Epidemiological and mycological characteristics of candidemia in Iran: A systematic review and meta-analysis

Assessment of incidence and risk factors of COVID-19-associated candidemia using diagnosis procedure combination data

BACKGROUND

Candidemia is an important coronavirus disease 2019 (COVID-19)-associated invasive fungal infection. Patients with COVID-19 may be susceptible to candidemia; however, evidence regarding its incidence, risk factors, and involvement in mortality is insufficient.

OBJECTIVES

To explore the incidence of and potential risk factors for candidemia in patients with severe or critical COVID-19 and evaluate the relationship between candidemia and mortality in patients with severe or critical COVID-19.

METHODS

The incidence of candidemia in patients with severe and critical COVID-19 was evaluated using administrative claims data from acute care hospitals in Japan. Multivariable regression models were used to explore potential risk factors for candidemia and their contribution to mortality in patients with severe and critical COVID-19.

RESULTS

Candidemia occurred in 0.3-1.1 % of patients with severe or critical COVID-19. Renal impairment, use of steroid, blood transfusion, and use of central venous catheter were potential risk factors for candidemia in patients with severe to critical COVID-19.

CONCLUSIONS

Candidemia in patients with COVID-19 was an independent risk factor for mortality. Candidemia in patients with severe to critical COVID-19 is a grave complication and may increase mortality.

Epidemiology and risk factors of fungal pathogens in sepsis: a prospective nationwide multicenter cohort study

BACKGROUND

The incidence of sepsis with identified fungal pathogens is increasing and is associated with higher morbidity and mortality. Co-infection with fungal infections in COVID-19 patients is attracting clinical attention. This study examines the epidemiology, risk factors, and outcomes among sepsis patients with identified fungal pathogens.

METHODS

We conducted a nationwide cohort study of adult patients with sepsis from the Korean Sepsis Alliance Database in South Korea between September 2019 and December 2021. We identified 407 patients with documented fungal pathogens, categorized according to the presence of hemato-oncologic malignancies.

RESULTS

Of the 11,981 patients with sepsis, fungal pathogens were identified in 3.4% of cases. Among these patients, 38.3% had co-existing hematologic or solid organ cancer. Older age, higher clinical frailty scale scores, and underlying conditions, such as chronic kidney disease, cerebrovascular disease, and dementia, were more prevalent in patients without hemato-oncologic malignancies. The most common fungal pathogens were Candida albicans (47.9%), Candida glabrata (20.6%), and Candida tropicalis (13.5%). Only 6.6% of the patients with confirmed fungal pathogens received antifungal treatment. The presence of hemato-oncologic malignancies did not significantly affect patient outcomes. Factors associated with the presence of identified fungal pathogens included chronic kidney disease (Odds ratio [OR] 1.662; 95% confidence interval [CI] 1.216-2.273; p = 0.001), connective tissue disease (OR 1.885; 95% CI 1.058-3.358; p = 0.032), immunocompromised status (OR 2.284; 95% CI 2.186-3.753; p = 0.001), and invasive mechanical ventilation (OR 2.864; 95% CI 2.186-3.753; p < 0.001).

CONCLUSIONS

Sepsis identified fungal pathogen are associated with chronic kidney disease, immunocompromised status and other risk factors, demonstrating the need for early detection, targeted management and improved antifungal strategies to improve patient outcomes.

An 11-Year retrospective analysis of candidiasis epidemiology, risk factors, and antifungal susceptibility in a tertiary care hospital in China

Candidiasis poses a significant threat to human health, especially in immunocompromised patients. However, there is a paucity of epidemiological data concerning the prevalence of candidiasis in developing regions of China. We conducted a retrospective study on patients positive for Candida infections in a tertiary care hospital in Shantou, China, to identify the clinical characteristics and risk factors for candidiasis. Of 5,095 cases of candidiasis, 489 (9.59%) were candidemia infections. Candida albicans (n = 230, 47.0%) was the predominant species identified among all patients. Non-albicans Candida (NAC) was more prevalent in adult patients, while Candida glabrata was slightly more frequent in pediatric patients (n = 10, 14.7%). Pulmonary diseases (n = 200, 47.8%) were the most common underlying comorbidities in adult patients (n = 25, 35.2%). Thrombocytopenia was the only laboratory finding higher in adult patients than in pediatric patients. Respiratory dysfunction, the presence of a central venous catheter, septic shock, and thrombocytopenia were independent risk factors for candidemia-related 30-day mortality. Amphotericin B exhibited high efficacy (100%), and itraconazole exhibited the lowest efficacy against all tested Candida isolates. C. glabrata had a lower susceptibility to azole, although this was not statistically significant. The epidemiological data on candidiasis, specifically candidemia in pediatric and adult patients, varied regarding the prevalence of Candida species and associated risk factors. This study provides guidance for prescribing the appropriate therapy and yields insights into the susceptibility patterns of different Candida isolates to antifungal drugs.

Epidemiology of Candidemia in Mashhad, Northeast Iran: A Prospective Multicenter Study (2019-2021)

Candidemia is a major cause of morbidity and mortality in health care settings, and its epidemiology is changing. In the last two decades, the proportion of non-albicans Candida (NAC) yeasts in candidemia has increased. These yeasts more often display resistance to common antifungals. In many western countries, candidemia is mainly caused by susceptible C. albicans, while in resource-limited countries, including Iran, the candidemia species distribution is studied less often. Here, we investigated the species distribution, resistance levels, and characteristics of patients with candidemia in five hospitals in Mashhad (northeast Iran) for two years (2019-2021). Yeast isolates from blood were identified with MALDI-TOF MS and subjected to antifungal susceptibility testing (AFST) using the broth microdilution method, while molecular genotyping was applied to Candida parapsilosis isolates. In total, 160 yeast isolates were recovered from 160 patients, of which the majority were adults (60%). Candidemia was almost equally detected in men (48%) and women (52%). Almost half of patients (n = 67, 49%) were from intensive care units (ICUs). C. parapsilosis (n = 58, 36%) was the most common causative agent, surpassing C. albicans (n = 52, 33%). The all-cause mortality rate was 53%, with C. albicans candidemia displaying the lowest mortality with 39%, in contrast to a mortality rate of 59% for NAC candidemia. With microbroth AFST, nearly all tested isolates were found to be susceptible, except for one C. albicans isolate that was resistant to anidulafungin. By applying short tandem repeat (STR) genotyping to C. parapsilosis, multiple clusters were found. To summarize, candidemia in Mashhad, Iran, from 2019 to 2021, is characterized by common yeast species, in particular C. parapsilosis, for which STR typing indicates potential nosocomial transmission. The overall mortality is high, while resistance rates were found to be low, suggesting that the high mortality is linked to limited diagnostic options and insufficient medical care, including the restricted use of echinocandins as the first treatment option.

Distribution of Nosocomial Pathogens and Antimicrobial Resistance among Patients with Burn Injuries in China: A Comprehensive Research Synopsis and Meta-Analysis

INTRODUCTION

Over the past decade, numerous studies have described the types of pathogens and their antibiotic resistance patterns in patients with burn injuries in China; however, the findings have generally been inconsistent. We conducted a literature search and meta-analysis to summarize the infection spectra and antimicrobial resistance patterns in patients with burn injuries.

METHODS

We searched the PubMed, Embase, Web of Science, China National Knowledge Infrastructure, China Biomedical Literature, Wanfang, and Weipu databases for relevant articles published between January 2010 and December 2023. The DerSimonian-Laird random-effects model was used to estimate the proportions and 95% confidence intervals (CIs) of pathogens among Chinese patients with burn injuries. Meta-regression analyses were performed to explore differences in the proportions of pathogens among different subgroups and their resistance patterns. This study was registered with PROSPERO (CRD42024514386).

RESULTS

The database searches yielded 2017 records; after removing duplicates and conducting initial screening, 219 articles underwent full-text screening. Ultimately, 60 studies comprising a total of 62,819 isolated strains reported the proportions of pathogens in patients with burn injuries and were included in this meta-analysis. Meta-analyses were conducted on 18 types of pathogens. The most common pathogens causing infections in Chinese patients with burn injuries were Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, and Staphylococcus epidermidis. Similar results were observed in the subgroup analysis focusing on wound infections. Since 2015, there has been a significant decrease in the proportion of Pseudomonas aeruginosa (R2 = 4.89%) and a significant increase in the proportion of Klebsiella pneumoniae (R2 = 9.60%). In terms of antibiotic resistance, there has been a significant decrease in the resistance of Staphylococcus aureus to multiple antibiotics and an increasing trend in the resistance of Klebsiella pneumoniae.

CONCLUSIONS

We systematically summarized the epidemiological characteristics and antibiotic resistance patterns of pathogens among individuals suffering from burns in China, thus providing guidance for controlling wound infections and promoting optimal empirical antimicrobial therapy. The observed high levels of antibiotic resistance underscore the need for ongoing monitoring of antibiotic usage trends.

