Azole Susceptibility Profiles of More than 9,000 Clinical Yeast Isolates Belonging to 40 Common and Rare Species

Candida guilliermondii fungemia: a 12-year retrospective review of antimicrobial susceptibility patterns at a reference laboratory and tertiary care center

The prevalence of invasive candidiasis caused by non-albicans Candida species is increasing. Candida guilliermondii is an infrequent cause of candidemia but has been associated with decreased susceptibility to triazoles. Clinical data related to the infection with C. guilliermondii are sparse. Our study evaluated the antifungal susceptibility testing (AST) for C. guilliermondii isolates submitted to a reference laboratory over a 12-year period (2012-2023). AST patterns were examined using Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) epidemiological cutoff values (ECVs) and breakpoints. Where isolates were identified from patients treated at our institution, retrospective chart review was performed to describe patient risk factors, treatment approaches, and outcomes associated with C. guilliermondii fungemia. One hundred twelve blood culture isolates of C. guilliermondii were identified, and clinical data were available for 21 fungemic patients. A significant number of isolates (9.8-20.5%) were observed to be non-wild type for various triazoles. All isolates were susceptible to micafungin. A majority (76.2%) of cases of C. guilliermondii fungemia treated at our tertiary care center were hospital-acquired, and two-thirds of patients were immunocompromised at the time of diagnosis. Ten of the 21 patients died within 60 days of fungemia, although mortality was directly or partially attributed to C. guilliermondii fungemia in only four cases (19.0%). Echinocandins may be used for empiric therapy for C. guilliermondii until the results of AST are available. Further research is required to determine appropriate clinical breakpoints for triazoles.

IMPORTANCE

Our study addresses a significant knowledge gap in the clinical management of this non-Candida albicans species. Our retrospective review includes comprehensive AST data for 112 Candida guilliermondii isolates, which is the largest number of isolates reported from the United States to date. Susceptibility data are supplemented by clinical outcomes, where isolates were identified for patients treated at Mayo Clinic. Key findings from our study include the observation that a notable proportion of C. guilliermondii isolates exhibit non-wild-type profiles for various triazoles. Importantly, all isolates remained susceptible to echinocandins, suggesting their efficacy as first-line therapy in the absence of timely susceptibility results. Furthermore, our study highlights the high mortality associated with C. guilliermondii fungemia in immunocompromised patients, emphasizing the urgent need for optimized treatment strategies.

Epidemiology of Invasive Candidiasis

Invasive candidiasis (IC) is an increasingly prevalent, costly, and potentially fatal infection brought on by the opportunistic yeast, Candida. Previously, IC has predominantly been caused by C. albicans which is often drug susceptible. There has been a global trend towards decreasing rates of infection secondary to C. albicans and a rise in non-albicans species with a corresponding increase in drug resistance creating treatment challenges. With advances in management of malignancies, there has also been an increase in the population at risk from IC along with a corresponding increase in incidence of breakthrough IC infections. Additionally, the emergence of C. auris creates many challenges in management and prevention due to drug resistance and the organism's ability to transmit rapidly in the healthcare setting. While the development of novel antifungals is encouraging for future management, understanding the changing epidemiology of IC is a vital step in future management and prevention.

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

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

Breakthrough Invasive Fungal Infections in Patients With High-Risk Hematological Disorders Receiving Voriconazole and Posaconazole Prophylaxis: A Systematic Review

BACKGROUND

Primary antifungal prophylaxis with mold-active azoles is used to prevent invasive fungal infections in patients with high-risk hematological disorders; however, breakthrough infections occur, and the reasons for treatment failure are still not fully understood. To help inform clinical decisions, we sought to define microbiological, clinical, and pharmacological characteristics of proven and probable breakthrough invasive fungal infections (bIFIs) in patients with high-risk hematological disorders receiving voriconazole or posaconazole prophylaxis.

METHODS

We performed a systematic review of the literature following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search strategy was last conducted on 19 April 2023.

RESULTS

We assessed 5293 studies for eligibility, and 300 were selected for data extraction. These studies described 1076 cases of bIFIs occurring under voriconazole (42.5%) or posaconazole (57.5%). The most commonly found pathogens were Aspergillus (40%), Mucorales (20%), Candida (18%), and Fusarium (9%) species. Mucorales were more frequent among voriconazole-emerging cases, whereas Aspergillus and Fusarium were more prevalent among posaconazole-emerging cases. Definitive, putative, or probable antifungal resistance was found in 31% of cases. Therapeutic drug monitoring showed subtherapeutic azole concentration in 32 of 90 (36%) cases. Infection-related mortality was reported in 117 cases and reached 35%.

