Natural history and prognostic factors of candidemia in kidney transplant recipients: A retrospective, multinational study.

BACKGROUND: The natural history of candidemia in kidney transplant recipients (KTR) remains poorly understood. This study aimed to evaluate mortality, prognostic factors and overall graft loss after candidemia in KTRs. METHODS: This is a retrospective multicentre study enrolling all KTRs ≥15 years old with candidemia diagnosed at hospitals in Brazil, Spain and Italy from 2010 to 2020. Primary endpoints were mortality rates at 14 and 30 days. Secondary endpoints were prognostic factors of 14-day mortality and overall graft loss. RESULTS: We enrolled 93 KTRs of which 75 were from Brazil. The mean time interval from transplantation to the onset of candidemia was 45.2 ± 61.5 months. 42% of all patients were on haemodialysis, 31.3% had an episode of sepsis and 39% underwent surgery within 30 days before fungemia. European patients were more likely to receive echinocandin (32 vs. 72%, p < .001). 22.7% of Brazilian patients did not receive any antifungal before death. All-cause mortality at 14 days was higher in Brazil (41.3 vs. 11.1%, p = .016). Candida colonisation (OR 6.91 [95% CI: 1.08-44.3], p = .042) and hypotension (OR 4.87 [95% CI: 1.62-14.66], p = .005) were associated with 14-day mortality. Echinocandin treatment had a protective effect (OR 0.19 [95% CI: 0.05-0.73], p = .015). Graft loss at 90 days occurred in 48% of patients (70.7 in Brazil vs. 22.2% in Europe, p < .01). CONCLUSIONS: Candidemia in KTR is usually documented late after engraftment in patients requiring HD, surgical procedures and dysbiosis secondary to antibiotic use. Mortality was higher in Brazil. Echinocandin therapy was associated with improved survival.

HIV and fungal priority pathogens.

The burden of invasive fungal infections associated with opportunistic fungal pathogens is a persistent challenge, particularly among people with advanced HIV disease. In October, 2022, WHO published the Fungal Priority Pathogens List (FPPL)-the first global effort to systematically prioritise fungal pathogens. Of the 19 pathogens in the WHO FPPL, four opportunistic pathogens in particular cause invasive diseases in people living with HIV: Cryptococcus neoformans, Histoplasma spp, Pneumocystis jirovecii, and Talaromyces marneffei. These four fungal pathogens are major causes of illness and death in people with advanced HIV and overwhelmingly affect those in low-income and middle-income countries. Access to diagnostics, improved surveillance, targeted support for innovation, and an enhanced public health focus on these diseases are needed in the effort to reduce HIV-associated deaths.

Emergence of cryptic species and clades of Meyerozyma guilliermondii species complex exhibiting limited in vitro susceptibility to antifungals in patients with candidemia.

Members of the Meyerozyma guilliermondii species complex are able to cause superficial and life-threatening systemic infections with low susceptibility to azoles and echinocandins. We tested 130 bloodstream M. guilliermondii complex isolates collected from eight Latin American medical centers over 18 years (period 1 = 2000-2008 and period 2 = 2009-2018) to investigate trends in species distribution and antifungal resistance. The isolates were identified by rDNA ITS region sequencing, and antifungal susceptibility tests were performed against fluconazole, voriconazole, anidulafungin, and amphotericin B using the CLSI microbroth method. M. guilliermondii sensu stricto (s.s.; n = 116) was the most prevalent species, followed by Meyerozyma caribbica (n = 12) and Meyerozyma carpophila (n = 2). Based on rDNA ITS identification, three clades within M. guilliermondii sensu stricto were characterized (clade 1 n = 94; clade 2 n = 19; and clade 3 n = 3). In the second period of study, we found a substantial increment in the isolation of M. caribbica (3.4% versus 13.8%; P = 0.06) and clade 2 M. guilliermondii s.s. exhibiting lower susceptibility to one or more triazoles. IMPORTANCE Yeast-invasive infections play a relevant role in human health, and there is a concern with the emergence of non-Candida pathogens causing disease worldwide. There is a lack of studies addressing the prevalence and antifungal susceptibility of different species within the M. guilliermondii complex that cause invasive infections. We evaluated 130 episodes of M. guilliermondii species complex candidemia documented in eight medical centers over 18 years. We detected the emergence of less common species within the Meyerozyma complex causing candidemia and described a new clade of M. guilliermondii with limited susceptibility to triazoles. These results support the relevance of continued global surveillance efforts to early detect, characterize, and report emergent fungal pathogens exhibiting limited susceptibility to antifungals.