COVID-19 associated candidemia: From a shift in fungal epidemiology to a rise in azole drug resistance

Our understanding of fungal epidemiology and the burden of antifungal drug resistance in COVID-19-associated candidemia (CAC) patients is limited. Therefore, we conducted a retrospective multicenter study in Iran to explore clinical and microbiological profiles of CAC patients. Yeast isolated from blood, were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and subjected to antifungal susceptibility testing (AFST) using the broth microdilution method M27-A3 protocol. A total of 0.6% of the COVID-19 patients acquired CAC (43/6174). Fluconazole was the most widely used antifungal, and 37% of patients were not treated. Contrary to historic candidemia patients, Candida albicans and C. tropicalis were the most common species. In vitro resistance was high and only noted for azoles; 50%, 20%, and 13.6% of patients were infected with azole-non-susceptible (ANS) C. tropicalis, C. parapsilosis, and C. albicans isolates, respectively. ERG11 mutations conferring azole resistance were detected for C. parapsilosis isolates (Y132F), recovered from an azole-naïve patient. Our study revealed an unprecedented rise in ANS Candida isolates, including the first C. parapsilosis isolate carrying Y132F, among CAC patients in Iran, which potentially threatens the efficacy of fluconazole, the most widely used drug in our centers. Considering the high mortality rate and 37% of untreated CAC cases, our study underscores the importance of infection control strategies and antifungal stewardship to minimize the emergence of ANS Candida isolates during COVID-19.

Consensus on the treatment of second-degree burn wounds (2024 edition)

Second-degree burns are the most common type of burn in clinical practice and hard to manage. Their treatment requires not only a consideration of the different outcomes that may arise from the dressing changes or surgical therapies themselves but also an evaluation of factors such as the burn site, patient age and burn area. Meanwhile, special attention should be given to the fact that there is no unified standard or specification for the diagnosis, classification, surgical procedure, and infection diagnosis and grading of second-degree burn wounds. This not only poses great challenges to the formulation of clinical treatment plans but also significantly affects the consistency of clinical studies. Moreover, currently, there are relatively few guidelines or expert consensus for the management of second-degree burn wounds, and no comprehensive and systematic guidelines or specifications for the treatment of second-degree burns have been formed. Therefore, we developed the Consensus on the Treatment of Second-Degree Burn Wounds (2024 edition), based on evidence-based medicine and expert opinion. This consensus provides specific recommendations on prehospital first aid, nonsurgical treatment, surgical treatment and infection treatment for second-degree burns. The current consensus generated a total of 58 recommendations, aiming to form a standardized clinical treatment plan.

Microbial Analysis of Obturators During Maxillofacial Prosthodontic Treatment Over an 8-Year Period

The aim of the study was to investigate the microbial colonization (by Candida species, anaerobic and facultative anaerobic bacteria) of maxillary obturators used for the restoration of maxillary defects, including during radiotherapy.

Retrospective cohort study.

Fifteen patients requiring a maxillary obturator prosthesis had swabs of their obturators and adjacent tissues taken at different stages of their treatment over a period of 8 years.

Identification of microbial species from the swabs was carried out using randomly amplified polymorphic DNA polymerase chain reaction (RAPD PCR) analysis, checkerboard DNA-DNA hybridization, CHROMagar Candida chromogenic agar, and DNA sequencing.

Candida species were detected in all patients and all patients developed mucositis and candidiasis during radiotherapy which was associated with an increase in colonization of surfaces with Candida spp., particularly C albicans. Microbial colonization increased during radiotherapy and as an obturator aged, and decreased following a reline, delivery of a new prosthesis, or antifungal treatment during radiotherapy.

Microbial colonization of maxillary obturators was related to the stage of treatment, age of the obturator material, radiotherapy and antifungal medications, and antifungal treatment may be recommended if C albicans colonization of palatal tissues is greater than 105 colony-forming units per cm2 following the first week of radiotherapy.

In-vivo efficiency of the novel azole compounds (ATTAF-1 and ATTAF-2) against systemic candidiasis in a murine model

BACKGROUND

Antifungal resistance is the main health concern in the control of invasive fungal infections. This research was designed to further assess the antifungal activity of aryl-1,2,4-triazole-3-ylthio analogs of fluconazole (ATTAFs) against Candida albicans systemic candidiasis in the murine model.

MATERIALS & METHODS

The murine model of systemic candidiasis was designed via the inoculation of 1 × 106 CFU of Candida albicans. The treatment dosages of 3.5 and 35 mg/kg per day were selected for ATTAFs and fluconazole, respectively. The median survival time (MST) was assayed for 30 days post-infection. The quantitative and qualitative (via histopathology staining) fungal burden was also assessed. Furthermore, immunohistochemistry and biochemistry assays were performed to monitor anti-inflammatory activity using the Cyclooxygenase-2 (Cox-2) marker and changes in serum protein levels.

RESULTS

ATTAFs considerably improved the survival of the murine model (P < 0.003). Compared with fluconazole, the antifungal activity of ATTAFs and their MST showed no difference (P > 0.05). However, these compounds decreased the fungal burden in the kidneys, spleen, and liver.

CONCLUSION

Our research indicates that ATTAF-1 and ATTAF-2 are effective therapeutic agents due to their fungal clearing and increasing the MST in the murine model of systemic candidiasis. Although we concluded that these components are novel and promising candidates for the management of invasive candidiasis, further studies are warranted to correlate these findings with clinical outcomes.

Catheter-associated blood stream infections due to Candida pararugosa in a patient with acute myeloid leukemia: A case report

Infections caused by uncommon Candida species have dramatically increased in recent decades, mostly among hematological malignancies. This report aims to present a case of Candida pararugosa bloodstream infection, review previous cases with C. pararugosa infections, and provide a concise review of the clinical background, risk factors, and brief the management of infections. A 3-year-old boy with a history of acute myeloid leukemia was hospitalized in Omid Hospital, Isfahan, Iran. Two consecutive blood cultures were taken from the peripheral vein and port catheter; after that, empirically meropenem was administered. Candida pararugosa were isolated from blood-based on conventional and molecular assays. Furthermore, the antifungal susceptibility profiles of the isolate were determined, which exhibited resistance to fluconazole (8 μg/mL). Antifungal therapy with caspofungin and removing the patient's port led to a significant clinical improvement of the patient's conditions. So far, in the literature review, 10 cases of clinical C. pararugosa isolates were found, of which 5 patients had bloodstream infections. Most patients with C. pararugosa infection presented with specific underlying conditions, such as malignancy, sarcoma, surgery, and adult acute myeloid leukemia. Patients with indwelling catheters run a high risk of acquiring C. pararugosa bloodstream infection. Therefore, special consideration should be given to opportunistic fungal infections in immunocompromised individuals using catheters.

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

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

Comparative Analysis of Epidemiological and Clinical Characteristics Between Invasive Candida Infection versus Colonization in Critically Ill Patients in a Tertiary Hospital in Anhui, China

Objective

Invasive infections due to Candida spp. have unique epidemiology, strain distribution, antimicrobial susceptibility, and clinical features. This study aimed to compare and evaluate these characteristic variables between invasive Candida infection and colonization of critically ill patients in local China to potentially improve differential diagnosis and therapy.

Methods

A total of 193 critically ill patients were recruited and followed up for the study, and 133 Candida isolates were obtained from invasive Candida-infected or -colonized subjects. The strains were identified to species level through matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry, assisted by DNA sequencing. Candida susceptibility to common antifungals, including azoles, was determined by microbroth ATB Fungus 3 methodology. Azole resistance–related gene sequencing and homologous 3D-structure modeling were employed. Patient demographics and clinical risk factors were documented and comparatively analyzed from the hospital information-management system.

Results

Non–C. albicans Candida (56%) principally caused invasive Candida infections, while C. albicans (55.17%) contributed more to Candida colonization in critically ill patients. Additional risk factors exerted significant impact on both Candida cohorts, primarily including invasive interventions, cancers, and concurrent infections in common. Most colonized Candida spp. harbored relatively higher sensitivity to azoles. ERG11 gene mutations of T348A and A1309G, A395T and C461T, and a novel G1193T to our knowledge were identified in azole-resistant C. albicans, C. tropicalis, and C. parapsilosis respectively, and their corresponding homologous 3D-structure modeling was putatively achieved.

Conclusion

Distinct epidemiological and clinical characteristics existed between invasive Candida infection and colonization in critically ill patients. Multiple risk factors significantly involved both the Candida cohorts. Colonized Candida exhibited generally higher azole sensitivity than invasively infectious counterparts. ERG11 point mutations had mechanistically potential ties with local Candida resistance to azoles.

Synthesis, Cytotoxicity Evaluation, and Antifungal Activity of Novel Nitroglycerin Derivatives against Clinical Candida albicans Isolates

Background

Candida albicans remains the main cause of candidiasis in most clinical settings. Available drugs for candidiasis treatment have many side effects. In this work, novel nitroglycerin derivatives were synthesized and their cytotoxic and antifungal effects evaluated against fluconazole susceptible and resistant clinical C. albicans isolates.

Methods

This experimental study was performed in Tehran University of Medical Sciences and Baqiatallah University of Medical Sciences, Tehran, Iran between Feb to Dec 2019. The in vitro activities of two novel nitroglycerin derivatives (1b and 2b) against 25 clinical fluconazole-susceptible and resistant C. albicans isolates and four standard C. albicans strains were determined according to CLSI reference M27-A3 documents. The cytotoxicity of chemical compounds was investigated near the SNL76/7 cells by colorimetric assay. Real-time PCRs were performed to evaluate the alterations in the regulation of ERG11 and CDR1 genes under nitroglycerin derivatives-treated and untreated conditions.