CONCLUSIONS

In our systemic review, the most common bIFIs were aspergillosis, mucormycosis, candidiasis, and fusariosis. Antifungal resistance explains only a minority of cases. Subtherapeutic prophylaxis was frequent but rarely reported. Prospective studies are needed to better understand these infections and to establish optimal management.

Features of cryptococcosis among 652 HIV-seronegative individuals in France: a cross-sectional observational study (2005-2020)

OBJECTIVES

We aimed to describe features and outcomes of cryptococcosis among HIV-seronegative individuals in a large surveillance network for cryptococcosis in France.

METHODS

We included incident cases of cryptococcosis in HIV-seronegative individuals from 2005 to 2020. We compared patient characteristics, disease presentations, cryptococcal antigen results, and induction antifungal treatments according to underlying disease. We examined factors associated with 90-day mortality. Among patients with disseminated infections, we investigated whether receipt of flucytosine and polyene combination was associated with lower mortality.

RESULTS

Among 652 individuals, 209 (32.1%) had malignancy, 130 (19.9%) were solid-organ transplant recipients, 204 (31.3%) had other immunocompromising conditions, and 109 (16.7%) had no reported underlying factor. The commonest presentations were disseminated infections (63.3%, 413/652) and isolated pulmonary infections (25.3%, 165/652). Solid-organ transplant patients were most likely to have disseminated infections and a positive serum cryptococcal antigen result. Patients with malignancy were older and less likely to receive a flucytosine-containing regimen for disseminated infections than others (58.7%, 78/133 vs. 73.2%, 194/265; p 0.029). The crude 90-day case-fatality ratio was 27.2% (95% CI, 23.5%-31.1%). Age ≥60 years (aOR: 2.75 [1.78-4.26]; p < 0.001), meningitis/fungaemia (aOR: 4.79 [1.80-12.7]; p 0.002), and malignancy (aOR: 2.4 [1.14-5.07]; p 0.02) were associated with higher 90-day mortality. Receipt of flucytosine and polyene combination was associated with lower 90-day mortality (aOR: 0.40 [0.23-0.71]; p 0.002) in multivariable analysis and inverse probability of treatment weighted analysis (aOR: 0.45 [0.25-0.80]; p 0.006).

DISCUSSION

HIV-seronegative individuals with cryptococcosis comprise a wide range of underlying conditions with different presentations and outcomes, requiring a tailored approach to diagnosis and management.

Pan-azole-resistant Meyerozyma guilliermondii clonal isolates harbouring a double F126L and L505F mutation in Erg11

BACKGROUND

Meyerozyma guilliermondii is a yeast species responsible for invasive fungal infections. It has high minimum inhibitory concentrations (MICs) to echinocandins, the first-line treatment of candidemia. In this context, azole antifungal agents are frequently used. However, in recent years, a number of azole-resistant strains have been described. Their mechanisms of resistance are currently poorly studied.

OBJECTIVE

The aim of this study was consequently to understand the mechanisms of azole resistance in several clinical isolates of M. guilliermondii.

METHODS

Ten isolates of M. guilliermondii and the ATCC 6260 reference strain were studied. MICs of azoles were determined first. Whole genome sequencing of the isolates was then carried out and the mutations identified in ERG11 were expressed in a CTG clade yeast model (C. lusitaniae). RNA expression of ERG11, MDR1 and CDR1 was evaluated by quantitative PCR. A phylogenic analysis was developed and performed on M. guilliermondii isolates. Lastly, in vitro experiments on fitness cost and virulence were carried out.

RESULTS

Of the ten isolates tested, three showed pan-azole resistance. A combination of F126L and L505F mutations in Erg11 was highlighted in these three isolates. Interestingly, a combination of these two mutations was necessary to confer azole resistance. An overexpression of the Cdr1 efflux pump was also evidenced in one strain. Moreover, the three pan-azole-resistant isolates were shown to be genetically related and not associated with a fitness cost or a lower virulence, suggesting a possible clonal transmission.