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.

Extracellular Vesicles from Candida haemulonii var. vulnera Modulate Macrophage Oxidative Burst.

Members of the Candida haemulonii species complex are multidrug-resistant emergent yeast pathogens able to cause superficial and invasive infections in risk populations. Fungal extracellular vesicles (EVs) play a critical role in the pathogenicity and virulence of several species and may perform essential functions during infections, such as carrying virulence factors that behave in two-way communications with the host, affecting survival and fungal resistance. Our study aimed to describe EV production from Candida haemulonii var. vulnera and evaluate whether murine macrophage RAW 264.7 cells respond to their stimuli by generating an oxidative response after 24 h. For this purpose, reactive oxygen species detection assays demonstrated that high concentrations of yeast and EVs (1010 particles/mL) of Candida haemulonii did not change macrophage viability. However, the macrophages recognized these EVs and triggered an oxidative response through the classical NOX-2 pathway, increasing O2•- and H2O2 levels. However, this stress did not cause lipid peroxidation in the RAW 264.7 cells and neither lead to the activation of the COX-2-PGE2 pathway. Thus, our data suggest that low concentrations of C. haemulonii EVs are not recognized by the classical pathway of the oxidative burst generated by macrophages, which might be an advantage allowing the transport of virulence factors via EVs, not identified by the host immune system that could work as fine tube regulators during infections caused by C. haemulonii. In contrast, C. haemulonii var. vulnera and high EV concentrations activated microbicidal actions in macrophages. Therefore, we propose that EVs could participate in the virulence of the species and that these particles could be a source of antigens to be exploited as new therapeutic targets.

Novel Non-Hot Spot Modification in Fks1 of Candida auris Confers Echinocandin Resistance.

We determined the echinocandin susceptibility and FKS1 genotypes of 13 clinical isolates of Candida auris that were recovered from 4 patients at a tertiary care center in Salvador, Brazil. Three isolates were categorized as echinocandin-resistant, and they harbored a novel FKS1 mutation that led to an amino acid change W691L located downstream from hot spot 1. When introduced to echinocandin-susceptible C. auris strains by CRISPR/Cas9, Fks1 W691L induced elevated MIC values to all echinocandins (anidulafungin, 16 to 32×; caspofungin, >64×; micafungin, >64×).

Worldwide emergence of fluconazole-resistant Candida parapsilosis: current framework and future research roadmap.

Candida parapsilosis is one of the most commen causes of life-threatening candidaemia, particularly in premature neonates, individuals with cancer of the haematopoietic system, and recipients of organ transplants. Historically, drug-susceptible strains have been linked to clonal outbreaks. However, worldwide studies started since 2018 have reported severe outbreaks among adults caused by fluconazole-resistant strains. Outbreaks caused by fluconazole-resistant strains are associated with high mortality rates and can persist despite strict infection control strategies. The emergence of resistance threatens the efficacy of azoles, which is the most widely used class of antifungals and the only available oral treatment option for candidaemia. The fact that most patients infected with fluconazole-resistant strains are azole-naive underscores the high potential adaptability of fluconazole-resistant strains to diverse hosts, environmental niches, and reservoirs. Another concern is the multidrug-resistant and echinocandin-tolerant C parapsilosis isolates, which emerged in 2020. Raising awareness, establishing effective clinical interventions, and understanding the biology and pathogenesis of fluconazole-resistant C parapsilosis are urgently needed to improve treatment strategies and outcomes.

A contemporary investigation of burden and natural history of aspergillosis in people living with HIV/AIDS.

