Antifungal Susceptibility Testing Research Articles

Update on diagnosis and treatment of fungal meningitis: lessons from recent outbreaks.

Recently, fungal meningitis outbreaks have occurred in association with neuraxial and epidural anesthesia in immunocompetent patients. Herein, we describe the course of those outbreaks, their diagnosis, treatment, prognosis, and lessons learned. Two outbreaks of Fusarium solani meningitis during 2022-2023 were associated with epidural anesthesia in two distant cities in Mexico (Durango and Matamoros). The initial etiological agent identification was delayed due to insensitivity of cultures. A Fusarium solani qPCR was validated and positive in 38% cerebrospinal fluid (CSF) samples from Durango, while BD-Glucan allowed early diagnosis of the index case in Matamoros. Antifungal treatment with voriconazole and liposomal amphotericin B (L-AmB) was recommended. Overall mortality was 51%. Once the cause was confirmed, some patients received fosmanogepix. Fungal meningitis outbreaks due to filamentous fungi are usually associated with direct epidural inoculation. They result in severe presentations and high mortality. Early diagnosis should be suspected, BD-Glucan CSF testing screening is recommended. Aggressive antifungal treatment based on antifungal susceptibility testing should be administered as early as possible. The advent of molecular diagnostic methods and new antifungal drugs may allow for timely diagnosis and treatment, increasing the chances of survival.

Vulvovaginal candidiasis, an increasing burden to women in the tropical regions attending Bharatpur Hospital, Chitwan

Vulvovaginal candidiasis is a yeast infection commonly caused by the overgrowth of Candida species in and around the vulva and vagina. Abnormal vaginal discharge, itching and irritation, swelling and redness of the vaginal area, pain during sexual intercourse, and dyspareunia are important clinical findings of the infection. Currently, the infection is one of the growing burdens to married women. Moreover, the infection with antifungal-resistant Candida species adds challenges to managing the disease. Hence, this study was conducted to identify the different Candida species causing vulvovaginal candidiasis and to determine its susceptibility pattern against different antifungal drugs. A hospital-based cross-sectional and quantitative study was conducted for the period of six months from September 2022 to March 2023 among symptomatic married women in the Gynecology and Obstetrics Department of Bharatpur Hospital, Chitwan. A total of 300 symptomatic cases were enrolled in the study. Candida species were isolated from vaginal swabs following standard microbiological procedures and antifungal susceptibility testing was performed with different antifungal agents. The total prevalence of vulvovaginal candidiasis was found to be 37.3 % (112/300). Among different isolates, Candida albicans was found to be the most predominant (52.6 %), followed by Candida glabrata (29.3 %) among non-albicans. Women from the age group 25–35 years were found to be more infected (47.3 %) and the relationship between contraceptive use and vulvovaginal candidiasis was found to be statistically significant (p < 0.05). Candida species showed higher susceptibility toward Amphotericin-B (68.1 %), followed by fluconazole (Diflucan), and Clotrimazole (50.9 %). Whereas the least susceptibility was observed to Voriconazole (27.6 %) and Itraconazole (35.30 %). Candida albicans was comparatively more susceptible to different antifungal drugs than non-albicans species. Candida parapsilosis was only susceptible to Amphotericin-B and the increasing incidence of vaginal candidiasis due to non-albicans Candida indicates the need for routine speciation of Candida.

Association between in vitro susceptibility and clinical outcomes in fungal keratitis

PurposeThe purpose of this study was to assess the association between antifungal susceptibility as measured by minimum inhibitory concentration (MIC) and clinical outcomes in fungal keratitis.MethodsThis pre-specified secondary analysis of the Mycotic Ulcer Treatment Trial II (MUTT II) involved patients with filamentous fungal keratitis presenting to Aravind Eye Hospitals in South India. Antifungal susceptibility testing for natamycin and voriconazole was performed on all samples with positive fungal culture results according to Clinical and Laboratory Standards Institute Guidelines. The relationship between MIC and clinical outcomes of best-corrected visual acuity, infiltrate or scar size, corneal perforation, need for therapeutic penetrating keratoplasty, and time to re-epithelialization were assessed.ResultsWe obtained MIC values from 141 patients with fungal keratitis. The most commonly cultured organisms were Aspergillus (46.81%, n = 66) and Fusarium (44.68%, n = 63) species. Overall, there was no association between antifungal MICs and clinical outcomes. Subgroup analysis revealed that among Fusarium-positive cases, higher voriconazole MIC was correlated with worse three-month best-corrected visual acuity (p = 0.03), increased need for therapeutic penetrating keratoplasty (p = 0.04), and time to re-epithelialization (p = 0.03). No significant correlations were found among Aspergillus-positive cases. There were no significant correlations found between natamycin MIC and clinical outcomes among organism subgroups.ConclusionsDecreased susceptibility to voriconazole was associated with increased odds of requiring a therapeutic penetrating keratoplasty in Fusarium-positive cases. Susceptibility to natamycin was not associated with any of the measured outcomes.

