Neonatal Candidemia Caused by Candida haemulonii: Case Report and Review of Literature

The multidrug-resistant Candida auris, Candida haemulonii complex and phylogenetic related species: Insights into antifungal resistance mechanisms

The rise of multidrug-resistant (MDR) fungal pathogens poses a serious global threat to human health. Of particular concern are Candida auris, the Candida haemulonii complex (which includes C. haemulonii sensu stricto, C. duobushaemulonii and C. haemulonii var. vulnera), and phylogenetically related species, including C. pseudohaemulonii and C. vulturna. These emerging, widespread, and opportunistic pathogens have drawn significant attention due to their reduced susceptibility to commonly used antifungal agents, particularly azoles and polyenes, and, in some cases, therapy-induced resistance to echinocandins. Notably, C. auris is classified in the critical priority group on the World Health Organization's fungal priority pathogens list, which highlights fungal species capable of causing systemic infections with significant mortality and morbidity risks as well as the challenges posed by their MDR profiles, limited treatment and management options. The mechanisms underlying antifungal resistance within these emerging fungal species is still being explored, but some advances have been achieved in the past few years. In this review, we compile current literature on the distribution of susceptible and resistant clinical strains of C. auris, C. haemulonii complex, C. pseudohaemulonii and C. vulturna across various antifungal classes, including azoles (fluconazole, voriconazole, itraconazole), polyenes (amphotericin B), echinocandins (caspofungin, micafungin, anidulafungin), and pyrimidine analogues (flucytosine). We also outline the main antifungal resistance mechanisms identified in planktonic cells of these yeast species. Finally, we explore the impact of biofilm formation, a classical virulence attribute of fungi, on antifungal resistance, highlighting the resistance mechanisms associated with this complex microbial structure that have been uncovered to date.

Spectrum and management of rare Candida/yeast infections in Kuwait in the Middle East

Invasive fungal infections (IFIs) are associated with high mortality rates and mostly affect patients with compromised immunity. The incidence of IFIs is increasing worldwide with the expanding population of susceptible patients. Candida and other yeast infections represent a major component of IFIs. Rare Candida/yeast infections have also increased in recent years and pose considerable diagnostic and management challenges as they are not easily recognized by routine phenotypic characteristic-based diagnostic methods and/or by the automated yeast identification systems. Rare Candida/yeasts also exhibit reduced susceptibility to antifungal drugs making proper management of invasive infections challenging. Here, we review the diagnosis and management of 60 cases of rare Candida/yeast IFIs described so far in Kuwait, an Arabian Gulf country in the Middle East. Interestingly, majority (34 of 60, 56.7%) of these rare Candida/yeast invasive infections occurred among neonates or premature, very-low-birth-weight neonates, usually following prior bacteremia episodes. The clinical details, treatment given, and outcome were available for 28 of 34 neonates. The crude mortality rate among these neonates was 32.2% as 19 of 28 (67.8%) survived the infection and were discharged in healthy condition, likely due to accurate diagnosis and frequent use of combination therapy. Physicians treating patients with extended stay under intensive care, on mechanical ventilation, receiving broad spectrum antibiotics and with gastrointestinal surgery/complications should proactively investigate IFIs. Timely diagnosis and early antifungal treatment are essential to decrease mortality. Understanding the epidemiology and spectrum of rare Candida/yeast invasive infections in different geographical regions, their susceptibility profiles and management will help to devise novel diagnostic and treatment approaches and formulate guidelines for improved patient outcome.

Neonatal fungemia caused by Lodderomyces elongisporus: first case report in Latin America

Premature hospitalized neonates have a greater risk for candidemia, however, fungemia due to rare opportunistic yeasts have been recently reported and is associated with high mortality rates. We herein report the first case in Latin America of Lodderomyces elongisporus fungemia in a premature neonate with a fatal outcome.

Candida haemulonii Species Complex: A Mini-review

Candida haemulonii species complex (CHSC) are emerging multidrug-resistant yeast pathogens able to cause life-threatening human infections in at-risk populations for invasive candidiasis worldwide. A recent laboratory survey conducted in 12 medical centers found that prevalence rates of Candida haemulonii complex isolates rose from 0.9 to 1.7% along the period between 2008 and 2019. We present a mini-review addressing recent aspects of the epidemiology, diagnosis and therapy of infections due to CHSC.

