In vitro activity of posaconazole and comparators versus opportunistic filamentous fungal pathogens globally collected during 8 years

A compound heterozygote case of glutaric aciduria type II in a patient carrying a novel candidate variant in ETFDH gene: A case report and literature review on compound heterozygote cases

BACKGROUND

Glutaric aciduria type II (GA2) is a rare genetic disorder inherited in an autosomal recessive manner. Double dosage mutations in GA2 corresponding genes, ETFDH, ETFA, and ETFB, lead to defects in the catabolism of fatty acids, and amino acids lead to broad-spectrum phenotypes, including muscle weakness, developmental delay, and seizures. product of these three genes have crucial role in transferring electrons to the electron transport chain (ETC), but are not directly involve in ETC complexes.

METHODS

Here, by using exome sequencing, the cause of periodic cryptic gastrointestinal complications in a 19-year-old girl was resolved after years of diagnostic odyssey. Protein modeling for the novel variant served as another line of validation for it.

RESULTS

Exome Sequencing (ES) identified two variants in ETFDH: ETFDH:c.926T>G and ETFDH:c.1141G>C. These variants are likely contributing to the crisis in this case. To the best of our knowledge at the time of writing this manuscript, variant ETFDH:c.926T>G is reported here for the first time. Clinical manifestations of the case and pathological analysis are in consistent with molecular findings. Protein modeling provided another line of evidence proving the pathogenicity of the novel variant. ETFDH:c.926T>G is reported here for the first time in relation to the causation GA2.

CONCLUSION

Given the milder symptoms in this case, a review of GA2 cases caused by compound heterozygous mutations was conducted, highlighting the range of symptoms observed in these patients, from mild fatigue to more severe outcomes. The results underscore the importance of comprehensive genetic analysis in elucidating the spectrum of clinical presentations in GA2 and guiding personalized treatment strategies.

Mucorales: A systematic review to inform the World Health Organization priority list of fungal pathogens

The World Health Organization, in response to the growing burden of fungal disease, established a process to develop a fungal priority pathogens list (FPPL). This systematic review aimed to evaluate the epidemiology and impact of invasive fungal disease due to Mucorales. PubMed and Web of Science were searched to identify studies published between January 1, 2011 and February 23, 2021. Studies reporting on mortality, inpatient care, complications and sequelae, antifungal susceptibility, risk factors, preventability, annual incidence, global distribution, and emergence during the study time frames were selected. Overall, 24 studies were included. Mortality rates of up to 80% were reported. Antifungal susceptibility varied across agents and species, with the minimum inhibitory concentrations lowest for amphotericin B and posaconazole. Diabetes mellitus was a common risk factor, detected in 65%-85% of patients with mucormycosis, particularly in those with rhino-orbital disease (86.9%). Break-through infection was detected in 13.6%-100% on azole or echinocandin antifungal prophylaxis. The reported prevalence rates were variable, with some studies reporting stable rates in the USA of 0.094-0.117/10 000 discharges between 2011 and 2014, whereas others reported an increase in Iran from 16.8% to 24% between 2011 and 2015. Carefully designed global surveillance studies, linking laboratory and clinical data, are required to develop clinical breakpoints to guide antifungal therapy and determine accurate estimates of complications and sequelae, annual incidence, trends, and global distribution. These data will provide robust estimates of disease burden to refine interventions and better inform future FPPL.

An updated list of eumycetoma causative agents and their differences in grain formation and treatment response

SUMMARYIn 2023, the World Health Organization designated eumycetoma causative agents as high-priority pathogens on its list of fungal priority pathogens. Despite this recognition, a comprehensive understanding of these causative agents is lacking, and potential variations in clinical manifestations or therapeutic responses remain unclear. In this review, 12,379 eumycetoma cases were reviewed. In total, 69 different fungal species were identified as causative agents. However, some were only identified once, and there was no supporting evidence that they were indeed present in the grain. Madurella mycetomatis was by far the most commonly reported fungal causative agent. In most studies, identification of the fungus at the species level was based on culture or histology, which was prone to misidentifications. The newly used molecular identification tools identified new causative agents. Clinically, no differences were reported in the appearance of the lesion, but variations in mycetoma grain formation and antifungal susceptibility were observed. Although attempts were made to explore the differences in clinical outcomes based on antifungal susceptibility, the lack of large clinical trials and the inclusion of surgery as standard treatment posed challenges in drawing definitive conclusions. Limited case series suggested that eumycetoma cases caused by Fusarium species were less responsive to treatment than those caused by Madurella mycetomatis. However, further research is imperative for a comprehensive understanding.