BACKGROUND: Untreated HIV infection can lead to profound immunosuppression and increase susceptibility of people living with HIV/AIDS (PLHA) to aspergillosis. OBJECTIVES: Reporting the burden and natural history of aspergillosis documented in PLHA admitted in five medical centres in Brazil. PATIENTS AND METHODS: Clinical, epidemiological and laboratory data were collected in all sequential cases of proven or probable aspergillosis documented in PLHA hospitalised in five medical centres between 2012 and 2020. RESULTS: We enrolled 25 patients ageing between 23 and 58 years (mean = 39) including 11 patients with invasive aspergillosis (IA) and 14 with chronic pulmonary aspergillosis (CPA). The prevalence rate of aspergillosis was 0.1% of 19.616 PLHA. Overall, 72.7% of patients with IA exhibited CD4 < 100 cells/mL and 42.8% of patients with CPA exhibited CD4 count >200 cells/mL. Most patients had a history of tuberculosis, especially those with CPA (85.7%). IA was documented after a mean of 16.5 days of hospitalisation, mainly in critically ill patients exposed to corticosteroids and broad-spectrum antibiotics. In the CPA group, a positive culture (71.4%) and radiological alterations were the most frequent findings supporting their diagnosis. Episodes of IA were mostly documented by tissue biopsies. Crude mortality rates were 72.7% and 42.8% in patients with IA and CPA, respectively. CONCLUSIONS: Despite being considered an unusual complication in PLHA (0.1%), IA should be considered in patients with profound immunosuppression and pneumonia refractory to conventional therapy. CPA should be investigated in PLHA with chronic deterioration of pulmonary function and previous diagnosis of tuberculosis.

Identification of Clinical Trichosporon asteroides Strains by MALDI-TOF Mass Spectrometry: Evaluation of the Bruker Daltonics Commercial System and an In-House Developed Library.

Trichosporon asteroides is an emerging yeast-like pathogen commonly misidentified by commercial biochemical identification systems. We evaluated the performance of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for the identification of 21 clinical T. asteroides strains using the Bruker Daltonics database (BDAL) and an in-house developed library. Mass spectra were obtained by the FlexControl system v.3.4, and characterizations were performed in the Biotyper BDAL database v.4.1 and the developed in-house library. Species identification for T. asteroides failed as all 21 strains were misidentified as T. japonicum (log-scores 1.89-2.19). Extending the existing database was crucial to achieving 100% correct species-level identification and accurate distinction between species. Our results indicate that the commercial BDAL database has no discriminatory power to distinguish between T. japonicum and T. asteroides. Whereas improvement of the current BDAL database is pending, we strongly advise system users not to exclude the possibility of the failure to report T. asteroides.

Prognostic Trends and Current Challenges in Candidemia: A Comparative Analysis of Two Multicenter Cohorts within the Past Decade.

Candidemia remains a major public health challenge due to its high mortality rates, especially in developing countries. Monitoring epidemiological trends may provide insights for better clinical outcomes. This study aimed to describe trends in the epidemiology, therapeutic practices, and mortality in candidemia through a retrospective comparative analysis between two surveillance cohorts of all candidemic adults at eleven tertiary hospitals in Brazil, from 2010-2011 (Period I) versus 2017-2018 (Period II). A total of 616 cases were diagnosed, with 247 being from Period II. These patients were more likely to have three or more coexisting comorbidities [72 (29.1%) vs. 60 (16.3%), p < 0.001], had a prior history of in-hospital admissions more often [102 (40.3%) vs. 79 (21.4%), p = 0.001], and presented with candidemia earlier after admission, within 15 days (0-328) vs. 19 (0-188), p = 0.01. Echinocandins were more frequently prescribed [102 (41.3%) vs. 50 (13.6%), p = 0.001], but time to antifungal initiation [2 days (0-14) vs. 2 (0-13), p = 0.369] and CVC removal within 48 h [90/185 (48.6%) vs. 148/319 (46.4%), p = 0.644] remained unchanged. Additionally, many patients went untreated in both periods I and II [87 (23.6%) vs. 43 (17.4%), p = 0.07], respectively. Unfortunately, no improvements in mortality rates at 14 days [123 (33.6%) vs. 93 (37.7%), p = 0.343] or at 30 days [188 (51.4%) vs. 120 (48.6%), p = 0.511] were observed. In conclusion, mortality rates remain exceedingly high despite therapeutic advances, probably associated with an increase in patients' complexity and suboptimal therapeutic interventions. Management strategies should be tailored to suit epidemiological changes, expedite diagnosis to reduce the number of untreated eligible patients and guarantee early antifungal initiation and source control.

