high, timely diagnosis of candidemia and start of correct therapeutic treatment are essential.

OBJECTIVES

To investigate characteristics and factors influencing outcomes for patients with candidemia in a Swedish setting.

METHOD

All positive blood cultures for any Candida species in Östergötland County from 2012 to 2016 were screened. Medical records of patients fulfilling all inclusion criteria and no exclusion criteria were retrospectively reviewed to obtain data on risk factors, diagnostic and therapeutic procedures and at what wards candidemia was diagnosed. Univariate logistic regression and multivariable regression analysis were used to obtain odds ratio to determine risk factors for 30-day all-cause mortality associated with candidemia. A p-value <.05 was considered statistically significant.

RESULTS

Of all analysed risk factors, increasing age, renal failure with haemodialysis, immunosuppressant treatment, and severity of the infection (i.e. if septic shock was present) were significantly associated with 30-day mortality in univariate analysis (p < .05). Removal of a central venous catheter or an infectious diseases consultant was associated with a significantly lower odds ratio for death at 30 days (p < .05). With multivariable analysis, age, time to start of treatment and infectious disease consultant remained significant (p < .05).

CONCLUSION

In conclusion, this study provides an update of the epidemiology and outcomes of candidemia in a Swedish setting, highlighting that patients with candidemia are present at various departments and indicates the importance of an infectious disease consultant when candidemia is present.

Should Empiric Anti-Fungals Be Administered Routinely for All Patients with Perforated Peptic Ulcers? A Critical Review of the Existing Literature

A perforated peptic ulcer (PPU) is a surgical emergency with a high mortality rate. PPUs cause secondary peritonitis due to bacterial and fungal peritoneal contamination. Surgery is the main treatment modality and patient's comorbidites impacts perioperative morbidity and surgical outcomes. Even after surgery, resuscitation efforts should continue. While empiric antibiotics are recommended, the role of empiric anti-fungal treatment is unclear due to a lack of scientific evidence. This literature review demonstrated a paucity of studies evaluating the role of empiric anti-fungals in PPUs, and with conflicting results. Studies were heterogeneous in terms of patient demographics and underlying surgical pathology (PPUs vs. any gastrointestinal perforation), type of anti-fungal agent, timing of administration and duration of use. Other considerations include the need to differentiate between fungal colonization vs. invasive fungal infection. Despite positive fungal isolates from fluid culture, it is important for clinical judgement to identify the right group of patients for anti-fungal administration. Biochemistry investigations including new fungal biomarkers may help to guide management. Multidisciplinary discussions may help in decision making for this conundrum. Moving forward, further research may be conducted to select the right group of patients who may benefit from empiric anti-fungal use.

Oral candidiasis in liver transplant patients: species identification and antifungal susceptibility profile

OBJECTIVE

This study aimed to verify oral candidiasis, identify the causative species, and investigate the antifungal susceptibility of yeasts isolated from liver transplant patients.

METHODS

A descriptive analysis of 97 patients who underwent liver transplantation was conducted at a hospital. Two clinical examinations (Collections A and B) of the oral cavity were performed. Oral material was collected from all patients, inoculated in Sabouraud Dextrose Agar, and incubated at 35℃ for 48 hours. Samples were identified by molecular sequencing of the internal trascribed space region of rDNA.

RESULTS

An antifungal susceptibility test with fluconazole, amphotericin B, and micafungin was performed using the Clinical and Laboratory Standards Institute yeast broth microdilution method. Among the patients, 15 presented with oral candidiasis: eight in Collection A and seven in Collection B. The primary type of candidiasis was atrophic, followed by pseudomembranous candidiasis. The most prevalent species was Candida albicans (nine), followed by Candida glabrata (three), Candida tropicalis (two), and Candida dubliniensis (one). Regarding susceptibility to fluconazole, of the 15 samples, 11 were susceptible, three were susceptible in a dose-dependent manner, and one was resistant.

CONCLUSION

The most commonly identified type of candidiasis was atrophic, with C. albicans and C. glabrata being the most prevalent causative species. One fluconazole-resistant isolate each of C. tropicalis and C. albicans were identified.

Molecular Epidemiology and Antifungal Susceptibility Profile in Nakaseomyces glabrata Species Complex: A 5-Year Countrywide Study

BACKGROUND

The current study aimed to identify Iranian Nakaseomyces (Candida) glabrata complex species in the clinical isolates and determine their antifungal susceptibility profile.

METHODS

In total, 320 N. glabrata clinical isolates were collected from patients hospitalized in different geographical regions of Iran. The initial screening was performed by morphological characteristics on CHROMagar Candida. Each isolate was identified by targeting the D1/D2 rDNA using a multiplex-PCR method. To validate the mPCR method and determine genetic diversity, the ITS-rDNA region was randomly sequenced in 40 isolates. Additionally, antifungal susceptibility was evaluated against nine antifungal agents following the CLSI M27-A4 guidelines.

RESULTS

All clinical isolates from Iran were identified as N. glabrata. The analysis of ITS-rDNA sequence data revealed the presence of eight distinct ITS clades and 10 haplotypes among the 40 isolates of N. glabrata. The predominant clades identified were Clades VII, V, and IV, which respectively accounted for 22.5%, 17.5%, and 17.5% isolates. The widest MIC ranges were observed for voriconazole (0.016-8 μg/mL) and isavuconazole (0.016-2 μg/mL), whereas the narrowest ranges were seen with itraconazole and amphotericin B (0.25-2 μg/mL).

CONCLUSION

Haplotype diversity can be a valuable approach for studying the genetic diversity, transmission patterns, and epidemiology of the N. glabrata complex.

Antifungal drug resistance in Candida: a special emphasis on amphotericin B

Invasive fungal infections in humans caused by several Candida species, increased considerably in immunocompromised or critically ill patients, resulting in substantial morbidity and mortality. Candida albicans is the most prevalent species, although the frequency of these organisms varies greatly according to geographic region. Infections with C. albicans and non-albicans Candida species have become more common, especially in the past 20 years, as a result of aging, immunosuppressive medication use, endocrine disorders, malnourishment, extended use of medical equipment, and an increase in immunogenic diseases. Despite C. albicans being the species most frequently associated with human infections, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei also have been identified. Several antifungal drugs with different modes of action are approved for use in clinical settings to treat fungal infections. However, due to the common eukaryotic structure of humans and fungi, only a limited number of antifungal drugs are available for therapeutic use. Furthermore, drug resistance in Candida species has emerged as a result of the growing use of currently available antifungal drugs against fungal infections. Amphotericin B (AmB), a polyene class of antifungal drugs, is mainly used for the treatment of serious systemic fungal infections. AmB interacts with fungal plasma membrane ergosterol, triggering cellular ion leakage via pore formation, or extracting the ergosterol from the plasma membrane inducing cellular death. AmB resistance is primarily caused by changes in the content or structure of ergosterol. This review summarizes the antifungal drug resistance exhibited by Candida species, with a special focus on AmB.

Candida Non-albicans and Non-auris Causing Invasive Candidiasis in a Fourth-Level Hospital in Colombia: Epidemiology, Antifungal Susceptibility, and Genetic Diversity

Increasingly common and associated with healthcare settings, Candida infections are very important, since some species of this genus can develop antifungal resistance. We contribute data on the epidemiology, antifungal susceptibility, and genetic diversity of Candida non-albicans and non-auris affecting critically ill patients in a fourth-level hospital in Colombia. Ninety-seven isolates causing invasive infections, identified by conventional methods over 18 months, were studied. Data from patients affected by these yeasts, including sex, age, comorbidities, treatment, and outcome, were analysed. The antifungal susceptibility of the isolates was determined, and the ribosomal DNA was sequenced. Candida parapsilosis, Candida tropicalis, Candida glabrata, Candida dubliniensis, and Candida guilliermondii caused 48.5% of all cases of invasive candidiasis. The species were mainly recovered from blood (50%). Patients were mostly men (53.4%), between 18 days and 93 years old, hospitalized in the ICU (70.7%). Overall mortality was 46.6%, but patients in the ICU, using antibiotics, with diabetes mellitus, or with C. glabrata infections were more likely to die. Resistant isolates were identified in C. parapsilosis, C. tropicalis, and C. glabrata. This study provides epidemiological data for the surveillance of emerging Candida species, highlighting their clinical impact, as well as the emergence of antifungal resistance and clonal dispersal.

