High prevalence of clinical and environmental triazole-resistant Aspergillus fumigatus in Iran: is it a challenging issue?

High Prevalence of Azole-Resistant Aspergillus fumigatus Among Iranian Cystic Fibrosis Patients: Should We Be Concerned?

BACKGROUND

Cystic fibrosis (CF), an inherited autosomal recessive disorder, is linked with high morbidity and mortality rates due to bacteria, filamentous, yeast and black yeast-like fungi colonisation in the upper respiratory tract. Although Candida species are the most common fungi isolated from CF patients, azole-resistant Aspergillus fumigatus (ARAf) is a big concern for invasive aspergillosis. Notably, the exact prevalences of Aspergillus species and the prevalence of ARAf isolates among Iranian CF patients have yet to be previously reported and are unknown. We aimed to investigate the prevalence of ARAf isolates in CF patients among Iranian populations by focusing on molecular mechanisms of the mutations in the target gene.

METHODS

The 1 year prospective study recovered 120 sputum samples from 103 CF patients. Of these, 55.1% (86/156) yielded Aspergillus species, screened for ARAf using plates containing itraconazole (4 mg/L) and voriconazole (1 mg/L). According to the CLSI-M38 guidelines, antifungal susceptibility testing was performed using the broth microdilution method. In all phenotypically resistant isolates, the target of azole agents, the cyp51A gene, was sequenced to detect any possible single nucleotide polymorphisms (SNP) mediating resistance.

RESULTS

Of 120 samples, 101 (84.2%) were positive for filamentous fungi and yeast-like relatives, with 156 fungal isolates. The most common colonising fungi were Aspergillus species (55.1%, 86/156), followed by Candida species (39.8%, 62/156), Exophiala species (3.8%, 6/156) and Scedosporium species (1.3%, 2/156). Forty out of 86 (46.5%) were identified for section Fumigati, 36 (41.9%) for section Flavi, 6 (7%) for section Nigri and 4 (4.6%) for section Terrei. Fourteen out of 40 A. fumigatus isolates were phenotypically resistant. The overall proportion of ARAf in total fungal isolates was 9% (14/156). cyp51A gene analysis in resistant isolates revealed that 13 isolates harboured G448S, G432C, T289F, D255E, M220I, M172V, G138C, G54E and F46Y mutations and one isolate carried G448S, G432C, T289F, D255E, M220I, G138C, G54E and F46Y mutations. Additionally, this study detects two novel cyp51A single-nucleotide polymorphisms (I242V and D490E).

CONCLUSIONS

This study first investigated ARAf isolates in Iranian CF patients. Due to a resistance rate of up to 9%, it is recommended that susceptibility testing of Aspergillus isolates from CF patients receiving antifungal treatment be a part of the routine diagnostic workup. However, extensive multicentre studies with a high volume of CF patients are highly warranted to determine the impact of ARAf on CF patients.

Insights into Aspergillus fumigatus Colonization in Cystic Fibrosis and Cross-Transmission between Patients and Hospital Environments

BACKGROUND

Approximately 60% of individuals with cystic fibrosis (CF) are affected by Aspergillus fumigatus infection. This condition is correlated with a decline in lung function and is identified as an independent risk factor contributing to hospital admissions among CF patients. This study investigates the dynamic interplay of A. fumigatus within the context of CF patients, tracing its evolution over time, with a specific emphasis on colonization dynamics.

METHODS

An analysis was conducted on 83 sequential A. fumigatus isolates derived from sputum samples of six patients receiving care at a renowned CF hospital in Brazil. Employing microsatellite genotyping techniques, alongside an investigation into cyp51A gene mutations, this research sheds light on the genetic variations, colonization, and resistance of A. fumigatus within the CF respiratory environment.

RESULTS

Our research findings indicate that CF patients can harbor A. fumigatus strains from the same clonal complexes for prolonged periods. Additionally, we identified that clinical isolates have the potential to spread among patients in the same healthcare facility, evidencing hospital contamination. Two patients who underwent long-term Itraconazole treatment did not show phenotypic resistance. However, one of these patients exhibited mutations in the cyp51A gene, indicating the need to monitor resistance to azoles in these patients colonized for long periods by A. fumigatus. We also observed co-colonization or co-infection involving multiple genotypes in all patients over time.

CONCLUSION

This comprehensive examination offers valuable insights into the pathogenesis of A. fumigatus infections in CF patients, potentially shaping future therapeutic strategies and management approaches. This enhanced understanding contributes to our knowledge of A. fumigatus impact on disease progression in individuals with cystic fibrosis. Additionally, the study provides evidence of cross-contamination among patients undergoing treatment at the same hospital.

Aspergillus fumigatus-a systematic review to inform the World Health Organization priority list of fungal pathogens

Recognizing the growing global burden of fungal infections, the World Health Organization established a process to develop a priority list of fungal pathogens (FPPL). In this systematic review, we aimed to evaluate the epidemiology and impact of invasive infections caused by Aspergillus fumigatus to inform the first FPPL. The pre-specified criteria of mortality, inpatient care, complications and sequelae, antifungal susceptibility, risk factors, preventability, annual incidence, global distribution, and emergence were used to search for relevant articles between 1 January 2016 and 10 June 2021. Overall, 49 studies were eligible for inclusion. Azole antifungal susceptibility varied according to geographical regions. Voriconazole susceptibility rates of 22.2% were reported from the Netherlands, whereas in Brazil, Korea, India, China, and the UK, voriconazole susceptibility rates were 76%, 94.7%, 96.9%, 98.6%, and 99.7%, respectively. Cross-resistance was common with 85%, 92.8%, and 100% of voriconazole-resistant A. fumigatus isolates also resistant to itraconazole, posaconazole, and isavuconazole, respectively. The incidence of invasive aspergillosis (IA) in patients with acute leukemia was estimated at 5.84/100 patients. Six-week mortality rates in IA cases ranged from 31% to 36%. Azole resistance and hematological malignancy were poor prognostic factors. Twelve-week mortality rates were significantly higher in voriconazole-resistant than in voriconazole-susceptible IA cases (12/22 [54.5%] vs. 27/88 [30.7%]; P = .035), and hematology patients with IA had significantly higher mortality rates compared with solid-malignancy cases who had IA (65/217 [30%] vs. 14/78 [18%]; P = .04). Carefully designed surveillance studies linking laboratory and clinical data are required to better inform future FPPL.

Clinical performance of metagenomic next-generation sequencing for diagnosis of pulmonary Aspergillus infection and colonization

Background

Investigations assessing the value of metagenomic next-generation sequencing (mNGS) for distinguish Aspergillus infection from colonization are currently insufficient.

Methods

The performance of mNGS in distinguishing Aspergillus infection from colonization, along with the differences in patients' characteristics, antibiotic adjustment, and lung microbiota, were analyzed.

Results

The abundance of Aspergillus significantly differed between patients with Aspergillus infection (n=36) and colonization (n=32) (P < 0.0001). Receiver operating characteristic (ROC) curve result for bronchoalveolar lavage fluid (BALF) mNGS indicated an area under the curve of 0.894 (95%CI: 0.811-0.976), with an optimal threshold value of 23 for discriminating between Aspergillus infection and colonization. The infection group exhibited a higher proportion of antibiotic adjustments in comparison to the colonization group (50% vs. 12.5%, P = 0.001), with antibiotic escalation being more dominant. Age, length of hospital stay, hemoglobin, cough and chest distress were significantly positively correlated with Aspergillus infection. The abundance of A. fumigatus and Epstein-Barr virus (EBV) significantly increased in the infection group, whereas the colonization group exhibited higher abundance of A. niger.

Conclusion

BALF mNGS is a valuable tool for differentiating between colonization and infection of Aspergillus. Variations in patients' age, length of hospital stay, hemoglobin, cough and chest distress are observable between patients with Aspergillus infection and colonization.

Electronic equipment and appliances in special wards of hospitals as a source of azole-resistant Aspergillus fumigatus: a multi-centre study from Iran

BACKGROUND

Azole-resistant Aspergillus fumigatus (ARAf), reported as a global public health concern, has been unexpectedly observed in different countries.

AIM

To identify ARAf and detect azole resistance related to the CYP51A mutation in different hospital environmental samples.

METHODS

In this multi-centre study from Iran, surfaces of electronic equipment and appliances from different hospitals in Iran were sampled using cotton swabs. All samples were cultured using azole-containing agar plates (ACAPs). Recovered Aspergillus isolates were identified at the species level using partial DNA sequencing of the β-tubulin gene. The azole susceptibility testing of A. fumigatus isolates was performed using the Clinical and Laboratory Standards Institute M38-A3 guideline. The sequencing of the CYP51A gene was also performed to detect mutations related to resistance.

