Fungaemia due to rare yeasts in paediatric intensive care units: A prospective study

A novel diagnostic method for a rare fungus: FcMBL facilitates Wickerhamomyces anomalus identification in an immunocompromised neonate

Fungemia negatively impacts patient outcomes, current diagnostics lack sensitivity to identify emerging rare mycoses, and fungal infections are increasing in prevalence, variety, and resistance. We report a case of Wickerhamomyces anomalus in an immunocompromised neonate in which FcMBL bead-based matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) resulted in species identification roughly 30 hours before standard pathogen identification methods. Deploying FcMBL bead-based MALDI-TOF MS may improve the speed and accuracy of identification, and therefore treatment, of rare pathogens.

The Intricate Connection between Bacterial α-Diversity and Fungal Engraftment in the Human Gut of Healthy and Impaired Individuals as Studied Using the In Vitro SHIME® Model

From the estimated 2.2 to 3.8 million fungal species existing on Earth, only a minor fraction actively colonizes the human gastrointestinal tract. In fact, these fungi only represent 0.1% of the gastrointestinal biosphere. Despite their low abundance, fungi play dual roles in human health-both beneficial and detrimental. Fungal infections are often associated with bacterial dysbiosis following antibiotic use, yet our understanding of gut fungi-bacteria interactions remains limited. Here, we used the SHIME® gut model to explore the colonization of human fecal-derived fungi across gastrointestinal compartments. We accounted for the high inter-individual microbial diversity by using fecal samples from healthy adults, healthy babies, and Crohn's disease patients. Using quantitative Polymerase Chain Reaction and targeted next-generation sequencing, we demonstrated that SHIME®-colonized mycobiomes change upon loss of transient colonizers. In addition, SHIME® reactors from Crohn's disease patients contained comparable bacterial levels as healthy adults but higher fungal concentrations, indicating unpredictable correlations between fungal levels and total bacterial counts. Our findings rather link higher bacterial α-diversity to limited fungal growth, tied to colonization resistance. Hence, while healthy individuals had fewer fungi engrafting the colonic reactors, low α-diversity in impaired (Crohn's disease patients) or immature (babies) microbiota was associated with greater fungal abundance. To validate, antibiotic-treated healthy colonic microbiomes demonstrated increased fungal colonization susceptibility, and bacterial taxa that were negatively correlated with fungal expansion were identified. In summary, fungal colonization varied individually and transiently, and bacterial resistance to fungal overgrowth was more related with specific bacterial genera than total bacterial load. This study sheds light on fungal-bacterial dynamics in the human gut.

The Epidemiology and Clinical Characteristics of Fungemia in a Tertiary Hospital in Southern China: A 6-Year Retrospective Study

Knowledge of the epidemiology and clinical characteristics of fungemia in southern China is limited. We conducted a six-year retrospective descriptive study to analyze the epidemiological and clinical characteristics of fungemia at the largest tertiary hospital in Guangxi, southern China. Data were obtained from the laboratory registry of patients with fungemia between January 2014 and December 2019. Demographic characteristics, underlying medical conditions, and outcomes for each case were analyzed. A total of 455 patients with fungemia were identified. Unexpectedly, Talaromyces marneffei (T. marneffei) was the most frequently isolated agent causing fungemia in the region (149/475, 31.4%), and Candida albicans (C. albicans) was the most commonly isolated Candida spp. (100/475, 21.1%). We identified that more than 70% of talaromycosis fungemia developed in AIDS patients, whereas candidemia was most commonly associated with a history of recent surgery. Notably, the total mortality rate of fungemia and the mortality rate in patients with T. marneffei and Cryptococcus neoformans (C. neoformans) fungemia were significantly higher in HIV-uninfected patients than in HIV-infected patients. In conclusion, the clinical pattern of fungemia in Guangxi is different from that in previous studies. Our study may provide new guidance for the early diagnosis and prompt treatment of fungemia in similar geographic regions.

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

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

Clinical utility of time to positivity of blood cultures in cases of fungaemia: A prospective study

PURPOSE

Fungaemia due to yeast is a major cause of morbidity and mortality in critically ill patients. Although, automated blood cultures have improved the time to diagnosis, very few studies have systematically evaluated the utility of blood culture time to positivity (TTP) of fungaemia in the clinical scenario. In this study, we evaluated the TTP for different yeast species to determine its clinical utility.