Oral Candida carriage and resistance against common antifungal agents in hematopoietic stem cell transplantation recipients

PURPOSE

Allogeneic hematopoietic stem cell transplant (HSCT) recipients receiving long-term and high-dose immunosuppressive medications suffer commonly from oral candida infections. This prospective cohort study examined oral fungal carriage in HSCT recipients and screened the susceptibility against commonly used antifungal agents. An increasing oral occurrence of Candida spp. and the development of resistance against clinically administered fluconazole were hypothesized.

METHODS

Two hundred HSCT recipients were included and followed up for 2 years post-HSCT. Oral microbiological specimens were analyzed with matrix-assisted laser desorption/ionization-time of flight mass spectrometry assays (MALDI-TOF). The colorimetric method was applied for the susceptibility testing by commercially available Sensititre YeastOne (SYO®, TREK Diagnostics Systems, Thermo-Fisher, UK).

RESULTS

The prevalence of oral Candida spp. carriage increased statistically significantly after a year post-HSCT being 30, 26, 35, 44, and 47%, pre-HSCT, 3, 6, 12, and 24 months post-HSCT, respectively. Altogether, 169 clinical oral Candida strains were isolated. Fourteen Candida spp. were identified, and C. albicans was predominant in 74% of the isolates pre-HSCT with a descending prevalence down to 44% 2 years post-HSCT. An increasing relative proportion of non-albicans species post-HSCT was evident. No development of resistance of C. albicans against fluconazole was found. Instead, a shift from C. albicans towards non-albicans species, especially C. dubliensis, C. glabrata, and relatively seldom found C. krusei, was observed.

CONCLUSION

Oral Candida carriage increases after HSCT. Instead of the expected development of resistance of C. albicans against fluconazole, the relative proportion of non-albicans strains with innate resistance against azole-group antifungals increased.

Occidiofungin inhibition of Candida biofilm formation on silicone elastomer surface

IMPORTANCE

Candida are opportunistic fungal pathogens with medical relevance given their association with superficial to life-threatening infections. An important component of Candida virulence is the ability to form a biofilm. These structures are highly resistant to antifungal therapies and are often the cause of treatment failure. In this work, we evaluated the efficacy of the antifungal compound, occidiofungin, against Candida biofilms developed on a silicone surface. We demonstrate that occidiofungin eliminated cells at all stages of biofilm formation in a dose-dependent manner. Consistent with our understanding of occidiofungin bioactivity, we noted alterations to actin organization and cell morphology following antifungal exposure. Given the challenges associated with the treatment of biofilm-associated infections, occidiofungin exhibits potential as a therapeutic antifungal agent in the future.

Convergent and divergent roles of the glucose-responsive kinase SNF4 in Candida tropicalis

The sucrose non-fermenting 1 (SNF1) complex is a heterotrimeric protein kinase complex that is an ortholog of the mammalian AMPK complex and is evolutionally conserved in most eukaryotes. This complex contains a catalytic subunit (Snf1), a regulatory subunit (Snf4) and a scaffolding subunit (Sip1/Sip2/Gal73) in budding yeast. Although the function of AMPK has been well studied in Saccharomyces cerevisiae and Candida albicans, the role of AMPK in Candida tropicalis has never been investigated. In this study, we focused on SNF4 in C. tropicalis as this fungus cannot produce a snf1Δ mutant. We demonstrated that C. tropicalis SNF4 shares similar roles in glucose derepression and is necessary for cell wall integrity and virulence. The expression of both SNF1 and SNF4 was significantly induced when glucose was limited. Furthermore, snf4Δ strains exhibited high sensitivity to many surface-perturbing agents because the strains contained lower levels of glucan, chitin and mannan. Interestingly, in contrast to C. albicans sak1Δ and snf4Δ, C. tropicalis snf4Δ exhibited phenotypes for cell aggregation and pseudohypha production. These data indicate that SNF4 performs convergent and divergent roles in C. tropicalis and possibly other unknown roles in the C. tropicalis SNF1-SNF4 AMPK pathway.

Biocontrol of Pathogen Microorganisms in Ripened Foods of Animal Origin

Ripened foods of animal origin comprise meat products and dairy products, being transformed by the wild microbiota which populates the raw materials, generating highly appreciated products over the world. Together with this beneficial microbiota, both pathogenic and toxigenic microorganisms such as Listeria monocytogenes, Salmonella enterica, Staphylococcus aureus, Clostridium botulinum, Escherichia coli, Candida spp., Penicillium spp. and Aspergillus spp., can contaminate these products and pose a risk for the consumers. Thus, effective strategies to hamper these hazards are required. Additionally, consumer demand for clean label products is increasing. Therefore, the manufacturing sector is seeking new efficient, natural, low-environmental impact and easy to apply strategies to counteract these microorganisms. This review gathers different approaches to maximize food safety and discusses the possibility of their being applied or the necessity of new evidence, mainly for validation in the manufacturing product and its sensory impact, before being implemented as preventative measures in the Hazard Analysis and Critical Control Point programs.

Clonal Diversity of Candida auris, Candida blankii, and Kodamaea ohmeri Isolated from Septicemia and Otomycosis in Bangladesh as Determined by Multilocus Sequence Typing

Candida auris, Candida blankii, and Kodamaea ohmeri have been regarded as emerging fungal pathogens that can cause infections with high mortality. For genotyping of C. auris, a multilocus sequence typing (MLST) scheme based on four locus sequences has been reported, while there is no typing scheme for C. blankii and K. ohmeri. In the present study, the existing MLST scheme of C. auris was modified by adding more locus types deduced from sequence data available in the GenBank database. Furthermore, MLST schemes of C. blankii and K. ohmeri were developed using the four cognate loci (ITS, RPB1, RPB2, D1/D2) and similar sequence regions to those of C. auris. These MLST schemes were applied to identify the ST (sequence type) of clinical isolates of C. auris (n = 7), C. blankii (n = 9), and K. ohmeri (n = 6), derived from septicemia or otomycosis in Bangladesh in 2021. All the C. auris isolates were classified into a single ST (ST5) and clade I, having a Y132F substitution in ERG11p, which is associated with azole resistance. Similarly, all the C. blankii isolates belonged to a single type (ST1). In contrast, six K. ohmeri isolates were assigned to five types (ST1-ST5), suggesting its higher genetic diversity. These findings revealed the availability of MLST schemes for these three fungal species for understanding their clonal diversity among clinical isolates.

A 3-year study of Candida infections among patients with malignancy: etiologic agents and antifungal susceptibility profile

Objective

Opportunistic fungal infections by Candida species arise among cancer patients due to the weakened immune system following extensive chemotherapy. Prophylaxis with antifungal agents have developed the resistance of Candida spp. to antifungals. Accurate identification of yeasts and susceptibility patterns are main concerns that can directly effect on the treatment of patients.

Methods

Over a period of three years, 325 cancer patients suspected to Candida infections were included in the current investigation. The clinical isolates were molecularly identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). All strains, were examined for in vitro susceptibility to the amphotericin B, itraconazole, fluconazole, and anidulafungin according to the CLSI M27 document.

Results

Seventy-four cancer patients had Candida infections (22.7%). Candida albicans was the most common species (83.8%). Antifungal susceptibility results indicated that 100% of the Candida isolates were sensitive to amphotericin B; however, 17.6%, 9.4%, and 5.4% of clinical isolates were resistant to anidulafungin, fluconazole, and itraconazole, respectively.

Conclusion

The findings of the present work shows a warning increase in resistance to echinocandins. Since all fluconazole resistance isolates were obtained from candidemia, we recommend amphotericin B as the first line therapy for this potentially fatal infection.

Emerging threat of candida resistance among neonates at a teaching institute of Jharkhand

Purpose

In the past few decades, candidemia has escalated to worrisome levels, leading to substantial morbidity and mortality in neonates. The rise in anti-fungal drug resistance demands prompt diagnosis and treatment. This study aimed to determine the speciation and susceptibility pattern of Candida species recovered from special care new-born units and identify risk factors for developing candidemia in neonates.