Short Tandem Repeat Genotyping and Antifungal Susceptibility Testing of Latin American Candida tropicalis Isolates.

Candida tropicalis is emerging as one of the most common Candida species causing opportunistic infections in Latin America. Outbreak events caused by C. tropicalis were reported, and antifungal resistant isolates are on the rise. In order to investigate population genomics and look into antifungal resistance, we applied a short tandem repeat (STR) genotyping scheme and antifungal susceptibility testing (AFST) to 230 clinical and environmental C. tropicalis isolates from Latin American countries. STR genotyping identified 164 genotypes, including 11 clusters comprised of three to seven isolates, indicating outbreak events. AFST identified one isolate as anidulafungin-resistant and harboring a FKS1 S659P substitution. Moreover, we identified 24 clinical and environmental isolates with intermediate susceptibility or resistance to one or more azoles. ERG11 sequencing revealed each of these isolates harboring a Y132F and/or Y257H/N substitution. All of these isolates, except one, were clustered together in two groups of closely related STR genotypes, with each group harboring distinct ERG11 substitutions. The ancestral C. tropicalis strain of these isolates likely acquired the azole resistance-associated substitutions and subsequently spread across vast distances within Brazil. Altogether, this STR genotyping scheme for C. tropicalis proved to be useful for identifying unrecognized outbreak events and better understanding population genomics, including the spread of antifungal-resistant isolates.

Diagnosis and Treatment of Pulmonary Coccidioidomycosis and Paracoccidioidomycosis.

Coccidioidomycosis (CM) and paracoccidioidomycosis (PCM) are systemic mycoses that are highly endemic in Latin America and have recently been included on the World Health Organization (WHO) Fungal Priority Pathogens List. Coccidioides immitis and Coccidioides posadasii are recognized as etiological agents of CM, with peculiarities in their geographic distribution. The genus Paracoccidioides now includes Paracoccidioides lutzii and the Paracoccidioides brasiliensis complex, which encompasses four phylogenetic species. In both diseases, pulmonary signs and symptoms are the main reasons for patients to seek medical assistance, and they are frequently misdiagnosed as tuberculosis. In this paper, we present a critical view of the strategies for diagnosis and clinical management of CM and PCM. Over the past few decades, there has been an increase in the number of reports of endemic fungal infections in areas previously thought to be "non-endemic" due to climate change and increased travel, among other factors. Learning to recognize their main epidemiological aspects and clinical manifestations is crucial so that clinicians can include them in the differential diagnosis of lung disease and avoid late diagnosis.

In vitro activity of isavuconazole against clinically relevant Trichosporon species: a comparative evaluation of EUCAST broth microdilution and MIC Test Strip methods.

OBJECTIVES: To evaluate the in vitro activity of isavuconazole on 154 clinical and reference strains of Trichosporon asahii, Trichosporon asteroides, Trichosporon coremiiforme, Trichosporon faecale and Trichosporon inkin by using the EUCAST broth microdilution method (BMD) and Liofilchem MIC Test Strips (MTS). METHODS: Antifungal susceptibility testing for isavuconazole, fluconazole, voriconazole and posaconazole was assessed by EUCAST E.DEF 7.3.2. MIC values of isavuconazole obtained by BMD after 48 h of incubation were compared with MTS MICs after 24 and 48 h of incubation. RESULTS: T. asahii and T. asteroides showed the highest isavuconazole MIC90 values (0.5 mg/L). In clinical isolates, T. asahii exhibited the highest MIC90 values (0.5 mg/L) compared with non-T. asahii (0.06-0.25 mg/L). The five non-WT T. asahii isolates for fluconazole, voriconazole and posaconazole also exhibited high MICs of isavuconazole (≥0.5 mg/L). A better correlation between MTS and BMD MICs was observed after 24 h incubation for all species tested. MTS measurements performed at 48 h increased by at least 122% the number of isolates with >2 dilutions compared with the standard method. CONCLUSIONS: Isavuconazole exhibited variable in vitro activity among the Trichosporon species tested, showing higher or equal MICs than the other azoles. The five non-WT T. asahii clinical isolates tested also exhibited high isavuconazole MICs, suggesting the occurrence of triazole cross-resistance. Our MTS data indicate that there is no advantage in extended reading time for MTS from 24 to 48 h for Trichosporon yeasts.