In vitro antifungal activity of eucalyptol and its interaction with antifungal drugs against clinical dermatophyte isolates including Trichophyton indotineae

BackgroundDermatophytosis, a prevalent fungal infection, often exhibits treatment failure. It poses ongoing public health concerns, urging exploration of alternative treatment strategies. This study examines eucalyptol’s in vitro activity and its interaction with antifungal agents against dermatophyte isolates.MethodsOverall, 489 patients clinically suspected of dermatophytosis were investigated, and the causative agents were molecularly identified. The antifungal activity of eucalyptol, itraconazole, terbinafine, and griseofulvin was assessed according to the guideline of the Clinical and Laboratory Standards Institute (CLSI M38 ed3). The interaction between eucalyptol and the aforementioned antifungals was determined using a checkerboard method.ResultsDermatophytosis was confirmed in 30 out of 489 (6.13%) patients, with a female-to-male ratio of 3:2 and an age range of 8–67 years. The most commonly observed clinical manifestation was tinea corporis (34.21%), and Trichophyton indotineae (n = 14, 46%) was the most common causative agent. Antifungal susceptibility testing revealed that eucalyptol exhibited antidermatophyte properties with minimum inhibitory concentrations (MIC) ranging from 0.78 to 25 mg/mL. Itraconazole demonstrated the lowest geometric mean (GM) value (MIC range: 0.0019–0.25 µg/mL, GM: 0.015 µg/mL), while griseofulvin exhibited the highest GM value (MIC range: 0.125–8 µg/mL, GM: 2.37 µg/mL). The in vitro interaction of eucalyptol with antifungal drugs, except for its combination with terbinafine against two Trichophyton tonsurans isolates resulting in synergistic effects, showed indifference (n = 70, 77.77%) and antagonistic types (n = 18, 20%).ConclusionAmong the evaluated antifungals, itraconazole demonstrated the highest effectiveness against clinical isolates, while eucalyptol alone exhibited a more pronounced effect than when combined with antifungal agents.

Clinical Characteristics of Candidemia Due to Candida parapsilosis with Serial Episodes: Insights from 5-Year Data Collection at a Tertiary Hospital in Korea

Candida parapsilosis is a common cause of non-albicans Candida species causing candidemia, particularly invasive candidiasis. This study aimed to characterize candidemia due to the C. parapsilosis complex with serial episodes, including clinical and mycological features. Methods: Blood isolates of the C. parapsilosis complex were collected from February 2019 to January 2023 at a tertiary Korean hospital. Species identification was performed using Vitek 2 or matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and antifungal susceptibility testing was performed using the Sensititre YeastOne® system. Clinical information was collected, and characteristics were analyzed according to single or serial isolates. Results: A total of 586 blood isolates of the C. parapsilosis complex were recovered from 68 candidemia patients during the study period. Of them, only the first isolate per patient was investigated. The only two isolates were resistant to fluconazole and no isolate was resistant to echinocandins, amphotericin B, or 5-FC. A single episode of candidemia occurred in 35 patients, while serial episodes occurred in 33 patients. Underlying liver diseases, use of vasopressors, ICU admission, severe sepsis, and CVC use were more frequent in patients with serial episodes. There was no significant difference in the median MIC values of antifungal agents or the use of azoles or amphotericin B between single and serial episodes. However, patients with serial episodes more frequently received echinocandin therapy. Overall, there was no significant difference in the 30-day mortality rate between patients with single and serial episodes. Conclusion: Our data indicate that several factors related to the underlying conditions of the patients are associated with C. parapsilosis candidemia with serial episodes, rather than the characteristics of Candida itself.

