Detection of ERG11 gene in fluconazole resistant urinary candida isolates

Abstract

Candida species resistant to fluconazole and voriconazole were screened for the presence of ERG11gene by polymerase chain reaction (PCR). Also, the association of this gene with the demonstration of Candida virulence factors; biofilm formation, phospholipase and proteinases activities were studied. A total of 61 Candida isolates were collected from urine specimens. Candida species were identified by API 20 C Aux test. Extracellular phospholipase, secretory aspartyl proteinase and biofilm formation were determined. ERG11 gene was detected by PCR. C. albicans was identified in 34.5%, C. glabrata in 29.5% and C. tropicalis and C. krusei in 18% each. Candida species was resistant to fluconazole and voriconazole in 55.7% and 27.9%, respectively. Seventeen (50%) of fluconazole resistant Candida isolates were sensitive to voriconazole. The most frequently Candida species revealed fluconazole resistance were C. glabrata (47.1%), C. krusei (29.4%), and C. tropicalis and C. albicans (11.8% each). Biofilm formation, phospholipase and proteinase activity were determined in 41.2%, 67.6% and 35.3% of fluconazole resistant Candida isolates, respectively. Erg 11 gene was determined in 82.4% of fluconazole resistant Candida isolates and prominent in C. glabrata (93.75%), followed by C. krusei (90%), C. tropicalis (75%) and C. albicans (25%). Erg 11 gene was detected in 64.7% (11/17) of fluconazole resistant-voriconazole sensitive Candida isolates. Regarding, correlation of Erg11 gene positivity and virulence factors among fluconazole resistant Candida isolates, 34.5% exhibited biofilm formation and 62.1% and 31% showed phospholipase and proteinase activities, respectively. There were statistically significant difference concerning the association of proteinase activities and Erg 11 gene expression among fluconazole resistance Candida isolates (P=0.04). The study emphasizes the high prevalence of Erg11 gene among fluconazole resistant Candida species. There was association between the proteinase activity, fluconazole resistance and the presence of Erg11 among Candida species. Voriconazole maintains better activity towards Candida species and represent an alternative therapy.

Molecular and Associative Evaluation of ERG11, ERG3, CDR1, and SNQ2 Genes Linked to Fluconazole Resistance in Candida glabrata in a Colombian Population

“…Another mechanism of resistance is associated with alterations in the expression and mutations of genes encoding enzymes involved in the ergosterol biosynthesis pathway, such as lanosterol 14-alphademethylase and C-5 desaturase, which is responsible for synthesizing toxic sterols that accumulate in the fungus when exposed to azoles. The ERG11 gene encodes for the enzyme lanosterol 14-alphademethylase and its overexpression and/or mutations are associated with resistance whose biological basis responds to the maintenance of the integrity of the fungal membrane in the presence of azole and to the decrease in the affinity between the azole and the enzyme that serves as a pharmacological target, On the other hand, mutations in the ERG3 gene coding for the C-5 desaturase enzyme have been described as mechanisms associated with resistance, because the enzyme loses activity and stops synthesizing toxic sterols in the presence of azoles, which facilitates the survival of the fungus; At the same time, activation of synthesis routes of constituent compounds of the fungal membrane has been found [17][18][19][20].…”