Invasive Aspergillosis in Patients with Acute Leukemia: Comparison Between Acute Myeloid and Acute Lymphoid Leukemia.

BACKGROUND: The epidemiology of invasive aspergillosis (IA) in patients with acute lymphoid leukemia (ALL) has not been well characterized. OBJECTIVES: To identify potential peculiarities in the natural history, treatment response and outcome of IA diagnosed in patients with ALL and AML. METHODS: This is a retrospective cohort study conducted in seven tertiary-care hospitals between 2009 and 2017 of all consecutive episodes of IA occurring in adult patients with acute leukemia. Demographic characteristics, underlying disease and recent treatment, antifungal prophylaxis, neutropenia, receipt of corticosteroids, clinical and radiological findings, mycological results, antifungal therapy, and 6-week and 12-week survival were recorded. RESULTS: We identified 77 cases of IA in 54 patients with AML and 23 patients with ALL. The majority of patients developed IA in the context of induction chemotherapy for newly diagnosed (48.0%) or relapsed (41.6%) leukemia, with no differences between ALL and AML. Lung involvement was more frequent in AML (96.3% vs. 82.6%, p = 0.06) and rhinosinusitis was more common in ALL (43.5% vs. 24.1%, p = 0.09). Galactomannan was the microbiologic documentation of IA in 76.6%, with similar patterns of positivity in AML and ALL. The 6-week survival of IA in patients with AML and ALL was 63.0% and 56.5%, respectively (p = 0.60). CONCLUSIONS: The epidemiology, clinical presentation, diagnosis and outcome of IA in ALL patients are similar to patients with AML.

ERG11 Analysis among Clinical Isolates of Trichosporon asahii with Different Azole Susceptibility Profiles.

We analyzed a cohort of Trichosporon asahii strains with different MICs of fluconazole and voriconazole and evaluated the presence of ERG11 mutations. ERG11 mutation conferring an amino acid change was found and its resistance potential was evaluated by cloning into Saccharomyces cerevisiae susceptible host strain. Transformants were not resistant to either fluconazole nor voriconazole. Our results suggest that ERG11 variants exist among T. asahii isolates, but are not responsible for resistance phenotypes.

Quandaries of deciding when to change first-line therapy in invasive pulmonary aspergillosis.

We read the excellent viewpoint by Slavin et al. (J Antimicrob Chemother 2022; 77: 16-23) that draws upon the experience of an advisory board of notable experts to comprehensively address many of the clinical factors that drive the need for changes in antifungal therapy for invasive aspergillosis (IA). As noted by the authors, there remains a paucity of quality data to support many of the decisions faced by clinicians managing patients with IA. However, we would like to highlight several other important issues, not fully addressed in that viewpoint, that play an important role in deciding when to change antifungal therapy for IA.

Determinants of fluconazole resistance and echinocandin tolerance in C. parapsilosis isolates causing a large clonal candidemia outbreak among COVID-19 patients in a Brazilian ICU.

Patients presenting with severe COVID-19 are predisposed to acquire secondary fungal infections such as COVID-19-associated candidemia (CAC), which are associated with poor clinical outcomes despite antifungal treatment. The extreme burden imposed on clinical facilities during the COVID-19 pandemic has provided a permissive environment for the emergence of clonal outbreaks of multiple Candida species, including C. auris and C. parapsilosis. Here we report the largest clonal CAC outbreak to date caused by fluconazole resistant (FLZR) and echinocandin tolerant (ECT) C. parapsilosis. Sixty C. parapsilosis strains were obtained from 57 patients at a tertiary care hospital in Brazil, 90% of them were FLZR and ECT. Although only 35.8% of FLZR isolates contained an ERG11 mutation, all of them contained the TAC1L518F mutation and significantly overexpressed CDR1. Introduction of TAC1L518F into a susceptible background increased the MIC of fluconazole and voriconazole 8-fold and resulted in significant basal overexpression of CDR1. Additionally, FLZR isolates exclusively harboured E1939G outside of Fks1 hotspot-2, which did not confer echinocandin resistance, but significantly increased ECT. Multilocus microsatellite typing showed that 51/60 (85%) of the FLZR isolates belonged to the same cluster, while the susceptible isolates each represented a distinct lineage. Finally, biofilm production in FLZR isolates was significantly lower than in susceptible counterparts Suggesting that it may not be an outbreak determinant. In summary, we show that TAC1L518F and FKS1E1393G confer FLZR and ECT, respectively, in CAC-associated C. parapsilosis. Our study underscores the importance of antifungal stewardship and effective infection control strategies to mitigate clonal C. parapsilosis outbreaks.