FINDINGS

Out of the 693 collected samples, 89 (12.8%) Aspergillus species were recovered from ACAPs. Aspergillus fumigatus (41.6%) was the most prevalent, followed by A. tubingensis (23.6%) and A. niger (15.6%). Among 37 isolates of A. fumigatus, 19 (51.3%) showed high minimum inhibitory concentration (MIC) values to at least one of the three azoles, voriconazole, itraconazole, and posaconazole. CYP51A polymorphisms were detected in all 19 isolates, of which 52.6% showed the TR34/L98H mutation. Other detected mutations were G432C, G448S, G54E/G138C, F46Y, and Y121F/M220I/D255E. T289F and G432C were the first reported mutations in ARAf.

CONCLUSION

There was a considerable level of azole resistance in hospital environmental samples, a serious warning for patients vulnerable to aspergillosis. Our findings have also revealed a different mutation pattern in the CYP51A gene.

Uncovering a Novel cyp51A Mutation and Antifungal Resistance in Aspergillus fumigatus through Culture Collection Screening

BACKGROUND

Aspergillus fumigatus is an important concern for immunocompromised individuals, often resulting in severe infections. With the emergence of resistance to azoles, which has been the therapeutic choice for Aspergillus infections, monitoring the resistance of these microorganisms becomes important, including the search for mutations in the cyp51A gene, which is the gene responsible for the mechanism of action of azoles. We conducted a retrospective analysis covering 478 A. fumigatus isolates.

METHODS

This comprehensive dataset comprised 415 clinical isolates and 63 isolates from hospital environmental sources. For clinical isolates, they were evaluated in two different periods, from 1998 to 2004 and 2014 to 2021; for environmental strains, one strain was isolated in 1998, and 62 isolates were evaluated in 2015. Our primary objectives were to assess the epidemiological antifungal susceptibility profile; trace the evolution of resistance to azoles, Amphotericin B (AMB), and echinocandins; and monitor cyp51A mutations in resistant strains. We utilized the broth microdilution assay for susceptibility testing, coupled with cyp51A gene sequencing and microsatellite genotyping to evaluate genetic variability among resistant strains.

RESULTS

Our findings reveal a progressive increase in Minimum Inhibitory Concentrations (MICs) for azoles and AMB over time. Notably, a discernible trend in cyp51A gene mutations emerged in clinical isolates starting in 2014. Moreover, our study marks a significant discovery as we detected, for the first time, an A. fumigatus isolate carrying the recently identified TR46/F495I mutation within a sample obtained from a hospital environment. The observed cyp51A mutations underscore the ongoing necessity for surveillance, particularly as MICs for various antifungal classes continue to rise.

CONCLUSIONS

By conducting resistance surveillance within our institution's culture collection, we successfully identified a novel TR46/F495I mutation in an isolate retrieved from the hospital environment which had been preserved since 1998. Moreover, clinical isolates were found to exhibit TR34/L98H/S297T/F495I mutations. In addition, we observed an increase in MIC patterns for Amphotericin B and azoles, signaling a change in the resistance pattern, emphasizing the urgent need for the development of new antifungal drugs. Our study highlights the importance of continued monitoring and research in understanding the evolving challenges in managing A. fumigatus infections.

Azole-Containing Agar Plates and Antifungal Susceptibility Testing for the Detection of Azole-Resistant Aspergillus Species in Hospital Environmental Samples

The indoor environment of hospitals should be considered as an important reservoir of azole resistant Aspergillus species. In this study, we evaluated azole-containing agar plates (ACAPs) and antifungal susceptibility testing (AFST) for the detection of azole-resistant Aspergillus species in hospital environmental samples. Between September 2021 and January 2022, environmental samples (108 instruments and 12 air) were collected from different wards of 4 educational hospitals in Mazandaran province, Iran. All samples were cultured using ACAPs. Recovered Aspergillus isolates were molecularly identified at species level using partial DNA sequencing of beta-tubulin gene. AFST of Aspergillus species was performed using the Clinical and Laboratory Standards Institute M38-A3 guideline. Screening for cyp51A mutations was also done. Overall, 18 (15.0%) isolates of Aspergillus species were recovered from ACAPs, of which Aspergillus tubingensis (50%) and Aspergillus fumigatus (38.9%) were the commonest species. No isolate of Aspergillus species grew on posaconazole (PCZ)-containing agar plates. Among the 18 Aspergillus isolated species from ACAPs, 83.3% were related to samples from instruments. Of the nine isolates of A. tubingensis, 22.2% and 44.4% isolates showed minimum inhibitory concentration (MIC) = 2 μg/mL against voriconazole (VCZ) and itraconazole, respectively; and 44.4% isolates showed MIC = 1 μg/mL against PCZ. Of the seven isolates of A. fumigatus, one (14.3%) was resistant to VCZ. This isolate showed F46Y, G54E, G138C, M172V, M220I, D255E, T289F, G432C, and G448S mutation in cyp51A. Our finding showed the emergence of high MICs in cryptic and non-fumigatus species of Aspergillus such as A. tubingensis and VCZ resistance in A. fumigatus in indoor environment of hospitals.

Evolution of neuroimaging findings in angioinvasive cerebral aspergillosis in a pediatric patient with leukemia during long-term observation

The central nervous system is one of the most common sites of aspergillosis involvement in immunocompromised people, just after sinopulmonary infections. Neuroimaging modalities are crucial for the diagnosis of cerebral aspergillosis (CA). Here, we describe a rare case of concurrent mixed aspergillosis infection with Aspergillus fumigatus and Aspergillus niger in a 2-year-old leukemic boy. The first neuroimaging finding, which was followed by focal seizures, was recognized as extensive cerebral hemorrhage in the absence of thrombocytopenia and coagulopathy. As the patient survived for more than 4 months after diagnosis, we were able to perform a neuroimaging evaluation during long-term observation. In serial neuroimaging studies, a secondary fungal abscess was observed at the site of hemorrhagic infarctions. Finally, the patient died from bacterial sepsis. In this case study, we try to categorize the neuroimaging findings of CA into distinct phases to better understand how CA changes over time.

First Report of Azole-Resistant Aspergillus fumigatus with TR46/Y121F/T289A Mutations in Kuwait and an Update on Their Occurrence in the Middle East

Pulmonary aspergillosis is a common fungal infection with several clinical manifestations including invasive, allergic and chronic chest diseases. Invasive pulmonary aspergillosis (IPA) is a leading cause of death in immunocompromised patients, particularly those receiving chemotherapy and among bone marrow transplant recipients. Aspergillus fumigatus is the most prevalent causative agent and voriconazole is the first-line therapy for IPA. In this study, we report the first isolation of voriconazole-resistant A. fumigatus carrying TR46/Y121F/T289A mutations from an immunocompromised pregnant lady in Kuwait. The patient was successfully treated for a probable respiratory infection with caspofungin and voriconazole. The literature review from PubMed has identified itraconazole-resistant clinical and environmental A. fumigatus isolates with TR34/L98H mutations in the cyp51A from several Middle Eastern countries including Kuwait. However, clinical A. fumigatus isolates with cyp51A TR46/Y121F/T289A mutations have not been reported previously from any country in the region while environmental isolates have been reported only from Iran. The source of voriconazole-resistant A. fumigatus CYP51A TR46/Y121F/T289A mutant in our patient remained unknown. Surveillance for azole resistance among clinical and environmental isolates of A. fumigatus is warranted in Kuwait.

Antifungal activity of miltefosine against both azole-susceptible and -resistant Aspergillus strains

Miltefosine, an alkylphosphocholine, has been approved recently for the treatment of visceral leishmaniasis. Miltefosine has shown promise as a treatment for paracoccidioidomycosis, and has mixed activity against other fungi and yeast. There are limited data on the in-vitro activity of miltefosine against azole-resistant and -susceptible Aspergillus spp. As such, the aim of this study was to determine the in-vitro activity of miltefosine against Aspergillus strains. Miltefosine was tested against 108 azole-susceptible and -resistant Aspergillus strains isolated from Iran and other countries using the broth microdilution method. Miltefosine was found to be effective against azole-resistant Aspergillus isolates, with minimum inhibitory concentrations (MICs) ranging from 1.562 to 6.25 µg/mL. MIC₅₀ and MIC₉₀ were 1.562 and 3.125 µg/mL, respectively. Miltefosine had a higher geometric mean MIC (2.459 µg/mL) for wild-type Aspergillus isolates than itraconazole (0.220 µg/mL) and voriconazole (0.298 µg/mL). No significant difference was found between miltefosine MICs for azole-resistant Aspergillus isolates and azole-susceptible Aspergillus isolates (P>0.05). Miltefosine appears to have good in-vitro activity against azole-resistant Aspergillus strains, according to these findings. Furthermore, the findings suggest that miltefosine could be used to treat infections caused by azole-resistant Aspergillus spp.

