Fungemia in non-HIV-infected patients: a five-year review

Genetic analysis of emerging fungal pathogens: Trichosporon asahii

Trichosporon asahii is an emerging opportunistic fungus that mainly causes fatal disseminated trichosporonosis, especially in immunocompromised patients. T. asahii infection has been reported in Thailand, but few studies of this fungus have been published. Therefore, this study investigated the genetic diversity of 51 clinical strains of T. asahii from urine samples in Thailand. We sequenced and characterized the beta-1-tubulin (TUB1), copper-exporting ATPase (ATP), phosphate carrier protein (PHCP), and topoisomerase-1 (TOP1) genes. In addition, intergenic spacer 1 (IGS1) sequences from our previous studies were investigated. The numbers of haplotypes were 3, 3, 2, 2, and 2 for IGS1, TUB1, ATP, PHCP, and TOP1, respectively. The results suggested a relatively low level of genetic diversity among the strains. The findings illustrated that IGS1, TUB1, ATP, PHCP, and TOP1 can be collectively used as an alternative molecular typing tool for investigating the population diversity and structure of T. asahii.

A Predictive Model for 30-Day Mortality of Fungemia in ICUs

Background

Few predictive models have been established to predict the risk of 30-day mortality from fungemia. This study aims to create a nomogram to predict the 30-day mortality of fungemia in ICUs.

Methods

Data of ICU patients with fungemia from both the Medical Information Mart for Intensive Care (MIMIC-III) database and the Grade-III Class-A hospital in China were collected. The data extracted from the MIMIC-III database functioned as the training dataset, which was used to construct a predictive model for 30-day mortality risk in ICU patients with fungemia; the data from the hospital functioned as the validation dataset, which was used to validate the model. A predictive model for 30-day mortality risk in ICU patients with fungemia was then built based on R software. Such indicators as C-index and calibration curve were utilized to evaluate the prediction ability of the model. Data of ICU patients with fungemia from the hospital were used as a validation dataset to validate the model.

Results

Predictive models were constructed by age, international normalized ratio (INR), renal failure, liver disease, respiratory rate (RR), glucocorticoid therapy, antifungal therapy, and platelets. The C-index value of the models was 0.838 (95% CI: 0.79096-0.88504). Attested by external validation results, the model has satisfactory predictive ability.

Conclusion

The 30-day mortality risk predictive model for ICU patients with fungemia constructed in this study has good predictive ability and may hopefully provide a 30-day mortality risk screening tool for ICU patients with fungemia.

Genotyping, antifungal susceptibility testing, and biofilm formation of Trichosporon spp. isolated from urine samples in a University Hospital in Bangkok, Thailand

The basidiomycetes yeast Trichosporon is widespread in the natural environment, but can cause disease, mainly in immunocompromised patients. However, there have been only few studies about this infection in Thailand. In this study, we characterized 53 Trichosporon spp. isolated from urine samples from patients admitted to a single hospital in Bangkok, Thailand over a one-year period from 2019 to 2020. The strains were identified using colony morphology, microscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and nucleotide sequence analysis of intergenic spacer 1 (IGS1). Fifty-one isolates were Trichosporon asahii, and the remaining isolates were Trichosporon inkin and other Trichosporon species. Three genotypes of IGS1-1, 3, and 7 were observed among T. asahii. The sensitivity of the yeasts to the antifungal drugs amphotericin B, fluconazole, and voriconazole ranged from 0.25 to >16 μg ml-1, 0.5-8 μg ml-1, and 0.01-0.25 μg ml-1, respectively. We investigated biofilm formation by the isolates, and no biofilm production was found in one isolate, low biofilm production in forty-four isolates, and medium biofilm production in six isolates. T. inkin produced biofilms at low levels, and Trichosporon spp. produced biofilms at medium levels. This research increases our understanding of the molecular epidemiology of Trichosporon spp. isolated from one university hospital in Bangkok, Thailand, and reveals their genetic diversity, antifungal susceptibility profiles, and capacity for in vitro biofilm production.

