OBJECTIVETo performance susceptibility testing of antifungal agents. Due to the increasing number of resistant strains, susceptibility testing of antifungal agents is gaining importance.

METHODSWe compared the results of standard macrotube dilution reference method with two different microdilution methods, as well as the disc diffusion method in order to test the susceptibility of 150 Candida strains to fluconazole.

RESULTSOverall correlation between microdilution and macrodilution methods was 86%. It was 91% between the Minimal Inhibitory Concentrations obtained from macrodilution and disc diffusion zone diameters.

CONCLUSIONThe disc diffusion test was evaluated as a low-cost, reproducible, and efficient way of assessing the in vitro susceptibility of Candida strains to fluconazole.

Antifungal Agents ; pharmacology ; Candida ; drug effects ; Diffusion ; Fluconazole ; pharmacology ; Microbial Sensitivity Tests ; methods

BACKGROUNDCandida albicans (C. albicans) can become a pathogen causing superficial as well as life-threatening systemic infections, especially in immunocompromised patients. Many phenotypic attributes contribute to its capacity to colonize human organs. In our study, 93 C. albicans isolates from patients of various candidiasis in a hospital of China were surveyed. We aimed to investigate the white-opaque (WO) switching competence, drug sensitivity, and virulence of mating type-like (MTL) a/α isolates.

METHODSInternal transcribed spacer (ITS) gene and the MTL configuration were detected in all the isolates by reverse transcription-polymerase chain reaction. White/opaque phenotype and doubling time of cell growth were determined. The minimum inhibitory concentrations of antifungal agent were measured using broth microdilution method.

RESULTSSixty-four isolates (69.6%) were classified to serotype A, 19 (20.6%) to serotype B, and 9 (9.8%) to serotype C. Moreover, phylogenetic analysis showed that these isolates were divided into four different subgroups of ITS genotypes. Most of our clinical isolates were MTL a/α type, while 6.8% remained MTL a or MTLα type. The frequency of opaque phenotype was 71.0% (66 isolates). Following the guidelines of Clinical and Laboratory Standards Institute M27-A3, all isolates were susceptible to caspofungin and a few (0.6-3.2%) of them showed resistance against amphotericin B, flucytosine, fluconazole, itraconazole, and voriconazole.

CONCLUSIONSFrom these analyses, there were comparatively more C. albicans strains classified into serotype B, and the frequency of opaque phase strains was significant in the clinical isolates from China. Genetic, phenotypic, or drug susceptibility patterns were not significantly different from previous studies. MTL a/α isolates could also undergo WO switching which facilitates their survival.

Amphotericin B ; pharmacology ; Antifungal Agents ; pharmacology ; Candida albicans ; classification ; drug effects ; genetics ; Fluconazole ; pharmacology ; Genotype ; Humans ; Microbial Sensitivity Tests ; Phylogeny

BACKGROUNDVulvovaginal candidiasis (VVC) was a common infection associated with lifelong harassment of woman's social and sexual life. The purpose of this study was to describe the species distribution and in vitroCandidaCandida spp.) isolated from patients with VVC over 8 years.

METHODSSpecies which isolated from patients with VVC in Peking University First Hospital were identified using chromogenic culture media. Susceptibility to common antifungal agents was determined using agar diffusion method based on CLSI M44-A2 document. SPSS software (version 14.0, Inc., Chicago, IL, USA) was used for statistical analysis, involving statistical description and Chi-square test.

RESULTSThe most common strains were Candida (C.) albicans, 80.5% (n = 1775) followed by C. glabrata, 18.1% (n = 400). Nystatin exhibited excellent activity against all species (<4% resistant [R]). Resistance to azole drugs varied among different species. C. albicans: clotrimazole (3.1% R) < fluconazole (16.6% R) < itraconazole (51.5% R) < miconazole (54.0% R); C. glabrata: miconazole (25.6% R) < clotrimazole (50.5% R) < itraconazole (61.9% R) < fluconazole (73.3% R); Candida krusei: clotrimazole (0 R) < fluconazole (57.7% R) < miconazole (73.1% R) < itraconazole (83.3% R). The susceptibility of fluconazole was noticeably decreasing among all species in the study period.