Five-year surveillance study of clinical and environmental Triazole-Resistant Aspergillus fumigatus isolates in Iran

BACKGROUND

Invasive aspergillosis is one of the most common fungal infections and azole resistance in Aspergillus fumigatus (ARAf) is a growing medical concern in high-risk patients. To our knowledge, there is no comprehensive epidemiological surveillance study on the prevalence and incidence of ARAf isolates available in Iran.

OBJECTIVES

The study aimed to report a five-year survey of triazole phenotypes and genotype patterns concerning the resistance in clinical and environmental A. fumigatus in Iran.

METHODS

During the study time frame (2016-2021), a total of 1208 clinical and environmental Aspergillus species were collected. Isolates were examined and characterised by in vitro antifungal susceptibility testing (CLSI M38 broth microdilution) and cyp51A sequencing.

RESULTS

In total, 485 Aspergillus section Fumigati strains were recovered (clinical, n = 23; 4.74% and environment, n = 462; 95.26%). Of which A. fumigatus isolates were the most prevalent species (n = 483; 99.59%). Amphotericin B and the echinocandins demonstrated good in vitro activity against the majority of isolates in comparison to triazole. Overall, 16.15% (n = 78) of isolates were phenotypically resistant to at least one of the azoles. However, 9.73% of A. fumigatus isolates for voriconazole were classified as resistant, 89.03% were susceptible, and 1.24% were intermediate. While, for itraconazole and posaconazole, using the epidemiological cut-off value 16.15% and 6.83% of isolates were non-wild types, respectively. Remarkably, in 21.79% (n = 17) phenotypically resistant isolates, no mutations were detected within the cyp51A gene.

CONCLUSION

Although the incidence of ARAf varies from country to country, in Iran the rate has ranged from 3.3% to 18%, significantly increasing from 2013 to 2021. Strikingly, a quarter of the phenotypically resistant isolates harboured no mutations in the cyp51A gene. It seems that other mechanisms of resistance are importantly increasing. To fill a gap in our understanding of the mechanism for azole resistance in the non-cyp51A strains, we highly recommend further and more extensive monitoring of the soil with or without exposure to fungicides in agricultural and hospital areas.

Biocompatible phospholipid-based mixed micelles for posaconazole ocular delivery: Development, characterization, and in - vitro antifungal activity

Current study intended to prepare and evaluate phospholipid-based, mixed micelles (MMs) to improve the ocular delivery of posaconazole (POS), a broad-spectrum antifungal drug. For this, MMs based on egg phosphatidylcholine (EPC), as the main component, in combination with various bile salts (sodium cholate (NaC), sodium deoxycholate (NaDC), sodium taurocholate (NaTC)) or non-ionic surfactants (Pluronic® F-127, Pluronic® F-68, Tween 80, Labrasol® ALF, and d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS)) were prepared. Particle size, polydispersity index, zeta potential and entrapment efficiency were evaluated to optimize the composition and preparation method of the MMs. Finally, morphology, stability, in vitro release pattern, and in vitro antifungal activity of the optimized formulation were investigated. Among the prepared MMs, vesicles composed of EPC: TPGS with a molar ratio of 70:30, prepared by the thin-film hydration method, showed more appropriate features. Among the prepared MMs, vesicles composed of EPC: TPGS with a molar ratio of 70:30 showed more appropriate features, including an entrapment efficiency (EE) greater than 80%, spherical shape morphology, an average particle size of about 58 nm, desirable stability over a month, slow-release without a noticeable initial burst, and a significantly higher in vitro antifungal activity in comparison with the drug suspension. Therefore, this formulation was selected as the optimal MMs and could be considered as a promising carrier for topical ocular delivery of POS.

Caspian Sea Mycosands: The Variety and Abundance of Medically Important Fungi in Beach Sand and Water

Samples from a total of 67 stations, distributed amongst 32 cities along the Caspian Sea coastline, were collected during the summer of 2021 on sunny days. The samples were collected from each station, including both dry/wet sand and shoreline water. The grown samples were primarily analyzed for the macro/microscopic morphologic features of the fungi. Moreover, identification by PCR-RFLP was performed for yeasts, dermatophytes, and Aspergillus sp. strains. Antifungal susceptibility tests were performed for probable-isolated Aspergillus and Candida sp. A total of 268 samples were collected, from which 181 (67.54%) isolates were recovered. Yeast-like fungi and potential pathogenic black fungi were detected in 12 (6.6%) and 20 (11%) of the sand (dry/wet) samples. Potential pathogenic hyaline fungi were identified in 136 (75.1%) samples, in which Aspergillus sp. was the predominant genus and was detected in 76/136 (47.8%) samples as follows: A. section Flavi n = 44/76 (57.9%), A. section Nigri n = 19/76 (25%), A. section Nidulantes n = 9/76 (11.8%), and A. section Fumigati n = 4/76 (5.3%). The most effective azole antifungal agent was different per section: in A. section Fumigati, PSZ; in Aspergillus section Nigri, ITZ and ISZ; in A. section Flavi, EFZ; and in A. section Nidulantes, ISZ. Candida isolates were susceptible to the antifungals tested.

Multicenter Study of Susceptibility of Aspergillus Species Isolated from Iranian University Hospitals to Seven Antifungal Agents

Aspergillus species are a major cause of life-threatening invasive infections and noninvasive diseases. This study seeks to investigate the frequency of Aspergillus species among Iranian patients and their susceptibility to seven antifungals. In a cross-sectional study, 233 Aspergillus isolates were collected from 11 university hospitals in Iran between 2018 and 2021. Aspergillus isolates were identified based on colony morphology, microscopic characteristics, PCR-restriction fragment length polymorphism (RFLP), and sequencing of the beta-tubulin gene. The CLSI M38-A2 reference methodology was used for antifungal susceptibility testing of amphotericin B, voriconazole, posaconazole, itraconazole, luliconazole, isavuconazole, and caspofungin. Members of Aspergillus section Flavi (117/233, 50.2%), Aspergillus section Nigri (77/233, 33.1%), Aspergillus section Fumigati (21/233, 9%), Aspergillus section Terrei (14/233, 6%), Aspergillus pseudodeflectus (2/233, 0.85%), and Aspergillus melleus (2/233, 0.85%) were isolated from the samples. The lowest 0.25 MIC90 values for all isolates tested were for luliconazole (0.016 μg/mL) and isavuconazole (0.250 μg/mL), and the highest value was observed for itraconazole (≥ 8μg/mL). The 90% minimum effective concentration (MEC90) value for caspofungin was 0.125 μg/mL. MIC90 values for voriconazole, amphotericin B, and posaconazole were 1, 2, and 2 μg/mL, respectively. The non-wild-type species were presented for amphotericin B (3%), voriconazole (1.3%), posaconazole (2.6%), luliconazole (1.3%), isavuconazole (1.7%), and caspofungin (4.7%). Positive correlations in the MIC values of azole antifungals were observed, and using one azole increases the MIC value rates of other ones. None of the species were pan-azole resistant. Species of Aspergillus section Flavi were the most common Aspergillus species isolated from Iranian samples. Luliconazole, caspofungin, and isavuconazole present the most effective antifungal agents for treatment of infection due to Aspergillus species. Susceptibility tests should be performed frequently in each region for the best management of patients. IMPORTANCE Aspergillus species are the leading cause of invasive aspergillosis in immunocompromised hosts. The susceptibility of Aspergillus species to antifungal agents might be different. Azole-resistant species have emerged worldwide. Performing susceptibility testing in each region can help in the best management of patients. Here, we show the epidemiology and distribution of Aspergillus species in Iran and their susceptibility patterns for seven antifungal agents. The significant points of the present study are that species of Aspergillus section Flavi are the most prevalent Aspergillus species isolated from 11 university hospitals. Luliconazole, caspofungin, and isavuconazole were effective antifungal agents against all Aspergillus species.

Aspergillus Endophthalmitis: Epidemiology, Pathobiology, and Current Treatments

Fungal endophthalmitis is one of the leading causes of vision loss worldwide. Post-operative and traumatic injuries are major contributing factors resulting in ocular fungal infections in healthy and, more importantly, immunocompromised individuals. Among the fungal pathogens, the Aspergillus species, Aspergillus fumigatus, continues to be more prevalent in fungal endophthalmitis patients. However, due to overlapping clinical symptoms with other endophthalmitis etiology, fungal endophthalmitis pose a challenge in its diagnosis and treatment. Hence, it is critical to understand its pathobiology to develop and deploy proper therapeutic interventions for combating Aspergillus infections. This review highlights the different modes of Aspergillus transmission and the host immune response during endophthalmitis. Additionally, we discuss recent advancements in the diagnosis of fungal endophthalmitis. Finally, we comprehensively summarize various antifungal regimens and surgical options for the treatment of Aspergillus endophthalmitis.