Method

A total of 580 blood samples from clinically suspected septicemic neonates were collected and subjected to culture. Cultures positive for yeasts were sub-cultured on Sabouraud dextrose agar. Identification of a suspected purified colony of Candida was confirmed to the species level by both conventional and automated techniques matrix-assisted laser desorption and ionization time-of-flight mass spectrometry. Anti-fungal susceptibility of isolates was performed by an automated method (VITEK 2 system) using VITEK 2 cards. Multi-variate logistic regression analysis was used to identify risk factors associated with candidemia.

Result

A total of 56 (9.66%) isolates of Candida species were recovered from 580 blood cultures. Non-albicans Candida species predominated with 82.14% of cases, whereas 17.86% of cases were caused by Candida albicans. Candida tropicalis (46.42%) was the most common isolate recovered, followed by Candida albicans (17.8%). Risk factor analyses identified a very low birth weight [odds ratio (OR) =4.05, 95% confidence interval (CI) =2.03-8.08] and prolonged antibiotic therapy (OR = 3.79, 95% CI = 1.7-8.7) among others as significant predictors of candidemia. All the Candida isolates showed 100% sensitivity to voriconazole and micafungin, whereas the overall sensitivities for fluconazole, amphotericin B, caspofungin, and flucytosine were 85.71%, 96.43%, 96.43%, and 91.07%, respectively.

Conclusion

Candidemia is a life-threatening condition in neonates. Identification of Candida species and routine anti-fungal susceptibility is a must to select a suitable and effective anti-fungal therapy to revoke emerging resistance to anti-fungals.

Endocarditis due to Candida albicans in an immunocompromised patient: A case report

BACKGROUND

Fungal endocarditis is a low-frequency disease with a challenging diagnosis, as it can be mistaken with bacterial endocarditis. Fungal endocarditis causes higher mortality rates in immunocompromised patients. In the clinical practice, the endocarditis caused by fungi represents up to 10% of all infectious endocarditis cases and has a mortality rate of nearly 50%.

CASE REPORT

Here we present the case of a 53-year-old woman under corticosteroid therapy with a history of rheumatic heart disease, aortic valve replacement, and rheumatoid arthritis, who presented with fungal endocarditis caused by Candida albicans. Even though the patient received 3 years of antifungal prophylaxis with fluconazole, had valve replacement surgery, and received intensive care, the patient finally worsened and died.

CONCLUSIONS

Comorbidities and corticosteroid therapy predisposed the patient to acquire fungal endocarditis. This case highlights the importance of implementing procedures for the isolation and identification of fungi, and for carrying out antifungal-susceptibility testing, as well as establishing surveillance programs to identify infection-causing species and drug resistance patterns in hospitals. Moreover, designing and upgrading the algorithm for infectious endocarditis is the key to future improvements in diagnosis.

Candida lipolytica Bloodstream Infection in an Adult Patient with COVID-19 and Alcohol Use Disorder: A Unique Case and a Systematic Review of the Literature

Candida lipolytica is an uncommon Candida species causing invasive fungemia. This yeast is mainly associated with the colonisation of intravascular catheters, complicated intra-abdominal infections, and infections in the paediatric population. Here, we report a case of C. lipolytica bloodstream infection in a 53-year-old man. He was admitted for an alcohol withdrawal syndrome and mild COVID-19. Among the primary risk factors for candidemia, only the use of broad-spectrum antimicrobials was reported. The empiric treatment was commenced with caspofungin and then targeted with intravenous fluconazole. Infective endocarditis was ruled out using echocardiography, and PET/TC was negative for other deep-seated foci of fungal infection. The patient was discharged after blood culture clearance and clinical healing. To the best of our knowledge, this is the first case of C. lipolytica candidemia in a patient with COVID-19 and alcohol use disorder. We performed a systematic review of bloodstream infections caused by C. lipolytica. Clinicians should be aware of the possibility of C. lipolytica bloodstream infections in patients with alcohol use disorder, especially in a COVID-19 setting.

Changing Trends in Antimicrobial Susceptibility Patterns of Bloodstream Infection (BSI) in Secondary Care Hospitals of India

Introduction Bloodstream infection (BSI) and subsequent sepsis are life-threatening medical conditions. The onset of antimicrobial resistance and subsequent multi-drug resistant organisms (MDRO) significantly increase healthcare-associated expenditure with adverse clinical outcomes. The present study was undertaken to identify the trends of BSI in community settings in secondary care hospitals (smaller private hospitals and district hospitals) in the state of Madhya Pradesh in Central India with the support of the Indian Council of Medical Research (ICMR) and National Health Mission, Madhya Pradesh. Methodology The present study was a prospective, longitudinal observational chart review type of study. The study was carried out at 10 secondary care hospitals (eight smaller private hospitals and two government district hospitals) nominated by the State Government as part of the ICMR Antimicrobial Resistance Surveillance and Research Network (AMRSN). The hospitals were nominated depending on the availability of a microbiology laboratory and a full-time microbiologist. Result A total of 6202 blood samples were received from patients with suspected BSI, out of which 693 samples were positive for aerobic culture. Among these, 621 (89.6%) showed bacterial growth and 72 (10.3%) grew Candida species (spp). Out of the 621 bacterial growth samples, Gram-negative bacteria were 406 (65.3%) and Gram-positive bacteria were 215 (34.6%). Among the Gram-negative isolates (406), the predominant isolate was Escherichia coli (115; 28.3%) followed by Klebsiella pneumoniae (109; 26.8%), Pseudomonas aeruginosa (61; 15%), Salmonella spp. (52; 12.8%), Acinetobacter spp. (47; 11.6%) and the other Enterobacter spp. (22; 5.4%). Among the Gram-positive isolates (215), the predominant isolate was Staphylococcus aureus (178; 82.8%) followed by Enterococcus spp. (37; 17.2%). Among the Escherichia coli, third-generation cephalosporin resistance was identified in 77.6%, piperacillin-tazobactam resistance in 45.2%, carbapenem resistance in 23.5% and colistin resistance in 16.5% of cases. Among the Klebsiella pneumoniae, third-generation cephalosporin resistance was identified in 80.7%, piperacillin-tazobactam resistance in 72.8%, carbapenem resistance in 63.3% and colistin resistance in 14% of cases. Among the Pseudomonas aeruginosa, ceftazidime resistance was identified in 61.2%, piperacillin-tazobactam resistance in 55%, carbapenem resistance in 32.8%, and colistin resistance in 38.3% of cases. Among the Acinetobacter spp., piperacillin-tazobactam resistance was identified in 72.7%, carbapenem resistance in 72.3%, and colistin resistance in 9.3% cases. While analyzing the antibiogram for Staphylococcus aureus isolates, methicillin resistance (MRSA) was seen in 70.3% of cases, followed by vancomycin resistance (VRSA) in 8% of cases and linezolid resistance in 8.1%. Among the Enterococcus spp. isolates, linezolid resistance was found in 13.5%, vancomycin resistance (VRE) in 21.6%, and teicoplanin resistance in 29.7% of cases. Conclusion In conclusion, the first-ever study to identify the risk of high-end antibiotics causing significant drug resistance in secondary and tertiary care settings has highlighted the urgent need for more randomized control studies and proactive measures from healthcare authorities and serves as a beacon for future research efforts and underscores the importance of implementing antibiograms to combat the growing threat of antibiotic resistance.

Fatty acids as molecular carriers in cleavable antifungal conjugates

Conjugates composed of C_2-18 fatty acid (FA) residues as a molecular carrier and 5-fluorocytosine (5-FC) as an active agent, released upon the action of intracellular esterases on the ester bond between FA and "trimethyl lock" intramolecular linker, demonstrate good in vitro activity against human pathogenic yeasts of Candida spp. The minimal inhibitory concentrations (MIC) values for the most active conjugates containing caprylic (C₈), capric (C₁₀), lauric (C₁₂), or myristic (C₁₄) acid residues were in the 2-64 μg mL^-1 range, except for these against the least susceptible Candida krusei. The least active conjugates containing C₂, C_16, or C₁₈ FA were slowly hydrolyzed by esterase and probably poorly taken up by Candida cells, as found for their analogs containing a fluorescent label, Nap-NH₂ instead of 5-FC.