CONCLUSIONSNystatin was the optimal choice for the treatment of VVC at present. The species distribution and in vitroCandida spp. isolated from patients with VVC had changed over time.

Antifungal Agents ; pharmacology ; Candida ; drug effects ; pathogenicity ; Candidiasis, Vulvovaginal ; microbiology ; China ; Clotrimazole ; pharmacology ; Drug Resistance, Fungal ; Female ; Fluconazole ; pharmacology ; Humans ; Itraconazole ; pharmacology ; Miconazole ; pharmacology ; Microbial Sensitivity Tests

Objective: To explore the epidemiological characteristics of sample distribution and antifungal susceptibilities of clinically invasive C. tropicalis isolates from 2017 to 2021 in East China. Methods: Using a retrospective analysis, the East China Invasive Fungal Infection Group (ECIFIG) collected C. tropicalis clinically isolated from 32 hospitals in East China between January 2017 and December 2021. The identification results of the strains were reviewed using mass spectrometry by the central laboratory of the Shanghai East Hospital. The minimum inhibitory concentrations (MICs) of the strains against fluconazole (FLU), voriconazole (VOR), itraconazole (ITR), Posaconazole (POS), isavuconazole (ISA), anidulafungin (ANI), caspofungin (CAS), micafungin (MICA) and 5-fluorocytosine (FCT) were tested by the ThermoFisher CMC1JHY colorimetric microdilution method. The MIC of amphotericin B (AMB) was tested by the broth microdilution method. The MIC results were analyzed based on the clinical breakpoints and epidemiological cutoff values (ECV) published by the Clinical and Laboratory Standards Institute (CLSI) M27 Ed3 and M57 Ed4 documents. Data analysis was conducted using the Kruskal-Wallis test and paired t-test. Results: In total, 305 C. tropicalis isolates were collected. There were 38.0% (116/305) strains isolated from blood, 11.5% (35/305) ascites, 8.9% (27/305) catheter and 8.9% (27/305) drainage fluid. The resistance rate of C. tropicalis to FLU was 32.5%, to VOR was 28.5%, and the cross-resistance rate to FLU and VOR was 28.5%. The wild-type proportions for ITR and POS were 79.3% and 29.2% respectively. There was no significant difference in resistance rates, MIC₅₀, and MIC₉₀ of FLU and VOR, or in the wild-type rates of ITR and POS over five years. More than 95.0% of the isolates were susceptible to echinocandins. However, one strain was identified as being multi-drug resistant. In azole antifungals, voriconazole, itraconazole, posaconazole, and isavuconazole have similar GM MIC values. The GM MIC of fluconazole is significantly higher than that of itraconazole (t=9.95, P<0.05), posaconazole (t=9.99, P<0.05), and voriconazole (t=10.01, P<0.05), Meanwhile, among echinocandins, the GM MIC of ANI was comparable to that of CAS (t=1.17, P>0.05), both of which were significantly higher than MICA (t=11.56, P<0.05; t=4.15, P<0.05). Conclusion: The clinical isolates of C. tropicalis in East China from 2017 to 2021 were relatively susceptible to echinocandins. However, there was consistently high resistance to fluconazole and voriconazole. More intensive efforts should be made on the monitoring of drug resistance in C. tropicalis.
Humans ; Antifungal Agents/pharmacology* ; Fluconazole/pharmacology* ; Candida tropicalis ; Voriconazole/pharmacology* ; Itraconazole/pharmacology* ; Retrospective Studies ; Candida ; China/epidemiology* ; Echinocandins/pharmacology* ; Microbial Sensitivity Tests