Fungicide effects on human fungal pathogens: Cross-resistance to medical drugs and beyond

Fungal infections are underestimated threats that affect over 1 billion people, and Candida spp., Cryptococcus spp., and Aspergillus spp. are the 3 most fatal fungi. The treatment of these infections is performed with a limited arsenal of antifungal drugs, and the class of the azoles is the most used. Although these drugs present low toxicity for the host, there is an emergence of therapeutic failure due to azole resistance. Drug resistance normally develops in patients undergoing azole long-term therapy, when the fungus in contact with the drug can adapt and survive. Conversely, several reports have been showing that resistant isolates are also recovered from patients with no prior history of azole therapy, suggesting that other routes might be driving antifungal resistance. Intriguingly, antifungal resistance also happens in the environment since resistant strains have been isolated from plant materials, soil, decomposing matter, and compost, where important human fungal pathogens live. As the resistant fungi can be isolated from the environment, in places where agrochemicals are extensively used in agriculture and wood industry, the hypothesis that fungicides could be driving and selecting resistance mechanism in nature, before the contact of the fungus with the host, has gained more attention. The effects of fungicide exposure on fungal resistance have been extensively studied in Aspergillus fumigatus and less investigated in other human fungal pathogens. Here, we discuss not only classic and recent studies showing that environmental azole exposure selects cross-resistance to medical azoles in A. fumigatus, but also how this phenomenon affects Candida and Cryptococcus, other 2 important human fungal pathogens found in the environment. We also examine data showing that fungicide exposure can select relevant changes in the morphophysiology and virulence of those pathogens, suggesting that its effect goes beyond the cross-resistance.

Genetic Analyses of Amphotericin B Susceptibility in Aspergillus fumigatus

Aspergillus fumigatus is a ubiquitous saprophytic mold that can cause a range of clinical syndromes, from allergic reactions to invasive infections. Amphotericin B (AMB) is a polyene antifungal drug that has been used to treat a broad range of systemic mycoses since 1958, including as a primary treatment option against invasive aspergillosis in regions with high rates (≥10%) of environmental triazole resistance. However, cases of AMB-resistant A. fumigatus strains have been increasingly documented over the years, and high resistance rates were recently reported in Brazil and Canada. The objective of this study is to identify candidate mutations associated with AMB susceptibility using a genome-wide association analysis of natural strains, and to further investigate a subset of the mutations in their putative associations with differences in AMB minimum inhibitory concentration (MIC) and in growths at different AMB concentrations through the analysis of progeny from a laboratory genetic cross. Together, our results identified a total of 34 candidate single-nucleotide polymorphisms (SNPs) associated with AMB MIC differences-comprising 18 intergenic variants, 14 missense variants, one synonymous variant, and one non-coding transcript variant. Importantly, progeny from the genetic cross allowed us to identify putative SNP-SNP interactions impacting progeny growth at different AMB concentrations.

Molecular typing of clinical and environmental Aspergillus fumigatus isolates from Iran using microsatellites

Background and Purpose

Because of the growing incidence of Aspergillus infection, typing methods of Aspergillus species are increasingly being used. Accordingly, studying the spread and population dynamics of strains isolating from clinical and environment, from a single host to large-scale ecosystems is definitely needed. In the current study, we carried out a genetic analysis of nine microsatellite loci in isolates from different regions of Iran to compare and explore the genetic diversity between environmental and clinical A. fumigatus strains.

Materials and Methods

Sixty-six clinical (n=43) and environmental (n= 23) isolates of A. fumigatus, have collected from six cities of Iran. All A. fumigatus isolates identified based on macroscopic and microscopic characters, the ability to grow at above 45°C, and confirmed using DNA sequencing of the partial b-tubulin gene. Sixty-six A. fumigatus isolates were subjected by microsatellite typing using three separate multiplex PCRs with a panel of nine short tandem repeats (STR) to evaluate the genetic relatedness.

Results

The STR typing of 66 A. fumigatus isolates revealed 38 distinct genotypes distributed among environmental and clinical isolates. We identified 12 clones including 40 different isolates representing 60% of all isolates tested, which each clone included 2-7 isolates.

Conclusion

The STR typing is considered as a valuable tool with excellent discriminatory power to study the molecular epidemiology and genotypic diversity of A. fumigatus isolates. These findings show that the high genetic diversity observed of Iranian A. fumigatus isolates with those outside Iran and formed a separate cluster.

Aspergillus fumigatus and aspergillosis: From basics to clinics

The airborne fungus Aspergillus fumigatus poses a serious health threat to humans by causing numerous invasive infections and a notable mortality in humans, especially in immunocompromised patients. Mould-active azoles are the frontline therapeutics employed to treat aspergillosis. The global emergence of azole-resistant A. fumigatus isolates in clinic and environment, however, notoriously limits the therapeutic options of mould-active antifungals and potentially can be attributed to a mortality rate reaching up to 100 %. Although specific mutations in CYP 51A are the main cause of azole resistance, there is a new wave of azole-resistant isolates with wild-type CYP 51A genotype challenging the efficacy of the current diagnostic tools. Therefore, applications of whole-genome sequencing are increasingly gaining popularity to overcome such challenges. Prominent echinocandin tolerance, as well as liver and kidney toxicity posed by amphotericin B, necessitate a continuous quest for novel antifungal drugs to combat emerging azole-resistant A. fumigatus isolates. Animal models and the tools used for genetic engineering require further refinement to facilitate a better understanding about the resistance mechanisms, virulence, and immune reactions orchestrated against A. fumigatus. This review paper comprehensively discusses the current clinical challenges caused by A. fumigatus and provides insights on how to address them.

The effect of biosynthesized selenium nanoparticles on the expression of CYP51A and HSP90 antifungal resistance genes in Aspergillus fumigatus and Aspergillus flavus

The application of biological nanoparticles (NPs) can be considered as a way to overcome the problem of antifungal resistance in pathogenic fungi. This study takes a new approach to biosynthesized NPs influence on the expression of CYP51A and HSP90 antifungal resistance genes in Aspergillus fumigatus and A. flavus, and comparison with antifungal agents. Selenium NPs (Se-NPs) were biosynthesized using Aspergillus strains and their production was proved by several methods including, UV-Vis, XRD, FTIR, FESEM, and EDX techniques. The minimum inhibitory concentrations (MICs) of Aspergillus strains were determined using the CLSI M38-A2 broth microdilution method. The differences in expression levels of CYP51A and HSP90 genes were examined between untreated and treated of A. fumigatus and A. flavus using itraconazole and amphotericin B and biosynthesized Se-NPs through real-time PCR. After confirming the results of NPs synthesis, the MIC of itraconazole and amphotericin B against A. fumigatus and A. flavus was 4 μg/ml. Based on the real-time PCR results, the obtained ∆∆CTs for these strains were -0.18, -1.46, and -1.14. Whereas the MIC values for treated samples with Se-NPs have decreased to 0.5 μg/ml, and the ∆∆CTs for these were -0.25, -1.76, and -1.68. The expression of CYP51A and HSP90 genes was significantly down-regulated through the use of Se-NPs against A. fumigatus and A. flavus.

Genome-Wide Association Analysis for Triazole Resistance in Aspergillus fumigatus

Aspergillus fumigatus is a ubiquitous fungus and the main agent of aspergillosis, a common fungal infection in the immunocompromised population. Triazoles such as itraconazole and voriconazole are the common first-line drugs for treating aspergillosis. However, triazole resistance in A. fumigatus has been reported in an increasing number of countries. While most studies of triazole resistance have focused on mutations in the triazole target gene cyp51A, >70% of triazole-resistant strains in certain populations showed no mutations in cyp51A. To identify potential non-cyp51A mutations associated with triazole resistance in A. fumigatus, we analyzed the whole genome sequences and triazole susceptibilities of 195 strains from 12 countries. These strains belonged to three distinct clades. Our genome-wide association study (GWAS) identified a total of six missense mutations significantly associated with itraconazole resistance and 18 missense mutations with voriconazole resistance. In addition, to investigate itraconazole and pan-azole resistance, Fisher's exact tests revealed 26 additional missense variants tightly linked to the top 20 SNPs obtained by GWAS, of which two were consistently associated with triazole resistance. The large number of novel mutations related to triazole resistance should help further investigations into their molecular mechanisms, their clinical importance, and the development of a comprehensive molecular diagnosis toolbox for triazole resistance in A. fumigatus.