CONCLUSION

In conclusion, this study identified an original combination of ERG11 mutations responsible for pan-azole-resistance in M. guilliermondii. Moreover, we proposed a new MLST analysis for M. guilliermondii that identified possible clonal transmission of pan-azole-resistant strains. Future studies are needed to investigate the distribution of this clone in hospital environment and should lead to the reconsideration of the treatment for this species.

Changes in fungal taxonomy: mycological rationale and clinical implications

Numerous fungal species of medical importance have been recently subjected to and will likely continue to undergo nomenclatural changes as a result of the application of molecular approaches to fungal classification together with abandonment of dual nomenclature. Here, we summarize those changes affecting key groups of fungi of medical importance, explaining the mycological (taxonomic) rationale that underpinned the changes and the clinical relevance/importance (where such exists) of the key nomenclatural revisions. Potential mechanisms to mitigate unnecessary taxonomic instability are suggested, together with approaches to raise awareness of important changes to minimize potential clinical confusion.

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 thoracic solid organ transplant recipients: Characteristics and outcomes relative to matched uninfected and bacteremic thoracic organ transplant recipients

BACKGROUND

Little is understood about the risk factors and outcomes from candidemia in thoracic solid organ transplant recipients.

METHODS

This is a single-center retrospective cohort study of patients undergoing heart or lung transplant between January 1, 2013 and December 31, 2022. We performed two comparisons among heart and lung transplant recipients: (1) recipients with candidemia versus matched, uninfected recipients, and (2) recipients with candidemia versus recipients with bacteremia.

RESULTS

During the study 384 heart and 194 lung transplants were performed. Twenty-one (5.5%) heart and six (3.1%) lung recipients developed candidemia. Heart recipients with candidemia were more likely to have had delayed chest closure (38.1% vs. 0%, p < .0001), temporary mechanical circulatory support (57.1% vs. 11.9%, p = .0003), and repeat surgical chest exploration 76.2% vs. 16.7%, p < .0001) than uninfected controls. Heart and lung recipients who developed candidemia were more likely to have been on renal replacement therapy prior to infection relative to uninfected controls (57.1% vs. 11.9%, p = .0003 and 66.7% vs. 0%, p = .0041, respectively). Heart recipients with candidemia had significantly lower post-transplant survival and lower post-infection survival relative to matched uninfected controls and heart recipients with bacteremia, respectively (p < .0001 and p = .0002, respectively).

CONCLUSIONS

Candidemia following heart and lung transplantation is associated with significant morbidity and mortality. Further research is needed to understand if heart recipients with delayed chest closure, temporary mechanical circulatory support, renal replacement therapy, and repeat surgical chest exploration may benefit from targeted antifungal prophylaxis.

Real-life comparison of posaconazole versus fluconazole for primary antifungal prophylaxis during remission-induction chemotherapy for acute leukemia

BACKGROUND

Patients undergoing remission-induction intensive chemotherapy for acute leukemia are at high risk for life-threatening invasive fungal infections (IFIs). Primary antifungal prophylaxis with posaconazole has been shown to reduce the incidence of IFI compared to fluconazole, but real-life data are limited and the effect on mortality remains unclear.

METHODS

This retrospective cohort study compared fluconazole and posaconazole as primary prophylaxis in real-life practice over a 10-year period, in a Canadian hospital.

RESULTS

A total of 299 episodes were included (fluconazole, n = 98; posaconazole, n = 201), of which 68% were first inductions. The underlying hematologic malignancy was acute myeloid leukemia or myelodysplastic syndrome in 88% of episodes and acute lymphoblastic leukemia in 9%. Overall, 20 cases of IFI occurred (aspergillosis, n = 17; candidiasis, n = 3) and 14 were considered as breakthrough IFI. IFI incidence was significantly lower in the posaconazole group (3.5% versus 13.2%; p = 0.001). Empirical or targeted antifungal therapy was also reduced in the posaconazole cohort. Mortality was similar in both groups.

CONCLUSIONS

In a real-life setting in Canada, primary posaconazole prophylaxis reduces the incidence of IFI during remission-induction chemotherapy, compared to fluconazole.

