ABSTRACT
Objective To evaluate the application of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) technology in the identification of filamentous fungi,and analyze the susceptibility of filamentous fungi to commonly used antibiotics.Methods A total of 100 strains of filamentous fungi were collected and identified rapidly by MALDI-TOF MS.The obtained results were compared with those from microscopic examination.The susceptibility of filamentous fungi was detected by the Etest method.Results Among 100 strains of filamentous fungi identified by MALDI-TOF MS,61 reached to the species level(score≥2.000),36 to the genus level(score between 1.700 and 1.999),and 3 failed to be identified (score ＜ 1.700).There was inconsistent results for one strain of filamentous fungi between MALDI-TOF MS and microscopic examination.The MIC90 of amphotericin B against Epidermophytonfloccosum was 0.19 μg/mL,while that against Aspergillus flavus was above 32 μg/mL.The MIC90 of itraconazole against Trichophyton tonsurans,Microsporum canis and Epidermophytonfloccosum were all below 0.38 μg/mL,while that against Aspergillus niger was above 32 μg/mL.The MIC90 of fluconazol were above 256 μg/mL for most of strains.The MIC90 of voriconazole and caspofungin against Aspergillus fumigatus,Aspergillus flavus,Aspergillus niger,Trichophyton rubrum,Trichophyton tonsurans and Microsporum canis were ≤0.38 μg/mL and ≤ 1 μg/mL,respectively.Conclusion The MALDI-TOF MS technology may be used to identify the filamentous fungi isolated from clinical specimens quickly,accurately and high-throughput.Voriconazole and caspofungin have effective anti-filamentous fungi activity.
ABSTRACT
Objective To explore the different apoptotic gene expressions and apoptotic signaling transduction of human rhabdomyosarcoma (RD) cells infected by enterovirus 71 (EV71) in different stage.Methods The survival of EV71-infected RD cells was observed by trypan blue staining.The apoptotic morphology and rates of RD cells were surveyed and detected by Annexin V-FITC/PI staining and flow cytometry,respectively.PCR array was employed to analyze 88 apoptotic gene expressions from EV71-infected RD cells at 8 h and 20 h postinfection (p.i),respectively.Results After RD cells were infected with EV71 (MOI =5) at 8 h p.i,the viability was significantly decreased.Flow cytometry data demonstrated that the apoptotic rates of EV71-infected RD cells had increased to 18.0％ and 19.1％ at 20 h p.i in early and later stage respectively.RT-PCR array studies revealed significant variations in the expression of apoptotic genes.Among 88 genes,only the expression of IFN-β1 was upregulated 5.22 folds,whereas 47 genes including ACIN1,Akt,Apaf1,caspase and CIDEB were found to be downregulated that were lower than 2 folds at 8 h p.i.However,28 genes including FasL,CD40L,TNF,caspase-10 and caspase-3 were induced more than 2 folds after EV71 infection at 20 h.Conclusion The downregulation of apoptosis-related genes is associated with viral apoptosis-suppressing effect in RD cells in the early stage of EV71 infection.The death receptor signaling pathways including Fas/FasL and TNF/TNFR are activated to induce cell apoptosis in the late stage of EV71 infection.Moreover,host cell can also inhibit apoptosis by regulating signal pathway of CD40/CD40L,NF-κB/RelA and PI3K/Akt activation.