Results

The derivatives 1b and 2b exhibited potent antifungal activity against C. albicans isolates; MICs and MFCs varied from 18 μg/ml to 72 μg/ml and 36 μg/ml to 144 μg/ml, respectively. The cell viability evaluation demonstrated that both chemical compounds are safe within 24h. The nitroglycerin derivatives were able to reduce the transcription level of CDR1 and ERG11 genes in all susceptible and resistant C. albicans isolates.

Conclusion

Considering the potential and efficacy of these compounds against clinical C. albicans isolates, the complementary in vivo and clinical trials should be investigated.

Novel fluconazole-resistant zoonotic yeast isolated from mastitis

A hospital-based cross-sectional study was conducted during 2018-2019 to decipher the prevalence of yeast mastitis. The results indicated a 19.68% prevalence of clinical mastitis in bovines. Among them, 5.51% of samples revealed yeasts constituting 1.09% overall prevalence. Candida albicans was recorded as a significant fungal agent involved in clinical bovine mastitis. We record the association of Kodamaea ohmeri in clinical bovine mastitis. On proteomic and molecular confirmation, K. ohmeri isolates were re-identified from phenotypically identified Candida isolates associated with bovine mastitis. After conventional identification, the yeast isolates were re-identified by MALDI-TOF MS-based proteomic approaches. The D1/D2 domains of 26S-rRNA gene and 5.8S-internal transcribed spacer (ITS) rDNA regions based molecular phylogenetic analysis identified the isolates as K. ohmeri. The isolates were resistant to fluconazole. This study reports the first systemic study of K. ohmeri isolates recovered from bovine clinical mastitis, utilizing conventional, automated, proteomic, and genomic approaches followed by antifungal susceptibility. The findings suggest K. ohmeri as a potent opportunistic emerging pathogen of veterinary and public health concern, need for accurate identification of fungal agents from mycotic mastitis, and use of validated antifungal susceptibility assay because of developing resistance to antimycotic agents. Our findings suggest judicious use of fluconazole and alternative antifungal agents may be considered in case of an outbreak.

Virulence Factors and Azole-Resistant Mechanism of Candida Tropicalis Isolated from Candidemia

BACKGROUND

Limited knowledge exists on the virulence factors of Candida tropicalis and the mechanisms of azole resistance that lead to an intensified pathogenicity and treatment failure. We aimed to evaluate the virulence factors and molecular mechanisms of azole resistance among C. tropicalis isolated from patients with candidemia.

MATERIALS AND METHODS

Several virulence factors, including extracellular enzymatic activities, cell surface hydrophobicity (CSH), and biofilm formation, were evaluated. Antifungal susceptibility pattern and expression level of ERG11, UPC2, MDR1, and CDR1 genes of eight (4 fluconazole resistance and 4 fluconazole susceptible) clinical C. tropicalis isolates were assessed. The correlation between the virulence factors and antifungal susceptibility patterns was analyzed.

RESULTS

During a 4 year study, forty-five C. tropicalis isolates were recovered from candidemia patients. The isolates expressed different frequencies of virulence determinants as follows: coagulase 4 (8.9%), phospholipase 5 (11.1%), proteinase 31 (68.9%), esterase 43 (95.6%), hemolysin 44 (97.8%), biofilm formation 45 (100%) and CSH 45(100%). All the isolates were susceptible to amphotericin B and showed the highest resistance to voriconazole. There was a significant positive correlation between micafungin minimum inhibitory concentrations (MICs) and hemolysin production (r_s = 0.316). However, we found a negative correlation between fluconazole MICs and esterase production (r_s = -0.383). We observed the high expression of ERG11 and UPC2 genes in fluconazole-resistant C. tropicalis isolates.

CONCLUSION

C. tropicalis isolated from candidemia patients extensively displayed capacities for biofilm formation, hemolysis, esterase activity, and hydrophobicity. In addition, the overexpression of ERG11 and UPC2 genes was considered one of the possible mechanisms of azole resistance.

Yeast-Host Interactions: Anadenanthera colubrina Modulates Virulence Factors of C. albicans and Inflammatory Response In Vitro

Oral candidiasis is one of the most common fungal infections in humans. Its incidence has increased widely, as well as the antifungal resistance, demanding for the search for novel antifungal therapeutic agents. Anadenanthera colubrina (Vell.) Brenan is a plant species that has been proven to possess pharmacological effects, including antifungal and anti-inflammatory activities. This study evaluated in vitro the effects of standardized A. colubrina extract on virulence factors of Candida albicans and its regulation on immune response through C. albicans-host interaction. Antifungal activity was evaluated by Broth Microdilution Method against reference Candida strains (C. albicans, C. glabrata, C. tropicalis; C. dubliniensis). Anti-biofilm effect was performed on C. albicans mature biofilm and quantified by CFU/mL/g of biofilm dry weight. Proleotlytic enzymatic activities of proteinase and phospholipase were assessed by Azocasein and Phosphatidylcholine assays, respectively. Cytotoxicity effect was determined by Cell Titer Blue Viability Assay on Human Gingival Fibroblasts. Co-cultured model was used to analyze C. albicans coexisting with HGF by Scanning Electron Microscopy and fluorescence microscopies; gene expression was assessed by RT-PCR of C. albicans enzymes (SAP-1, PLB-1) and of host inflammatory cytokines (IL-6, IL-8, IL-1β, IL-10). Cytokines secretion was analysed by Luminex. The extract presented antifungal effect with MIC<15.62 μg/ml against Candida strains. Biofilm and proteolytic activity were significant reduced at 312.4 μg/ml (20 × 15.62 μg/ml) extract concentration. Cell viability was maintained higher than 70% in concentrations up to 250 μg/ml (LD50 = 423.3 μg/ml). Co-culture microscopies demonstrated a substantial decreased in C. albicans growth and minimal toxicity against host cells. Gene expressions of SAP-1/PLB-1 were significantly down-regulated and host immune response was modulated by a significant decreased on IL-6 and IL-8 cytokines secretion. A. colubrina had antifungal activity on Candida strains, antibiofilm, and anti-proteolytic enzyme effects against C. albicans. Presented low cytotoxicity to the host cells and modulatory effects on the host immune response.

Molecular genotyping of Candida albicans isolated from different sites may trace the etiological infection routes: Observation in China

BACKGROUND

Invasive candidiasis is a growing concern worldwide, especially in immunocompromised patients, including ICU patients.

OBJECTIVES

As Candida albicans is the leading cause of candidaemia, it is important to investigate the evolution of C. albicans in patients with candidaemia.

METHODS

We analysed 238 strains of C. albicans isolated from different body sites. Antifungal susceptibility testing, CAI loci genotyping and multilocus sequence typing (MLST) of all isolates were performed. The relationships among the total isolates that differed in sequence at only one of the seven housekeeping gene loci were analysed using eBURST.

RESULTS

Multilocus sequence typing analysis in 238 isolates by combining seven housekeeping alleles revealed 175 diploid sequence types, in which 84 were newly identified. eBURST analysis for these data recognised 19 clonal complexes (CCs) and 79 singletons. Besides, seventy-three CAI genotypes were identified. Blood isolates showed maximum genotypes (49), and the dominant genotypes were CAI 17-21 and CAI 21-21. Oral isolates possessed 25 CAI genotypes, and the dominant genotypes were CAI 17-21 and CAI 21-21 as well. Since isolates with CAI allele numbers <30 showed easier transmission, CAI 17-21 and CAI 21-21 were the most frequently transmitted. Finally, the CAI genotypes were classified into six groups.

CONCLUSIONS

This work revealed the oral and blood strains isolated from the patients with candidaemia in ICU shared the identical dominant CAI genotypes. Our data expanded the C. albicans MLST database and helped with understanding the evolution and spread of invasive candidiasis.

Catastrophic Candida prosthetic valve endocarditis and COVID-19 comorbidity: A rare case

BACKGROUND AND PURPOSE

Coronavirus disease 2019 (COVID-19) and Candida prostatic valve endocarditis present various clinical manifestations which may overlap; hence, discrimination between them is extremely difficult.

CASE REPORT

The case was a 66-year-old man with a past medical history of mitral and aortic valves replacement one year before COVID-19 co-infection. He was admitted with fever (for 7 days), shortness of breath, cough, seizure, lethargy, headache, and 85% oxygen saturation. Transesophageal echocardiography revealed multiple large-sized, highly mobile masses on both sides of the mechanical mitral valve highly suggestive of vegetation. Chest computed tomography scanning showed simulating scattered COVID-19 peripheral ground-glass opacities confirmed by reverse-transcription polymerase chain reaction. The set of blood cultures yielded yeast colonies that were identified as Candida tropicalis. The patient died of septic shock shortly after receiving antifungal therapy.

CONCLUSION

This case emphasized the importance of early diagnosis and implementation of antifungal treatment, particularly in patients with prosthetic cardiac valves, to reduce their unfavorable outcomes in COVID-19 patients.