In vitro interaction between glabridin and voriconazole against Aspergillus fumigatus isolates

BACKGROUND

Voriconazole (VRC) is widely recommended as the first-line therapy for invasive aspergillosis. However, surveillance studies have demonstrated that there is an increase in the frequency of azole resistance among Aspergillus fumigates isolates. In recent years, more studies on effective synergisms between natural agents and antifungal drugs have been published.

AIMS

To evaluate the synergistic antifungal effect of glabridin (Gla) and VRC against A. fumigatus isolates.

METHODS

Potential interactions between Gla and VRC were studied by using a microdilution checkerboard method based on the CLSI reference technique. To assess the interaction of drugs the fractional inhibitory concentration index (FICI) was calculated based on the Loewe Additivity model.

RESULTS

The minimum inhibitory concentrations (MIC) obtained with Gla alone were relatively high (MIC₅₀ 16μg/ml). However, our results showed synergistic interaction between Gla and VRC against A. fumigatus strains, with FICI range values between 0.15 and 0.5.

CONCLUSIONS

Synergistic activity of Gla and VRC against both VRC-sensitive and -resistant A. fumigatus isolates may lead to design new antifungal agents, especially for inhibiting those azole-resistant strains.

Successful treatment of pulmonary aspergillosis due to Aspergillus fumigatus in a child affected by systemic lupus erythematosus: A case report from Northeastern Iran

A6-year-old girl affected to systemic lupus erythematosus with symptoms of fever, weakness, and lethargy, cough, chest pain, and abnormalchest x-ray. The isolated Aspergillus fumigatus was identified using partial calmodulin gene sequencing. Gradual improvement was observed onday 19 of treatment with amphotericinB (50 mg /day).

Extensive Genetic Diversity and Widespread Azole Resistance in Greenhouse Populations of Aspergillus fumigatus in Yunnan, China

Aspergillus fumigatus is the main cause of invasive aspergillosis (IA) with a high annual global incidence and mortality rate. Recent studies have indicated an increasing prevalence of azole-resistant A. fumigatus (ARAF) strains, with agricultural use of azole fungicides as a potential contributor. China has an extensive agricultural production system and uses a wide array of fungicides for crop production, including in modern growth facilities such as greenhouses. Soils in greenhouses are among the most intensively cultivated. However, little is known about the occurrence and distribution of ARAF in greenhouse soils. Here, we investigated genetic variation and triazole drug susceptibility in A. fumigatus from greenhouses around metropolitan Kunming in Yunnan, southwest China. Abundant allelic and genotypic variations were found among 233 A. fumigatus strains isolated from nine greenhouses in this region. Significantly, ∼80% of the strains were resistant to at least one medical triazole drug, with >30% showing cross-resistance to both itraconazole and voriconazole. Several previously reported mutations associated with triazole resistance in the triazole target gene cyp51A were also found in our strains, with a strong positive correlation between the frequency of mutations at the cyp51A promoter and that of voriconazole resistance. Phylogenetic analyses of cyp51A gene sequences showed evidence for multiple independent origins of azole-resistant genotypes of A. fumigatus in these greenhouses. Evidence for multiple origins of azole resistance and the widespread distributions of genetically very diverse triazole-resistant strains of A. fumigatus in greenhouses calls for significant attention from public health agencies.

IMPORTANCE The origin and prevalence of azole-resistant Aspergillus fumigatus have been attracting increasing attention from biologists, clinicians, and public health agencies. Current evidence suggests agricultural fungicide use as a major cause. In southwest China, greenhouses are used to produce large amounts of fruits, flowers, and vegetables for consumers throughout China as well as those in other countries, primarily in southeast Asia. Here, we found a very high frequency (∼80%) of triazole-resistant A. fumigatus in our sample, the highest reported so far, with a significant proportion of these strains resistant to both tested agricultural fungicides and medical triazole drugs. In addition, we found novel allelic and genotypic diversities and evidence for multiple independent origins of azole-resistant genotypes of A. fumigatus in greenhouse populations in this region. Our study calls for a systematic evaluation of the effects of azole fungicide usage in greenhouses on human health.

Hazard of agricultural triazole fungicide: Does cyproconazole induce voriconazole resistance in Aspergillus fumigatus isolates?

Background and Purpose

The present study aimed to evaluate the effect of cyproconazole, the most used fungicide in Iranian wheat farms, on the induction of voriconazole resistance in Aspergillus fumigatus isolates.

Materials and Methods

A collection of 20 clinical and environmental isolates were selected for investigation of the in vitro activity of fungicides. The minimum inhibitory concentrations (MICs) were determined by the documented broth microdilution method M38-A2 (CLSI, 2008). Induction experiments were performed and the possibly induced isolate(s) were subjected to antifungal susceptibility testing, sequencing of the CYP51A promoter, and full coding gene. Furthermore, CYP51-protein homology modeling and docking modes were evaluated using SWISS-MODEL (https://swissmodel.expasy.org/) and SEESAR software (version 9.1).

Results

Among 10 susceptible isolates, only one strain showed a high MIC value against voriconazole (MIC=4µg/ml) after 25 passages. Nevertheless, sequencing of the CYP51A promoter and full coding gene did not reveal any mutations. Cyproconazole, which has three nitrogen atoms in the aromatic ring, coordinated to the iron atom of heme through a hydrogen bond contact to residue Lys147 present in the active site of the A. fumigates Cyp51 homology model.

Conclusion

Cyproconazole is being applied extensively in wheat farms in Iran. According to the results, cyproconazole may not play a key role in the induction of azole resistance in the isolates through the environmental route. However, the potential ability of the fungicide to induce medically triazole-resistant strains over a long period of application should not be neglected.

Azole resistance in Aspergillus isolates by different types of patients and correlation with environment - An Italian prospective multicentre study (ARiA study)

BACKGROUND

A wide range of frequency of azole-resistance in A fumigatus in different patient populations worldwide was observed threatening to reduce therapeutic options.

OBJECTIVES

Estimate the prevalence of azole-resistance, investigate the molecular mechanisms of resistance, compare the genotypes of resistant clinical isolates with those from the surrounding environment.

METHODS

Aspergillus isolates were collected by seven Italian hospital microbiology laboratories. Strains were isolated from different clinical samples from unselected patients. The azole-resistance was evaluated using screening test and microdilution EUCAST method. The molecular mechanism of resistance was performed sequencing the cyp51A gene. Resistant isolates were genotyped by microsatellite analysis and their profiles compared with those of azole-resistant isolates from previous Italian studies.

RESULTS

425 Aspergillus isolates from 367 patients were analysed. The azole-resistance rates were 4.9% and 6.6% considering all Aspergillus spp. isolates and the A fumigatus sensu stricto, respectively. All resistant isolates except one were from a single hospital. Two rare azole-resistant species were identified: A thermomutatus and A lentulus. The predominant resistance mechanism was TR₃₄ /L98H. No correlation between the clinical resistant strains and environmental isolates from patients' home/work/ward was observed. The analysis of the molecular correlation between the resistant clinical strains collected in the present study and those of environmental and clinical origin collected in previous Italian studies reveals a progressive diversification of azole-resistant genotypes starting from a founder azole-resistant genotype.

CONCLUSIONS

This study confirms the trend of azole-resistance rate in Italy, showing a geographical difference. Data reinforce the importance of surveillance programmes to monitor the local epidemiological situation.

Azole antifungal resistance in fungal isolates from wastewater treatment plant effluents

Wastewater treatment plants (WWTPs) can be significant sources of antifungal resistant fungi, which can disseminate further in the environment by getting into rivers together with effluents discharged from WWTPs and pose a risk for human health. In this study, the presence of azole resistance was determined in fungal isolates from treated effluents of two WWTPs using the standard microdilution method from Clinical and Laboratory Standards Institute (CLSI). A total of 41 fungal isolates representing 23 fungal species and 16 fungal genera were obtained. Fungal genera related to the known human and/or plant pathogens such as Aspergillus, Fusarium, and Candida were detected. Among the observed species, the susceptibility of Aspergillus fumigatus and Fusarium oxysporum was tested against fluconazole (FCZ), ketoconazole (KTZ), itraconazole (ITZ), and voriconazole (VCZ). The isolate A. fumigatus was susceptible to KTZ, ITZ, and VCZ, while it showed resistance against FCZ. On the contrast, the isolate F. oxysporum showed resistance to KTZ, ITZ, and VCZ. Comparatively, VCZ showed highest activity against both A. fumigatus and F. oxysporum. Analysis of the gene Cyp51A for the A. fumigatus isolate showed no evidence of drug resistance that could be related to point mutations and/or tandem repeats in the gene. To the best of our knowledge, this is the first susceptibility test study on A. fumigatus and F. oxysporum isolates from the WWTPs of South Africa. In conclusion, this study indicated an urgent need for thorough investigation with larger group of fungal isolates from different regions of South Africa to broadly understand the role of WWTPs in the dissemination of azole antifungal drug resistance.

