| Candida albicans is the most common conditions of pathogenic fungi, due to extensive use of antifungal drugs,leading to the increase in resistant strains,the mechanism of resistance on Candida albicans is still not entirely clear.Cyanide-resistant respiration is a kind of respiration which is free of cyanide inhibition,it was commonly found in many plants and some fungi, algae,the cyanide-resistant respiration will increase under the adversity threaten.Antifungal agents as a threaten of Candida albicans,the impact for cyanide-resistant respiration has little been reported at home and abroad.Therefore,this experiment select different Candida albicans strains of Lanzhou city to determined resistance,RAPD type and cyanide-resistant respiration,explore the drug resistance of Candida albicans and its relationship with cyanide-resistant respiration.It Provide experimental evidence for drug resistance mechanisms of Candida albicans and have some inspiration for clinical treatment,diagnosis,and drug development.Collecting 37 strains of Candida albicans from the clinical and through isolation and identification proved to be Candida albicans.①Determinated the drug resistance of 37 strains Candida albicans with the fungal susceptibility determination kit and judged the results by observing the color changes of each hole on the determination board;②Random primer PCR(RAPD-PCR)amplified the DNA of 20 strains Candida albicans,recorded the result using GIS2010 gel image processing system,analyzed the correlation of RAPD band pattern with drug resistance;③To choose the five drug-resistant strains and the five sensitive strains,Cyanide-resistant respiration is determined using Clark-type oxygen electrode at 30℃;④Determinating the growth situation of Candida albicans under potassium cyanide concentration of 0,0.5 mM,1.0 mM,2.0mM using spectrophotometer.Statistics is dealed with statistical software of SPSS 11.5, the experimental results are indicated with mean±standard deviation ( x±S).Amang the groups of drug-resistant strains and sensitive strains significant difference of cyanide-resistant respiration were showed by (?) test, The results were considered when P＜0.05 that the difference is statistically significant. The results are as follows:1. Candida albicans susceptibility test resultsLanzhou city Candida albicans resistance rate of econazole is the highest,reaching 54.1%,the resistance rate of itraconazole is lower of 5.4%,and the resistance rates of miconazole and fluconazole were 2.7%,other 3 kinds of drugs without resistance.2. The cyanide-resistant respiration rate of Candida albicansThe Candida albicans of 20 strains different drug susceptibility was amplified by PCR amplification using two kinds of primers KIT A3 and KIT A9 and obtained the RAPD banding patterns,which had good stability.The Candida albicans of 20 strains different drug susceptibility was amplified by PCR amplification using the primers KIT A3 and obtained the RAPD banding patterns,which had 5 species.The RAPD banding patterns of the primer KIT A9 had a total of 8 species.Drug-resistant strains and sensitive strains are indicative of the polymorphism of the genotype,different drug-resistant Candida albicans was no difference between the RAPD banding patterns.That understand the resistance of Candida albicans has no correlation with genotypes.3. RAPD-PCRThe cyanide-resistant respiration rate of drug-resistant Candida albicans mean 17.56±6.75nmol/min/OD620,of sensitive Candida albicans mean 7.99±5.80nmol/min/OD620,the cyanide-resistant respiration rate of drug-resistant Candida albicans was significantly higher,and the proportion of the cyanide-resistant respiration of drug-resistant strains to total respiration rate was significantly higher than susceptible strains (P<0.05),and has a statistically significant.4. The impact of Potassium cyanide for the growth and the drug resistance of candida albicansWhen adding the low concentrations and the middle concentration potassium cyanide,it have little effect on the growth of Candida albicans.and the growth slow slightly when compared to without potassium cyanide and the growth peak is slightly lower in logarithmic growth phase and the plateau period;adding high concentrations of potassium cyanide was clearly hampered the growth of Candida albicans.but the growth had not completely arrest,only logarithmic growth phase delayed and reduced the growth of the peak.The presence of 1mM potassium cyanide,both sensitive and resistant strains has increased in the drug resistance,the change rates of resistance were 60% and 80% Respectively,but the change in resistance of resistance group and sensitive groups was no significant difference.The results show that:37 strains of Candida albicans isolated in Lanzhou city,have the highest resistance against econazole,up to 54.1%, these provide the Preliminary basis for the prevention and control the resistance in the region.The DNA polymorphism of Candida albicans is so rich and genotyping is clear,it has been confirmed that there is no correlation between resistance and RAPD banding patterns,this shows that drug resistance may be not a genetic result.Cyanide-resistant respiratory of Candida albicans resistant strains was higher than susceptible strains and the induction of cyanide-resistant respiration can changed Candida albicans drug resistance,show the resistance of Candida albicans is related to cyanide-resistant respiration pathway,and cyanide-resistant respiration may be another new mechanism for Candida albicans resistance,and provides a new breakthrough for clinical to solve drug resistance problem.
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