Candidemia in Brazilian neonatal intensive care units: risk factors, epidemiology, and antifungal resistance

Candidemia is responsible for substantial morbidity and mortality in neonatal intensive care units and represents a challenge due to the complexity of hospitalized neonates, the deficiency in approved and precise diagnostic techniques, and the increasing number of species resistant to antifungal agents. Thus, the objective of this study was to detect candidemia among neonates evaluating the risk factors, epidemiology, and antifungal susceptibility. Blood samples were obtained from neonates with suspected septicemia, and the mycological diagnosis was based on yeast growth in culture. The fungal taxonomy was based on classic identification, automated system, and proteomic, when necessary molecular tools were used. The in vitro susceptibility tests were performed according to the broth microdilution method from Clinical and Laboratory Standards Institute. Statistical analysis was performed using the R software version R-4.2.2. The prevalence of neonatal candidemia was 10.97%. The major risk factors involved were previous use of parenteral nutrition, exposure to broad-spectrum antibiotics, prematurity, and prior use central venous catheter, but only this last was statistically associated with mortality risk. Species from Candida parapsilosis complex and C. albicans were the most frequent. All isolates were susceptible to amphotericin B, except C. haemulonii that also exhibited elevated MICs to fluconazole. C. parapsilosis complex and C. glabrata exhibit the highest MICs to echinocandins. Considering these data, we emphasize that an effective management strategy to reduce the impact of neonatal candidemia should involve the knowledge of risk factors, rapid and precise mycological diagnostic, and tests of antifungal susceptibility to help in the selection of an appropriate treatment.

Microbiology of secondary infections in Buruli ulcer lesions; implications for therapeutic interventions

Background

Buruli ulcer (BU) is a skin disease caused by Mycobacterium ulcerans and is the second most common mycobacterial disease after tuberculosis in Ghana and Côte d’Ivoire. M. ulcerans produces mycolactone, an immunosuppressant macrolide toxin, responsible for the characteristic painless nature of the infection. Secondary infection of ulcers before, during and after treatment has been associated with delayed wound healing and resistance to streptomycin and rifampicin. However, not much is known of the bacteria causing these infections as well as antimicrobial drugs for treating the secondary microorganism. This study sought to identify secondary microbial infections in BU lesions and to determine their levels of antibiotic resistance due to the prolonged antibiotic therapy required for Buruli ulcer.

Results

Swabs from fifty-one suspected BU cases were sampled in the Amansie Central District from St. Peters Hospital (Jacobu) and through an active case surveillance. Forty of the samples were M. ulcerans (BU) positive. Secondary bacteria were identified in all sampled lesions (N = 51). The predominant bacteria identified in both BU and Non-BU groups were Staphylococci spp and Bacilli spp. The most diverse secondary bacteria were detected among BU patients who were not yet on antibiotic treatment. Fungal species identified were Candida spp, Penicillium spp and Trichodema spp. Selected secondary bacteria isolates were all susceptible to clarithromycin and amikacin among both BU and Non-BU patients. Majority, however, had high resistance to streptomycin.

Conclusions

Microorganisms other than M. ulcerans colonize and proliferate on BU lesions. Secondary microorganisms of BU wounds were mainly Staphylococcus spp, Bacillus spp and Pseudomonas spp. These secondary microorganisms were less predominant in BU patients under treatment compared to those without treatment. The delay in healing that are experienced by some BU patients could be as a result of these bacteria and fungi colonizing and proliferating in BU lesions. Clarithromycin and amikacin are likely suitable drugs for clearance of secondary infection of Buruli ulcer.

Clinical and epidemiological aspects of Candidemia in eight medical centers in the state of Parana, Brazil: Parana Candidemia Network

Objectives

Candida spp. has been reported as one of the common agents of nosocomial bloodstream infections and is associated with a high mortality. Therefore, this study evaluated the clinical findings, local epidemiology, and microbiological aspects of candidemia in eight tertiary medical centers in the state of Parana, South of Brazil.

Methods

In this study, we reported 100 episodes of candidemia in patients admitted to eight different hospitals in five cities of the state of Parana, Brazil, using data collected locally (2016 and 2017) and tabulated online.

Results

The incidence was found to be 2.7 / 1000 patients / day and 1.2 / 1000 admissions. C. albicans was responsible for 49% of all candidemia episodes. Cancer and surgery were the two most common underlying conditions associated with candidemia. The mortality rate within 30 days was 48%, and removal of the central venous catheter (p = 0.029) as well as empirical or prophylactic exposure to antifungals were both related to improved survival (p = 0.033).

Conclusions

This study highlights the high burden and mortality rates of candidemia in hospitals from Parana as well as the need to enhance antifungal stewardship program in the enrolled medical centers.