Navigating the New Reality: A Review of the Epidemiological, Clinical, and Microbiological Characteristics of Candida auris, with a Focus on Children

During the past decade, Candida auris emerged across the world, causing nosocomial outbreaks in both pediatric and adult populations, particularly in intensive care settings. We reviewed the epidemiological trends and the clinical and microbiological characteristics of C. auris infection, focusing on the pediatric population. The review is based on 22 studies, which included about 250 pediatric patients with C. auris infection, across multiple countries; neonates and premature babies were the predominant pediatric patient group affected. The most common type of infection reported was bloodstream infection, which was associated with exceptionally high mortality rates. Antifungal treatment varied widely between the patients; this signifies a serious knowledge gap that should be addressed in future research. Advances in molecular diagnostic methods for rapid and accurate identification and for detection of resistance may prove especially valuable in future outbreak situations, as well as the development of investigational antifungals. However, the new reality of a highly resistant and difficult-to-treat pathogen calls for preparedness of all aspects of patient care. This spans from laboratory readiness, to raising awareness among epidemiologists and clinicians for global collaborative efforts to improve patient care and limit the spread of C. auris.

Evaluation of the Sensitivity of Selected Candida Strains to Ozonated Water-An In Vitro Study

(1) Background and Objectives: Oral candidiasis has increased significantly in recent years. Increasingly, we encounter treatment difficulties related to drug resistance. Therefore, it is necessary to search for other therapies such as ozone therapy, which has antimicrobial activity. The aim of this study was to determine the sensitivity of selected Candida strains to ozonated water based on concentration and contact time (2) Methods: The sensitivity of Candida strains to ozonated water with a concentration of 5 µg/mL, 30 µg/mL, and 50 µg/mL was assessed using Mosmann's Tetrazolium Toxicity (MTT) assay. Statistical differences were assessed by the analysis of variance (ANOVA) and the Newman-Keuls post-hoc test. A p-value of ≤0.05 was considered to indicate a statistically significant difference. (3) Results: In all the strains and research trials, the number of viable cells was reduced by ozonated water. The reduction depended on the exposure time and concentration of ozonated water. The highest percentage reduction (34.98%) for the tested samples was obtained for the C. albicans strain after 120 s of exposure at the highest concentration-50 µg/mL. (4) Conclusions: The selected strains of Candida spp. were sensitive to ozonated water at all tested concentrations (5 µg/mL, 30 µg/mL, and 50 µg/mL). The sensitivity of strains to ozonated water increased with concentration and application time. Moreover, the sensitivity of Candida strains to ozonated water is comparable to that of 0.2% chlorhexidine gluconate.

Prevalence and Antifungal Susceptibility of Clinically Relevant Candida Species, Identification of Candida auris and Kodamaea ohmeri in Bangladesh

Candida species are major fungal pathogens in humans. The aim of this study was to determine the prevalence of individual Candida species and their susceptibility to antifungal drugs among clinical isolates in a tertiary care hospital in Bangladesh. During a 10-month period in 2021, high vaginal swabs (HVSs), blood, and aural swabs were collected from 360 patients. From these specimens, Candida spp. was isolated from cultures on Sabouraud dextrose agar media, and phenotypic and genetic analyses were performed. A total of 109 isolates were recovered, and C. albicans accounted for 37%, being derived mostly from HVSs. Among non-albicans Candida (NAC), C. parapsilosis was the most frequent, followed by C. ciferrii, C. tropicalis, and C. glabrata. Three isolates from blood and two isolates from aural discharge were genetically identified as C. auris and Kodamaea ohmeri, respectively. NAC isolates were more resistant to fluconazole (overall rate, 29%) than C. albicans (10%). Candida isolates from blood showed 95% susceptibility to voriconazole and less susceptibility to fluconazole (67%). Two or three amino acid substitutions were detected in the ERG11 of two fluconazole-resistant C. albicans isolates. The present study is the first to reveal the prevalence of Candida species and their antifungal susceptibility in Bangladesh.

Invasive Candidiasis: Update and Current Challenges in the Management of This Mycosis in South America

Invasive candidiasis encompassing Candida bloodstream infections and deep-seated candidiasis can become a persistent health problem. These infections are caused by Candida species and have high morbidity and mortality rates. Species distribution, access to diagnosis, treatment and mortality are different around the world. The mortality rate is high in South America (30–70%), and Candida albicans is the most prevalent species in this region. However, a global epidemiological shift to non-albicans species has been observed. In this group, C. parapsilosis is the species most frequently detected, followed by C. tropicalis, and at a slower rate, C. glabrata, which has also increased, in addition to the emerging C. auris, resistance to several drugs. This article summarizes relevant aspects of candidemia pathogenesis, such as the mechanisms of fungal invasion, immune response, and the impact of genetic defects that increase host susceptibility to developing the infection. We also discuss relevant aspects of treatment and future challenges in South America.

Candidemia Among ICU Patients: Species Characterisation, Resistance Pattern and Association With Candida Score: A Prospective Study

Introduction

Candidiasis is a significant cause of morbidity and mortality in immunocompromised patients admitted in intensive care units. Identification of Candida species is essential for effective treatment. However, in absence of proven fungemia, guidelines to initiate therapy are yet to be defined.

Materials and methods

During the study (16 months: September 2018 to December 2019), samples (urine, sputum, blood, tracheal aspirate, urinary catheter) were collected from ICU patients and prospectively evaluated. Microscopy, culture, and antifungal susceptibility testing were performed as per standard laboratory protocol. Demographic details and risk factors were noted from case records and correlated with Candida score.

Results

One hundred twenty-five non-duplicate samples (120 patients) positive on culture were included in the study. The most common co-morbid condition associated with fungemia was diabetes mellitus. The most common risk factor was total parenteral nutrition. Non-albicansCandida(C. tropicalis) was predominant. Candida species showed good sensitivity to voriconazole (80%) followed by fluconazole (67.78%) and amphotericin (62.22%). Twenty-nine patients had a Candida score of more than three.

Conclusion

Fluconazole available in both oral and parenteral formulations is an effective antifungal agent against the candida spp. Voriconazole should be reserved for non-responders. Rising resistance to common antifungals among Candida albicans is a matter of concern.

COVID-19-Associated Candidiasis: Possible Patho-Mechanism, Predisposing Factors, and Prevention Strategies

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is threatening public health. A large number of affected people need to be hospitalized. Immunocompromised patients and ICU-admitted patients are predisposed to further bacterial and fungal infections, making patient outcomes more critical. Among them, COVID-19-associated candidiasis is becoming more widely recognized as a part of severe COVID-19 sequelae. While the molecular pathophysiology is not fully understood, some factors, including a compromised immune system, iron and zinc deficiencies, and nosocomial and iatrogenic transmissions, predispose COVID-19 patients to candidiasis. In this review, we discuss the existing knowledge of the virulence characteristics of Candida spp. and summarize the key concepts in the possible molecular pathogenesis. We analyze the predisposing factors that make COVID-19 patients more susceptible to candidiasis and the preventive measures which will provide valuable insights to guide the effective prevention of candidiasis in COVID-19 patients.

Effect of Silver Nanoparticles (AgNPs) on Candida Albicans, Candida Dubliniensis, and Candida Guilliermondii

Background:

Candida species are the most important fungal pathogens and are sometimes considered the fourth most common cause of infection in hospitals. Today, research needs to be conducted on the antifungal effect of silver nanoparticles (AgNPs) due to toxicity, side effects, and drug interactions of antifungal chemical drugs.

Objective:

Therefore, this study was done to evaluate the antifungal activity of AgNPs on Candida albicans, Candida dubliniensis, and Candida guilliermondii.

Methodology:

Antifungal activity of AgNPs on Candida albicans, Candida dubliniensis, and Candida guilliermondii was assessed by agar and macrodilution diffusion methods in an in-vitro investigation. Structural changes were investigated by scanning electron microscope (SEM). Then, the obtained data were evaluated by SPSS statistical software.

Results:

Based on the results, the mean diameter of growth inhibition halos by AgNPs was equal to 20, 20.2, and 40.7mm for Candida albicans, Candida dubliniensis, and Candida guilliermondii, respectively. The minimum inhibitory concentrations (MIC) equal 62.50, 31.25, and 15.62 mg/ml for Candida albicans, Candida dubliniensis, and Candida guilliermondii, respectively. The minimum fungicidal concentrations (MFC) were equal to 125, 62.50, and 31.25 mg/ml for Candida albicans, Candida dubliniensis, and Candida guilliermondii, respectively.