Trends in the activity of mold-active azole agents against Aspergillus fumigatus clinical isolates with and without cyp51 alterations from Europe and North America (2017-2021)

Azole resistance in Aspergillus fumigatus (AFM) is increasing and often associated with cyp51 alterations. We evaluated the activity of isavuconazole and other mold-active azoles against 731 AFM isolates causing invasive aspergillosis collected in Europe (EU; n = 449) and North America (NA; n = 282). Isolates were submitted to CLSI susceptibility testing and epidemiological cutoff value (ECV) criteria. A posaconazole ECV of 0.5 mg/L was used as no CLSI ECV was determined. Azole non-wild-type (NWT) isolates were submitted for cyp51 sequencing by whole genome sequencing. Overall, isavuconazole activity (92.7%/94.0% WT in EU/NA) was comparable to other azoles (WT rate range, 90.9%-96.4%/91.8%-98.6%, respectively), regardless of the region. A total of 79 (10.8%) azole NWT isolates were detected, and similar rates of these isolates were noted in EU (10.7%) and NA (11.0%). Although most AFM were WT to azoles, increasing azole NWT rates were observed in NA (from 6.0% in 2017 to 29.3% in 2021). Azole NWT rates varied from 4.9% (2019) to 20.6% (2018) in EU without an observed trend. cyp51 alterations occurred in 56.3%/54.8% of azole NWT from EU/NA, respectively. The cyp51A TR34/L98H alteration was observed only in EU isolates (72.0% of EU isolates), while cyp51A I242V occurred only in NA isolates (58.3%). Isavuconazole remained active (MIC, ≤1 mg/L) against 18.5/47.1% of azole NWT AFM exhibiting cyp51 alterations in EU/NA, along with voriconazole (29.6/82.4%; MIC, ≤1 mg/L) and posaconazole (48.1/88.2%; MIC, ≤0.5 mg/L). Fourteen different cyp51 alterations were detected in 44 of 79 NWT isolates. The in vitro activity of the azoles varied in AFM that displayed cyp51 alterations. IMPORTANCE A few microbiology laboratories perform antifungal susceptibility testing locally for systemically active antifungal agents. The identification of emerging azole-resistant Aspergillus fumigatus is worrisome. As such, there is a critical role for antifungal surveillance in tracking emerging resistance among both common and uncommon opportunistic fungi. Differences in the regional prevalence and antifungal resistance of these fungi render local epidemiological knowledge essential for the care of patients with a suspected invasive fungal infection.

Scedosporium boydii finding in an immunocompromised patient and review of the literature

BACKGROUND

Scedosporiasis is an emerging mycosis that has gained importance in recent years due to its worldwide prevalence. It is caused by species of the Scedosporium apiospermum complex. These species can cause opportunistic infections in immunocompromised patients and, occasionally, in immunocompetent patients as well. The high intrinsic antifungal resistance make these infections difficult to manage.

AIMS

The objective of this study was to interpret the mycological findings in a transplant patient, together with the images obtained in the radiological studies, in order to provide an early and effective antifungal therapy.

METHODS

The mycological analysis of samples taken from a heart transplant patient with radiological images suggesting a fungal infection was performed. Computed tomography scan of the head and thorax showed space-occupying lesions in both the frontal lobe and cerebellum, and multiple pulmonary nodules. The nodules were punctured and the samples obtained were analyzed according to the procedures for mycological analysis. The identity of the isolates was confirmed by nucleotide sequencing. Eventually, the antifungal susceptibility was studied.

