Biofilm formation and antifungal susceptibility of Trichosporon asahii isolates from Mexican patients

Montoya, Alexandra M.; Elizondo-Zertuche, Mariana; Treviño-Rangel, Rogelio de J.; Becerril-García, Miguel A.; González, Gloria M.

doi:10.1016/j.riam.2017.02.008

Cited by 14 publications

(14 citation statements)

References 31 publications

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“…In Asia, it was almost 8.6 and 4 %, respectively, to FCZ and VCZ, in Europe it was 12.3 and 3.5 % and in Latin America it was 7.1 and 5.3 % [26]. In accordance with these results and taking into account ECV values recently considered by Francisco et al (MIC=8 µg ml −1 to FCZ and 0.25 µg ml −1 for VCZ) [23], we calculated a resistance rate of 16.1 % to FCZ and 3.2 % to VCZ. Only one isolate exhibited a MIC >0.25 µg ml −1 to VCZ (TN270HC09) in our study and was considered a resistant isolate.…”

Section: Discussionsupporting

confidence: 86%

“…Although, most clinical T. asahii isolates exhibited good sensitivity via azoles [24,25]. Recently, a decrease in the efficiency of azoles has been reported mainly due to FCZ [11,12,23,26]. An Antifungal Surveillance Study conducted from 1997 to 2007 showed that resistance frequency to FCZ and VCZ varied largely between countries.…”

Section: Discussionmentioning

confidence: 99%

“…Susceptibility was determined by measuring the MIC as the drug concentration at which the inhibition ellipse intercepted the scale on the antifungal strips after 24 and 48 h incubation at 37 °C as conveyed earlier on [22]. An isolate was considered resistant if MIC was ≥8 µg ml −1 for FCZ, MIC ≥0.25 µg ml −1 for VCZ and MIC ≥4 µg ml −1 for AMB [23].…”

Section: Methodsmentioning

confidence: 99%

“…The sensitivity of T. asahii isolates was estimated by the Etest method (bioMérieux, France) for FCZ, AMB and VCZ. Susceptibility was determined by measuring the MIC as the drug concentration at which the inhibition ellipse intercepted [23].…”

Section: Antifungal Susceptibility Testingmentioning

confidence: 99%

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Implication of efflux pumps and ERG11 genes in resistance of clinical Trichosporon asahii isolates to fluconazole

Abbes

Sellami

Neji

et al. 2021

Journal of Medical Microbiology

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Introduction. Trichosporon asahii has been recognized as an opportunistic agent having a limited sensitivity to antifungal treatment. Hypothesis/Gap Statement. Molecular mechanisms of azole resistance have been rarely reported for Trichosproron asahii. Similar to other fungi, we hypothesized that both ERG11 gene mutation and efflux pumps genes hyper-expression were implicated. Aim. The current work aimed to study the sensitivity of clinical T. asahii isolates to different antifungal agents and to explore their resistance mechanisms by molecular methods including real-time PCR and gene sequencing. Methods. The sensitivity of T. asahii isolates to fluconazole, amphotericin B and voriconazole was estimated by the Etest method. Real-time PCR was used to measure the relative expression of Pdr11, Mdr and ERG11 genes via the ACT1 housekeeping gene. Three pairs of primers were also chosen to sequence the ERG11 gene. This exploration was followed by statistical study including the receiver operating characteristic (ROC) curve analysis to identify a relationship between gene mean expression and the sensitivity of isolates. Results. In 31 clinical isolates, the resistance frequencies were 87, 16.1 and 3.2 %, respectively, for amphotericin B, fluconazole and voriconazole. Quantitative real-time PCR demonstrated that only Mdr over-expression was significantly associated with FCZ resistance confirmed by univariate statistical study and the ROC curve analysis (P <0.05). The ERG11 sequencing revealed two mutations H380G and S381A in TN325U11 (MIC FCZ=8 µg ml−1) and H437R in TN114U09 (MIC FCZ=256 µg ml−1) in highly conserved regions (close to the haem-binding domain) but their involvement in the resistance mechanism has not yet been assigned. Conclusion. T. asahii FCZ resistance mechanisms are proven to be much more complex and gene alteration sequence and/or expression can be involved. Only Mdr gene over-expression was significantly associated with FCZ resistance and no good correlation was observed between FCZ and VCZ MIC values and relative gene expression. ERG11 sequence alteration seems to play a major role in T. asahii FCZ resistance mechanism but their involvement needs further confirmation.

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Section: Discussionsupporting

confidence: 86%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Antifungal Susceptibility Testingmentioning

confidence: 99%

See 2 more Smart Citations

Implication of efflux pumps and ERG11 genes in resistance of clinical Trichosporon asahii isolates to fluconazole

Abbes

Sellami

Neji

et al. 2021

Journal of Medical Microbiology

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“…The ability of Trichosporon species to cause systemic infections is likely associated with the expression of virulence factors, such as extracellular lytic compounds, and, most importantly, biofilms (Montoya et al, 2018), microbial communities surrounded by a polymeric extracellular matrix (Zhao et al, 2017). This structure expresses several mechanisms to escape the action of antimicrobials, as well as to resist physical stress, desiccation, UV radiation, and host immune system (Martinez and Casadevall, 2007;Polke et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Trichosporon asahii and Trichosporon inkin Biofilms Produce Antifungal-Tolerant Persister Cells

Cordeiro

Aguiar

Silva

et al. 2021

Front. Cell. Infect. Microbiol.

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Persister cells are metabolically inactive dormant cells that lie within microbial biofilms. They are phenotypic variants highly tolerant to antimicrobials and, therefore, associated with recalcitrant infections. In the present study, we investigated if Trichosporon asahii and T. inkin are able to produce persister cells. Trichosporon spp. are ubiquitous fungi, commonly found as commensals of the human skin and gut microbiota, and have been increasingly reported as agents of fungemia in immunocompromised patients. Biofilms derived from clinical strains of T asahii (n=5) and T. inkin (n=7) were formed in flat-bottomed microtiter plates and incubated at 35°C for 48 h, treated with 100 μg/ml amphotericin B (AMB) and incubated at 35°C for additional 24 h. Biofilms were scraped from the wells and persister cells were assayed for susceptibility to AMB. Additionally, we investigated if these persister cells were able to generate new biofilms and studied their ultrastructure and AMB susceptibility. Persister cells were detected in both T asahii and T. inkin biofilms and showed tolerance to high doses of AMB (up to 256 times higher than the minimum inhibitory concentration). Persister cells were able to generate biofilms, however they presented reduced biomass and metabolic activity, and reduced tolerance to AMB, in comparison to biofilm growth control. The present study describes the occurrence of persister cells in Trichosporon spp. and suggests their role in the reduced AMB susceptibility of T. asahii and T. inkin biofilms.

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A glucuronoxylomannan-like glycan produced by Trichosporon mucoides

Zimbres

Albuquerque

Joffe

et al. 2018

Fungal Genetics and Biology

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Biofilm formation and antifungal susceptibility of Trichosporon asahii isolates from Mexican patients

Cited by 14 publications

References 31 publications

Implication of efflux pumps and ERG11 genes in resistance of clinical Trichosporon asahii isolates to fluconazole

Implication of efflux pumps and ERG11 genes in resistance of clinical Trichosporon asahii isolates to fluconazole

Trichosporon asahii and Trichosporon inkin Biofilms Produce Antifungal-Tolerant Persister Cells

A glucuronoxylomannan-like glycan produced by Trichosporon mucoides

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