Long-term mortality predictors of ICU fungaemia

Bloodstream fungal infections have a high mortality rate. There is little data about the long-term mortality rate of fungaemia.This study aimed to explore the mortality of fungaemia and the influencing factors associated with death. In total, 204 intensive care unit (ICU) patients with fungaemia from Multi-parameter Intelligent Monitoring in Intensive Care-III (MIMIC-III) Database were studied. Age, gender, major underlying diseases, data about vital signs and blood test results were analysed to identify the predictors of the mortality and prognosis of fungaemia in ICU patients. Cox regression models were constructed, together with Kaplan−Meier survival curves. The 30-day, 1-year, 2-year, 3-year and 4-year mortality rates were 41.2%, 62.3%, 68.1%, 72.5% and 75%, respectively. Age (P ＜ 0.001, OR = 1.530; P ＜ 0.001, OR = 1.485)，serum bilirubin (P = 0.016, OR = 2.125；P = 0.001, OR = 1.748) and international normalised ratio (INR) (P = 0.001, OR = 2.642; P ＜ 0.001 OR = 2.065) were predictors of both the 30-day and 4-year mortality rates. Renal failure (P = 0.009, OR = 1.643) performed good in prediction of the 4-year mortality. The mortality of fungaemia is high. Age，the serum bilirubin and INR are good predictors of the 30-day and 4-year mortality rates of fungaemia. Renal failure has good performance in predicting the long-term mortality.

Suppurative thyroiditis: Systematic review and clinical guidance

OBJECTIVE

Acute suppurative thyroiditis (AST) is a rare but potentially fatal condition which can initially be difficult to distinguish from the more common subacute thyroiditis (SAT). We aim to update understanding of this medical emergency.

DESIGN

A systematic review over the past 20 years was performed on the epidemiology, clinical features, investigations, management and outcomes of AST. All full-text cases of microscopy or culture- proven AST in the English literature were included.

RESULTS

200 cases of AST have been described in 148 articles from January 2000 - January 2020. Bacterial AST is most common, often presenting with neck pain (89%) and fever (82%). Immunosuppression and pyriform sinus fistula are the most common causes, most often due to gram-positive aerobes. Transient hyperthyroidism is common (42%). Aspiration and antibiotics are becoming a more common treatment. Overall mortality was 7.8%. Tuberculous and fungal AST are less likely to present with fever and neck pain. Fungal AST is more common in immunosuppressed individuals (31%) and has a high overall mortality (33%). Tuberculous AST is more common in TB endemic areas.

CONCLUSION

The symptoms and signs of AST commonly overlap with SAT and initially can be hard to diagnose. AST can be rapidly morbid or even fatal. Clinicians need to consider AST when they assess patients with thyroiditis who are systemically unwell, have high fever, high white cell count and c-reactive protein, tender neck and abnormal neck imaging. An investigative and treatment strategy is described based on a systematic review of the literature.

Serious fungal infections in Thailand

The burden of serious fungal infection in Thailand is increasing but data regarding its incidence and prevalence are lacking. In this study we aimed to estimate the burden of serious fungal diseases in Thailand based on the size of the populations at risk and available epidemiological databases. Data derived from The Bureau of Epidemiology, Department of Disease Control, Thai Ministry of Public Health, World Health Organisation, international and local reports, and some unreported data were used. When no data existed, risk populations were used to estimate frequencies of fungal infections, using previously described methodology by LIFE. Recurrent vulvovaginal candidiasis (>4 episodes per year) is estimated to occur in 3,310 per 100,000 population. Using a previously described rate that 14/10,000 admissions are with fungaemia and 94% of those are Candida, we estimated 8,650 patients with candidaemia. The prevalence of chronic pulmonary aspergillosis is relatively high with a total of 19,044, approximately half subsequent to pulmonary tuberculosis. Invasive aspergillosis is estimated to affect 941 patients following leukaemia therapy, transplantations, and chronic obstructive pulmonary disease, approximately 1.4/100,000. In addition, allergic bronchopulmonary aspergillosis and severe asthma with fungal sensitisation were estimated at approximately 58.4/100,000 and 77/100,000, respectively. Given approximately 8,134 new cases of AIDS annually, cryptococcal meningitis, Pneumocystis pneumonia, and Talaromyces marneffei infection are estimated at 1.9/100,000, 2.6/100,000, and 0.3/100,000, respectively. The present study indicates that about 1.93% (1,254,562) of the population is affected by serious fungal infections. Owing to the lack of data, reports, and statistics, the number of patients with mycoses in Thailand can only be estimated.