RESULTS

The fungal isolates obtained, whose identity was confirmed by sequencing, belonged to the species Scedosporium boydii. Injured tissues were surgically removed and a treatment with amphotericin B and voriconazole-minimum inhibitory concentration (MIC) 0.5μg/mL and ≥0.5μg/mL respectively - was administered.

CONCLUSIONS

Although the patient died due to complications of a Klebsiella pneumoniae sepsis refractory to treatment, the progression of the fungal disease, although slow, was favourable in the early phases of the treatment due to a correct diagnosis and the antifungal susceptibility test carried out. Clinical cases of this nature highlight the need to increase the epidemiological study of these microorganisms, as well as the proper treatment of the diseases caused, in order to achieve early diagnoses that reduce the morbidity and mortality of patients.

Susceptibility patterns of amphotericin B, itraconazole, posaconazole, voriconazole and caspofungin for isolates causing invasive mould infections from the SENTRY Antifungal Surveillance Program (2018-2021) and application of single-site epidemiological cutoff values to evaluate amphotericin B activity

We evaluated the activity of amphotericin B, itraconazole, posaconazole, voriconazole and caspofungin against 1468 invasive moulds collected worldwide from 2018 to 2021. Most (>92%) of the Aspergillus spp. isolates were wildtype (WT) to amphotericin B, caspofungin and the azoles. Azole-non-wildtype A. fumigatus rates were higher in Europe (9.5%) and North America (9.1%) than Latin America (0.0%; only 12 isolates) and the Asia-Pacific region (5.3%). Amphotericin B and caspofungin were active against azole-non-wildtype A. fumigatus isolates. Posaconazole and amphotericin B were the most active agents against the Mucorales. Among the less common moulds, several expressed a pan-azole-resistant phenotype; many of these species also showed elevated MIC values (MIC, >2 mg/L) for amphotericin B and caspofungin. Although most isolates of Aspergillus spp. remain WT to the azoles, azole resistance is increasing in both North America and Europe. Amphotericin B and caspofungin exhibit potentially useful activity against azole-resistant A. fumigatus.

Progress of triazole antifungal agent posaconazole in individualized therapy

WHAT IS KNOWN AND OBJECTIVE

Posaconazole is the second-generation triazole antifungal agent with widespread clinical application. Posaconazole exposure is influenced by various factors such as drug interactions, disease state and diet, resulting in a high interindividual variability in many patients and failure to ensure therapeutic efficacy. Therefore, it is necessary to conduct individualized therapy on posaconazole to ensure the efficacy and safety of treatment.

METHODS

Articles were identified through PubMed using the keywords such as "posaconazole," "therapeutic drug monitoring" and "Population pharmacokinetics" from 1 January 2001 to 30 April 2022.

RESULTS AND DISCUSSION

In this paper, we review the individualized treatment studies of posaconazole from the three aspects of therapeutic drug monitoring, population pharmacokinetic study and Monte Carlo simulation to provide reference for in-depth individualized posaconazole dosing studies.

WHAT IS NEW AND CONCLUSION

This review suggests that therapeutic drug monitoring should be performed in patients taking posaconazole to adjust the dosage and assess the efficacy and cost-effectiveness of posaconazole under different clinical conditions and different dosing regimens through Monte Carlo simulations. In the future, a more detailed delineation and comprehensive examination of posaconazole PPK for specific populations requires further study.