Conclusion:

Our results revealed that AgNPs inhibit the growth of Candida albicans, Candida dubliniensis, and Candida guilliermondii. SEM observations also showed that NPs disrupted cell membrane/wall. Changes in yeast levels from smooth to uneven were also observed.

Physicochemical characterization and in vitro evaluation of the antioxidant and anticandidal activities of Moroccan propolis

Background and Aim:

Human mycotic infections are one of the major health problems worldwide. Prolonged use of antimycotic drugs has contributed to the development of resistance in pathogenic fungi. This study was conducted to examine antioxidant and anticandidal activities of Moroccan propolis.

Materials and Methods:

Two ethanolic extracts of Moroccan propolis from the Fez-Meknes region were evaluated regarding the following physicochemical parameters: Yield, pH, total carbohydrates, total proteins, total lipids, minerals, total phenolic content, total flavonoid content, and antioxidant activity using ferric reducing antioxidant power (FRAP) and 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. In addition, we assessed the in vitro anticandidal activity against vulvovaginal candidiasis strains, that is, Candida albicans, Candida glabrata, Candida parapsilosis, and Candida krusei, using the broth micromethod according to the CLSI/M27-A3 reference guidelines.

Results:

The propolis samples exhibited a mean yield of 16%, with an acidic pH ranging from 4.8 to 5.9; the sample from the Oued Amlil area (OAPEE) contained high levels of resin, balsam, moisture, total carbohydrates, and total lipids: 59.8%, 0.71%, 2%, 1.01 gGlcEq/g, and 120 mg/g, respectively. Moreover, the sample from the Sefrou area (SFPEE) was richer in total proteins and minerals, with values of 2.5 g/100 g and 1.84%, respectively. The total polyphenol and flavonoid content in the propolis extracts were 117.38 and 194.68 mg of gallic acid equivalent/g, and 17.45–27.79 mg of quercetin equivalent/g, respectively. Regarding the antioxidant activity, the most effective propolis extract was the sample from the Sefrou area, at 72.5 μg/mL and 118.78 μmoL Fe²⁺/g for ABTS-half-maximal inhibitory concentration and FRAP-half maximal effective concentration, respectively. The analysis of phenolic compounds using high-performance liquid chromatography with a diode-array detector revealed the presence of 13 polyphenols. The main compound in the OAPEE sample was epicatechin (310 mg/g), whereas in the SFPEE sample was apigenin (410 mg/g). Regarding the antifungal activity against Candida species, the minimum inhibitory concentration and minimum fungicidal concentration of the Moroccan propolis ethanolic extracts ranged between 31.2 and 62.5 μg/mL and 62.5 and 125 μg/mL, respectively, comparable with fluconazole (as a reference antimycotic).

Conclusion:

This study suggests that Moroccan propolis (31.2 and 125 μg/mL) may be an important source of bioactive molecules with anticandidal activity. Propolis may be a promising naturally-occurring candidate for the development of antimycotic drugs.

Antifungal activity of a novel 3-Alkylpyridine analog derived from Marine sponge alkaloids

Candida spp. is considered an important cause of healthcare-associated infections worldwide. Currently, the emergence and spread of resistant Candida isolates are being increasingly reported, making the development of new agents urgently needed. In this study, we showed the in vitro anti-Candida activity of seven synthetic 3-alkylpyridine alkaloid analogs. Among them, alkaloid 1 presented a potent antifungal effect, which was independent of its capacity of binding with the fungal membrane ergosterol or cell wall. Analog 1 showed fungistatic and fungicidal effects against C. albicans (MIC 7.8 μg/mL and MFC 62.5 μg/mL), C. glabrata, C. krusei (MIC and MFC 31.2 μg/mL), and C. tropicalis (MIC 31.2 μg/mL and MFC 125 μg/mL). The time kill-curve study showed that compound 1 has a potent fungicidal effect in vitro, eliminating C. albicans cells. Furthermore, an in vitro synergistic effect with ketoconazole was observed for compound 1. This compound also eliminated the yeast-to-hypha transition. However, it showed high cytotoxicity against mammalian cells. Taken together, these findings support the use of compound 1 as a prototype to develop new anti-Candida agents, but molecular modifications should be done to minimize the high cytotoxicity obtained.

Update on Candida krusei, a potential multidrug-resistant pathogen

Although Candida albicans remains the main cause of candidiasis, in recent years a significant number of infections has been attributed to non-albicans Candida (NAC) species, including Candida krusei. This epidemiological change can be partly explained by the increased resistance of NAC species to antifungal drugs. C. krusei is a diploid, dimorphic ascomycetous yeast that inhabits the mucosal membrane of healthy individuals. However, this yeast can cause life-threatening infections in immunocompromised patients, with hematologic malignancy patients and those using prolonged azole prophylaxis being at higher risk. Fungal infections are usually treated with five major classes of antifungal agents which include azoles, echinocandins, polyenes, allylamines, and nucleoside analogues. Fluconazole, an azole, is the most commonly used antifungal drug due to its low host toxicity, high water solubility, and high bioavailability. However, C. krusei possesses intrinsic resistance to this drug while also rapidly developing acquired resistance to other antifungal drugs. The mechanisms of antifungal resistance of this yeast involve the alteration and overexpression of drug target, reduction in intracellular drug concentration and development of a bypass pathway. Antifungal resistance menace coupled with the paucity of the antifungal arsenal as well as challenges involved in antifungal drug development, partly due to the eukaryotic nature of both fungi and humans, have left researchers to exploit alternative therapies. Here we briefly review our current knowledge of the biology, pathophysiology and epidemiology of a potential multidrug-resistant fungal pathogen, C. krusei, while also discussing the mechanisms of drug resistance of Candida species and alternative therapeutic approaches.

Antimycotic Drugs and their Mechanisms of Resistance to Candida Species

Fungal infections have shown an upsurge in recent decades, which is mainly because of the increasing number of immunocompromised patients and the occurrence of invasive candidiasis has been found to be 7-15 fold greater than that of invasive aspergillosis. The genus Candida comprises more than 150 distinct species, however, only a few of them are found to be pathogenic to humans. Mortality rates of Candida species are found to be around 45% and the reasons for this intensified mortality are inefficient diagnostic techniques and unfitting initial treatment strategies. There are only a few antifungal drug classes that are employed for the remedy of invasive fungal infections. which include azoles, polyenes, echinocandins, and pyrimidine analogs. During the last 2-3 decades, the usage of antifungal drugs has increased several folds due to which the reports of escalating antifungal drug resistance have also been recorded. The resistance is mostly to the triazole- based compounds. Due to the occurrence of antifungal drug resistance, the success rates of treatment have been reduced as well as major changes have been observed in the frequency of fungal infections. In this review, we have summarized the major molecular mechanisms for the development of antifungal drug resistance.

Candida Bloodstream Infections: Changes in Epidemiology and Increase in Drug Resistance

The literature on bloodstream infections (BSIs) have predominantly been biased towards bacteria, given their superior clinical significance in comparison with the other types of microorganisms. Fungal pathogens have epidemiologically received relatively less attention, although they constitute an important proportion of BSI aetiologies. In this review, the authors discuss the clinical relevance of fungal BSIs in the context of Candida species, as well as treatment options for the infections, emphasizing the compelling need to develop newer antifungals and strengthen antimicrobial stewardship programmes in the wake of the rapid spread of antifungal resistance.

Deciphering the epidemiology of invasive candidiasis in the intensive care unit: is it possible?