Inhibitory effects and mode of antifungal action of isobavachalcone on Candida albicans growth and virulence factors

The fungus Candida albicans causes various kinds of human infections, including oral thrush, vulvovaginitis and life-endangering bloodstream infections, the incidence of which are rising. Worsening this, the clinical antifungals are limited to a few, highlighting the necessity to develop novel antifungal therapies. In this study, the antifungal activities of isobavachalcone against C. albicans SC5314 and nine C. albicans clinical isolates were tested. The effects of isobavachalcone (IBC) on C. albicans virulence factors, such as hyphal formation, adhesion, biofilm formation and extracellular phospholipase production, as well as the underlying mechanism, were also evaluated. Antifungal susceptibility test revealed that IBC has significant anti-Candida activities, with both MIC and MFC being 4–5 μg/mL against all strains tested. Hyphal formation in RPMI-1640, Spider and GlcNAc medium, adhesion to abiotic polystyrene surfaces and surfaces of A549 cells, could be inhibited by IBC. Most important, IBC could inhibit the C. albicans biofilm formation and development. PI staining tests showed that IBC could increase the cell membrane permeability, suggesting the damages to the fungal cell membrane. IBC was further demonstrated to induce excessive ROS production in C. albicans planktonic cells and its mature biofilms, as revealed by DCFH fluorescence detection through flowcytometry and relative fluorescence intensity analysis (with a microplate reader). The roles of ROS in the antifungal activity of IBC were further confirmed through antioxidant rescue assays in MIC and biofilm formation tests. Compared to its antifungal activity, the cytotoxicity against mammalian cells was low, indicating its potential in developing antifungal therapies.

Invasive aspergillosis due to cryptic Aspergillus species: A prospective study from a single centre in India

Background& objective: The existence of visually identical cryptic Aspergillus species that can be distinguished only by molecular techniques is becoming more widely acknowledged. For the majority of antifungal drugs, these are known to exhibit a greater minimal inhibitory concentration in vitro. For the purpose of receiving the proper care, it is crucial to identify these species at right time. Our aim in this work is to identify and describe the Aspergillus species that are cryptic from all of the clinical samples. MethodsRoutine samples from inpatients and outpatients received in department of Microbiology, All India Institute of Medical Sciences, New Delhi, showing growth of Aspergillus species were included in this study. Phenotypic and Matrix Assisted Laser Desorption Ionisation - Time of Flight identified isolates were analysed for cryptic species, by PCR and ITS/ß – tubulin sequencing. In accordance with CLSI recommendations, antifungal susceptibility testing was conducted using micro broth dilution. ResultsOf the 94 isolates, 54 A. fumigatus, 34 A. flavus, 3 A. nidulans, 2 A. terreus, and 1 A. niger were morphologically identified. MALDI-TOF misidentified 2 A. nidulans isolates and 1 A, stellatus isolate. The ß – tubulin sequence analysis revealed that 2 isolates (2.08 %) were cryptic, one was A. stellatus and another one was A. tubingensis.

Isolation and identification of Candida species from catheter-associated urinary tract infection in Thamar city hospitals, Yemen.

The incidence of urinary tract infections associated with Candida is increasing in Yemeni public hospitals. The primary objective of this research was to isolate specific Candida species responsible for catheter-associated urinary tract infections (UTIs) and to examine the antifungal sensitivity of these Candida isolates. A total of 200 samples were collected from patients with catheters admitted to multiple hospitals of Thamar city (Yemen). There were 50 positive samples with Candida out of 200 samples. We conducted the primary identification process using the established protocols. Before isolation and identification, all yeast isolates underwent sub-culturing on Sabouraud dextrose agar. We employed the standard microbiological procedures such as Gram staining, colonial morphology analysis, lactophenol cotton blue assay, germ tube formation assessment, colony staining on chrom agar Candida medium, and incubation at 37°C for 48h. The assessment of cultures was conducted by evaluating their predominant species. All Candida isolates were tested for antifungal susceptibility using the disk diffusion technique, as indicated by the Clinical and Laboratory Standards Institute (CLSI) M44-A document recommendations. In this study, the prevalence of Candida species obtained from catheter-associated UTIs was shown to be the highest among individuals aged 51-60years (28.0%) and the lowest was among those aged 10-20years (8.0%). Males exhibit higher rates than females, with males accounting for 56.0 and females for 44.0%, respectively. The predominant strain from catheters linked to urinary tract infections was Candida albicans. The Candida isolates had the highest susceptibility to itraconazole, with fluconazole and nystatin at sensitivity rates of 64, 60, and 50%, respectively. Amphotericin B and ketoconazole exhibited the most elevated concentrations. The p value of duration of catheterization < 5 was significant (p = 0.01), as well as significant in anti-fungal susceptibility testing of itraconazole, ketoconazole, and nystatin which are (p = 0.03), (p = 0.04), and (p = 0.03) respectively. Urinary tract infection due to candiduria was more common in patients with indwelling urinary catheter. The catheter-associated urinary tract infection caused by Candida species occurred mainly in old male patients. Candia albicans was the predominant Candida species isolated from urinary tract infection associated with urinary catheter at Thamar city hospitals. This study determined that diabetes and antibiotic use are significant predisposing factors associated with isolation of Candida in specimens submitted by patients at Thamar city hospitals.