Prevalence of fungemia in a tertiary hospital: Analysis of the last decade

INTRODUCTION

The prevalence of nosocomial fungemia has increased worldwide, and mortality caused by this disease is high.

OBJECTIVE

To assess progress in the last decade, and the prevalence and profile of fungal agents isolated in blood cultures performed in a tertiary university hospital.

METHOD

All the results of blood cultures processed at Hospital das Clínicas, Universidade Federal de Minas Gerais (HC-UFMG), in the time intervals 2001-2003 and 2011-2013 were analyzed retrospectively. For each three-year period, the number of collected blood cultures, the overall positivity rate and the percentage of fungemia were recorded. In addition, all identified fungal species were cataloged. All blood samples were incubated in the BacT/ALERT® (bioMérieux) automation system.

RESULTS

In 2001-2003, 34,822 samples were evaluated, with 5,510 (15.8%) positive results. In 2011-2013, the number of blood cultures processed increased to 55,052 samples, with 4,873 (8.9%) positive results. There was an increase in the number of positive cultures for fungi in the analyzed period (2001-2003: 4.16%; 2011-2013: 5.95%; p<0.001). Among the agents, candidemias were predominant, especially those caused by non-albicans Candida species (2001-2003: 57.64%; 2011-2013: 65.17%; p<0.05). There was also an increase in fungemia caused by other genera (2001-2003: 2.62%; 2011-2013: 4.48%; p<0.01).

CONCLUSION

There was an increase in the prevalence of fungemia in the last decade at HC-UFMG. Although candidemias have been responsible for most of the cases, there has been an increase in fungemias caused by other species.

Epidemiology and Outcome of Trichosporon Fungemia: A Review of 185 Reported Cases From 1975 to 2014

We first reviewed the English-language literature for reported cases of Trichosporon fungemia over the past four decades, and did comprehensive analysis in order to guide our understanding of epidemiology and outcome-related aspects, especially the antifungal treatment and CVC management.

Background. Trichosporon species have emerged as an important non-Candida spp yeast pathogen in immunocompromised patients in recent decades; however, the systemic analysis of Trichosporon epidemiology has seldom been reported.

Methods. We reviewed 185 reported cases of Trichosporon fungemia from 1975 to 2014 in the English-language literature, and the epidemiology and prognostic factors of the included cases are described.

Results. The number of cases reported has increased with time, especially over the past decade. During the 3 decades from 1975 to 2004, the most commonly used antifungal compounds were amphotericin B/liposomal amphotericin B; however, in recent decades (2005–2014), triazoles (especially voriconazole) have become the most widely used agents, significantly improving outcome in the reported cases. Correlation analysis revealed that negative outcome is associated with several prognostic factors, including a history of antimicrobial use, bacterial bloodstream coinfection, prophylactic/empirical antifungal therapy, Trichosporon beigelii infection, and receiving the antifungal regimen of amphotericin B/liposomal amphotericin B. In addition, a significantly greater proportion of patients with a positive outcome had fungemia without invasive tissue infection and received a voriconazole regimen or an AmB-triazole combined regimen. Significant positive outcome was also associated with patients who had recovered from neutropenia or after central venous catheter removal.

Conclusions. Voriconazole can be recommended as a first-line antifungal compound to treat Trichosporon fungemia; the immune status of the host plays a crucial role in the outcome of this infection, and the removal of vascular catheters should be considered if feasible.