Biofilm Formed by Candida haemulonii Species Complex: Structural Analysis and Extracellular Matrix Composition

Candida haemulonii species complex (C. haemulonii, C. duobushaemulonii, and C. haemulonii var. vulnera) has emerged as opportunistic, multidrug-resistant yeasts able to cause fungemia. Previously, we showed that C. haemulonii complex formed biofilm on polystyrene. Biofilm is a well-known virulence attribute of Candida spp. directly associated with drug resistance. In the present study, the architecture and the main extracellular matrix (ECM) components forming the biofilm over polystyrene were investigated in clinical isolates of the C. haemulonii complex. We also evaluated the ability of these fungi to form biofilm on catheters used in medical arena. The results revealed that all fungi formed biofilms on polystyrene after 48 h at 37 °C. Microscopic analyses demonstrated a dense network of yeasts forming the biofilm structure, with water channels and ECM. Regarding ECM, proteins and carbohydrates were the main components, followed by nucleic acids and sterols. Mature biofilms were also detected on late bladder (siliconized latex), nasoenteric (polyurethane), and nasogastric (polyvinyl chloride) catheters, with the biomasses being significantly greater than on polystyrene. Collectively, our results demonstrated the ability of the C. haemulonii species complex to form biofilm on different types of inert surfaces, which is an incontestable virulence attribute associated with devices-related candidemia in hospitalized individuals.

Candidemia in a public hospital in Northeastern Brazil: Epidemiological features and risk factors in critically ill patients

BACKGROUND

Candidemia is a life-threatening fungal infection characterized by the presence of Candida in the blood.

AIMS

To describe the clinical-epidemiological features and main risk factors among patients with candidemia admitted to Intensive Care Unit.

METHODS

A cross-sectional, retrospective and observational study was performed between January 2015 and July 2016. Laboratory reports and medical records from ICU patients admitted to a public hospital in northeastern Brazil were analyzed.

RESULTS

There were 1573 admissions and 67 of them were positive for candidemia. The majority of patients were male (53.3%) and remained at the hospital for more than seven days (86.6%). Non-C. albicansCandida infections (60%) were predominant. Broad-spectrum antibiotic therapy was prescribed in 98.4% of the cases. The most frequent underlying diseases were sepsis (73.3%), presence of solid tumors (15%), respiratory condition (60%), urinary tract disease (56.6%) and gastrointestinal tract diseases (23.3%). Surgeries were carried out on 43% of the patients, consisting of 23.3% abdominal surgeries, with a mortality rate of 92.8%. Risk factors were venous central access (93.3%), mechanical ventilation (81.6%), nasoenteral tube (83.3%), nasogastric tube (25%), indwelling bladder catheter (88.3%), diabetes mellitus (55%) and tracheostomy (36.6%). Statistical analysis correlated the use of indwelling bladder catheter with a higher mortality rate (r=0.07412, p=0.0353).

CONCLUSIONS

The current study reveals the high case fatality rates among critically ill patients suffering from candidemia admitted to ICU. Herein, we highlight the importance of identifying non-C. albicansCandida species and reinforce the idea of carrying out epidemiological surveillances and antifungal susceptibility tests.

From hidden outbreaks to epidemic emergencies: the threat associated with neglecting emerging pathogens

Not all infectious disease outbreaks undergo full epidemiological investigations. In certain situations, the resultant lack of knowledge has led to the development of epidemics and public health emergencies. This review will examine six emerging pathogens including their history, present status, and potential to expand to epidemics. Recommendations to improve our understanding of these hidden outbreaks and others also will be provided in the context of health systems policy.

Candida auris, what do paediatricians need to know?

The newly recognised and emerging fungal species, Candida auris, has caused worldwide invasive infections and has been implicated in difficult to control hospital outbreaks. Challenges are encountered in the correct identification of this fungus as commonly used phenotypic and biochemical methods fail to differentiate C. auris from other Candida species. Its resistance profile, over 90% of isolates are fluconazole resistant and 35% are resistant to amphotericin, confronts clinicians with the restricted arsenal of antifungals and concerns about optimal treatment. The very first C. auris isolate was recovered from a paediatric patient in retrospect. Although infections with the more antifungal-resistant Candida species are less frequently observed in paediatric patients, this seems to be different for C. auris infections.

Emerging multidrug-resistant Candida species

PURPOSE OF REVIEW

To describe the epidemiology, strategies for early detection, and clinical management of infections caused by the most commonly found multidrug-resistant (MDR) Candida spp.

RECENT FINDINGS

Increasing numbers of reports describing invasive infections by MDR Candida auris and Candida glabrata has been reported in medical centers worldwide.