The relationship between biofilm formation and mortality in patients with Candida tropicalis candidemia

BACKGROUND

Biofilm formation by Candida species is an influential virulence factor in candidemia pathogenesis. We investigated the relationship between biofilm formation of Candida tropicalis isolates with the clinical characteristics and mortality outcomes in patients with candidemia.

MATERIALS AND METHODS

Thirty-nine C. tropicalis isolates were recovered from patients with candidemia admitted to two university hospitals in Tehran, Iran. Biofilm mass and metabolic activity of C. tropicalis biofilms were assessed in vitro with two colorimetric methods. The sessile minimum inhibitory concentrations (SMICs) were evaluated in vitro by treating preformed biofilms with diluted concentrations of azoles according to CLSI-M27 A3/S4 protocol, followed by metabolic activity quantification. The expressions of ERG11, UPC2, MDR1, and CDR1 genes were also evaluated.

RESULTS

All C. tropicalis isolates produced biofilm. Respectively, higher <7-day and ≥7-day mortality rates were found among cases with high metabolic activity (46.7% vs. 13%, P = 0.03) and high biofilm mass (31.8% vs. 0, P = 0.029). Sessile cells had high resistance to fluconazole, voriconazole, and itraconazole. The azole minimum inhibitory concentrations (MICs) of C. tropicalis sessile were significantly greater than the planktonic minimum inhibitory concentrations (PMICs). In fluconazole-treated biofilms, the expression of ERG11 and UPC2 genes was increased.

CONCLUSION

Our findings highlight the importance of C. tropicalis biofilm formation as an important factor in candidemia pathogenesis and the clinical outcome of patients with candidemia.

Change in species distribution and antifungal susceptibility of candidemias in an intensive care unit of a university hospital (10-year experience)

Candidemia is a nosocomial infection mostly found in critically ill patients. Our objectives were to evaluate the change in distribution and resistance profile of Candida spp. isolated from candidemic patients in our intensive care unit over two 5-year periods spanning 15 years and to evaluate the risk factors. Records from the microbiology laboratory were obtained, from January 2004 to December 2008 and from January 2013 to December 2017, retrospectively. Antifungal susceptibility was performed by E-test and evaluated according to EUCAST breakpoints. A total of 210 candidemia cases occurred; 238 Candida spp. were isolated in 197 patients (58.8% male; mean age, 59.2 ± 19.6 years). The most predominant risk factor was central venous catheter use. Species distribution rates were 32%, 28%, 17%, and 11% for C. albicans (n = 76), C. parapsilosis (n = 67), C. glabrata (n = 40), and C. tropicalis (n = 27), respectively. Resistance rate to anidulafungin was high in C. parapsilosis over both periods and increased to 73% in the second period. Fluconazole showed a remarkable decrease for susceptibility in C. parapsilosis (94 to 49%). The prevalence of MDR C. parapsilosis (6%/33%) and C. glabrata (0%/44%) increased in the second period. We observed a predominance of non-albicans Candida spp., with C. parapsilosis being the most frequent and C. glabrata infections presenting with the highest mortality. High level of echinocandin resistance in C. parapsilosis and increasing prevalences of MDR C. parapsilosis and C. glabrata seem emerging challenges in our institution.

Candidemia in pediatric burn patients: Risk factors and outcomes in a retrospective cohort study

Background and Purpose :

Despite advances in burn care and management, infections are still a major contributor to morbidity and mortality rates in patients with burn injuries. Regarding this, the present study was conducted to investigate the prevalence and importance of candidemia in pediatric burn patients.

Materials and Methods:

Blood samples were collected from the patients and cultured in an automated blood culture system. Candida species were identified using specific culture media. The relationship between candidemia and possible risk factors was evaluated and compared to a control group.

Results:

A total of 71 patients with the mean age of 4.52±3.63 years were included in the study. Blood cultures showed candidemia in 19 (27%) patients. Based on the results, C. albicans was the most common fungus among patients with and without candidemia. The results of statistical analysis also showed that candidemia was significantly correlated with total body surface area (TBSA), mechanical ventilation, duration of total parenteral nutrition, length of intensive care unit (ICU) stay, presence of neutropenia, and R-Baux score (all P≤0.001). In this regard, TBSA, length of ICU stay, R-Baux score, and Candida score were identified as the determinant factors for mortality due to candidemia.

Conclusion:

Candidemia increases the mortality and morbidity rates associated with burn injuries. Prompt diagnostic and prevention measures can reduce the unfortunate outcomes via controlling the possible risk factors.

Assaying the effect of yeasts on growth of fungi associated with disease

Background

Pathogenic fungi often cause serious infections mainly in immunocompromised persons. The number of infections caused by the non-albicans Candida or other species has significantly increased over the last years. These infections present a major challenge in the health sector because these pathogenic fungi have strong virulence and often show resistance to the commonly used antifungal treatments. To solve the problems caused by the drug resistant pathogenic fungi, it is necessary to find new antifungal agents and their sources. The aim of this study was to give evidence that yeasts can effectively fight against strains which belong to pathogenic fungi and reveal those yeasts which are able to inhibit growth of Kodamaea ohmeri, Pichia kudriavzevii, Naganishia albida or Candida tropicalis. Furthermore, we wanted to determine the effects of certain culturing factors on the growth inhibition.

Results

Our screening revealed that although the strains belonging to pathogenic species were much more tolerant to the yeast-produced bioactive agents than the non-disease-associated yeasts, growth of Kodamaea ohmeri and Candida tropicalis could be inhibited by Metschnikowia andauensis, while Naganishia albida could be controlled by Pichia anomala or Candida tropicalis. Our data proved that the experimental circumstances could have a serious impact on the inhibitory capacity of the yeasts. Appearance of inhibition strongly depended on media, pH and temperature. Our data also shed some light on the fact that Pichia kudriavzevii must have high natural resistance to the yeast-produced agents, while other species, such as Saccharomycopsis crataegensis belonged to the easily inhibitable species.

Conclusions

Our study suggests that yeast-produced bioactive agents could be potential growth inhibitory agents against the disease-associated fungi and yeasts can also contribute to alternative approaches to combat against pathogenic fungi. Our data revealed an important role of the culturing factors in inhibition and pointed to the complex nature of antagonism.

High detection of virulence factors by Candida species isolated from bloodstream of patients with candidemia

OBJECTIVE

Candida species are the normal inhabitants of the skin and mucosa that cause a wide range of debilitating diseases in immunocompromised patients and other susceptible individuals. The present study aimed to evaluate the production of exoenzymes and the biofilm formation capacity of Candida species isolated from candidemia.

MATERIALS AND METHODS

In this study, a total of 100 stock Candida species isolates consist of 50 Candida albicans and 50 non-Candida albicans Candida species (24 C. glabrata, 15 C. parapsilosis, 5 C. dubliniensis, 3 C. tropicalis, 2 C. krusei and 1 C. fabianii) which previously were recovered from patients with candidemia were used. The enzymatic activity tests for hemolysin, proteinase, and phospholipase were performed by using blood Sabouraud dextrose agar, bovine serum albumin medium and egg yolk agar, respectively. Biofilm formation was determined by microplate assay method.

RESULT

All of the Candida albicans species could produce hemolysin. The predominant enzyme activity of species included strong and very strong levels of phospholipase, proteinase and hemolysin activity were belonged to Candida albicans isolates. There were statistically significant differences in hemolysin (P < 0.001), proteinase (P = 0.003) and phospholipase (P < 0.001) activity between two groups of albicans and non-albicans species. The biofilm formation was seen in 30 (60%) of C. albicans and 49 (98%) of non-C. albicans species. There was significant statistical differences between the two groups of isolates in biofilm formation (P < 0.001).

CONCLUSION

It is clear that Candida species have ability to produce several enzymes as virulence factors to contribute its pathogenicity. There were significant differences in virulence factors between the two C. albicans and non- C. albicans group. The ability for biofilm formation and producing exo-enzyme were an important virulence factors in Candida species isolates. This differences found in this report might have role in severity of disease caused by different species.

Clinical Characteristics and Outcomes of Candidemia Caused by Meyerozyma guilliermondii Complex in Cancer Patients Undergoing Surgery

Although Meyerozyma guilliermondii complex is an uncommon cause of invasive candidiasis worldwide, reported cases, mainly regarding bloodstream infections, increased over years, and patients with cancer who have undergone recent surgery are most commonly affected. However, the clinical characteristics and outcomes of candidemia caused by M. guilliermondii complex remain poorly understood. A retrospective case-control study was conducted to evaluate the clinical characteristics and mortality of candidemia caused by M. guilliermondii complex in cancer patients undergoing surgery. Demographic and clinical data were collected from the hospital medical records system with a standardized data collection form and were analyzed with SPSS 20.0. Sixty-six cancer patients who have undergone recent surgery and were diagnosed with candidemia caused by M. guilliermondii complex were included in the study. Regarding the clinical manifestations, most patients' body temperatures ranged from 38 to 40 °C, with a median fever duration of 4 (IQR: 3-6) days. Multivariate analysis indicated that the presence of central venous catheter (OR: 6.68; 95% CI 2.80-15.94) and gastric tube (OR: 3.55; 95% CI 1.22-10.34) were independent risk factors for M. guilliermondii complex fungemia. The 30-day crude mortality of candidemia caused by M. guilliermondii complex was 12.1%, twice that of the control group. Moreover, increased WBC count, age ≥ 60 years, septic shock, and ICU admission were identified as predictors of mortality through univariate analysis. These findings will provide a foundation for the clinical management of candidemia caused by M. guilliermondii complex in post-surgical cancer patients.