Water Quality, Heavy Metals, and Antifungal Susceptibility to Fluconazole of Yeasts from Water Systems

Aquatic environments could be reservoirs of pathogenic yeasts with acquired antifungal resistance. The susceptibility to antifungal agents of yeasts present in the wastewater and natural waters of the city of Cali was evaluated. Samples were taken from two types of water: drinking water (Meléndez River, drinking water treatment plant "Puerto Mallarino" in the Cauca River) and wastewater (South Channel of the Cauca River, "Cañaveralejo-PTAR" wastewater treatment plant). Physico-chemical parameters, heavy metal concentration, and yeast levels were determined using standard procedures. Yeasts were identified using API 20 C AUX (BioMérieux) and sequence analysis of the ITS1-5.8S-ITS2 and D1/D2 regions of the large subunit of the ribosome. Susceptibility assays against fluconazole and amphotericin B using the minimum inhibitory concentration (MIC) test were determined using the microdilution method. The influence of physico-chemical parameters and heavy metals was established using principal component analysis (PCA). Yeast counts were higher at WWTP "PTAR" and lower at Melendez River, as expected. A total of 14 genera and 21 yeast species was identified, and the genus Candida was present at all locations. Susceptibility tests showed a 32.7% resistance profile to fluconazole in the order DWTP "Puerto Mallarino = WWTP "PTAR" > South Channel "Navarro". There were significant differences (p < 0.05) in the physico-chemical parameters/concentration of heavy metals and yeast levels between the aquatic systems under study. A positive association was observed between yeast levels and total dissolved solids, nitrate levels, and Cr at the "PTAR" WWTP; conductivity, Zn, and Cu in the South Channel; and the presence of Pb in the "Puerto Mallarino" DWTP. Rhodotorula mucilaginosa, Candida albicans, and Candida sp. 1 were influenced by Cr and Cd, and Diutina catelunata was influenced by Fe (p < 0.05). The water systems explored in this study showed different yeast levels and susceptibility profiles, and, therefore, possible genetic differences among populations of the same species, and different physico-chemical and heavy metals concentrations, which were probably modulating the antifungal-resistant yeasts. All these aquatic systems discharge their content into the Cauca River. We highlight the importance to further investigate if these resistant communities continue to other locations in the second largest river of Colombia and to determine the risk posed to humans and animals.

Saprochaete clavata invasive infection: characterization, antifungal susceptibility, and biofilm evaluation of a rare yeast isolated in Brazil

Rare emerging pathogens such as Saprochaete clavata are associated with invasive fungal diseases, high morbidity, mortality, rapidly fatal infections, and outbreaks. However, little is known about S. clavata infections, epidemiology, risk factors, treatment, biofilms, and disease outcomes. The objective of this study was to describe a new case of severe S. clavata infection in a patient diagnosed at a referral children's hospital in Brazil, including antifungal minimal inhibitory concentration, S. clavata biofilm characterization, and molecular characterization. The S. clavata isolated from an immunocompromised 11-year-old male patient was characterized using MALDI-TOF, Gram staining, scanning electron microscopy (SEM), and next generation sequencing (NGS) of genomic DNA. Biofilm production was also evaluated in parallel with determining minimal inhibitory concentration (MIC) and biofilm sensitivity to antifungal treatment. We observed small to medium, whitish, farinose, dry, filamentous margin colonies, yeast-like cells with bacillary features, and biofilm formation. The MALDI-TOF system yielded a score of ≥ 2,000, while NGS confirmed S. clavata presence at the nucleotide level. The MIC values (in mg L-1) for tested drugs were as follows: fluconazole = 2, voriconazole ≤ 2, caspofungin ≥ 8, micafungin = 2, amphotericin B = 4, flucytosine ≤ 1, and anidulafungin = 1. Amphotericin B can be active against S. clavata biofilm and the fungus can be susceptible to new azoles. These findings were helpful for understanding the development of novel treatments for S. clavata-induced disease, including combined therapy for biofilm-associated infections.

Draft Genome Sequence of the Fluconazole-Resistant Candida palmioleophila Clinical Isolate CBS 18098

Candida palmioleophila belongs to the Saccharomycetales. This opportunistic yeast which has been associated with invasive infections in human and animals, warrants a specific attention as it is frequently misidentified and display reduced susceptibility to fluconazole. Here, we report the first draft genome of C. palmioleophila, obtained from a clinical isolate.