Invasive candidiasis (IC) has emerged in the last decades as an important cause of morbidity, mortality, and economic load in the intensive care unit (ICU). The epidemiology of IC is still a difficult and unsolved enigma for the literature. Accurate estimation of the true burden of IC is difficult due to variation in definitions and limitations inherent to available case-finding methodologies. Candidemia and intra-abdominal candidiasis (IAC) are the two predominant types of IC in ICU. During the last two decades, an increase in the incidence of candidemia has been constantly reported particularly in the expanding populations of elderly or immunosuppressed patents, with a parallel change in Candida species (spp.) distribution worldwide. Epidemiological shift in non-albicans spp. has reached worrisome trends. Recently, a novel, multidrug-resistant Candida spp., Candida auris, has globally emerged as a nosocomial pathogen causing a broad range of healthcare-associated invasive infections. Epidemiological profile of IAC remains imprecise. Though antifungal drugs are available for Candida infections, mortality rates continue to be high, estimated to be up to 50%. Increased use of fluconazole and echinocandins has been associated with the emergence of resistance to these drugs, which affects particularly C. albicans and C. glabrata. Crucial priorities for clinicians are to recognize the epidemiological trends of IC as well as the emergence of resistance to antifungal agents to improve diagnostic techniques and strategies, develop international surveillance networks and antifungal stewardship programmes for a better epidemiological control of IC.

Oropharyngeal Candida Colonization in Patients with Acute Myeloid Leukemia

Objectives:

Oral candidiasis has increased in recent years because of the increasing number of high-risk populations. The prevalence of Candida species is different worldwide because of the difference between population characteristics, sampling protocols, and geographic regions. Therefore, determining the more prevalent Candida species in different geographic regions seems essential. This study aimed to determine the more prevalent Candida species in acute myeloid leukemia (AML) patients in comparison with healthy individuals in Iran in 2016.

Materials and Methods:

Fifty-one patients with AML and 62 healthy controls participated in this cross-sectional study. Samples were collected using a swab rubbed softly on the dorsal surface of the tongue and the oropharynx. The samples were cultured on CHROMagar Candida for 2 to 4 days. For differentiation between albicans and non-albicans species, positive samples were linearly inoculated on Corn Meal Agar with Tween-80. Candida species were identified using a microscope. Data were analyzed using chi-square and Fisher’s exact tests.

Results:

Candida colonization was more frequent in AML patients (41.2%) in comparison with healthy participants (38.7%). Candida glabrata (C. glabrata; 27.5%) and Candida albicans (C. albicans; 32.3%) were the most common isolated species in the AML patients and the controls, respectively. There was a significant decrease in the frequency of C. albicans (P=0.022) and a significant increase in the frequency of C. glabrata (P=0.002) in the AML patients in comparison with the controls.

Conclusion:

AML patients are more susceptible to candidiasis. C. glabrata is the dominant Candida species in AML patients.

Histopathological study on the prevalence of trichosporonosis in formalin-fixed and paraffin-embedded tissue autopsy sections by in situ hybridization with peptide nucleic acid probe

Trichosporon species are some of the most common pathogenic yeasts in Asia, and many are resistant to echinocandin antifungal drugs. Effective treatment of fungal infections requires the selection of appropriate antifungals and the accurate identification of the causal organism. However, in histopathological specimens Trichosporon spp. are often misidentified as Candida species due to morphological similarities. In situ hybridization (ISH) is a useful technique for identifying fungal species in formalin-fixed and paraffin-embedded (FFPE) tissue sections. Although many novel probes for ISH are available, the practical use of ISH for identification of fungi remains limited, in part due to the lack of adequate verifications. We conducted a two-center retrospective observational study in which the ISH technique was used to differentiate Trichosporon spp. and C. albicans in FFPE tissue from autopsy specimens. The study included 88 cases with blood stream yeast infection without Cryptococci extracted from 459 autopsy files of cases with proven invasive fungal infection (IFI). Positive signals for the Trichosporon spp. protein nucleic acid (PNA) probe and C. albicans PNA probe were seen for 7 and 35 cases, respectively, whereas the remaining 46 were negative for both. For the Trichosporon spp.- positive specimens, 5/7 were reported as candidiasis in autopsy records. Our results suggested that accurate histological identification of fungal infections remains challenging, but ISH may be a suitable approach to support histological findings. In addition, this retrospective study suggested that trichosporonosis may have high prevalence among cases of bloodstream yeast infections in Japan.

N-acetylglucosamine-mediated morphological transition in Candida albicans and Candida tropicalis

Morphological transitions in Candida species are key factors in facilitating invasion and adapting to environmental changes. N-acetylglucosamine (GlcNAc) is a monosaccharide signalling molecule that can regulate morphological transitions in Candida albicans and Candida tropicalis. Interestingly, although the uptake and metabolic pathways of GlcNAc and GlcNAc-mediated white-to-opaque cell switching are similar between the two Candida species, GlcNAc induces hyphal development in C. albicans, whereas it suppresses hyphal development in C. tropicalis. These findings indicate that the characteristics of C. albicans and C. tropicalis in response to GlcNAc are remarkably different. Here, we compare the conserved and divergent GlcNAc-mediated signalling pathways and catabolism between the two Candida species. Deletion of NGT1, a GlcNAc transportation gene, inhibited hyphal formation in C. albicans but promoted hyphal development in C. tropicalis. To further understand these opposite effects on filamentous growth in response to GlcNAc in the two Candida species, the cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) signalling pathways in both C. albicans and C. tropicalis were compared. Interestingly, GlcNAc activated the cAMP/PKA signalling pathway of the two Candida species, suggesting that the hyphal development-regulated circuit is remarkably diverse between the two species. Indeed, the Ndt80-like gene REP1, which is critical for regulating GlcNAc catabolism, exhibits distinct roles in the hyphal development of C. albicans and C. tropicalis. These data suggest possible reasons for the divergent hyphal growth response in C. albicans and C. tropicalis upon GlcNAc induction.

A seven-year surveillance of Candida bloodstream infection at a university hospital in KSA

Objectives

Candidemia incidence has increased in the past few years, with high mortality. Previous studies have reported a variable distribution of Candida spp. among different regions. This study aimed to identify the species found in Candida bloodstream infections, routine antifungal susceptibility testing, and mortality outcomes in an academic medical centre.

Methods

Between January 2012 and December 2018, the positive blood cultures for candidemia infection were retrieved and statistically analysed for species prevalence, susceptibility pattern, and crude mortality at 14, 30, 60 and 90 days.

Results

Of 156 candidemia cases, a majority (69.2%) was caused by non-albicans Candida spp. After Candida albicans (30.8%), Candida tropicalis and Candida parapsilosis were the second and third most frequeunt isolates spp, each counting for 23.7%. Acquired resistance was detected in 14.8% of candidemia strains. No other antifungal resistance was detected. The overall crude mortality rates of all species were 29.3%, 47.9%, 56.4%, and 58.0% at 14, 30, 60, and 90 days, respectively. A higher mortality rate was noted in cases of Candida krusei infection (crude mortality 71.4–100%, p = 0.002).

Conclusion

In this study, a considerable shift to non-albicans Candida causing most bloodstream infections was observed. As such infections pose a serious threat to hospitalised patients, microbiology laboratories are urged to adopt rapid diagnostic and minimal inhibitory concentration-based testing for the detection of susceptible dose-dependent phenotypes. Prospective studies are essential to consider the prognosis of bloodstream infections by various Candida species in a multivariate model.

Drug-Resistant Fungi: An Emerging Challenge Threatening Our Limited Antifungal Armamentarium

The high clinical mortality and economic burden posed by invasive fungal infections (IFIs), along with significant agricultural crop loss caused by various fungal species, has resulted in the widespread use of antifungal agents. Selective drug pressure, fungal attributes, and host- and drug-related factors have counteracted the efficacy of the limited systemic antifungal drugs and changed the epidemiological landscape of IFIs. Species belonging to Candida, Aspergillus, Cryptococcus, and Pneumocystis are among the fungal pathogens showing notable rates of antifungal resistance. Drug-resistant fungi from the environment are increasingly identified in clinical settings. Furthermore, we have a limited understanding of drug class-specific resistance mechanisms in emerging Candida species. The establishment of antifungal stewardship programs in both clinical and agricultural fields and the inclusion of species identification, antifungal susceptibility testing, and therapeutic drug monitoring practices in the clinic can minimize the emergence of drug-resistant fungi. New antifungal drugs featuring promising therapeutic profiles have great promise to treat drug-resistant fungi in the clinical setting. Mitigating antifungal tolerance, a prelude to the emergence of resistance, also requires the development of effective and fungal-specific adjuvants to be used in combination with systemic antifungals.