Impact of biofilm production by Candida species and antifungal therapy on mortality of patients with candidemia

BACKGROUND AND OBJECTIVES

Few studies have investigated the clinical outcomes of patients with candidemia caused by Candida species with different levels of biofilm formation. We aimed to investigate the impact of antifungal therapy on the outcome of candidemia caused by Candida species that were categorised as low biofilm formers (LBFs), moderate biofilm formers (MBFs), and high biofilm formers (HBFs).

METHODS

Adults with candidemia caused by LBF and HBF/MBF Candida species that were susceptible to fluconazole and caspofungin were included to investigate the impact of treatment with fluconazole vs an echinocandin on 30-day crude mortality.

RESULTS

In total, 215 patients with candidemia received fluconazole and 116 patients received an echinocandin. In multivariate analysis, Pittsburgh bacteremia score ≥ 4 (adjusted odds ratio [AOR] =2.42; 95% confidence interval [CI], 1.32-4.41), malignancy (AOR = 3.45; 95% CI, 1.83-6.51), not removing the central venous catheter within 48 hours of a positive blood culture (AOR = 4.69; 95% CI, 2.61-8.45), and treatment with fluconazole for candidemia due to HBF/MBF Candida spp. (AOR = 2.23; 95% CI, 1.22-4.06) were independent factors associated with 30-day mortality. Of the 165 patients infected by HBF/MBF Candida isolates, those who received azole therapy had a significantly higher sepsis-related mortality rate than those who received echinocandin therapy (44.9% [49/109] vs 26.8% [15/56], P = .03).

CONCLUSIONS

There was a trend of an independent association between fluconazole treatment and poor outcomes in the patients infected by HBF/MBF Candida strains.

Prevalence of virulent Candida spp. in complicated urinary tract infection of nephrolithiatic patients from surgical units of tertiary care hospitals Islamabad

Candida species are the commensal organisms of human mucosa and opportunistically cause the diseases in susceptible persons. This study aimed to determine the prevalence and virulence of different Candida spp. among nephrolithiatic patients and their association with complicated UTI (cUTI). A total of 164 urine samples were collected from surgical units of two tertiary care hospitals (Poly Clinic and Pakistan Institute of Medical Sciences Hospital, Islamabad). From 74 kidney stone patients, 77 isolates of Candida spp. were confirmed through standard microbiological and molecular characterization. C. albicans was the predominant species with 51 isolates (66.2%) followed by 26 (33.8%) of C. non-albicans. The nephrolithiatic patients suffering from cUTI were more prone to be infected with Candida (P=0.047). Among all isolates, 83% (64) of the Candida isolates were biofilm formers, 80% (60) showed the esterase production and 64.9% (50) showed phospholipase production. Candida isolates positive for various virulence factors were more prevalently isolated from both catheterized and recurrent UTI patients. Among Candida spp., 16.9% (13) isolates showed resistance to fluconazole and 19.5% (15) against voriconazole and 11 isolates were resistant for both tested antifungals. Candida isolated from cUTI cases showed comparatively enhanced virulence attributes and antifungal resistance, suggesting that these factors might have role in development of cUTI in nephrolithiatic patients. Hence, this work highlights the high prevalence of both C. albicans and non albicans spp. in nephrolithiatic patients. So, there is need to administer evidence based antifungal therapy rather than empirical therapy to reduce the cUTI in nephrolithiatic patients.

Antifungal activity of Punicalagin-nystatin combinations against Candida albicans

OBJECTIVES

Oral candidiasis is the most common opportunistic fungal infection of oral mucosa and results from an overgrowth of Candida, especially Candida albicans. The potential anti-C. albicans and cytotoxicity of punicalagin (PCG), isolated from Punica granatum, alone or with nystatin (NYS) were evaluated.

METHODS

Activity of compounds alone or in combinations was determined against two C. albicans strains (ATCC 90028 and SC5314). Minimal inhibitory concentration (MIC)-50 and Minimum Fungicidal Concentration (MFC) were assessed by XTT assay and CFU counts, respectively. For combinations, determination of fractional inhibitory concentration index was performed. Ergosterol pathway was investigated as a possible PCG antifungal mechanism. Cytotoxicity assays were undertaken on human primary oral keratinocytes and gingival fibroblasts incubated with antifungal concentrations of PCG and/or NYS for 24 hr.

RESULTS

Combination of NYS and PCG increased antifungal efficacy, compared with compounds tested alone. Combinations 4 (PCG-6.25 μg/ml; NYS-3.9 μg/ml) and 5 (PCG-12.5 μg/ml; NYS-1.95 μg/ml) were more effective since they reduced the MIC-50 of PCG (50 μg/ml) by 8 and 4 times, respectively, increased the candidal inhibition and nullified the PCG cytotoxicity for keratinocytes. PCG antifungal mechanism did not involve ergosterol biosynthesis pathway.

CONCLUSIONS

The favorable outcomes for combination of PCG and NYS encourage further testing this therapeutic strategy against C. albicans.

Epidemiology, species distribution, and predictive factors for mortality of candidemia in adult surgical patients

Background

We evaluated the epidemiology, clinical characteristics, microbiology, outcomes, and risk factors for mortality of candidemia in adult surgical patients in Shenyang from 2012 to 2018.

Methods

We designed a retrospective observational study of adult patients with candidemia in a teaching hospital including three hospital campuses. Data regarding clinical and demographic characteristics were collected from the patient’s medical records.

Results

Of the 236 cases of candidemia, 172 (72.9%) were identified in surgical patients, including 146 (84.9%) general surgeries, 11 (6.4%) urologic surgeries, 6 (3.5%) thoracic surgeries, and others. Higher proportions of solid tumors, total parenteral nutrition, the presence of a urinary catheter, and the presence of a gastric tube were observed in surgical patients with candidemia versus non-surgical ones, whereas the percentages of hematological malignancy, diabetes mellitus, and renal replacement therapy were relatively lower in surgical patients. Renal failure, leukopenia, and thrombocytopenia were less common laboratory findings in surgical patients with candidemia than compared to non-surgical ones. Among surgical patients with candidemia, Candida parapsilosis was the predominant species (43%), followed by C. albicans (33.7%), C. glabrata (11%), C. tropicalis (8.1%), and others (4.1%). Overall susceptibility, susceptible dose dependent or intermediate susceptibility, and resistance to fluconazole were detected in 73.3, 19.8, and 3.5% Candida isolates from surgical patients, respectively, but no resistance to amphotericin B was observed. Overall, the 30-day mortality in surgical patients was 19.2%. At multivariable analysis, independent risk factors for death in surgical patients with candidemia were ICU stay, thrombocytopenia, and C. albicans infection.

Conclusions

Surgical patients account for the majority of candidemia cases. Among patients with recent surgery, risk factors for species distribution, antifungal sensitivity patterns of Candida isolates causing candidemia, and independent risk factors for mortality should be evaluated and considered for a better outcome in the antifungal treatment.

Update on invasive fungal infections in the Middle Eastern and North African region

In the recent years, the epidemiology of invasive fungal infections (IFIs) has changed worldwide. This is remarkably noticed with the significant increase in high-risk populations. Although surveillance of such infections is essential, data in the Middle Eastern and North African (MENA) region remain scarce. In this paper, we reviewed the existing data on the epidemiology of different IFIs in the MENA region. Epidemiological surveillance is crucial to guide optimal healthcare practices. This study can help to guide appropriate interventions and to implement antimicrobial stewardship and infection prevention and control programs in countries.

Candida-Associated Denture Stomatitis and Murine Models: What Is the Importance and Scientific Evidence?

Considering the high prevalence and recurrence of Candida-associated denture stomatitis (CADS), in vivo studies in animal models are necessary before those in humans to evaluate new therapeutic strategies. This study aimed to review the literature on murine models of CADS induction using acrylic intraoral devices simulating dentures. Rats are recommended as experimental animals in these models as well as the adoption of a pasty diet. For maintenance in the proper position during the experiments, intraoral appliances must be obtained by individual impressions, using and retained exclusively by cementation on the molars. The region of interest for histopathological analysis was standardized as that corresponding to the area between the first molars. However, there is no consensus among the studies on the CADS induction rat models in relation to the Candida albicans inoculation and need for immunosuppression and/or administration of antibacterial drugs of animals. The greatest difficulty of the available models refers to maintaining the course of the lesion for a sufficient period to evaluate the effectiveness of the proposed treatment, considering the rapid and efficient murine immune response to candidal colonization. Therefore, future studies are necessary for the development of a robust and reproducible CADS model.