Determinants of fluconazole resistance and the efficacy of fluconazole and milbemycin oxim combination against Candida parapsilosis clinical isolates from Brazil and Turkey.

Fluconazole-resistant Candida parapsilosis (FLZR-CP) outbreaks are a growing public health concern and have been reported in numerous countries. Patients infected with FLZR-CP isolates show fluconazole therapeutic failure and have a significantly increased mortality rate. Because fluconazole is the most widely used antifungal agent in most regions with outbreaks, it is paramount to restore its antifungal activity. Milbemycin oxim (MOX), a well-known canine endectocide, is a potent efflux pump inhibitor that significantly potentiates the activity of fluconazole against FLZR C. glabrata and C. albicans. However, the FLZ-MOX combination has not been tested against FLZR-CP isolates, nor is it known whether MOX may also potentiate the activity of echinocandins, a different class of antifungal drugs. Furthermore, the extent of involvement of efflux pumps CDR1 and MDR1 and ergosterol biosynthesis enzyme ERG11 and their link with gain-of-function (GOF) mutations in their transcription regulators (TAC1, MRR1, and UPC2) are poorly characterized among FLZR-CP isolates. We analyzed 25 C. parapsilosis isolates collected from outbreaks in Turkey and Brazil by determining the expression levels of CDR1, MDR1, and ERG11, examining the presence of potential GOF mutations in their transcriptional regulators, and assessing the antifungal activity of FLZ-MOX and micafungin-MOX against FLZR and multidrug-resistant (MDR) C. parapsilosis isolates. ERG11 was found to be universally induced by fluconazole in all isolates, while expression of MDR1 was unchanged. Whereas mutations in MRR1 and UPC2 were not detected, CDR1 was overexpressed in three Brazilian FLZR-CP isolates, which also carried a novel TAC1L518F mutation. Of these three isolates, one showed increased basal expression of CDR1, while the other two overexpressed CDR1 only in the presence of fluconazole. Interestingly, MOX showed promising antifungal activity against FLZR isolates, reducing the FLZ MIC 8- to 32-fold. However, the MOX and micafungin combination did not exert activity against an MDR C. parapsilosis isolate. Collectively, our study documents that the mechanisms underpinning FLZR are region specific, where ERG11 mutations were the sole mechanism of FLZR in Turkish FLZR-CP isolates, while simultaneous overexpression of CDR1 was observed in some Brazilian counterparts. Moreover, MOX and fluconazole showed potent synergistic activity, while the MOX-micafungin combination showed no synergy.

The emerging threat antifungal-resistant Candida tropicalis in humans, animals, and environment.

Antifungal resistance in humans, animals, and the environment is an emerging problem. Among the different fungal species that can develop resistance, Candida tropicalis is ubiquitous and causes infections in animals and humans. In Asia and some Latin American countries, C. tropicalis is among the most common species related to candidemia, and mortality rates are usually above 40%. Fluconazole resistance is especially reported in Asian countries and clonal spread in humans and the environment has been investigated in some studies. In Brazil, high rates of azole resistance have been found in animals and the environment. Multidrug resistance is still rare, but recent reports of clinical multidrug-resistant isolates are worrisome. The molecular apparatus of antifungal resistance has been majorly investigated in clinical C. tropicalis isolates, revealing that this species can develop resistance through the conjunction of different adaptative mechanisms. In this review article, we summarize the main findings regarding antifungal resistance and Candida tropicalis through an "One Health" approach.