E-test Determination of Antifungal Susceptibility of Candida Species Isolated from Turkeys

INTRODUCTION

Candida species are a natural component of the intestinal tract microflora, but in favourable conditions they can cause superficial, mucosal, or even systemic candidiasis. Poultry production might be a source of human drug-resistant yeast infections, including Candida spp. The limited data concerning the antifungal susceptibility of poultry Candida isolates prompted us to carry out research to determine the susceptibility of isolates from turkey intestinal tracts.

METHOD AND MATERIALS

The beak cavity, crop and cloaca were swabbed of 580 turkeys from 58 flocks in western Poland. The susceptibility tests were conducted using the E-test method with amphotericin B, fluconazole, itraconazole, and voriconazole on 52 isolates of C. albicans, C. catenulata, C. glabrata, C. palmioleophila, C. rugosa, C. krusei and C. lusitaniae.

RESULTS

All isolates were susceptible to voriconazole. According to the MIC values obtained for amphotericin B and fluconazole, all Candida spp. isolates were classified as susceptible according to the described breakpoints except for C. krusei, which was the only isolate that was amphotericin B-, fluconazole- and itraconazole-resistant. The susceptibility to itraconazole varied: 11 of the Candida isolates were susceptible (21.1%), 29 were dose-dependently susceptible (55.8%), and 12 isolates were resistant (23.1%).

CONCLUSION

There are few resistant strains of Candida in turkeys, and the drug resistance varies. When Candida passes from turkeys to humans, there is a wide range of antifungal treatment options.

The Galleria mellonella infection model as a system to investigate the virulence of Candida auris strains

Candida auris is a multiresistant pathogenic yeast commonly isolated from bloodstream infections in immunocompromised patients. In this work, we infected Galleria mellonella larvae with 105 CFU of a reference strains and two clinical isolates of C. albicans and C. auris and we compared the outcomes of infection between both species. Larvae were evaluated every 24 h for a total of 120 h following the G. mellonella Health Index Scoring System, and survival, activity, melanization and cocoon formation were monitored. Our results showed that clinical isolates were significantly more pathogenic than reference strains independently of the tested species, producing lower survival and activity scores and higher melanization scores and being C. albicans strains more virulent than C. auris strains. We did not find differences in mortality between aggregative and non-aggregative C. auris strains, although non-aggregative strains produced significantly lower activity scores and higher melanization scores than aggregative ones. Survival assays using Galleria mellonella have been previously employed to examine and classify strains of this and other microbial species based on their virulence before scaling the experiments to a mammal model. Taken together, these results show how a more complete evaluation of the model can improve the study of C. auris isolates.

Multilocus Sequence Typing Reveals Clonality of Fluconazole-Nonsusceptible Candida tropicalis: A Study From Wuhan to the Global

Candida tropicalis is a globally distributed human pathogenic yeast, and its increasing resistance to azoles makes clinical treatment difficult. In this study, we investigated the clinical features, azole resistance and genetic relatedness of 87 C. tropicalis isolates from central China and combined with the global database to explore the relationship between genetic information and fluconazole susceptibility. Of the 55 diploid sequence types (DSTs) identified by multilocus sequence typing (MLST), 27 DSTs were new to the C. tropicalis MLST database. Fluconazole-nonsusceptible (FNS) isolates were genetically closely related. goeBURST analysis showed that DST225, DST376, DST506, and DST546 formed a distinct and unique FNS clonal complex (CC) in Wuhan. The local FNS CC belongs to the large FNS CC (CC2) in China, in which the putative founder DST225 has been reported from the environment. The three most prevalent types (DST506, DST525, and DST546) in Wuhan had high minimum inhibitory concentrations (MICs) for antifungal azoles, and the six possible nosocomial transmissions we captured were all FNS strains, most of which were from CC2. Unique FNS CCs have been found in Singapore (CC8) and India (CC17) and are close to China's CC2 in the minimum spanning tree. There were no FNS CCs outside Asia. This study is the first to reveal a significant correlation between genetic information and fluconazole susceptibility worldwide and to trace geographical locations, which is of great value for molecular epidemiological surveillance and azole-resistance study of C. tropicalis globally.

Distribution of invasive fungal infections: Molecular epidemiology, etiology, clinical conditions, diagnosis and risk factors: A 3-year experience with 490 patients under intensive care

Recently, the prevalence of invasive fungal infections (IFIs) is rising. The global mortality rate of IFIs is 10-49%. This study aimed to determine the prevalence, the causative agents, and the risk factors associated with the invasive fungal infections in a tertiary health center to provide valid decision-grounds for healthcare professionals to effectively prevent, control, and treat fungal infections. The current study was conducted on 1477 patients suspected to have systemic fungal infections from different units of the hospital. After screening using routine mycological examination, the patients were confirmed with complementary mycological and molecular methods. Patients were included based on the confirmed diagnosis of IFI and excluded based on lack of a microbiologically and histologically proven diagnosis of IFI. Of the 1477 patients recruited in this study, confirmed cases of fungal infection were 490 (169 proven; 321 cases probable). Among the fungi recovered, Candida species had the highest frequency 337 (68.8%) followed by Aspergillus species 108 (22.1%), Zygomycetes species 21 (4.3%), non-Candida yeast 9 (1.8%). Others were black fungi 5 (1%), mycetoma agents 5 (1%), Fusarium 4 (0.8%), and Trichoderma (0.2%). Hematologic malignancies and diabetes mellitus were the most common underlying diseases among IFI-confirmed patients. This study observed an increased frequency of invasive candidiasis with non-albicans Candida and other invasive saprophytic fungal infections. The increased rate of invasive candidiasis with non-albicans agents highlights a new perspective in the epidemiology and treatment of invasive fungal infections.

Synergistic Antifungal Activity of Chitosan with Fluconazole against Candida albicans, Candida tropicalis, and Fluconazole-Resistant Strains

(1) Background: Few antifungal drugs are currently available, and drug-resistant strains have rapidly emerged. Thus, the aim of this study is to evaluate the effectiveness of the antifungal activity from a combinational treatment of chitosan with a clinical antifungal drug on Candida albicans and Candida tropicalis. (2) Methods: Minimum inhibitory concentration (MIC) tests, checkerboard assays, and disc assays were employed to determine the inhibitory effect of chitosan with or without other antifungal drugs on C. albicans and C. tropicalis. (3) Results: Treatment with chitosan in combination with fluconazole showed a great synergistic fungicidal effect against C. albicans and C. tropicalis, but an indifferent effect on antifungal activity when challenged with chitosan-amphotericin B or chitosan-caspofungin simultaneously. Furthermore, the combination of chitosan and fluconazole was effective against drug-resistant strains. (4) Conclusions: These findings provide strong evidence that chitosan in combination with fluconazole is a promising therapy against two Candida species and its drug-resistant strains.

A 5-Year Review of Invasive Fungal Infection at an Academic Medical Center

Background: Invasive fungal infection (IFI) is one of the most common nosocomial infections. However, data on the epidemiology of IFI and susceptibility to antifungal agents in China are quite limited, and in particular, no current data exist on the microbiological, and clinical characteristics of IFI patients in Northeast China.

Objectives: The purpose of this study was to provide a retrospective review of the clinical characteristics, laboratory test results, and risk factor predictions of inpatients diagnosed with IFI. Multivariate regression analysis was used to assess prognostic factors associated with the mortality of these patients.

Methods: We retrospectively analyzed the results from 509 patients with IFI extracted from the First Hospital of China Medical University from January 2013 to January 2018.

Results: Neutrophil numbers, total bilirubin, length of stay in the ICU, renal failure, use of immunosuppressants within the past 30 days, stomach tube placement and septic shock were risk factors for death from IFI. Recent surgery (within 2 weeks) and drainage tube placement did not increase mortality in these IFI patients. Increased serum levels of PCT (AUC 0.601, 95% CI 0.536–0.665, P = 0.003) and CRP (AUC 0.578, 95% CI 0.512–0.644, P = 0.020) provided effective predictors of 30-day mortality rates.

Conclusions: We report for the first time epidemiological data on invasive fungal infections in Northeast China over the past 5 years. Despite the limited available clinical data, these findings will greatly aid clinical health care workers with regard to the identification, prevention, and treatment of IFI in hospitalized patients.