Objective: To explore the epidemiological characteristics of sample distribution and antifungal susceptibilities of clinically invasive C. tropicalis isolates from 2017 to 2021 in East China. Methods: Using a retrospective analysis, the East China Invasive Fungal Infection Group (ECIFIG) collected C. tropicalis clinically isolated from 32 hospitals in East China between January 2017 and December 2021. The identification results of the strains were reviewed using mass spectrometry by the central laboratory of the Shanghai East Hospital. The minimum inhibitory concentrations (MICs) of the strains against fluconazole (FLU), voriconazole (VOR), itraconazole (ITR), Posaconazole (POS), isavuconazole (ISA), anidulafungin (ANI), caspofungin (CAS), micafungin (MICA) and 5-fluorocytosine (FCT) were tested by the ThermoFisher CMC1JHY colorimetric microdilution method. The MIC of amphotericin B (AMB) was tested by the broth microdilution method. The MIC results were analyzed based on the clinical breakpoints and epidemiological cutoff values (ECV) published by the Clinical and Laboratory Standards Institute (CLSI) M27 Ed3 and M57 Ed4 documents. Data analysis was conducted using the Kruskal-Wallis test and paired t-test. Results: In total, 305 C. tropicalis isolates were collected. There were 38.0% (116/305) strains isolated from blood, 11.5% (35/305) ascites, 8.9% (27/305) catheter and 8.9% (27/305) drainage fluid. The resistance rate of C. tropicalis to FLU was 32.5%, to VOR was 28.5%, and the cross-resistance rate to FLU and VOR was 28.5%. The wild-type proportions for ITR and POS were 79.3% and 29.2% respectively. There was no significant difference in resistance rates, MIC₅₀, and MIC₉₀ of FLU and VOR, or in the wild-type rates of ITR and POS over five years. More than 95.0% of the isolates were susceptible to echinocandins. However, one strain was identified as being multi-drug resistant. In azole antifungals, voriconazole, itraconazole, posaconazole, and isavuconazole have similar GM MIC values. The GM MIC of fluconazole is significantly higher than that of itraconazole (t=9.95, P<0.05), posaconazole (t=9.99, P<0.05), and voriconazole (t=10.01, P<0.05), Meanwhile, among echinocandins, the GM MIC of ANI was comparable to that of CAS (t=1.17, P>0.05), both of which were significantly higher than MICA (t=11.56, P<0.05; t=4.15, P<0.05). Conclusion: The clinical isolates of C. tropicalis in East China from 2017 to 2021 were relatively susceptible to echinocandins. However, there was consistently high resistance to fluconazole and voriconazole. More intensive efforts should be made on the monitoring of drug resistance in C. tropicalis.
Humans ; Antifungal Agents/pharmacology* ; Fluconazole/pharmacology* ; Candida tropicalis ; Voriconazole/pharmacology* ; Itraconazole/pharmacology* ; Retrospective Studies ; Candida ; China/epidemiology* ; Echinocandins/pharmacology* ; Microbial Sensitivity Tests