Evaluation of Molecular Epidemiology, Clinical Characteristics, Antifungal Susceptibility Profiles, and Molecular Mechanisms of Antifungal Resistance of Iranian Candida parapsilosis Species Complex Blood Isolates

Clonal expansion of fluconazole resistant (FLZ-R) Candida parapsilosis isolates is increasingly being identified in many countries, while there is no study exploring the antifungal susceptibility pattern, genetic diversity, and clinical information for Iranian C. parapsilosis blood isolates. Candida parapsilosis species complex blood isolates (n = 98) were recovered from nine hospitals located in three major cities, identified by MALDI-TOF MS, and their genetic relatedness was examined by AFLP fingerprinting. Antifungal susceptibility testing followed CLSI-M27-A3 and ERG11, MRR1 and hotspots 1/2 (HS1/2) of FKS1 were sequenced to assess the azole and echinocandin resistance mechanisms, respectively. Ninety-four C. parapsilosis and four Candida orthopsilosis isolates were identified from 90 patients. Only 43 patients received systemic antifungal drugs with fluconazole as the main antifungal used. The overall mortality rate was 46.6% (42/90) and death mostly occurred for those receiving systemic antifungals (25/43) relative to those not treated (17/47). Although, antifungal-resistance was rare, one isolate was multidrug-resistant (FLZ = 16 μg/ml and micafungin = 8 μg/ml) and the infected patient showed therapeutic failure to FLZ prophylaxis. Mutations causing azole and echinocandin resistance were not found in the genes studied. AFLP revealed five genotypes (G) and G1 was the main one (59/94; 62.7%). Clinical outcome was significantly associated with city (P = 0.02, α <0.05) and Mashhad was significantly associated with mortality (P = 0.03, α <0.05). Overall, we found a low level of antifungal resistance for Iranian C. parapsilosis blood isolates, but the noted MDR strain can potentially become the source of future infections and challenge the antifungal therapy in antifungal-naïve patients. AFLP typing results warrants confirmation using other resolutive typing methods.

Epidemiology of yeast species causing bloodstream infection in Tehran, Iran (2015-2017); superiority of 21-plex PCR over the Vitek 2 system for yeast identification

Introduction. Given the limited number of candidaemia studies in Iran, the profile of yeast species causing bloodstream infections (BSIs), especially in adults, remains limited. Although biochemical assays are widely used in developing countries, they produce erroneous results, especially for rare yeast species.Aim. We aimed to assess the profile of yeast species causing BSIs and to compare the accuracy of the Vitek 2 system and 21-plex PCR.Methodology. Yeast blood isolates were retrospectively collected from patients recruited from two tertiary care training hospitals in Tehran from 2015 to 2017. Relevant clinical data were mined. Identification was performed by automated Vitek 2, 21-plex PCR and sequencing of the internal transcribed spacer region (ITS1-5.8S-ITS2).Results. In total, 137 yeast isolates were recovered from 107 patients. The overall all-cause 30-day mortality rate was 47.7 %. Fluconazole was the most widely used systemic antifungal. Candida albicans (58/137, 42.3 %), Candida glabrata (30/137, 21.9 %), Candida parapsilosis sensu stricto (23/137, 16.8 %), Candida tropicalis (10/137, 7.3 %) and Pichia kudriavzevii (Candida krusei) (4/137, 2.9 %) constituted almost 90 % of the isolates and 10 % of the species detected were rare yeast species (12/137; 8.7 %). The 21-plex PCR method correctly identified 97.1 % of the isolates, a higher percentage than the Vitek 2 showed (87.6 %).Conclusion. C. albicans was the main cause of yeast-derived fungaemia in this study. Future prospective studies are warranted to closely monitor the epidemiological landscape of yeast species causing BSIs in Iran. The superiority of 21-plex PCR over automated Vitek 2 indicates its potential clinical utility as an alternative identification tool use in developing countries.

Candida africana vulvovaginitis: Prevalence and geographical distribution

Candida africana has been recovered principally as a causative agent of vulvovaginal candidiasis (VVC) from different countries, which is likely to be misidentified as the typical Candida albicans or Candida dubliniensis. The current study aimed to characterize C. albicans species complex obtained from VVC based on conventional and molecular assays. Furthermore, in vitro antifungal susceptibility testing was performed based on CLSI documents. Additionally, due to low knowledge concerning C. africana infections, we reviewed all published papers from 1991 to 2019. One hundred forty-four out of 287 patients were identified with Candida infection, among whom 151 isolates of Candida were obtained. Candida albicans 109 (72.1%), Candida glabrata 21 (13.9%), Candida krusei 8 (5.2%), Candida tropicalis 5 (3.3%), Candida africana 3 (1.9%), Candida parapsilosis 3 (1.9%) and C. dubliniensis 2 (1.3%) were isolated from patients. MIC results showed that C. africana isolates were susceptible to all tested antifungal drugs. Candida africana infections were more prevalent in Africa. One hundred fifteen (40.6%) of patients with C. africana candidiasis were from seven African countries, and Madagascar and Angola had the majority of cases. The epidemiological data, phenotypic, clinical features, ecologic similarity, and antifungal susceptibility profiles for better understanding of the pathogenic mechanisms and optimal treatment underlying non-CandidaalbicansCandida vulvovaginitis are highly recommended.

Comparative in vitro activities of seven antifungal drugs against clinical isolates of Candida parapsilosis complex

OBJECTIVE

Candida parapsilosis species complex, an important set of non-albicans Candida species, is known to cause candidaemia particularly in neonates and infants. However, the incidence has increased in recent years, owing to higher numbers of at individuals at risk for these infections. Our objective was to evaluate the in vitro susceptibility of clinical isolates of C. parapsilosis complex isolates from Iran to seven antifungal drugs.

MATERIAL AND METHODS

One hundred-one clinical isolates of C. parapsilosis species complex cultured from humans were included. Species identification had been previously confirmed by combined phenotypic characteristics, matrix-assisted laser desorption ionization-time of flight mass spectrometry-based assay and reconfirmed by DNA sequence analysis of the ITS rDNA region and D1/D2 gene. Minimum inhibitory concentrations (MICs) for amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, micafungin and anidulafungin were determined against well-characterized isolates by broth microdilution susceptibility testing according to the CLSI M27-A3 guideline.

RESULTS

Species identifications were performed on 101 isolates, of which 88 (87.2%) C. parapsilosis sensu stricto and 13 (12.8%) C. orthopsilosis. Amphotericin B and posaconazole were the most active drugs with 100% of isolates being wild-type (WT). Voriconazole and micafungin, 99% of isolates were WT. The low activity was recorded for fluconazole and itraconazole with 93.1% and 89.1% of isolates being WT, respectively. At the species level, all Candida parapsilosis sensu stricto isolates were WT to amphotericin B and posaconazole and all Candida orthopsilosis isolates were WT to amphotericin B, voriconazole, posaconazole, anidulafungin and micafungin. In contrast, the highest rate of non-WT was observed in C. orthopsilosis to itraconazole (4 of 13, 30.8%).

CONCLUSIONS

Although almost all of the tested drugs demonstrated potent activity against C. parapsilosis species complex, it seems that more especially C. orthopsilosis isolates had decreased susceptibility to itraconazole. Further studies are needed to determine how these findings may switch into in vivo efficacy.

Epidemiological features of nosocomial candidaemia in neonates, infants and children: A multicentre study in Iran

Nosocomial bloodstream candidaemia is a life-threatening fungal infection with high morbidity and mortality, especially among paediatric patients undergoing intensive immunosuppressive therapy. Limited data on the epidemiology of candidaemia and susceptibility profiles are available for Iran. To characterise candidaemia epidemiology, comorbidity risk factors, species distribution, and antifungal susceptibility profiles among paediatric patients in Iran. This observational cross-sectional study enrolled 26 189 patients <18 years old at three reference paediatric hospitals in Mazandaran and Tehran over 2 years. Blood samples from patients with suspected fungal bloodstream infection were analysed using the BACTEC culture system. Fungal isolates were identified using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF) and DNA sequencing. Antifungal susceptibility testing was performed using the Clinical and Laboratory Standards Institute broth microdilution guideline. We observed 109 episodes of nosocomial candidaemia in paediatric patients with or without immunosuppressive therapy. The most common healthcare-associated factor was central vascular catheter use (97%). The all-cause mortality rate was 40%, of which 48% was attributable to candidaemia. While Candida albicans was the most frequent causative agent (49%), emerging and uncommon Candida species were also isolated. Candidaemia mortality by non-albicans Candida species was significantly higher than that by C. albicans (P < .05). All fluconazole-resistant species were non-albicans Candida species. Uncommon Candida species with reduced susceptibility to antifungals are emerging as major agents of nosocomial candidaemia in high-risk paediatric patients in Iran. Appropriate source control, antifungal regimens and improved antifungal stewardship are warranted for managing and decreasing the burden of nosocomial candidaemia.