Molecular identification, antifungal susceptibility, and resistance mechanisms of pathogenic yeasts from the China antifungal resistance surveillance trial (CARST-fungi) study

To have a comprehensive understanding of epidemiology and antifungal susceptibilities in pathogenic yeasts, the China Antifungal Resistance Surveillance Trial (CARST-fungi) study was conducted. All yeast isolates were identified by ribosomal DNA sequencing. Antifungal susceptibilities were performed using CLSI M27-A4 broth microdilution method. Sequence and expression level of resistant-related genes in resistant/non-wide-type (NWT) Candida isolates were analyzed. Totally 269 nonduplicate yeast isolates from 261 patients were collected. About half of the yeast isolates (127, 47.2%) were recovered from blood, followed by ascetic fluid (46, 17.1%). C. albicans remained the most prevalent (120, 44.6%), followed by C. parapsilosis complex (50, 18.6%), C. tropicalis (40, 14.9%), and C. glabrata (36, 13.4%). Fourteen (11.7%) C. albicans isolates and 1 (2.0%) C. parapsilosis isolate were resistant/NWT to triazoles. Only 42.5% (17/40) C. tropicalis were susceptible/WT to all the triazoles, with 19 (47.5%) isolates NWT to posaconazole and 8 (20%) cross-resistant to triazoles. Among C. glabrata, 20 (55.6%) and 8 (22.2%) isolates were resistant/NWT to voriconazole and posaconazole, respectively, and 4 (10.3%) isolates were cross-resistant to triazoles. Isavuconazole was the most active triazole against common Candida isolates. Except for 2 isolates of C. glabrata cross-resistant to echinocandins which were also NWT to POS and defined as multidrug-resistant, echinocandins exhibit good activity against common Candida species. All isolates were WT to AMB. For less common species, Rhodotorula mucilaginosa exhibited high MICs to echinocandins and FLC, and 1 isolate of Trichosporon asahii showed high MICs to all the antifungals except AMB. Among triazole-resistant Candida isolates, ERG11 mutations were detected in 10/14 C. albicans and 6/23 C. tropicalis, while 21/23 C. tropicalis showed MDR1 overexpression. Overexpression of CDR1, CDR2, and SNQ2 exhibited in 14, 13, and 8 of 25 triazole-resistant C. glabrata isolates, with 5 isolates harboring PDR1 mutations and 2 echinocandins-resistant isolates harboring S663P mutation in FKS2. Overall, the CARST-fungi study demonstrated that although C. albicans remain the most predominant species, non-C. albicans species accounted for a high proportion. Triazole-resistance is notable among C. tropicalis and C. glabrata. Multidrug-resistant isolates of C. glabrata and less common yeast have been emerging.

Active Surveillance Program to Increase Awareness on Invasive Fungal Diseases: the French RESSIF Network (2012 to 2018)

The French National Reference Center for Invasive Mycoses and Antifungals leads an active and sustained nationwide surveillance program on probable and proven invasive fungal diseases (IFDs) to determine their epidemiology in France. Between 2012 and 2018, a total of 10,886 IFDs were recorded. The incidence increased slightly over time (2.16 to 2.36/10,000 hospitalization days, P = 0.0562) in relation with an increase of fungemia incidence (1.03 to 1.19/10,000, P = 0.0023), while that of other IFDs remained stable. The proportion of ≥65-year-old patients increased from 38.4% to 45.3% (P < 0.0001). Yeast fungemia (n = 5,444) was due mainly to Candida albicans (55.6%) with stable proportions of species over time. Echinocandins became the main drug prescribed (46.7% to 61.8%), but global mortality rate remained unchanged (36.3% at 1 month). Pneumocystis jirovecii pneumonia (n = 2,106) was diagnosed mostly in HIV-negative patients (80.7%) with a significantly higher mortality than in HIV-positive patients (21.9% versus 5.4% at 1 month, P < 0.0001). Invasive aspergillosis (n = 1,661) and mucormycosis (n = 314) were diagnosed mostly in hematology (>60% of the cases) with a global mortality rate of 42.5% and 59.3%, respectively, at 3 months and significant changes in diagnosis procedure over time. More concurrent infections were also diagnosed over time (from 5.4% to 9.4% for mold IFDs, P = 0.0115). In conclusion, we observed an aging of patients with IFD with a significant increase in incidence only for yeast fungemia, a trend toward more concurrent infections, which raises diagnostic and therapeutic issues. Overall, global survival associated with IFDs has not improved despite updated guidelines and new diagnostic tools.