BACKGROUND: At present, the clinical breakpoints (CBPs) of both fluconazole and voriconazole are available only for 3 common Candida species in the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) methods. Epidemiological cutoff values (ECVs) were recently applied to both methods to detect the emergence of acquired resistance (i.e., non-wild-type isolates) among 5 common Candida species. METHODS: We performed a nationwide study to determine the fluconazole and voriconazole susceptibility of Candida bloodstream isolates (BSIs) using both the CLSI and EUCAST methods. A total of 423 BSIs of 5 Candida species were collected from 8 hospitals. The azole susceptibilities were assessed on the basis of the species-specific CBPs and ECVs. RESULTS: Of the 341 BSIs of 3 common Candida species (i.e., C. albicans, C. tropicalis, and C. parapsilosis), 0.3% and 0.9%, 0.0% and 1.5% of isolates were categorized as fluconazole and voriconazole resistant according to the CLSI and EUCAST CBPs, respectively. Of 423 total BSIs, 1.4% and 2.6% had fluconazole minimum inhibitory concentrations (MICs) exceeding the ECVs according to the CLSI and EUCAST, respectively; 1.0% and 2.1% had voriconazole MICs exceeding the ECVs according to the CLSI and EUCAST, respectively. Categorical agreement between the methods using ECVs was 98.3% for fluconazole and 98.3% for voriconazole. CONCLUSIONS: The EUCAST and CLSI methods using ECVs provide highly concordant results. Moreover, non-wild-type isolates with possibly acquired azole resistance were rare among the BSIs of 5 common Candida species in Korea.
Antifungal Agents/*pharmacology ; Candida/*drug effects/isolation & purification ; Candidiasis/epidemiology/microbiology ; Drug Resistance, Fungal/drug effects ; Fluconazole/*pharmacology ; Humans ; Microbial Sensitivity Tests ; Pyrimidines/*pharmacology ; Republic of Korea ; Triazoles/*pharmacology

BACKGROUND: At present, the clinical breakpoints (CBPs) of both fluconazole and voriconazole are available only for 3 common Candida species in the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) methods. Epidemiological cutoff values (ECVs) were recently applied to both methods to detect the emergence of acquired resistance (i.e., non-wild-type isolates) among 5 common Candida species. METHODS: We performed a nationwide study to determine the fluconazole and voriconazole susceptibility of Candida bloodstream isolates (BSIs) using both the CLSI and EUCAST methods. A total of 423 BSIs of 5 Candida species were collected from 8 hospitals. The azole susceptibilities were assessed on the basis of the species-specific CBPs and ECVs. RESULTS: Of the 341 BSIs of 3 common Candida species (i.e., C. albicans, C. tropicalis, and C. parapsilosis), 0.3% and 0.9%, 0.0% and 1.5% of isolates were categorized as fluconazole and voriconazole resistant according to the CLSI and EUCAST CBPs, respectively. Of 423 total BSIs, 1.4% and 2.6% had fluconazole minimum inhibitory concentrations (MICs) exceeding the ECVs according to the CLSI and EUCAST, respectively; 1.0% and 2.1% had voriconazole MICs exceeding the ECVs according to the CLSI and EUCAST, respectively. Categorical agreement between the methods using ECVs was 98.3% for fluconazole and 98.3% for voriconazole. CONCLUSIONS: The EUCAST and CLSI methods using ECVs provide highly concordant results. Moreover, non-wild-type isolates with possibly acquired azole resistance were rare among the BSIs of 5 common Candida species in Korea.
Antifungal Agents/*pharmacology ; Candida/*drug effects/isolation & purification ; Candidiasis/epidemiology/microbiology ; Drug Resistance, Fungal/drug effects ; Fluconazole/*pharmacology ; Humans ; Microbial Sensitivity Tests ; Pyrimidines/*pharmacology ; Republic of Korea ; Triazoles/*pharmacology

OBJECTIVETo establish a model of Candida biofilm and to explore its characteristics, ultrastructure, influences by saliva and serum, and sensitivity to antifungal agents.

METHODSEvaluations of the in vitro growth kinetics, influences by saliva and serum, and sensitivity to antifungal agents of Candida biofilm were performed with the abated tetrazolium salt XTT method on a 96-well microtire petri dish. The ultrastructure of Candida biofilm was observed under Confocal Laser Scanning Microscope (CLSM).

RESULTSThe bioactivity of Candida biofilm increased with culturing time and serum could obviously increase the action of biofilm. The Candida biofilm was significantly resistant to routine antifungal agents.

CONCLUSIONThe Candida cells adhered in biofilms are significantly different in morphology from those in suspension and are resistant to routine antifungal agents such as Amphotericine B, Fluconazole and Itraconazole.