Fungal presence and health implications in hospital water systems

ABSTRACT Given the increasing occurrence of invasive fungal infections and the limited efficacy of modern antifungal medications, it is crucial to disseminate information regarding the potential sources of nosocomial mycoses through the One Health approach. This study investigated the presence and antifungal susceptibility of fungi in biofilm and water samples obtained from the drinking water distribution system (DWDS) of hospitals. The positivity rate for fungi in biofilm and water samples was 41% and 9%, respectively, with Aspergillus species, a significant causative agent of nosocomial mycoses, being the predominant fungi identified. Analysis of antifungal susceptibility test revelead a comparable resistance profile between some isolated species from the DWDS and those reported for certain clinical samples. While further research is required to determine the specific contribution of waterborne fungi to nosocomial fungal infections, our results emphasize the importance of controlling biofilm formation within DWDSs, particularly in high-risk hospital wards.

Detection of terbinafine-resistant Trichophyton indotineae isolates within the Trichophyton mentagrophytes species complex isolated from patients in Hue City, Vietnam: A comprehensive analysis.

The Trichophyton mentagrophytes complex comprises a group of dermatophyte fungi responsible for various dermatological infections. The increasing drug resistance of this species complex, especially terbinafine resistance of Trichophyton indotineae, is a major concern in dermatologist practice. This study provides a comprehensive analysis of T. mentagrophytes complex strains isolated from patients in Hue City, Vietnam, focusing on their phenotypic and genetic characteristics, antifungal susceptibility profiles, and molecular epidemiology. Keratinophilic fungi from dermatophytosis culture samples were identified morphologically and phenotypically, with species and genotypes confirmed by internal transcribed spacer sequencing and phylogenetic analysis. Antifungal susceptibility testing was carried out to evaluate their susceptibility to itraconazole, voriconazole, and terbinafine. The 24% (n=27/114) of superficial mycoses were phenotypically attributed to T. mentagrophytes complex isolates. Trichophyton interdigitale, mainly genotype II*, was predominant (44.4%), followed by T. mentagrophytes genotype III* (22.2%), T. indotineae (14.8%), T. tonsurans (11.2%), and T. mentagrophytes (7.4%). While all isolates were susceptible to itraconazole and voriconazole, half of T. indotineae isolates exhibited resistance to terbinafine, linked to the Phe397Leu mutation in the SQLE protein. This study highlighted the presence of terbinafine-resistant T. indotineae isolates in Vietnam, emphasizing the need to investigate dermatophyte drug resistance and implement effective measures in clinical practice.

An Unusual High Prevalence of Cryptococcus (Naganishia) diffluens Colonization in Neonates Hospitalized in a Referral Neonatal Intensive Care Unit.

Although the Candida species continue to be the most frequent colonizer of neonatal skin, a clear increase of colonization due to rare yeast-like fungi has been reported. In this study, we report an unusual high prevalence of Cryptococcus diffluens colonization in neonates admitted to the neonatal intensive care unit (NICU) over a 1-month period. From January 2020 to June 2021, the study included all neonates who were admitted to the NICU of Bu Ali Sina Hospital at least 28 days old. Skin swabs from different anatomical areas were collected. Sampling was done 3 times/week. Each sample was inoculated into Sabouraud Dextrose Agar containing chloramphenicol and CHROMagar Candida, separately. The plates were incubated at 30 °C and 35 °C, respectively. Identification of the isolates was molecularly confirmed. In vitro antifungal susceptibility testing of the isolates was performed against different antifungal agents using the Clinical Laboratory Standards Institute protocol. Among 1026 samples collected from 78 neonates, 213 yeast isolates were recovered, of which the Candida species were the most common (77.5%), followed by C. diffluens (16.9%). During the study, 55 isolated yeasts were collected from December 26, 2020, to January 26, 2021, of which 65.5% were C. diffluens, while Candida spp. constituted 100% and 98.3% of the isolates before and after this period, respectively. The most frequent sources of C. diffluens were genital regions (27.8%). Of 36 C. diffluens isolates, 13.9%, 22.2%, 52.8%, and 83.3% were non-wild type to fluconazole, amphotericin B, itraconazole and 5-flucytosine, respectively. We reported for the first time an unusual high prevalence of C. diffluens colonization in neonates hospitalized in NICU. Our findings also showed the high minimum inhibitory concentration of amphotericin B and 5-flucytosine against C. diffluens.