A Pragmatic Approach to Susceptibility Classification of Yeasts without EUCAST Clinical Breakpoints

EUCAST has established clinical breakpoints for the six most common Candida species and Cryptococcus neoformans but not for less common yeasts because sufficient evidence is lacking. Consequently, the question “How to interpret the MIC?” for other yeasts often arises. We propose a pragmatic classification for amphotericin B, anidulafungin, fluconazole, and voriconazole MICs against 30 different rare yeasts. This classification takes advantage of MIC data for more than 4000 isolates generated in the EUCAST Development Laboratory for Fungi validated by alignment to published EUCAST MIC data. The classification relies on the following two important assumptions: first, that when isolates are genetically related, pathogenicity and intrinsic susceptibility patterns may be similar; and second, that even if species are not phylogenetically related, the rare yeasts will likely respond to therapy, provided the MIC is comparable to that against wild-type isolates of more prevalent susceptible species because rare yeasts are most likely “rare” due to a lower pathogenicity. In addition, the treatment recommendations available in the current guidelines based on the in vivo efficacy data and clinical experience are taken into consideration. Needless to say, it is of utmost importance (a) to ascertain that the species identification is correct (using MALDI-TOF or sequencing), and (b) to re-test the isolate once or twice to confirm that the MIC is representative for the isolate (because of the inherent variability in MIC determinations). We hope this pragmatic guidance is helpful until evidence-based EUCAST breakpoints can be formally established.

Fungal Infections Caused by Kazachstania spp., Strasbourg, France, 2007-2020

Rare fungal pathogens are emerging as agents of invasive fungal infections. We analyzed 13 cases of fungal infections caused by Kazachstania (Arxiozyma) spp. in Strasbourg University Hospital, Strasbourg, France. Among the cases, 4 patients had proven fungal disease (3 cases of invasive fungal disease and 1 mucocutaneous infection) and 9 were colonized by Kazachstania (Arxiozyma) spp. Candida albicans was also isolated from 11 of the 13 patients. None of the patients with proven invasive fungal disease met host criteria, but most had underlying diseases. All strains were identified as K. telluris by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and 3 were confirmed as K. bovina by internal transcribed spacer sequencing. For all tested strains, the MICs for fluconazole were >2 μg/mL. Emergence of this rare fungal infection might be explained by the increasing number of patients with immunocompromised conditions and gastroesophageal diseases.

Bloodstream infections caused by Magnusiomyces capitatus and Magnusiomyces clavatus: epidemiological, clinical and microbiological features of two emerging yeast species

BACKGROUND

Magnusiomyces clavatus and Magnusiomyces capitatus are emerging yeasts with intrinsic resistance to many commonly used antifungal agents. Identification is difficult, and determination of susceptibility patterns with commercial and reference methods is equally challenging. For this reason, few data on invasive infections by Magnusiomyces spp. are available.

OBJECTIVES

To determine the epidemiology and susceptibility of Magnusiomyces isolates from bloodstream infections (BSI) isolated in Germany and Austria from 2001-2020.

METHODS

In seven institutions a total of 34 Magnusiomyces BSI were identified. Identification was done by ITS sequencing and MALDI-TOF MS. Antifungal susceptibility was determined by EUCAST broth microdilution and gradient tests.

RESULTS

Of the 34 isolates, M. clavatus was more common (N=24) compared to M. capitatus (N=10). BSI by Magnusiomyces spp. were more common in men (62%) and mostly occurred in patients with haemato-oncological malignancies (79%). The highest in vitro antifungal activity against M. clavatus/M. capitatus was observed for voriconazole (MIC₅₀ 0.03/0.125 mg/L), followed by posaconazole (MIC₅₀ 0.125/0.25 mg/L). M. clavatus isolates showed overall lower MICs compared to M. capitatus. With the exception of amphotericin B, low essential agreement between gradient test and microdilution was recorded for all antifungals (0-70%). Both species showed distinct morphologic traits on ChromAgar Orientation and Columbia blood agar, which can be used for differentiation if no MALDI-TOF or molecular identification is available.

CONCLUSION

Most BSI were caused by M. clavatus. The lowest MICs were recorded for voriconazole. Gradient tests demonstrated unacceptably low agreement and should preferably not be used for susceptibility testing of Magnusiomyces spp.

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.