Molecular epidemiology of Candida tropicalis isolated from urogenital tract infections

Candida tropicalis is a common human pathogenic yeast, and its molecular typing is important for studying the population structure and epidemiology of this opportunistic yeast, such as epidemic genotype, population dynamics, nosocomial infection, and drug resistance surveillance. In this study, the antifungal susceptibility test and multilocus sequence typing (MLST) analysis were carried out on C. tropicalis from central China. Among 64 urogenital isolates, 45 diploid sequence types (DST) were found, of which 20 DSTs (44.4%) were new to the central database. The goeBURST analysis showed that CC1 (clonal complex) was the only azole‐resistant (100%, 10/10) cluster in Wuhan, which was composed of DST546, DST225, DST376, and DST506, and most of the strains (90%, 9/10) were isolated from the urinary tract. Potential nosocomial infections were mainly caused by CC1 strains. The azole resistance rate of urinary isolates (50.0%, 21/42) was higher than that of vaginal isolates (27.3%, 6/22). The genotype diversity and novelty of vaginal isolates were higher than those of urinary isolates. C. tropicalis population in Wuhan was genetically diverse and divergent from that seen in other countries. In this study, there were significant differences in genotype and azole susceptibility between urine and vaginal strains. The azole‐resistant cluster (CC1) found in urine is of great significance for the clinical treatment and prevention of nosocomial infection. The newly discovered DSTs will contribute to further study the similarity, genetic relationship, and molecular epidemiology of C. tropicalis worldwide.

A seven-year surveillance study of the epidemiology, antifungal susceptibility, risk factors and mortality of candidaemia among paediatric and adult inpatients in a tertiary teaching hospital in China

Background

There are no current national estimates of the candidaemia burden in China, and epidemiological candidaemia data from the underdeveloped region of China are lacking.

Methods

A 7-year retrospective study was carried out to analyse the prevalence, species distribution, antifungal susceptibility, risk factors and inpatient mortality of candidaemia among paediatric and adult patients in a regional tertiary teaching hospital in China.

Results

During the seven-year study period, a total of 201 inpatients with candidaemia were identified. The median age of the patients was 65 years (range, 1 day to 92 years), and 114 of the patients (56.7%) were male. The mean annual incidence of candidaemia was 0.26 cases per 1000 admissions (0.42 cases per 1000 paediatric admissions vs 0.24 cases per 1000 adult admissions, P < 0.05). Candida albicans was the most common fungal species (81/201, 40.3%) in all patients, Candida glabrata was the most common fungal species (18/35, 51.4%) in paediatric patients. Most isolates were susceptible to flucytosine (99.0%) and amphotericin B (99.0%), and the activity of antifungal agents against Candida species was no significant difference in satisfaction between paediatric and adult patients (P > 0.05). The all-cause mortality rate was 20.4% (paediatric patients: 11.4% vs adult patients:22.3%, P > 0.05). Fewer univariate predictors of poor outcomes were identified for paediatric patients than for adult patients (4 vs 11 predictors). Respiratory dysfunction and septic shock were independent predictors of 30-day mortality for all patients.

Conclusions

The epidemiological data of candidaemia in paediatric and adult patients are only different in the distributions of Candida species and the mean annual incidence of candidaemia. Flucytosine and amphotericin B can be used as first-choice agents when no antifungal susceptibility test results are available.

Candida tropicalis RON1 is required for hyphal formation, biofilm development, and virulence but is dispensable for N-acetylglucosamine catabolism

NDT80-like family genes are highly conserved across a large group of fungi, but the functions of each Ndt80 protein are diverse and have evolved differently among yeasts and pathogens. The unique NDT80 gene in budding yeast is required for sexual reproduction, whereas three NDT80-like genes, namely, NDT80, REP1, and RON1, found in Candida albicans exhibit distinct functions. Notably, it was suggested that REP1, rather than RON1, is required for N-acetylglucosamine (GlcNAc) catabolism. Although Candida tropicalis, a widely dispersed fungal pathogen in tropical and subtropical areas, is closely related to Candida albicans, its phenotypic, pathogenic and environmental adaptation characteristics are remarkably divergent. In this study, we focused on the Ron1 transcription factor in C. tropicalis. Protein alignment showed that C. tropicalis Ron1 (CtRon1) shares 39.7% identity with C. albicans Ron1 (CaRon1). Compared to the wild-type strain, the C. tropicalis ron1Δ strains exhibited normal growth in different carbon sources and had similar expression levels of several GlcNAc catabolic genes during GlcNAc treatment. In contrast, C. tropicalis REP1 is responsible for GlcNAc catabolism and is involved in GlcNAc catabolic gene expressions, similar to C. albicans Rep1. However, REP1 deletion strains in C. tropicalis promote hyphal development in GlcNAc with low glucose content. Interestingly, CtRON1, but not CaRON1, deletion mutants exhibited significantly impaired hyphal growth and biofilm formation. As expected, CtRON1 was required for full virulence. Together, the results of this study showed divergent functions of CtRon1 compared to CaRon1; CtRon1 plays a key role in yeast-hyphal dimorphism, biofilm formation and virulence.

LAY ABSTRACT

In this study, we identified the role of RON1, an NDT80-like gene, in Candida tropicalis. Unlike the gene in Candida albicans, our studies showed that RON1 is a key regulator of hyphal formation, biofilm development and virulence but is dispensable for N-acetylglucosamine catabolism in C. tropicalis.

Drug Repurposing of Haloperidol: Discovery of New Benzocyclane Derivatives as Potent Antifungal Agents against Cryptococcosis and Candidiasis

Despite the high morbidity and mortality of invasive fungal infections (IFIs), effective and safe antifungal agents are rather limited. Starting from antifungal lead compound haloperidol that was identified by drug repurposing, a series of novel benzocyclane derivatives were designed, synthesized, and assayed. Several compounds showed improved antifungal potency and broader antifungal spectra. Particularly, compound B10 showed good inhibitory activities against a variety of fungal pathogens and was proven to be an inhibitor of several virulence factors important for drug resistance. In the in vivo cryptococcosis and candidiasis models, compound B10 could effectively reduce the brain fungal burden of Cryptococcus neoformans and synergize with fluconazole to treat resistant Candida albicans infections. Preliminary antifungal mechanism studies revealed that compound B10 regained cell membrane damage and down-regulated the overexpression of ERG11 and MDR1 genes when used in combination with fluconazole. Taken together, haloperidol derivative B10 represents a promising lead compound for the development of a new generation of antifungal agents.

Mecanismos de resistencia a fluconazol expresados por Candida glabrata: una situación para considerar en la terapéutica

Introducción: Los esfuerzos terapéuticos orientados a atender las micosis por Candida spp. se han enfocado en el empleo de azoles; sin embargo, en la literatura científica se discute su beneficio, por los amplios y descritos mecanismos de resistencia. Objetivo: Describir los mecanismos de resistencia al fluconazol expresados por la especie Candida glabrata, con la intención de que sean considerados dentro de las variables de elegibilidad para la intervención. Método: Se realizó una revisión integrativa utilizando la pregunta orientadora: ¿cuáles son los mecanismos de resistencia al fluconazol expresados por la especie Candida glabrata? Veintinueve estudios obtenidos de la base de datos PubMed cumplieron los criterios del análisis crítico propuesto por el instrumento PRISMA, utilizado para la selección de los artículos incluidos para su revisión en este manuscrito. Las categorías bajo las cuales se organizaron los elementos de análisis fueron: sobrexpresión de bombas de eflujo y modificaciones en la enzima lanosterol 14-alfa-desmetilasa. Resultados: Los mecanismos de resistencia al fluconazol expresados por Candida glabrata están determinados principalmente por la regulación a la alza de bombas de adenosina-trifosfato Binding Cassette (ABC) y por la modificación del punto de unión con su blanco farmacológico: la enzima lanosterol 14-alfa-desmetilasa. Conclusión: Los mecanismos de resistencia expresados por Candida glabrata se asocian con la modificación estructural de la diana farmacológica y la sobreexpresión de bombas de eflujo de manera diferencial a otras especies. Se sugiere que Candida glabrata es intrínsecamente menos susceptible al fluconazol.