Sensitivity of antifungal preparations of Сandida isolates from sub-biotopes of the human oral cavity

Candidiasis is the commonest opportunistic infection of the oral cavity. As a result of immune-deficiency of the organism, yeasts of Candida genus by acting as commensal organisms transmute into pathogenic organisms. The article presents frequency of isolation, topographic peculiarities, species range, sensitivity of the Candida yeasts to antimycotics and newly-synthesized derivatives of amino alcohols isolated from the sub-biotopes of the oral cavity of patients with oncopathologies. The survey of the material included microscopic, mycologic, statistical-analytical methods. For all the clinical isolates the sensitivity to antifungal preparations was determined. Over the study 492 sub-biotopes of the oral cavity were examined. The extraction of the material was made from the mucous membrane of the cheek, angle of the mouth, mucous membrane of the surface of the tongue and the palate. According to the results of the conducted studies, the level of candidal carriage on the mucous membrane of the oral cavity in the patients with oncopathologies without clinical signs of candidiasis equaled 25.0%, active candidiasis infection was found in 47.0% of cases. Among the clinical strains, we isolated: C. albicans, C. glabrata, C. tropicalis and C. krusei. Among all the isolated strains, in all 4 sub-biotopes C. albicans dominated accounting for 73.1%. In 4 sub-biotopes we detected the association of two species of Candida. Analysis of the obtained results of the susceptibility of strains to modern antymicotics and newly-synthesized substances revealed that the representatives of non-albicans are more resistant to the antifungal preparations. Among the commercial preparations, amphotericin B exerted the highest activity against the clinical isolates of yeast-like fungi. The concentration of 0.97 µg/mL inhibited 50.0% of representatives of non-albicans, and also 75.0% of isolates of C. albicans. Fluconazole exhibited activity in the concentration of 1 µg/mL towards 17.0% of non-albicans and 25.0% of С. albicans. Itraconazole was observed to have no significant antifungal activity. Among the newly-synthesized aryl acyclic amino alcohols, compound Kc22 displayed high activity against both groups of Candida (experimental and control) making it promising for creating new therapeutic preparations. The parameters of resistance of clinical isolates to modern antimycotics indicate the necessity of constant monitoring of the sensitivity of the pathogens of candidiasis and precise species identification for rational use of antifungal preparations and prevention of the development of antimycotic resistance.

In vitro synergy of echinocandins with triazoles against fluconazole-resistant Candida parapsilosis complex isolates

INTRODUCTION

Candida parapsilosis (C. parapsilosis) is a common non-albicans Candida species ranked as the second common cause of bloodstream infections. Azole resistance and elevated echinocandin MICs have been reported for these fungi. This study was conducted to determine the interactions between azoles and echinocandins against C. parapsilosis species complex.

MATERIALS AND METHODS

Fifteen fluconazole-resistant clinical isolates of C. parapsilosis complex were included: C. parapsilosis sensu stricto (n = 7), C. orthopsilosis (n = 5) and C. metapsilosis (n = 3). The activity of azoles (fluconazole, itraconazole) and echinocandins (anidulafungin, micafungin) alone and in combination was determined using checkerboard broth microdilution. The results were determined based on the fractional inhibitory concentration index (FICI).

RESULTS

In vitro combination of fluconazole with anidulafungin was found to be synergistic (FICI 0.07-0.37) and decreased the MIC range from 4-64 μg/mL to 0.5-16 μg/mL for fluconazole and from 2-8 μg/mL to 0.125-1 μg/mL for anidulafungin. Similarly, interactions of fluconazole with micafungin (FICI 0.25-0.5), itraconazole with anidulafungin (FICI 0.15-0.37) and itraconazole with micafungin (FICI 0.09-0.37) were synergistic.

CONCLUSION

The combination of fluconazole and itraconazole with either anidulafungin or micafungin demonstrated synergistic interactions against C. parapsilosis species complex, especially against isolates with elevated MIC values. However, the use of these combinations in clinical practice and the clinical relevance of in vitro combination results remain unclear.

Two New 1,3,4-Oxadiazoles With Effective Antifungal Activity Against Candida albicans

Candida infections have become a serious public health problem with high mortality rates, especially in immunocompromised patients, since Candida albicans is the major opportunistic pathogen responsible for systemic or invasive candidiasis. Commercially available antifungal agents are restricted and fungal resistance to such drugs has increased; therefore, the development of a more specific antifungal agent is necessary. Using assays for antifungal activity, here we report that two new compounds of 1,3,4-oxadiazoles class (LMM5 and LMM11), which were discovered by in silico methodologies as possible thioredoxin reductase inhibitors, were effective against C. albicans. Both compounds had in vitro antifungal activity with MIC 32 μg/ml. Cytotoxicity in vitro demonstrated that LMM5 and LMM11 were non-toxic in the cell lines evaluated. The kinetic of the time-kill curve suggested a fungistatic profile and showed an inhibitory effect of LMM5 and LMM11 in 12 h that remained for 24 and 36 h, which is better than fluconazole. In the murine systemic candidiasis model by C. albicans, the two compounds significantly reduced the renal and spleen fungal burden. According to the SEM and TEM images, we hypothesize that the mechanism of action of LMM5 and LMM11 is directly related to the inhibition of the enzyme thioredoxin reductase and internally affect the fungal cell. In view of all in vitro and in vivo results, LMM5 and LMM11 are effective therapeutic candidates for the development of new antifungal drugs addressing the treatment of human infections caused by C. albicans.

The epidemiology of Candida species in the Middle East and North Africa

In recent decades, the epidemiology of invasive candidiasis (IC) has progressively changed worldwide. This notably includes emergence of several Candida species. Although some surveillance programs provided global trends in IC epidemiology, data from countries from the Middle East and North Africa (MENA) remain scarce. In this manuscript, we reviewed the existing available data on the epidemiology of Candida species associated with IC, particularly candidemia, in MENA region regarding species distribution. As witnessed worldwide, an evident shift of Candidaalbicans towards non-albicansCandida (NAC) has been observed in the MENA region. The worrying emergence of multi-drug resistant Candida species in MENA calls for a better understanding of their epidemiology. This represents an essential prerequisite for the implementation of effective infection control strategies and surveillance systems to prevent IC among high-risk patients.

A Predominance of Clade 17 Candida albicans Isolated From Hemocultures in a Tertiary Care Hospital in Thailand

Candida albicans is one of the most common human fungal pathogens. Candidemia has significant mortality globally. No epidemiological study of C. albicans based on multilocus sequence typing (MLST) has been conducted in Thailand. Therefore, MLST was used to study the molecular epidemiology of C. albicans blood strains in a large Thai teaching hospital. In vitro virulence phenotypes and antifungal susceptibility testing by broth microdilution were also conducted. Forty-six C. albicans blood strains from 37 patients were collected from the Department of Microbiology, Siriraj Hospital, in 2016 and 2017. Most patients (71.8%) were more than 60 years old, and the case fatality rate was 54.8%. The male-to-female ratio was 5:3. Thirty-four diploid sequence types (DSTs), including six new DSTs, were identified, with DST2514 (8.7%) and DST2876 (8.7%) as the most common DSTs. Strains were clustered into nine clades. Unlike other studies of C. albicans blood strains in Asia, clade 17 was the most common (13 strains, 28.3%). Sequential allelic changes were evident in sequential strains from one patient. All strains produced phospholipase and hemolysin, while none produced proteinase. The ability to form biofilm was found in 82.6% of the strains. Clade 17 strains showed significantly stronger hemolytic activity than non–clade 17 strains (69.2% versus 27.3%; p = 0.022). However, no significant association existed between clades and patient mortalities. All were susceptible or wild type to anidulafungin (MIC range = 0.015–0.12 and GM = 0.030), micafungin (MIC range = ≤ 0.008–0.015 and GM = 0.008), caspofungin (MIC range = 0.008–0.12 and GM = 0.036), and amphotericin B (MIC range = 0.25–0.5 and GM = 0.381). Only one strain was resistant to voriconazole (MIC range = ≤ 0.008 to ≥ 8 and GM = 0.010) and fluconazole (MIC range = 0.12–16 and GM = 0.398). In conclusion, a high prevalence of clade 17 C. albicans blood strains was found in Thailand, in contrast to other Asian countries. This unique finding might be explained by the strong hemolytic activity that is required for bloodstream infection of C. albicans.

Isolation, characterization, and molecular identification of Candida species from urinary tract infections

BACKGROUND AND PURPOSE

Candida species are reportedly the most common human fungal pathogens. The incidence of urinary tract infections (UTIs) caused by Candida pathogens has increased in recent decades. However, such infections rarely occur in the absence of any predisposing factors. Regarding this, the aim of the present study was to identify the Candida species causing UTIs and determine the predisposing factors for candiduria.

MATERIALS AND METHODS

The current study was conducted on 1,450 urine samples obtained from patients suspected of UTI. Out of this number, 19 cases were candidiasis, and 2 cases were mixed infections caused by bacteria and fungi. Candida species were diagnosed differentially using the germ tube test, colony staining on CHROMagar medium, intracellular beta-glucosidase enzyme activity, and glucose absorption pattern. Then, the colonies with the same morphology were confirmed by the DNA sequencing of internal transcribed spacer regions.

RESULTS

According to the results, 38%, 28.6%, 14.3%, and 9.5% of the isolates were identified as C. albicans, C. glabrata, C. tropicalis, and C. kefir/C. krusei, respectively. The presence of one or more predisposing factors was proved in all patients in whom diabetes was the most prevalent predisposing factor (21.1%).

CONCLUSION

Based on the obtained results, C. albicans species was the most prevalent fungal species. In addition, urinary fungal infections were less prevalent than bacterial urinary infections.