Implication of genotypes for prognosis of Candida glabrata bloodstream infections.

Genotyping isolates of a specific pathogen may demonstrate unique patterns of antimicrobial resistance, virulence or outcomes. However, evidence for genotype-outcome association in Candida glabrata is scarce. We aimed to characterize the mycological and clinical relevance of genotypes on C. glabrata bloodstream infections (BSIs). Non-duplicated C. glabrata blood isolates from hospitalized adults were genotyped by MLST, and further clustered by the unweighted pair group method with arithmetic averages (UPGMA). A clonal complex (CC) was defined by UPGMA similarities of >90%. Antifungal susceptibility testing was performed by a colorimetric microdilution method and interpreted following CLSI criteria. Of 48 blood isolates evaluated, 13 STs were identified. CC7 was the leading CC (n = 14; 29.2%), including 13 ST7. The overall fluconazole and echinocandin resistance rates were 6.6% and 0%, respectively. No specific resistance patterns were associated with CC7 or other CCs. Charlson comorbidity index (adjusted OR, 1.49; 95% CI, 1.05-3.11) was the only predictor for CC7. By multivariable Cox regression analyses, CC7 was independently associated with 28 day mortality [adjusted HR (aHR), 3.28; 95% CI, 1.31-8.23], even after considering potential interaction with neutropenia (aHR, 3.41; 95% CI, 1.23-9.42; P for interaction, 0.24) or limited to 34 patients with monomicrobial BSIs (aHR, 2.85; 95% CI, 1.15-7.08). Also, the Kaplan-Meier estimate showed greater mortality with CC7 (P = 0.003). Fluconazole resistance or echinocandin therapy had no significant impact on mortality. Our data suggested comorbid patients were at risk of developing CC7 BSIs. Further, CC7 was independently associated with worse outcomes.

Prolonged treatment of dermatophytosis caused by Trichophyton indotinea with terbinafine or itraconazole impacts better outcomes irrespective of mutation in the squalene epoxidase gene.

Over the past decades, the increasing incidence of recurrent dermatophytosis associated with terbinafine-resistant Trichophyton has posed a serious challenge in management of dermatophytosis. Independent reports of failure of treatment and high minimum inhibitory concentrations (MIC) of antifungals are available, but data correlating MIC and clinical outcomes is still sparse. Therefore, the present study was conducted to evaluate the outcomes of systemic treatment of dermatophytosis and its correlation with MIC of the etiological agents isolated from such patients. Retrospective analysis of 587 consecutive patients with dermatophytosis was done from March 2017 to March 2019. Demographic and clinical details of the patients were noted, along with the results of direct microscopy and fungal culture. The isolates were identified by sequencing the internal transcribed spacer region of rDNA. Antifungal susceptibility testing was performed following the CLSI M38 protocol. Mutation in the squalene epoxidase (SE) gene was detected by DNA sequencing and ARMS-PCR. Based on the culture-positivity and prescribed systemic antifungal, patients were categorised into Group I culture-positive cases treated with systemic terbinafine and Group II culture-positive cases treated with systemic itraconazole, each for a total period of 12 weeks. In the present study, 477 (81.39%) were culture-positive; however, 12 weeks follow-up was available for 294 patients (Group I-157 and Group II-137) who were included for statistical analysis. In both groups [Group I-37/63 (51.4%) and Group II-14/54 (58.3%)], a better cure rate was observed if the initiation of therapy was performed within <6 months of illness. Treatment outcome revealed that if therapy was extended for 8-12 weeks, the odds of cure rate are significantly better (p < .001) with either itraconazole (Odd Ratio-15.5) or terbinafine (Odd Ratio-4.34). Higher MICs for terbinafine were noted in 41 cases (cured-18 and uncured-23) in Group I and 39 cases (cured-16 and uncured-23) in Group II. From cured (Group I-17/18; 94.4% and Group II-14/16; 87.5%) and uncured (Group I-20/23; 86.9% and Group II-21/23; 91.3%) cases had F397L mutation in the SE gene. No significant difference in cure rate was observed in patients with Trichophyton spp. having terbinafine MIC ≥ 1or <1 μg/mL (Group I-p = .712 and Group II-p = .69). This study revealed that prolonging terbinafine or itraconazole therapy for beyond 8 weeks rather than the standard 4 weeks significantly increases the cure rate. Moreover, no correlation has been observed between antifungal susceptibility and clinical outcomes. The MIC remains the primary parameter for defining antifungal activity and predicting the potency of antifungal agents against specific fungi. However, predicting therapeutic success based solely on the MIC of a fungal strain is not always reliable, as studies have shown a poor correlation between invitro data and invivo outcomes. To address this issue, further correlation of antifungal susceptibility testing (AFST) data with clinical outcomes and therapeutic drug monitoring is needed. It also highlights that initiation of the treatment within <6 months of illness increases cure rates and reduces recurrence. Extensive research is warranted to establish a better treatment regime for dermatophytosis.