Clinical characteristics and risk factors of non-Candida fungaemia

Background

The incidence of fungaemia has been increasing worldwide. It is important to distinguish non-Candida fungaemia from candidaemia because of their different antifungal susceptibilities. The aims of this study were to investigate the clinical characteristics of non-Candida fungaemia and identify the clinical factors that differentiate it from candidaemia.

Methods

We investigated the clinical manifestations and mortality of non-Candida fungaemia in Kyoto University Hospital from 2004 to 2009.

Results

There were 110 episodes of fungaemia during the study period. There were 11 renal replacement therapy episodes of fungaemia due to non-Candida yeasts (10.0%), including 6 episodes with Cryptococcus neoformans, 4 with Trichosporon asahii, and 1 with Kodamaea ohmeri, in addition to 99 episodes of candidaemia (90.0%). The presence of collagen disease [odds ratio (OR) 9.00; 95% confidence interval (CI) 1.58-51.4; P = 0.01] or renal replacement therapy (OR 15.0; 95% CI 3.06-73.4; P < 0.01) was significantly more common in non-Candida fungaemia patients than in candidaemia patients. Prior colonisation by the species may be a predictor of non-Candida fungaemia. Non-Candida fungaemia had a higher mortality than candidaemia (54.5% versus 21.2%, P = 0.03).

Conclusions

Although Candida species frequently cause fungaemia, we should also be aware of non-Candida yeasts because of their high mortality, particularly among high-risk patients, such as those with collagen disease and those under renal replacement therapy. Prior colonisation by the causative organisms may be an important predictor of non-Candida fungaemia.

Risk factors for systemic Candida infections in pediatric small bowel transplant recipients

BACKGROUND

Fungal infections are an important cause of morbidity and mortality after small bowel transplantation (SBT). Little information about risk factors for Candida infections in pediatric SBT is available.

METHODS

We performed a 1:1 matched retrospective case-control study including 23 Candida culture-positive patients (cases) and 23 culture-negative patients (controls), matched based on age and time of transplantation. Patients' characteristics were compared using Wilcoxon rank-sum, χ, or Fisher exact tests. McNemar test was used to assess discordance between pretransplant and posttransplant fungemia. Univariate and multivariable conditional logistic regression analyses were performed to identify risk factors.

RESULTS

The median age of the group was 1.87 years (range, 0.87-17.60); 59% patients were male. Within 1 month before transplant, 8.7% cases had fungemia and within 1-6 months before transplant, 30.4% cases had fungemia, compared with 69.6% within the 12 months after transplantation (P = 0.0001 and P = 0.02). By univariate analysis, total parenteral nutrition (TPN) (odds ratio [OR], 17.0 [95% confidence interval: 2.12, 2198]; P = 0.003) and antibiotic administration (OR, 18.99 [2.42, 2449]; P = 0.002) were risk factors for fungal infections. By multivariable analysis, both remained independent risk factors (TPN: OR, 10.86 [1.23, 1425], P = 0.03; antibiotic administration: OR, 12.83 [1.52, 1672], P = 0.01).

CONCLUSIONS

Fungemia was significantly more frequent after SBT than before transplantation. Patients receiving TPN and antibiotic treatment had, respectively, 11 and 13 times higher risk of developing Candida infections after SBT.

Epidemiology and risk factors for non-Candida albicans candidemia in non-neutropenic patients at a Chinese teaching hospital

The purpose of this study was to describe the epidemiology of nosocomial candidemia and identify risk factors involved in infections caused by non-C. albicans Candida species in a Chinese tertiary care center over a 10-year period. A total of 102 cases of nosocomial candidemia in non-neutropenic patients admitted from 1998 through 2007 were included in the study. Candida albicans remained the most common causative agent, accounting for 57.8% of all cases, followed by C. tropicalis (12.8%), C. parapsilosis (10.8%) and C. glabrata (10.8%). Comparison of C. albicans and non-C. albicans candidemia by multivariate logistic regression showed that factors independently associated with non-C. albicans candidemia included head trauma (OR, 5.34; 95% CI, 1.18-24.17; P = 0.029) and bacterial sepsis (OR, 3.58; 95% CI, 1.17-10.98; P = 0.026). Factors independently associated with C. albicans candidemia included tracheal intubation (OR, 0.26; 95% CI, 0.08-0.92; P = 0.037), and increased peripheral WBC count (OR, 0.84; 95% CI, 0.74-0.95; P = 0.006).