Candidemia due to Candida guilliermondii in an immuno-compromised infant: a case report and review of literature

Background and Purpose:

Candidemia is a life-threatening fungal infection with significant mortality and morbidity in neutropenic individuals, immunosuppressive chemotherapy recipients, and broad-spectrum antibiotics consumers. The epidemiology and antifungal susceptibility testing of non-albicans Candida species have been poorly studied. These species are characterized by low susceptibility to azoles and echinocandins. Herein, we report the first pediatric case of candidemia due to C. guilliermondii in Iran and review the literature on fungemia caused by C. guilliermondii.

Case report:

We presented the first candidemia case due to C. guilliermondii in a 4-month-old male infant with neuroblastoma in Iran. This study also involves a comprehensive literature review on fungemia caused by C.guilliermondii during a period of 18 years (i.e., 2000-2018) to discuss the epidemiology, clinical features, and treatment of this disease. The literature review resulted in the identification of 501 cases of candidemia caused by C. guilliermondii. Most of the patients were adults and had multiple risk factors. However, the main risk factors were significantly related to cancer chemotherapy, followed by central venous catheter use and Intensive Care Unit admission. Mortality rate due to this disease had a range of 3.4-66.6%, in this regard, the patients with cancer had the highest mortality rate.

Conclusion:

Given the high mortality of candidemia, the early diagnosis of this infection and timely initiation of antifungal therapy significantly improve the patients’ survival rate and result in better outcomes. Consequently, it is highly recommended to monitor the local epidemiology of this life-threatening infection and raise awareness in this regard.

Changing trends in epidemiology and antifungal susceptibility patterns of six bloodstream Candida species isolates over a 12-year period in Kuwait

Changing trends in incidence and antifungal susceptibility patterns of six Candida species causing candidemia in Kuwait between 2006–2017 are reported. A total of 2075 isolates obtained from 1448 patients were analyzed. Identity of Candida species isolates was determined by phenotypic methods and confirmed by PCR amplification/PCR-sequencing of rDNA and/or MALDI-TOF MS. Antifungal susceptibility was determined by Etest. C. albicans accounted for 539 (37.22%) cases followed by C. parapsilosis (n = 502, 34.67%), C. tropicalis (n = 210, 14.5%), C. glabrata (n = 148, 10.22%), C. krusei (n = 27, 1.81%) and C. dubliniensis (n = 22, 1.5%). The comparative percent distribution of Candida species causing candidemia between 2006–2011 and 2012–2017 was as follows: C. albicans 41.8% and 33.1%, C. parapsilosis complex 32.01% and 37.04%, C. tropicalis 13.59% and 15.31%, and C. glabrata 8.77% and 11.51%, C. krusei 2.0% and 1.7%, and C. dubliniensis 1.75 and 1.3%, respectively. Three of 371 C. albicans isolates during 2006–2011 and five of 363 during 2012–2017 were resistant to fluconazole. Among C. parapsilosis isolates, one of 310 during 2006–2011 and 21 of 446 during 2012–2017 were resistant to this drug. Furthermore, at an epidemiologic cutoff value (ECV) of ≤0.5 μg/ml, 70.1% C. albicans isolates were wild-type for fluconazole during 2006–2011 as compared to 58.1% during 2012–2017. Likewise, at an ECV of ≤2 μg/ml, 98.0% of C. parapsilosis isolates were wild-type during 2006–2011 as compared to 93.4% during 2012–2017. Clonal spread of fluconazole-resistant C. parapsilosis in one major hospital was documented. An 8.8% shift in favor of non-albicans Candida species with concomitant increase in MICs between the two periods preludes emergence of fluconazole-resistant candidemia cases in Kuwait.

Analyses of the Global Multilocus Genotypes of the Human Pathogenic Yeast Candida tropicalis

Candida tropicalis is a globally distributed human pathogenic yeast, especially prevalent in tropical and sub-tropical regions. Over the last several decades, a large number of studies have been published on the genetic diversity and molecular epidemiology of C. tropicalis from different parts of the world. However, the global pattern of genetic variation remains largely unknown. Here we analyzed the published multilocus sequence data at six loci for 876 isolates from 16 countries representing five continents. Our results showed that 280 of the 2677 (10.5%) analyzed nucleotides were polymorphic, resulting in a mean of 82 (a range of 38–150) genotypes per locus and a total of 633 combined diploid sequence types (DSTs). Among these, 93 combined DSTs were shared by 336 strains, including 10 by strains from different continents. Analysis of Molecular Variance (AMOVA) showed that 89% of the observed genetic variations were found within regional and national populations while < 10% was due to among-country separations. Pairwise geographic population analyses showed overall low but statistically significant genetic differentiation between most geographic populations, with the Singaporean and Indian populations being the most distinct from other populations. However, the Mantel test showed no significant correlation between genetic distance and geographic distance among the geographic populations. Consistent with high genetic variation within and limited variations among geographic populations, results from STRUCTURE analyses showed that the 876 isolates could be grouped into 15 genetic clusters, with each cluster having a broad geographic distribution. Together, our results suggest frequent gene flows among certain regional, national, and continental populations of C. tropicalis, resulting in abundant regional and national genetic diversities of this important human fungal pathogen.

Incidence and spectrum of yeast species isolated from the oral cavity of Iranian patients suffering from hematological malignancies

Background: Oral candidiasis (OC) has a profound effect on the life quality of immunocompromised patients, such as those undergoing chemotherapy. Objective: Systematic investigation of clinical outcome and microbiological features of yeast isolates recovered from the oral cavity of 150 Iranian patients with hematological malignancies. Design: MALDI-TOF MS, 21-plex PCR, and rDNA sequencing were used for identification. Antifungal susceptibility testing (broth microdilution, CLSI M27-A3/S4) and genotypic diversity of yeast isolates (amplified fragment length polymorphism) were assessed. Results: Nystatin treatment resulted in 70% therapeutic failure and administration of 150 mg fluconazole (FLZ) + nystatin for patients with OC relapse showed 70% clinical failure. Previous history of OC was significantly correlated with FLZ treatment requirement and nystatin failure (P = 0.005, α < 0.05). Candida albicans (80.3%) and Kluyveromyces marxianus (C. kefyr) (12.7%) were the two most prevalent yeast species isolated. FLZ and AMB exhibited the highest geometric mean values. 21-PCR showed 98.9% agreement with MALDI-TOF MS. K. marxianus isolates had the same genotype, while C. albicans isolates grouped in 15 genotypes. Conclusions: Marked rate of therapeutic failure of nystatin necessitated OC treatment with systemic antifungals. K. marxianus was the second most prevalent yeast and 21-plex PCR could be considered as an inexpensive identification tool.

Antifungal activity of oils macerates of North Sardinia plants against Candida species isolated from clinical patients with candidiasis

Antibiotic resistance is one of the bigger problem of public health: the rise of multi-drug resistant organisms causes a challenge in the treatment of infective diseases. Anti-Candida resistance to conventional antifungal agents has increased in the last period. Our research was intended to evaluate antimicrobial activity of oil macerate (OM) of Helichrysum microphyllum Cambess. subsp. tyrrhenicum Bacch., Brullo & Giusso and OM of Hypericum perforatum subsp. angustifolium against several clinical strains. The study included 30 patients with candidiasis who had not received any antifungal treatment before they were enrolled. A collection of 30 clinical isolates belonging to 5 different species of Candida spp. was selected for this study. The data obtained showed an interesting activity of both Oil Macerate especially against C. krusei and C. parapsilosis. On the contrary, H. microphyllum Oil Macerate has had a better activity than the H.perforatum especially in relation to C. glabrata and C. krusei.

Evaluation of a new matrix-assisted laser desorption/ionization time-of-flight mass spectrometry system for the identification of yeast isolation

BACKGROUND

Currently, three commercial in vitro diagnostic matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems are widely used in clinical laboratories. The ASTA MicroIDSys system (ASTA Inc, South Korea) is a newly developed MALDI-TOF MS system used for the identification of pathogenic microorganisms. In the present study, we assessed the performance of the ASTA MALDI-TOF MS system for the identification of pathogenic yeast from clinical samples.

METHODS

We tested 284 clinical yeast isolates from various clinical specimens using ASTA MALDI-TOF MS, and the results were compared with those using molecular sequencing of the ITS or D1-D2 regions of rDNA and biochemical assays.

RESULTS

A total of 284 isolates were tested and found to be distributed across 14 species including Candida albicans (n = 100) and other yeast species (n = 184). ASTA MALDI-TOF MS correctly identified 95.1% (270/284) of the yeast species compared to molecular sequencing. Among them, 262 isolates showed acceptable MALDI-TOF MS scores (≥140), and 98.1% (257/262) isolates were identified correctly. In addition, among 22 isolates with a MALDI-TOF MS score <140, 59.1% (13/22) of the isolates showed concordance with molecular typing at the species level. Clustering analysis revealed the effectiveness of the new MALDI-TOF MS system for the identification of yeast species.

CONCLUSIONS

ASTA MALDI-TOF MS showed high accuracy in the identification of yeast species; it involves facile sample preparation and extraction procedures. ASTA MALDI-TOF MS is expected to be useful for yeast identification in clinical microbiology laboratories due to its reliability and cost-effectiveness.