Multi-state evaluation of Candida infections in burn patients.

Burn patients are at high risk of developing secondary invasive fungal infections due to their compromised skin barrier, extensive use of antibiotics, and immunosuppression. We investigated demographic characteristics and clinical factors associated with Candida infections in intensive care unit (ICU) burn patients, and the invitro antifungal susceptibility of species of isolates. A total of 353 burn patients admitted to three major ICUs of burn centers in Iran were evaluated between 2021 and 2023. Patients were considered as colonisation and candidemia. Demographic characteristics, burn-related factors, and clinical conditions were compared among the groups. Furthermore, we identified fungi at the species level and performed antifungal susceptibility testing according to CLSI guidelines. Overall, 46.2% of patients were colonised with a Candida species, leading to candidemia in 15.3%. The most frequently isolated species from candidemia and burn wound colonisation were Candida parapsilosis (37.0%) and Candida albicans (31.9%), respectively. Risk factors linked to candidemia included larger total body surface area (TBSA) (>50%), older patients, indwelling catheters, diabetes, and an extended ICU stay. Mortality rate was higher among candidemia patients (82.5%) compared to colonised patients (7.3%). The resistance rate of the strains isolated from candidemia to fluconazole and voriconazole was 28% and 18.2%, respectively. We found that a higher percentage of TBSA burn injuries, longer hospital stays, and catheterization are important predictors of candidemia. The mortality rate was significantly higher in people infected with non-albicans Candida species. Prevention and treatment strategies for candidemia should be based on updated, regional epidemiological data.

Synergistic antifungal activity against Candida albicans between voriconazole and cyclosporine a loaded in polymeric nanoparticles

The goal of this work is to investigate if the synergistic antifungal activity between cyclosporine A, CsA, and voriconazole, VRZ, increases when both drugs are encapsulated in a nanocarrier as compared when they are free. The preparation and characterization of blank and VRZ and CsA loaded polymeric based PLGA nanoparticles (PLGA, PLGA-PEG, and PLGA+PEG) was a necessary previous step. Using the more suitable NPs, those of PLGA, the antifungal susceptibility tests performed with VRZ-loaded PLGA NPs, show no significant increase of the antifungal activity in comparison to that of free VRZ. However, the synergistic behavior found for the (VRZ+CsA)-loaded PLGA NPs was fourfold stronger than that observed for the two free drugs together. On the other hand, the investigation into the suppression of C. albicans biofilm formation showed that blank PLGA NPs inhibit the biofilm formation at high NPs concentrations. However, a minor effect or even a slight biofilm increase formation was observed at low and moderate NPs concentrations. Therefore, the enhancement of the biofilm inhibition found for the three tested treatments (CsA alone, VRZ alone, and VRZ+CsA) when comparing free and encapsulated drugs, within the therapeutic window, can be attributed to the drug encapsulation approach. Indeed, polymeric PLGA NPs loaded with CsA, VRZ, or VRZ+CsA are more effective at inhibiting the C. albicans biofilm growth than their free counterparts.

Emerging Aspergillus lentulus infections in Taiwan: clinical and environmental surveillance.