Evaluation of species distribution and risk factors of candidemia: a multicenter case-control study

This study was planned to determine the risk factors of candidemia, and the most common Candida species causing bloodstream infections. A case-control study which included adult patients was conducted over a 1-year period at tertiary-care educational hospitals in Turkey. A total of 83 candidemia episodes were identified during the study period. Candida albicans was the most common species recovered (45.8%) followed by Candida tropicalis (24.1%) Candida parapsilosis (14.5%) and Candida glabrata which was isolated from only four (4.8%) patients. Presence of a urethral catheter (odds ratio [OR] 2.38; 95% confidence interval [CI] 1.09-5.19; P = 0.02), previous use of antibiotics (OR 2.61; 95% CI 1.05-6.46; P = 0.03), RBC transfusions (OR 2.14; 95% CI 1.16-3.94; P = 0.01) and parenteral nutrition (OR 4.44; 95% CI 2.43-8.11; P < 0.01) were found as independent risk factors for candidemia. TPN (Total Parenteral Nutrition) was an independent risk factor for both C. albicans and non-Candida albicans Candida species (P < 0.001). Most of the risk factors were invasive procedures and former medications. We conclude that a great number of candidemia cases are preventable by means of reduction of unnecessary invasive procedures and the use of antimicrobials.

Genotyping and antifungal drug susceptibility of the pathogenic yeast Trichosporon asahii isolated from Thai patients

Trichosporonosis due to Trichosporon asahii is a life-threatening infection with a very poor prognosis. We analyzed the genotype of intergenic transcribed spacer (IGS) region 1 of the rRNA gene and determined the drug susceptibility of 101 T. asahii isolates obtained from Thai patients to collect basic information on trichosporonosis in Thailand. Of the five genotypes in the IGS region identified in this study, types 1 and 3 were predominant in Thailand. The distribution in Thailand differs from that in other countries, suggesting that there is a geographic substructure among T. asahii clinical isolates. Voriconazole appeared to be the most active drug.

Haemolytic and proteinase activities in clinical isolates of Candida parapsilosis and Candida tropicalis with reference to the isolation anatomic site

The aim of this study was to determine in vitro haemolytic and protease activities of Candida parapsilosis and Candida tropicalis isolates, obtained from anatomically distinct sites. Analysis of haemolytic activity of C. parapsilosis and C. tropicalis isolates obtained from the same anatomic site revealed that C. tropicalis isolates from blood had statistically higher activity (P < 0.05) than C. parapsilosis. On comparison of haemolytic activities of Candida isolates obtained from different anatomic sites, C. parapsilosis isolates from tracheal secretion were found to have higher activity than blood isolates. Protease activity was detected in the majority of the isolates analysed. Analysis of proteinase activity of C. parapsilosis and C. tropicalis isolates obtained from the same anatomic site revealed that C. parapsilosis isolates from tracheal secretion had statistically higher activity than C. tropicalis isolates. On comparison of proteinase activities of Candida isolates obtained from different anatomic sites, C. parapsilosis isolates from tracheal secretion were found to have higher activity than blood and superficial lesions isolates. Furthermore, C. tropicalis isolates from superficial lesions had higher activity than tracheal secretion isolates. Our results show the potential of C. parapsilosis and C. tropicalis isolates, obtained from distinct anatomic sites, to produce haemolytic factor and proteinases. Anatomic sites of isolation seem to be correlated with these activities, particularly for C. parapsilosis isolates.