Antifungal activity of liriodenine on agents of systemic mycoses, with emphasis on the genus Paracoccidioides

BACKGROUND

Endemic systemic mycoses remain a health challenge, since these opportunistic diseases are increasingly infecting immunosuppressed patients. The simultaneous use of antifungal compounds and other drugs to treat infectious or non-infectious diseases has led to several interactions and undesirable effects. Thus, new antifungal compounds should be investigated. The present study aimed to evaluate the activity of liriodenine extracted from Annona macroprophyllata on agents of systemic mycoses, with emphasis on the genus Paracoccidioides.

METHODS

The minimum inhibitory concentration (MIC) and minimum fungicide concentration (MFC) were determined by the microdilution method. The cellular alterations caused by liriodenine on a standard P. brasiliensis (Pb18) strain were evaluated by transmission and scanning electron microscopy.

RESULTS

Liriodenine was effective only in 3 of the 8 strains of the genus Paracoccidioides and in the Histoplasma capsulatum strain, in a very low concentration (MIC of 1.95 μg.mL-1); on yeasts of Candida spp. (MIC of 125 to 250 μg.mL-1), including C. krusei (250 μg.mL-1), which has intrinsic resistance to fluconazole; and in Cryptococcus neoformans and Cryptococcus gattii (MIC of 62.5 μg.mL-1). However, liriodenine was not effective against Aspergillus fumigatus at the studied concentrations. Liriodenine exhibited fungicidal activity against all standard strains and clinical isolates that showed to be susceptible by in vitro tests. Electron microscopy revealed cytoplasmic alterations and damage to the cell wall of P. brasiliensis (Pb18).

CONCLUSION

Our results indicate that liriodenine is a promising fungicidal compound that should undergo further investigation with some chemical modifications.

Compare Catalase Activity Between Aspergillus flavus and A. fumigatus, Isolated from Clinical and Environmental Specimens

Background: Catalase enzyme is a potential virulence factor for Aspergillus species. Objectives: This study aimed to evaluate the catalase activity in conidium and mycelium of Aspergillus flavus and A. fumigatus isolated from environmental and clinical samples. Methods: Forty Aspergillus species (20 A. fumigatus and 20 A. flavus) were evaluated. Species were identified using the macroscopic and microscopic criteria of the isolates on culture media and the PCR-RFLP method, using the MwoI enzyme. The activity of the enzyme was evaluated using the Amplex red catalase assay kit. The Shapiro Wilk, Kolmogorov-Smirnov, Mann-Whitney, and Wilcoxon Signed Rank tests were used to analyze the data. Results: The mean conidial and mycelial catalase activities in A. flavus clinical and environmental isolates were 58.10, 57.80 mU/mL, and 1328.30, 531.60 mU/mL, respectively. In A. fumigatus clinical and environmental isolates, the activities were 61.10 and 61.40 mU/mL, and 1248.90 and 722.90 mU/mL, respectively. A significant difference was found between conidial and mycelial catalase activity in Aspergillus species (P = 0.01). The mycelial catalase activity of Aspergillus species isolated from clinical samples was higher than the environmental ones (A. flavus P = 0.01 and A. fumigatus P = 0.04). Conclusions: The mycelial catalase activity was higher than conidia. Clinical isolates of A. flavus had similar mycelium activity to A. fumigatus. By using the information provided in the present study, the severity of aspergillosis can be predicted, which paves the way for identifying new antifungal agents.

Clonal Expansion of Environmental Triazole Resistant Aspergillus fumigatus in Iran

Azole-resistance in Aspergillus fumigatus is a worldwide medical concern complicating the management of aspergillosis (IA). Herein, we report the clonal spread of environmental triazole resistant A. fumigatus isolates in Iran. In this study, 63 A. fumigatus isolates were collected from 300 compost samples plated on Sabouraud dextrose agar supplemented with itraconazole (ITR) and voriconazole (VOR). Forty-four isolates had the TR34/L98H mutation and three isolates a TR46/Y121F/T289A resistance mechanism, while two isolates harbored a M172V substitution in cyp51A. Fourteen azole resistant isolates had no mutations in cyp51A. We found that 41 out of 44 A. fumigatus strains with the TR34/L98H mutation, isolated from compost in 13 different Iranian cities, shared the same allele across all nine examined microsatellite loci. Clonal expansion of triazole resistant A. fumigatus in this study emphasizes the importance of establishing antifungal resistance surveillance studies to monitor clinical Aspergillus isolates in Iran, as well as screening for azole resistance in environmental A. fumigatus isolates.

A 9-Year Experience of Aspergillus Infections from Isfahan, Iran

Purpose

Aspergillosis is an important fungal disease affecting millions of individuals worldwide. The genus of Aspergillus consist of various complexes, causing a wide spectrum of diseases from superficial infections in immunocompetent hosts to life-threatening disseminated infections among immunocompromised patients. This study aimed to identify Aspergillus species by phenotypic (total isolates) and molecular tests (35 isolates), obtained from patients in Isfahan (the third-largest city of Iran) between 2010 and 2018, and determine the susceptibility of 35 clinical isolates to itraconazole (ITR), amphotericin-B (AMB), and voriconazole (VOR).

Patients and Methods

Based on clinical signs, a total of 2385 suspected cases were included in this retrospective study from January 2010 to December 2018. Direct microscopic examination with potassium hydroxide, sabouraud dextrose agar with chloramphenicol, and czapekdox agar media was applied to identify etiologic agents. Thirty-five Aspergillus species collected from January 2016 to December 2018 were identified by PCR-sequencing of ITS1-5.8SrDNA-ITS2 region, and their susceptibility to ITR, AMB, and VOR was determined using E-test.

Results

Based on direct microscopy and positive culture, 132 out of 2385 suspected cases had Aspergillus infection (5.5%). Fifty-four patients were male, and 78 patients were female. Patients in the age groups of 41–50 and 21–30 years had the highest and lowest frequencies, respectively. Aspergillus flavus/oryzae (n=54), A. fumigatus (n=24), A. niger (n=15), and A. terreus (n=12) were the most prevalent Aspergillus species, respectively. Among 35 Aspergillus species, the MIC ranges of AMB, ITR, and VOR for A. flavus/oryzae, A. niger, and A. terreus were (0.5–4 μg/mL; 0.5–16 μg/mL; 0.25–8 μg/mL), (1 μg/mL, 1 μg/mL, 1 μg/mL), and (4–4 μg/mL, 0.5–1 μg/mL, 0.5–1 μg/mL), respectively.

Conclusion

Aspergillus infections have a wide spectrum of clinical manifestations and often occur in immunocompromised patients. Accurate identification at the species level is essential since the emergence of cryptic species is connected to different patterns of AFST that affect patient treatment outcomes. Azole-resistant Aspergillus spp. is a global concern, and the detection of the route of resistance is pivotal to prevent and control infection.

Screening for triazole resistance in clinically significant Aspergillus species; report from Pakistan

Background

Burden of aspergillosis is reported to be significant from developing countries including those in South Asia. The estimated burden in Pakistan is also high on the background of tuberculosis and chronic lung diseases. There is concern for management of aspergillosis with the emergence of azole resistant Aspergillus species in neighbouring countries in Central and South Asia.

Hence the aim of this study was to screen significant Aspergillus species isolates at the Microbiology Section of Aga Khan Clinical Laboratories, Pakistan, for triazole resistance.

Methods

A descriptive cross-sectional study, conducted at the Aga Khan University Laboratories, Karachi, from September 2016–May 2019. One hundred and fourteen, clinically significant Aspergillus isolates [A. fumigatus (38; 33.3%), A. flavus (64; 56.1%), A. niger (9; 7.9%) A. terreus (3; 2.6%)] were included. The clinical spectrum ranged from invasive aspergillosis (IA) (n = 25; 21.9%), chronic pulmonary aspergillosis (CPA) (n = 58; 50.9%), allergic bronchopulmonary aspergillosis (ABPA) (n = 4; 3.5%), severe asthma with fungal sensitization (SAFS) (n = 4; 3.5%), saprophytic tracheobronchial aspergillosis (n = 23; 20.2%). Screening for triazole resistance was performed by antifungal agar screening method. The minimum inhibitory concentration (MIC) of 41 representative isolates were tested and interpreted according to the Clinical and Laboratory Standards Institute broth microdilution method.

Results

All the isolates were triazole-susceptible on agar screening. MICs of three azole antifungals for 41 tested isolates were found to be ≤1 ml/L; all isolates tested were categorized as triazole-susceptible, including 4 isolates from patients previously on triazole therapy for more than 2 weeks. The minimum inhibitory concentration required to inhibit the growth of 90% organisms (MIC₉₀) of itraconazole, voriconazole and posaconazole of the representative Aspergillus isolates was 1 mg/L, 1 mg/L and 0.5 mg/L, respectively.