SUMMARY

We checked all papers published along the last 10 years describing epidemiological, diagnostic, and clinical aspects of infections by MDR Candida spp., with emphasis on C. auris and C. glabrata spp. C. auris has been reported in 15 countries and multidrug resistance rates is usually above 30%. Horizontal transmission is a great concern regarding C. auris. C. glabrata ranks the second most reported Candida spp. in deep-seated infections from United States and some European Centers, although multidrug resistance rates above 10% are restricted to some US centers. Candida haemulonii complex isolates with poor susceptibility to azoles and amphotericin B have been isolated in superficial and deep-seated infections, whereas Candida guilliiermondii complex isolates with poor susceptibility to azoles and echinocandins have been recovered from catheter-related bloodstream infections. Other potential MDR Candida species are Candida krusei, Candida lusitaniae, Candida kefyr, Yarrowia (Candida) lypolitica, and Candida rugosa.

Diversity of culturable yeasts associated with zoanthids from Brazilian reef and its relation with anthropogenic disturbance

Some of the main threats to coral reefs come from human actions on marine environment, such as tourism, overfishing and pollution from urban development. While several studies have demonstrated an association between bacteria and corals, demonstrating how these communities react to different anthropogenic stressors, yeast communities associated with corals have received far less attention from researchers. The aim of this work was therefore to describe cultivable yeasts associated with three coral species and to evaluate the influence of sewage discharge on yeasts community. We obtained 130 isolates, mostly belonging to phylum Ascomycota and many of them had previously been isolated from human samples or are considered pathogens. The mycobiota was more similar among corals collected from the same reef, indicating that the composition of reef yeast community is more influenced by environmental conditions than host species. We suggest further studies to elucidate which factors are most influential on the composition of the coral-associated yeast community.

Identification and Antifungal Susceptibility Profiles of Candida haemulonii Species Complex Clinical Isolates from a Multicenter Study in China

Candida haemulonii complex (Candida haemulonii, Candida haemulonii var. vulnera, and Candida duobushaemulonii) consists of emerging pathogens. Thirty-one isolates from 14 hospitals in China were studied for their species classification and antifungal susceptibilities. Performances of molecular (i.e., ribosomal DNA [rDNA] internal transcribed spacer [ITS] sequencing, D1/D2 sequencing, and ITS sequencer-based capillary gel electrophoresis [SCGE]) and phenotypic identification methods in species identification were compared. Twenty-six (83.9%) of 31 isolates were identified as C. haemulonii and 5 isolates were identified as C. duobushaemulonii by ITS sequencing as the reference method; results obtained by D1/D2 sequencing and ITS SCGE were concordant with those obtained by ITS sequencing for all (100%) of the isolates. All 31 isolates were identified as C. haemulonii by the Vitek matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) system (bioMérieux, France), whereas the Bruker MS system (Bruker Daltoniks, Germany) correctly provided species identification for 77.4% and 100% of isolates using cutoff scores for species of ≥2.0 and ≥1.70, respectively. The Vitek 2 compact (bioMérieux) only identified 9 (29%) of 31 isolates. All isolates showed high MICs for amphotericin B (range, 2 to >8 μg/ml) and fluconazole (≥128 μg/ml) but low MICs (≤0.5 μg/ml) for the echinocandins. Our results reinforce the need for MALDI-TOF MS and/or molecular differentiation of species within the C. haemulonii complex. The multiresistant antifungal susceptibility profile of these isolates represents a challenge to therapy.

Candida vulturna pro tempore sp. nov., a dimorphic yeast species related to the Candida haemulonis species complex isolated from flowers and clinical sample

In a taxonomic study of yeasts isolated from flowers in Cagayan de Oro, Mindenao Island, The Philippines, strains were identified as representing Kabatiella microsticta, Metschnikowia koreensis and a hitherto undescribed dimorphic species. Sequences of the D1/D2 domains of the LSU 26S rRNA genes, the internal transcribed spacer (ITS) regions and the SSU 18S rRNA genes were identical in the strains of the last-named group and differed from the corresponding sequences of the type strain of the closest related species, Candida duobushaemulonii, by 4 % (D1/D2), 7 % (ITS) and 1 % (SSU). In an independent study, a strain with D1/D2 and ITS sequences very similar to those of the Philippine strains was isolated in Malaysia from the blood of a patient dying of aspiration pneumonia. Both groups of isolates were moderately sensitive to anidulafungin, caspofungin, fluconazole, itraconazole and voriconazole but resistant to amphotericin B. Molecular phylogenetic analysis of the sequences placed the Philippine and Malaysian isolates close to the Candida haemulonis complex of Candida species. To reflect the geographical location of the sites of sample collection, the novel species name Candida vulturna pro tempore sp. nov. is proposed to accommodate these strains. The type strain is 11-1170T (=CBS 14366T=CCY 094-001-001T=NCAIM-Y02177T) isolated in Cagayan de Oro, The Philippines. Mycobank: MB 817222.