MATERIAL AND METHODS

A prospective study including 244 consecutive patients admitted to the adult (n ​= ​76) and paediatric (n ​= ​168) intensive care units (ICUs) was conducted between December 2017 through March 2019. The clinical and demographic characteristics, BACTEC blood culture results and TTP for yeast positive blood cultures were recorded for analysis.

RESULTS

A total of 244 patients with 357 episodes of candidaemia were enrolled during the study period. The TTP (mean ​± ​SD) for all yeast species was 26.8 ​± ​23.6 ​h while it was significantly longer in paediatric than adult patients (30.5 ± 24.7 vs. 25.2 ​± ​22.9 ​h; p ​= ​<0.0001). Wickerhamomyces anomalus and Cyberlindnera jadinii (previously C. utilis) were exclusively isolated from paediatric population where W. anomalus demonstrated significantly longer TTP than C. jadinii. Among adult cases, C. albicans exhibited significantly longer TTP than C. tropicalis. In paediatric cases, >80% of C. tropicalis and C. utilis flagged positive in blood culture before 24 ​h while majority (65.9%) of W. anomalus isolates flagged positive later than 24 ​h. Similarly in adult samples, 63% of C. tropicalis isolates beeped positive before 24 ​h.

CONCLUSION

TTP for yeast may provide insight regarding the responsible yeast species before final identification among critical patients with candidaemia. Larger studies are warranted for evaluating clinical utility of TTP considering other complex factors like yeast burden, generation time, virulence and host factors, which may affect TTP.

Distribution of Yeast Species and Risk Factors of Oral Colonization after Oral-Care Education among the Residents of Nursing Homes

Most yeasts causing infections in humans are part of commensal microflora and etiological agents of different infections when hosts become susceptible, usually due to becoming immunocompromised. The colonization of potentially pathogenic microbes in the oral cavity is increased by poor oral hygiene. This follow-up survey was conducted approximately two months after providing information on proper oral care at 10 nursing homes in Taiwan. Among the 117 of 165 residents colonized by yeasts, 67 were colonized by more than one yeast species. A total of 231 isolates comprising eight fungal genera and 25 species were identified. Candida albicans (44.6%) was the dominant species, followed by Candida glabrata (17.7%), Candida parapsilosis (8.7%), Candida tropicalis (7.8%), and Candida pararugosa (7.3%). Residents having a yeast colony-forming unit >10 (OR, 8.897; 95% CI 2.972−26.634; p < 0.001) or using a wheelchair (OR, 4.682; 95% CI 1.599−13.705; p = 0.005) were more likely to be colonized by multiple species. By comparing before and after oral-care education, dry mouth (OR, 3.199; 95% CI 1.448−7.068; p = 0.011) and having heart disease (OR, 2.681; 95% CI 1.068−6.732; p = 0.036) emerged as two independent risk factors for increased density of colonizing yeast.

Epidemiology of Candidemia in Kuwait: A Nationwide, Population-Based Study

The Candida species cause a majority of invasive fungal infections. In this article, we describe the nationwide epidemiology of candidemia in Kuwait in 2018. Yeast bloodstream isolates submitted from all major hospitals and identified by phenotypic MALDI-TOF MS and/or by molecular methods were studied. Susceptibility testing was performed by Etest. Out of 313 bloodstream yeasts, 239 Candida spp. isolates (excluding duplicate isolates) were obtained during 234 candidemic episodes among 223 patients. Mixed-species candidemia and re-infection occurred in 5 and 11 patients, respectively. C. albicans (n = 74), C. parapsilosis (n = 54), C. tropicalis (n = 35), C. auris (n = 33), C. glabrata (n = 32), other Candida spp. (n = 11), and other yeasts (n = 9) caused fungemia. Nearly 50% of patients were in intensive care units. Candida spp. isolates (except C. glabrata) were susceptible to caspofungin and 27% of C. auris were amphotericin B-resistant. Resistance to fluconazole was 100% in C. auris, 17% in C. parapsilosis, 12% in C. glabrata, and 1% in C. albicans. Mortality was 47% for other Candida/yeast infections. Nationwide candidemia incidence in 2018 was 5.29 cases/100,000 inhabitants. Changes in species spectrum, increasing fluconazole resistance in C. parapsilosis, and the emergence of C. auris as a major pathogen in Kuwait are noteworthy findings. The data could be of help in informing decisions regarding planning, in the allocation of resources, and in antimicrobial stewardship.