Conclusion

Triazole resistance could not be detected amongst clinical Aspergillus isolates from the South of Pakistan. However, environmental strains remain to be tested for a holistic assessment of the situation. This study will set precedence for future periodic antifungal resistance surveillance in our region on Aspergillus isolates.

First azole-resistant Aspergillus fumigatus isolates with the environmental TR46 /Y121F/T289A mutation in Iran

Background

Azole resistance in Aspergillus fumigatus is an emerging problem and reported from all continents. As triazole antifungals are the mainstay of therapy in the management of invasive aspergillosis, azole‐resistant A fumigatus has become a major medical concern and with complicated clinical management.

Objective

Screening of environmental presence of azole‐resistant A fumigatus in Iran.

Methods

Compost from Northern Iran, collected between 2017 and 2018, was screened for the presence of azole‐resistant A fumigatus with azole‐containing agar. Phenotypic MICs were obtained from selected, molecularly confirmed isolates. cyp51A gene sequencing and genotyping of azole‐resistant isolates were done.

Results

Among 300 compost samples, three A fumigatus isolates had high voriconazole MICs (≥16 mg/L) and harboured the TR₄₆/Y121F/T289A mutation in the cyp51A gene. Microsatellite typing of these isolates showed that two strains had the same allele across all nine examined microsatellite loci and were genotypically related to Indian azole‐resistant strains. The other isolate had a different genotype.

Conclusion

This is the first report of A fumigatus with TR₄₆/Y121F/T289A mutation from the region. Monitoring and surveillance of antifungal susceptibility of clinical A fumigatus is warranted in Iran and elsewhere in the region.

An update on the application of nano-scaled carriers against fluconazole-resistant Candida species: nanostructured lipid carriers or solid lipid nanoparticles?

Background and Purpose:

Encapsulation can lead to improved efficacy and safety of antifungal compounds. The attention of scientists has recently turned to biocompatible lipids as the carriers for the delivery of antifungal drugs, such as fluconazole. Although several research reports have already been published on fluconazole loaded solid lipid nanoparticles (FLZ-SLNs) and fluconazole loaded nanostructured lipid carriers (FLZ-NLCs), the possible advantages of NLCs over SLNs have not yet been fully established. Studies performed so far have given several contradictory results.

Materials and Methods:

Both formulations of fluconazole were synthesized using probe ultrasonication method and the characteristics were analyzed. Antifungal susceptibility testing (AFST) was performed with FLZ, FLZ-SLNs, and FLZ-NLCs using CLSI document M60 against some common fluconazole-resistant Candida species.

Results:

A significant decrease was observed in minimum inhibitory concentration values when both formulations were applied. Nonetheless, FLZ-NLCs were significantly more effective (P<0.05). However, three species groups were not statistically different in terms of the activity of FLZ-NLCs.

Conclusion:

Based on the obtained results, FLZ-NLCs could reverse the azole-resistance phenomenon in the most common Candida species more effectively, as compared to FLZ-SLNs.

Mutation in cyp51A and high expression of efflux pump gene of Aspergillus fumigatus induced by propiconazole in liquid medium and soil

Triazole resistance in Aspergillus fumigatus is a major cause of clinical inefficacy in the treatment of invasive aspergillosis (IA). The hypothesis that triazole fungicides have driven the development of resistance in A. fumigatus has garnered substantial attention due to the similar structure and global detection of antifungal resistant A. fumigatus (ARAF) isolates in the soil. However, there is little evidence linking the application of triazole fungicides to the emergence of ARAF in the soil. This study was conducted to test if the resistance in A. fumigatus and its associated mutations in cyp51A could be induced by propiconazole in liquid medium and soil. The results indicate that propiconazole can induce resistance by alteration of G138S in cyp51A, and the overexpression of cyp51A, AfuMDR3 and AfuMDR4. G138S in cyp51A was first detected in the soil and associated with resistance. The emergence of the ARAFs in the soil may depends upon the level of propiconazole, and the number of ARAFs in soil treated with propiconazole at 2- and 5-fold dose was much greater than those in soil treated at the recommended dosage. The current data indicate that propiconazole can induce triazole resistance in A. fumigatus and should be applied for agricultural purposes at levels at or below the recommended dosage to avoid the emergence of ARAF in the soil.

Investigation of cgrA and cyp51A gene alternations in Aspergillus fumigatus strains exposed to kombucha fermented tea

BACKGROUND AND PURPOSE

Aspergillus fumigatus is one of the most common opportunistic fungus, which causes infection in immunocompromised and neutropenic patients. The current guidelines recommend voriconazole as the initial therapeutic and prophylactic agent for almost all cases, especially in patients with organ transplants, which leads to increased medication resistance in A. fumigatus. The aim of the present study was to evaluate the antifungal activity and effect of kombucha as a natural compound on A. fumigatus growth, as well as on the expression of cgrA and cyp51A genes.

MATERIALS AND METHODS

A panel of 15 A. fumigatus strains with two quality controls of CM237 and CM2627 as susceptible and resistant strains were obtained from Tehran Medical Mycology Laboratory, Tehran,Iran(TMML).Antifungal susceptibility testing assay was performed according to the Clinical and Laboratory Standards Institute (CLSI) M38-A2 document. Moreover, the mycelial dry weight of the fungus was calculated before and after being treated with kombucha. In addition, the quantitative changes in the expression of cgrA and cyp51A genes were analyzed by real-time polymerase chain reaction (real-time PCR) technique.

RESULTS

In the present study, the minimum inhibitory concentration ranges of kombucha were measured at 6,170 and 12,300 μg/mL for ten A. fumigatus azole-susceptible strains and 24,700 μg/mL for five A. fumigatus resistant strains. Moreover, changes in mycelial dry weight under kombucha treatment conditions underwent a significant reduction (P≤0.05). A coordinate down-regulation of expression in cgrA and cyp51A genes was observed in all azole-susceptible and -resistant A. fumigatus strains, after treating the fungus with different concentrations of kombucha (P≤0.05).

CONCLUSION

According to the obtained results, kombucha as a natural antioxidant , can exert inhibitory effects against the growth and expression of some genes in A. fumigatusstrains.

The Emergence of Rare Clinical Aspergillus Species in Qatar: Molecular Characterization and Antifungal Susceptibility Profiles

Aspergillus are ubiquitous mold species that infect immunocompetent and immunocompromised patients. The symptoms are diverse and range from allergic reactions, bronchopulmonary infection, and bronchitis, to invasive aspergillosis. The aim of this study was to characterize 70 Aspergillus isolates recovered from clinical specimens of patients with various clinical conditions presented at Hamad general hospital in Doha, Qatar, by using molecular methods and to determine their in vitro antifungal susceptibility patterns using the Clinical and Laboratory Standards Institute (CLSI) M38-A2 reference method. Fourteen Aspergillus species were identified by sequencing β-tubulin and calmodulin genes, including 10 rare and cryptic species not commonly recovered from human clinical specimens. Aspergillus welwitschiae is reported in this study for the first time in patients with fungal rhinosinusitis (n = 6) and one patient with a lower respiratory infection. Moreover, Aspergillus pseudonomius is reported in a patient with fungal rhinosinusitis which is considered as the first report ever from clinical specimens. In addition, Aspergillus sublatus is reported for the first time in a patient with cystic fibrosis. In general, our Aspergillus strains exhibited low MIC values for most of the antifungal drugs tested. One strain of Aspergillus fumigatus showed high MECs for echinocandins and low MICs for the rest of the drugs tested. Another strain of A. fumigatus exhibited high MIC for itraconazole and categorized as non-wild type. These findings require further analysis of their molecular basis of resistance. In conclusion, reliable identification of Aspergillus species is achieved by using molecular sequencing, especially for the emerging rare and cryptic species. They are mostly indistinguishable by conventional methods and might exhibit variable antifungal susceptibility profiles. Moreover, investigation of the antifungal susceptibility patterns is necessary for improved antifungal therapy against aspergillosis.

