RESUMEN

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.

Asunto(s)

Antifúngicos , Aspergillus fumigatus , Azoles , Fibrosis Quística , Sistema Enzimático del Citocromo P-450 , Farmacorresistencia Fúngica , Proteínas Fúngicas , Pruebas de Sensibilidad Microbiana , Humanos , Fibrosis Quística/microbiología , Fibrosis Quística/complicaciones , Irán/epidemiología , Aspergillus fumigatus/efectos de los fármacos , Aspergillus fumigatus/genética , Aspergillus fumigatus/aislamiento & purificación , Farmacorresistencia Fúngica/genética , Antifúngicos/farmacología , Antifúngicos/uso terapéutico , Estudios Prospectivos , Prevalencia , Sistema Enzimático del Citocromo P-450/genética , Azoles/farmacología , Azoles/uso terapéutico , Proteínas Fúngicas/genética , Masculino , Femenino , Aspergilosis/microbiología , Aspergilosis/epidemiología , Aspergilosis/tratamiento farmacológico , Adulto , Niño , Adolescente , Polimorfismo de Nucleótido Simple , Adulto Joven , Esputo/microbiología , Itraconazol/farmacología , Voriconazol/farmacología , Voriconazol/uso terapéutico , Preescolar , Mutación

RESUMEN

BACKGROUND: Antifungal resistance is the main health concern in the control of invasive fungal infections. This research was designed to further assess the antifungal activity of aryl-1,2,4-triazole-3-ylthio analogs of fluconazole (ATTAFs) against Candida albicans systemic candidiasis in the murine model. MATERIALS & METHODS: The murine model of systemic candidiasis was designed via the inoculation of 1 × 106 CFU of Candida albicans. The treatment dosages of 3.5 and 35 mg/kg per day were selected for ATTAFs and fluconazole, respectively. The median survival time (MST) was assayed for 30 days post-infection. The quantitative and qualitative (via histopathology staining) fungal burden was also assessed. Furthermore, immunohistochemistry and biochemistry assays were performed to monitor anti-inflammatory activity using the Cyclooxygenase-2 (Cox-2) marker and changes in serum protein levels. RESULTS: ATTAFs considerably improved the survival of the murine model (P < 0.003). Compared with fluconazole, the antifungal activity of ATTAFs and their MST showed no difference (P > 0.05). However, these compounds decreased the fungal burden in the kidneys, spleen, and liver. CONCLUSION: Our research indicates that ATTAF-1 and ATTAF-2 are effective therapeutic agents due to their fungal clearing and increasing the MST in the murine model of systemic candidiasis. Although we concluded that these components are novel and promising candidates for the management of invasive candidiasis, further studies are warranted to correlate these findings with clinical outcomes.

Asunto(s)

Candidiasis Invasiva , Fluconazol , Humanos , Animales , Ratones , Fluconazol/farmacología , Fluconazol/uso terapéutico , Antifúngicos/farmacología , Antifúngicos/uso terapéutico , Antifúngicos/química , Azoles/farmacología , Azoles/uso terapéutico , Modelos Animales de Enfermedad , Pruebas de Sensibilidad Microbiana , Candida albicans , Candidiasis Invasiva/tratamiento farmacológico , Farmacorresistencia Fúngica

RESUMEN

Background and Purpose: Scedosporium spp. is a saprophytic fungus that may cause invasive pulmonary infection due to the aspiration of contaminated water in both immunosuppressed and immunocompetent hosts. Case report: Herein, we report a fatal case of pulmonary infection caused by Scedosporium species associated with a car crash and near-drowning in a sewage canal. Scedosporium aurantiacum isolated from bronchoalveolar lavage was identified by PCR-sequencing of ß-tubulin genes. The minimum inhibitory concentration values for amphotericin B, itraconazole, posaconazole, isavuconazole were >16 µg/ml, and >8 µg/ml for anidulafungin, micafungin, and caspofungin. Voriconazole was found to be the most active agent with a MIC of 1 µg/ml. Conclusion: This report, as the first case of pulmonary scedosporiosis after near-drowning in Iran, highlights the importance of high suspicion in near-drowning victims, prompt identification of Scedosporium spp., and early initiation of appropriate antifungal therapy.

RESUMEN

BACKGROUND: Emergence of resistance to respective antifungal drugs is a primary concern for the treatment of candidiasis. Hence, determining antifungal susceptibility of the isolated yeasts is of special importance for effective therapy. For this purpose, the clinical laboratory standard institute (CLSI) has introduced a broth microdilution method to determine minimum inhibitory concentration (MIC). However, the so-called "Trailing effect" phenomenon might sometimes pose ambiguity in the interpretation of the results. OBJECTIVES: The present study aimed to determine the in vitro susceptibility of clinical isolates of Candida against azoles and the frequency of the Trailing effect. MATERIALS AND METHODS: A total of 193 Candida isolates were prospectively collected and identified through the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Using a broth microdilution test, according to the guidelines of CLSI M27-A3, antifungal susceptibilities of the isolated yeasts against Fluconazole (FLU), Itraconazole (ITR), Ketoconazole (KET) and Voriconazole (VOR) were assessed. Moreover, trailing growth was determined when a susceptible MIC was incubated for 24 hours, and turned into a resistant one after 48 hours of incubation. RESULTS: Among the tested antifungal drugs in this study, the highest rate of resistance was observed against ITR (28.5%) followed by VOR (26.4%), FLU (20.8%) and KET (1.5%). The trailing effect was induced in 27 isolates (14.0%) by VOR, in 26 isolates (13.5%) by ITR, in 24 isolates (12.4%) by FLU, and in 19 isolates (9.8%) by KET. CONCLUSIONS: The monitoring of antifungal susceptibilities of Candida species isolated from clinical sources is highly recommended for the efficient management of patients. Moreover, the trailing effect should be taken into consideration once the interpretation of the results is intended.