Amphotericin B ; pharmacology ; Antifungal Agents ; pharmacology ; Biofilms ; drug effects ; Candida ; drug effects ; ultrastructure ; Drug Resistance, Fungal ; Fluconazole ; pharmacology ; Itraconazole ; pharmacology ; Microbial Sensitivity Tests ; Microscopy, Confocal

Abstract: Our previous work revealed berberine can significantly enhance the susceptibility of fluconazole against fluconazole-resistant Candida albicans, which suggested that berberine has synergistic antifungal activity with fluconazole. Preliminary SAR of berberine needs to be studied for the possibility of investigating its target and SAR, improving its drug-likeness, and exploring new scaffold. In this work, 13-substitutited benzyl berberine derivatives and N-benzyl isoquinoline analogues were synthesized and characterized by 1H NMR and MS. Their synergetic activity with fluconazole against fluconazole-resistant Candida albicans was evaluated in vitro. The 13-substitutited benzyl berberine derivatives 1a-1e exhibited comparable activity to berberine, which suggested that the introduction of functional groups to C-13 can maintain its activity. The N-benzyl isoquinolines, which were designed as analogues of berberine with its D ring opened, exhibited lower activity than berberine. However, compound 2b, 2c, and 4b showed moderate activity, which indicated that berberine may be deconstructed to new scaffold with synergistic antifungal activity with fluconazole. The results of our research may be helpful to the SAR studies on its other biological activities.
Antifungal Agents ; pharmacology ; Berberine ; pharmacology ; Candida albicans ; drug effects ; Drug Resistance, Fungal ; Drug Synergism ; Fluconazole ; pharmacology ; Isoquinolines ; pharmacology ; Microbial Sensitivity Tests

OBJECTIVETo investigate the effects of ethyl acetate extract of Huanglian Jiedu decoction (EAHD) , alone and in combination with fluconazole (FLZ) on FLZ-resistant Candida albicans.

METHODThe minimum inhibitory concentrations (MIC) and sessile MIC80 (SMIC80) of EAHD and FLZ to FLZ-resistant C. albicans were determined by CLSI M27-A3 microdilution method, and the synergy of EAHD combined with FLZ were examined by the checkerboard microdilution assay. Agar plate-method was adopted to observe the rate of antifungal activity according to time-kill curve. HPLC and qRT-PCR were utilized to evaluate the changes of ergosterol content and expressions of related genes, respectively.

RESULTMICs of EAHD ranged from 156 to 1,250 mg · L(-1), those of FLZ from 256 to above 2,048 mg · L(-1) with FICI approximate 0.066 in combination; SMIC80 of EAHD were higher than 1,250 mg · L(-1), SMIC80 of FLZ were higher than 512 mg · L(-1) and up to above 2,048 mg · L(-1). Combination group also showed synergy effect except one group showing addition effect. The results of T-K experiment also confirmed obviously fungicidal effect when treated for 12 h. When compared with control groups, the ergosterol was reduced 85% and 50% in the treatments of combination and EAHD alone by HPLC, respective- ly. The expressions of ERG1, ERG2, ERG6, ERG7 and ERG11 were upregulated, and ACS1, ACS2, MET6 were downregulated when exposed to FLZ. The expressions of the above genes were downregulated by treatment of EAHD. The expressions of ERG2, ERG6, ERG11 were upregulated, while ERG1, ERG7, ACS1, ACS2, MET6 were downregulated in combination group.

CONCLUSIONThe combination of EAHD and FLZ exhibited synergy against FLZ-resistant C. albicans through decreasing the synthesis of ergosterol, and resulting in the breakage of cell membrane.

Antifungal Agents ; pharmacology ; Candida albicans ; drug effects ; growth & development ; metabolism ; Drug Resistance, Fungal ; drug effects ; Drug Synergism ; Drugs, Chinese Herbal ; pharmacology ; Ergosterol ; biosynthesis ; Fluconazole ; pharmacology ; Microbial Sensitivity Tests