This study aimed to investigate the prevalence and characteristics of Aspergillus lentulus clinical and environmental isolates in Taiwan. Aspergillus isolates obtained from patients at three hospitals and from 530 soil samples across Taiwan were screened. A. lentulus, confirmed by calmodulin sequencing, was subjected to antifungal susceptibility testing and cyp51A analyses. Soil samples yielding A. lentulus were analysed for residues of 25 azole fungicides. Nine A. lentulus isolates were identified, which included seven (1.2%, 7/601) isolates from three antifungal-naïve patients out of 601 Aspergillus section Fumigati clinical isolates and two (0.3%, 2/659) isolates out of 659 Aspergillus soil isolates. All isolates developed white colonies and failed to grow at 48°C. They were susceptible to anidulafungin but showed reduced susceptibility to amphotericin B (AmB), voriconazole and azole fungicides. One heart transplant recipient with proven invasive pulmonary aspergillosis (IPA) initially showed suboptimal response to voriconazole monotherapy but was cured with a combination of voriconazole-caspofungin, liposomal AmB (LAmB)-caspofungin, along with surgery, followed by voriconazole maintenance therapy. Among two critically ill patients with probable IPA, one survived with micafungin, while the other died of aspergillosis despite sequential isavuconazole and LAmB monotherapy. Clinical and environmental isolates sharing identical Cyp51A sequence are identified, matching the Cyp51A sequence of A. lentulus NIID0096. Flusilazole (0.0009 mg/kg) was detected in one soil sample. This study raises concerns about health threat posed by human pathogenic A. lentulus originating from natural environments and underscores the need for increased clinical and laboratory vigilance regarding A. lentulus infections.

A systematic review on the emergence of terbinafine-resistant Trichophyton indotineae in Europe: Time to act?

There is a recent growing global concern regarding the rise in antifungal resistance of dermatophytosis. The emergence of terbinafine-resistant Trichophyton indotineae (T. indotineae), previously known as Trichophyton mentagrophytes genotype VIII, is particularly alarming given that terbinafine is considered the treatment of choice for dermatophyte infections and the limited number of available antimycotics. This strain surfaced in the Indian subcontinent in the mid-2010s and more recently there have been reports of its arrival in Europe. The objective of this review is to document the presence of terbinafine-resistant T. indotineae in Europe with the aim to guide antifungal stewardship and ultimately prevent the spread of resistance. This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic literature search was performed using PubMed, Scopus and Web of Science databases. We extracted information from 16 studies published between 2019 and 2023 that described a total of 63 cases of antifungal-resistant dermatophytosis caused by T. indotineae in Europe. Antifungal susceptibility testing (AFST) revealed a wide range of terbinafine minimum inhibitory concentrations (MICs), varying from 0.014 to ≥16 μg/mL. However, these values are hard to interpret due to variations among used methodologies as well as the lack of clinical breakpoints. In all cases included in this study, elevated terbinafine MICs were associated with mutations in the squalene epoxidase (SQLE) gene. Itraconazole was the most frequently used alternative to terbinafine in this study and complete remission of tinea lesions after treatment switch was shown. Nevertheless, relapse rates are concerningly high. We propose the implementation of surveillance programmes for a fast identification through sequencing of T. indotineae (and SQLE mutations) and standardization of procedures for AFST to facilitate the establishment of clinical breakpoints and enable guidance on the appropriate use of antifungals.

Optical Nanomotion Detection to Rapidly Discriminate between Fungicidal and Fungistatic Effects of Antifungals on Single-Cell Candida albicans.

Candida albicans is an emerging pathogen that poses a significant challenge due to its multidrug-resistant nature. There are two types of antifungal agents, fungicidal and fungistatic, with distinct mechanisms of action against fungal pathogens. Fungicidal agents kill fungal pathogens, whereas fungistatic agents inhibit their growth. The growth can be restored once the agent is removed and favorable conditions are established. Recognizing this difference is crucial as it influences treatment selection and infection prognosis. We present a technique based on optical nanomotion detection (ONMD) (i.e., observing the movement of the cells using an optical microscope) to discriminate rapidly between fungicidal (caspofungin) and fungistatic (fluconazole) drugs. The technique is based on the change in a yeast cell's nanomotion as a function of time during a two-hour treatment with the antifungal of interest followed by a one-hour growth period. The cells are entrapped in microwells in a microfluidic chip, which allows a quick exchange of growth medium and antifungal agent, enabling ONMD measurements on the same individual cells before and after treatment. This procedure permits to discriminate between fungicidal and fungistatic antifungals in less than 3 h, with single-cell resolution by observing if the nanomotion recovers after removing the treatment and reintroducing growth medium (YPD), or continues to drop. The simplicity of the approach holds promise for further development into a user-friendly device for rapid antifungal susceptibility testing (AFST), potentially being implemented in hospitals and medical centers worldwide in developed and developing countries.