Molecular identification and antifungal susceptibility of clinically relevant and cryptic species of Aspergillus sections Flavi and Nigri

Introduction. Aspergillus sections Flavi and Nigri comprise clinically relevant and cryptic species that differ significantly in drug susceptibility, meaning that effective treatment depends on correct species identification.Hypothesis/Gap Statement. There are no comprehensive data for molecular identification and antifungal susceptibility testing (AFST) of clinically relevant and cryptic species of Aspergillus sections Flavi and Nigri as the main agents of invasive and non-invasive aspergillosis in Iran. We aimed to perform molecular identification and AFST of 213 clinical Aspergillus isolates belonging to sections Flavi and Nigri. Molecular identification of isolates was performed using sequencing of the β-tubulin gene and in vitro AFST was conducted according to the Clinical and Laboratory Standards Institute (CLSI) M38-A3 guidelines.Results. The most common isolates in sections Flavi and Nigri were Aspergillus flavus (110/113, 97.3 %) and Aspergillus tubingensis (49/100, 49.0 %), respectively. A total of 62/213 (29.1 %) isolates belonging to cryptic species were identified; among them, A. tubingensis was the most prevalent (49/62, 79.0%). Aspergillus flavus and A. niger isolates that responded to the minimum inhibitory concentrations (MICs) of itraconazole above the epidemiological cutoff values were the most frequently detected: 8/110 (7.3 %) and 3/41 (7.3 %), respectively. In section Flavi, Aspergillus alliaceus responded to amphotericin B at a high MIC (>16 µg mL^-1) and in section Nigri, one of the three Aspergillus luchuensis/awamori isolates responded to itraconazole at an MIC >16 µg ml^-1. Interestingly, for all Aspergillus welwitschiae isolates, the MIC₅₀ and MIC₉₀ of itraconazole were both 16 µg ml^-1.Conclusion. A considerable presence of A. flavus and A. niger isolates showing non-wild-type responses to azoles in clinical cases of aspergillosis indicates the importance of classifying clinical Aspergillus isolates at the species level and performing antifungal susceptibility testing on the isolates, which would ensure appropriate treatment.

Evaluation of Rezafungin Provisional CLSI Clinical Breakpoints and Epidemiological Cutoff Values Tested against a Worldwide Collection of Contemporaneous Invasive Fungal Isolates (2019 to 2020)

Rezafungin is a new echinocandin under development for the treatment of candidemia and invasive candidiasis. CLSI recently approved provisional susceptible-only breakpoints and epidemiological cutoff values for Candida spp. and rezafungin. The activities of rezafungin and comparators against 2019 to 2020 invasive fungal isolates was evaluated by applying the new CLSI breakpoints. Rezafungin demonstrated potent activity against Candida albicans (MIC 50 /MIC 90 , 0.03/0.06 mg/L; 100.0% susceptible), Candida tropicalis (MIC 50 /MIC 90 , 0.03/0.06 mg/L; 100% susceptible), Candida glabrata (MIC 50 /MIC 90 , 0.06/0.06 mg/L; 98.3% susceptible), Candida krusei (MIC 50 /MIC 90 , 0.03/0.03 mg/L; 100% susceptible), and Candida dubliniensis (MIC 50 /MIC 90 , 0.06/0.12 mg/L; 100% susceptible) when tested by the CLSI broth microdilution method. Rezafungin inhibited 99.6% of Candida parapsilosis isolates (MIC 50 /MIC 90 , 1/2 mg/L) at the susceptible breakpoint of ≤2 mg/L. All C. albicans , C. tropicalis , and C. krusei isolates, as well as most C. glabrata (96.2% to 97.9%) and C. parapsilosis (86.2% to 100%) isolates, were susceptible to comparator echinocandins. Fluconazole resistance was detected among 0.5%, 4.5%, 10.5%, and 1.2% of C. albicans , C. glabrata , C. parapsilosis , and C. tropicalis isolates, respectively. All echinocandins displayed limited activity against Cryptococcus neoformans . Rezafungin and other echinocandins were active against Aspergillus fumigatus (minimum effective concentration for 90% of isolates tested [MEC 90 ] range, 0.015 to 0.06 mg/L) and Aspergillus section Flavi (MEC 90 range, 0.015 to 0.03 mg/L). All but 16 (8.6%) A. fumigatus isolates were susceptible to voriconazole, and 100% of Aspergillus section Flavi isolates were WT to mold-active azoles. When applying the CLSI clinical breakpoints, rezafungin displayed high susceptibility rates (>98.0%) against Candida isolates from invasive fungal infections and showed potent activity against Aspergillus isolates.