A simple and low cost tetra-primer ARMS-PCR method for detection triazole-resistant Aspergillus fumigatus

The mutation at codon L98 accompanied by a tandem repeat of 34 base pairs (TR₃₄/L98H) in the 5´upstream region of cyp51A is the principal mechanism of triazole resistance of Aspergillus fumigatus. We aimed to evaluate a simple and low-cost tetra-primer amplification refractory mutation system (ARMS)-PCR technique for detection of TR₃₄/L98H mutations in the cyp51A gene of azole-resistant A. fumigatus. The tetra-primer ARMS-PCR assay optimized by four primers in one reaction consists of external primers for detection of tandem repeats in the promoter region and internal primers for detection of a point mutation in codon 98 (L98H) in the cyp51A gene of azole-resistant A. fumigatus. The specificity of TR₃₄/L98H mutation detection was assessed by testing 36 clinical and environmental A. fumigatus strains. The tetra-primer ARMS-PCR assay from A. fumigatus, containing wild-type sequence (T allele) and L98H mutation at cyp51A (A allele), yielded two DNA fragments of 908 bp and 740 bp and two of 942 bp and 212 bp, respectively. None of the A. fumigatus isolates without the TR₃₄/L98H mutation yielded false-positive results. The ARMS-PCR assay was 100% concordant with DNA sequencing results. Prevalence and screening of the TR₃₄/L98H mutation in the cyp51A gene in A. fumigatus isolates may now be determined by a fast, low-cost, and simple method in resource-poor settings.

Biochemical and cellular activity of chemically synthesized elastase inhibitor (S-AFUEI) from Aspergillus fumigatus

PURPOSE

Elastase, produced by Aspergillus fumigatus and A. flavus, is an important pathogenic factor in pulmonary aspergillosis. We investigated the possibility of using A. fumigatus-derived A. fumigatus elastase inhibitor (AFUEI) as a therapeutic agent. As native-AFUEI (N-AFUEI) has an extremely low yield, we generated a synthetic-AFUEI (S-AFUEI) and investigated whether S-AFUEI has a biological activity against A. fumigatus elastase (AFUE) and inhibits cytotoxicity.

METHODOLOGY

A. fumigatus was cultured in Yeast Carbon Base (YCB) -elastin culture medium for 3-7 days, and AFUE was purified by chromatography using DE52 cellulose and Sephadex G-75 column. Elastolytic activity was examined using Glt-Ala-Ala-Pro-Leu-pNA (GAAPLNA) as the substrate. The hydrolytic activity of AFUE was determined using the characteristic substrates, fibrinogen and collagen (Type IV), and human cell cytotoxicity was measured colorimetrically. Furthermore, the inhibitory effect of S-AFUEI on these activities was examined.

RESULTS

We confirmed that S-AFUEI demonstrated elastase inhibitory activity and heat stability equivalent to that demonstrated by N-AFUEI, and inhibited human collagen hydrolytic activity and human fibrinogen hydrolytic activity. Further, S-AFUEI inhibited cytotoxicity in AFUE human pulmonary artery endothelial cells (HPAEC), human small airway epithelial cells (HSAEC), and human pulmonary alveolar epithelial cells (HPAEpiC).

CONCLUSION

As S-AFUEI strongly inhibited cytotoxicity induced by elastase in human-derived cells, it could prove beneficial for the treatment of pulmonary aspergillosis.

Triazole-Resistant Aspergillus fumigatus from Fungicide-Experienced Soils in Naivasha Subcounty and Nairobi County, Kenya

The mainstay in prevention and treatment of aspergillosis is the use triazole drugs. In Kenya, the use of agricultural azole is one of the predisposing factors in development of resistance. One hundred fifty-six (156) experienced soils were collected from agricultural farms and cultured on Sabouraud DextroseAagar. The study isolated 48 yielded Aspergillus fumigatus and 2 A. flavus. All the isolates were subjected to antifungal susceptibility testing against three triazoles: posaconazole, voriconazole, and itraconazole. Out of the isolates, 3 had MIC of 32 and 1 had MIC of 16 against itraconazole, and 1 isolate had MIC of 32 against posaconazole. CYP51A gene was sequenced, and TR34/L98H mutation was identified. Triazole resistance existing in Kenya calls for rational use of azole-based fungicides in agriculture over concerns of emerging antifungal resistance in clinical practice.

Morphological changes and induction of antifungal resistance in Aspergillus fumigatus due to different CO2 levels

Background and Purpose

Aspergillosis is one of the most common opportunistic fungal infections in immunocompromised and neutropenic patients. Aspergillus fumigatus (A. fumigatus) is the most common causative agent of this infection. Due to variable CO₂ concentrations that pathogens are exposed to during the infection process and to understand the role of CO₂, we examined the effects of various CO₂ concentrations as one of the environmental factors on morphological changes and induction of antifungal resistance in A. fumigatus.

Materials and Methods

A. fumigatus strains were cultured and incubated under 1%, 3%, 5%, and 12% CO₂ atmospheres, each time for one, two, and four weeks. The control culture was maintained for one week without CO₂ atmosphere. Morphological changes were investigated and antifungal susceptibility test was performed according to the recommendations of the Clinical and Laboratory Standards Institute (CLSI) M38-A2 document. The results of different CO₂ atmospheres were compared with that of the control sample.

Results

We found that 1%, 3%, 5%, and 12% CO₂ atmospheres were associated with morphological colony changes. Macroscopically, the colonies were shallow dark green, smooth, crisp to powdery with reduced growth; microscopic examination revealed the absence of conidiation. The induction of antifungal resistance in the susceptible strains to itraconazole, voriconazole, and amphotericin B increased after exposure to 12% CO₂ atmosphere and four weeks of incubation. The MIC values for itraconazole, voriconazole, and amphotericin B were 16 g/ml, 1 g/ml, and 16 g/ml, respectively. These values for the control group were 0.125 g/ml, 0.125 g/ml, and 2 g/ml, respectively.

Conclusion

Exposure to different CO₂ atmospheres induced morphological changes in A. fumigatus, it seems to increase the MIC values, as well. In parallel, resistance to both itraconazole and voriconazole was also observed.

Elevated MIC Values of Imidazole Drugs against Aspergillus fumigatus Isolates with TR34/L98H/S297T/F495I Mutation

The use of azole fungicides in agriculture is believed to be one of the main reasons for the emergence of azole resistance in Aspergillus fumigatus Though widely used in agriculture, imidazole fungicides have not been linked to resistance in A. fumigatus This study showed that elevated MIC values of imidazole drugs were observed against A. fumigatus isolates with TR₃₄/L98H/S297T/F495I mutation, but not among isolates with TR₃₄/L98H mutation. Short-tandem-repeat (STR) typing analysis of 580 A. fumigatus isolates from 20 countries suggested that the majority of TR₃₄/L98H/S297T/F495I strains from China were genetically different from the predominant major clade comprising most of the azole-resistant strains and the strains with the same mutation from the Netherlands and Denmark. Alignments of sterol 14α-demethylase sequences suggested that F495I in A. fumigatus was orthologous to F506I in Penicillium digitatum and F489L in Pyrenophora teres, which have been reported to be associated with imidazole resistance. In vitro antifungal susceptibility testing of different recombinants with cyp51A mutations further confirmed the association of the F495I mutation with imidazole resistance. In conclusion, this study suggested that environmental use of imidazole fungicides might confer selection pressure for the emergence of azole resistance in A. fumigatus.

In vitro combination of voriconazole with micafungin against azole-resistant clinical isolates of Aspergillus fumigatus from different geographical regions

In vitro interaction of voriconazole with micafungin was evaluated against 33 clinical Aspergillus fumigatus isolates, including azole-resistant (n=31) and -susceptible (n=2) isolates. Interaction was synergistic for only 1 resistant isolate carrying the TR₃₄/L98H mutation. No antagonistic effects were observed for 96.8% of azole-resistant isolates.

Use of cell surface protein typing for genotyping of azole-resistant and -susceptible Aspergillus fumigatus isolates in Iran

Aspergillus fumigatus is the leading cause of mortality in severely immunocompromised individuals. Understanding pathogen dispersion and relatedness is essential for determining the epidemiology of nosocomial infections. Therefore, the aim of this study was to investigate the diversity and putative origins of clinical and environmental azole-susceptible and -resistant A. fumigatus isolates from Iran. In all, 79 isolates, including 64 azole-susceptible and 15 -resistant isolates, were genotyped using the cell surface protein (CSP) gene. Seven distinct repeat types (r01, r02, r03, r04, r05, r06 and r07) and 11 different CSP variants (t01, t02, t03, t04A, t06A, t06B, t08, t10, t18A, t18B and t22) were observed. Interestingly, t06B, t18A and t18B were exclusively present in azole-resistant isolates. The Simpson's index of diversity (D) was calculated at 0.78. Resistant isolates were genetically less diverse than azole-susceptible isolates. However, azole-resistant A. fumigatus without TR₃₄ /L98H were more diverse than with TR₃₄ /L98H. The limited CSP type diversity of the TR₃₄ /L98H isolates versus azole-susceptible isolates suggests that repeated independent emergence of the TR₃₄ /L98H mechanism is unlikely. It has been suggested that CSP types might have a common ancestor that developed locally and subsequently migrated worldwide.