Resistant C. albicans implicated in recurrent vulvovaginal candidiasis (RVVC) among women in a tertiary healthcare facility in Kumasi, Ghana

BackgroundVulvovaginal candidiasis is a common fungal infection that affects the female lower genital tract. This study determined the major risk factors associated with vulvovaginal infection (VVI) in the Ashanti region of Ghana and also determined the antifungal resistance patterns of Candida albicans isolates to some antifungals.MethodsThree hundred and fifty (350) high vaginal swab (HVS) samples were collected from women who presented with signs and symptoms of VVI. A structured questionnaire was administered to one hundred and seventy-two (172) of the women. HVS samples were cultured on Sabouraud dextrose agar with 2% chloramphenicol. The polymerase chain reaction was employed to confirm C. albicans. Antifungal susceptibility testing was performed and the susceptibility of C. albicans isolates to fluconazole, clotrimazole, amphotericin B, nystatin, miconazole and 5-flurocytosine were assessed.ResultsVaginal infection was most prevalent amongst females in their reproductive age (21 to 30 years; 63.0%). The study found a significant association between vaginal infections and some risk factors such as sexual practices (p < 0.001), antibiotic misuse (p < 0.05), poor personal hygiene (p < 0.005) and birth control methods (p < 0.049). Out of the 350 HVS samples collected, 112 yielded yeast cells with 65 (58%) identified as C. albicans. The C. albicans isolates were resistant to 5’ flucytosine (100%), fluconazole (70%), voriconazole (69.2%), miconazole (58.5%) and nystatin (49.2%). C. albicans isolates were more susceptible to amphotericin B (53.8%) and clotrimazole (45.1%), although an appreciable number of isolates showed resistance (46.1% and 52.3%, respectively).ConclusionThere should be nationwide education on all associated risk factors of VVI. Also, use of the various antifungal agents in vaginal candidiasis should proceed after antifungal susceptibility testing to ensure efficacious use of these agents.

Epidemiology of cryptococcal meningitis and fluconazole heteroresistance in Cryptococcus neoformans isolates from a teaching hospital in southwestern China.

Cryptococcal meningitis (CM), a common and serious opportunistic infection mostly caused by Cryptococcus neoformans, is primarily treated with fluconazole. Nevertheless, Cryptococcus neoformans strains that undergo repeated exposure to azoles can gradually acquire heteroresistance to fluconazole. The management of this specific CM infection poses a substantial challenge. Determining a globally accepted definition for fluconazole heteroresistance and developing effective and prompt methods for identifying heteroresistance is of utmost importance. We collected data on the clinical and epidemiological characteristics of patients diagnosed with CM. All the available Cryptococcus neoformans strains isolated from these patients were collected and subjected to antifungal susceptibility testing and evaluation of fluconazole heteroresistance. AIDS was present in 40.5% of the patients, whereas 24.1% did not have any underlying diseases. Patients with chronic diseases or impaired immune systems are susceptible to infection by Cryptococcus neoformans, a fungus that frequently (39.6%, 19/48) shows heteroresistance to fluconazole, as confirmed by population analysis profile (PAP).IMPORTANCEFluconazole heteroresistance poses a significant threat to the efficacy of fluconazole in treating cryptococcal meningitis (CM). Unfortunately, the standard broth microdilution method often misses the subtle percentages of subpopulations exhibiting heteroresistance. While the population analysis profile (PAP) method is esteemed as the gold standard, its time-consuming and labor-intensive nature makes it impractical for routine clinical use. In contrast, the Kirby-Bauer (KB) disk diffusion method offers a simple and effective screening solution. Our study highlights the value of KB over PAP and minimum inhibitory concentration (MIC) by demonstrating that when adjusting the inoculum concentration to 1.0 McFarland and subjecting samples to a 72-hour incubation period at 35°C, the KB method closely mirrors the outcomes of the PAP approach in detecting fluconazole heteroresistance. This optimization of the KB method not only enhances assay efficiency but also provides a blueprint for developing a timely and effective strategy for identifying heteroresistance.