Study of Antifungal Susceptibility, Virulence Genes and Biofilm Formation in Candida albicans

Abstract

Background: Candida albicans has emerged as an important nosocomial pathogen. The morbidity and mortality associated with this pathogen are related to the presence of virulence genes and antifungal resistance. The objective of the present study was to investigate the prevalence of antifungal resistance, biofilm formation and some virulence genes such as ALS1, PLB1, INT1, SAP1 and HWP1, among clinical isolates of Candida albicans recovered from immunocompromised patients. Methods: The study included one hundred C. albicans isolates identified phenotypically and by a molecular technique using Polymerase Chain Reaction (PCR). The identified C. albicans was further subjected to antifungal study by the microdilution method, biofilm study and molecular study for virulence genes by PCR. Results: The resistance to antifungal drugs, fluconazole, caspofungin and itraconazole was 8% for each of them and for amphotericin B, it was 9%. The prevalence of the studied virulence genes was HWP1 77%, INT1 72%, ALS1 65%, SAP1 65% and PLB1 52%. The biofilm capacity was identified by the microplate method in 58% of C. albicans. The OD was intense in 20 isolates, moderate in 21 isolates and mild in 17 isolates. There was a statistically significant increase in the prevalence of the studied virulence genes INT1, ALS1, HWP1, SAP1 and PLB1 among biofilm forming C. albicans as compared to non-biofilm forming isolates (P=0.0001). Additionally, the resistance to fluconazole, itraconazole and caspofungin was statistically, significantly higher in C. albicans with the capacity to form biofilm as compared to non-biofilm forming C. albicans. Conclusion: The present study highlights the prevalence of resistance to antifungal drugs among C. albicans which are not uncommon. Moreover, there was a high prevalence of INT1, ALS1, HWP1, SAP1 and PLB1 genes in C. albicans. The resistance to antifungal drugs was common among isolates with the capacity to form the biofilm. There was an association between the biofilm formation and virulence genes.

Detection of als1 and hwp1 genes involved in biofilm formation in Candida albicans isolated from catheter associated candiduria.

“…Moreover, Shrief et al in Mansoura, Egypt revealed that the biofilm capacity was identified by the microplate method in 58% of C. albicans isolated from ICU patients with nosocomial infections. The OD was intense in 20 isolates, moderate in 21 isolates and mild in 17 isolates [26]. Similarly, İnci et al in Turkey reported that the slime factor was found to be positive in 34.5% of C. albicans isolates when using the microplate test that 43% of the C. albicans isolates from oral mucosa were capable of forming biofilm using the MTT assay [14].…”

Analysis of Biofilm-Related Genes and Antifungal Susceptibility Pattern of Vaginal Candida albicans and Non-Candida albicans Species

“…Shrief et al reported a frequency of 77% for the HWP1 gene and BioMed Research International 65% for the ALS1 gene of C. albicans isolated from blood and urine cultures. They also described that 58% of C. albicans were capable of biofilm production [48]. The prevalence of the ALS1 and HWP1 genes was detected in 48% and 3.9% of the strains isolated from vaginal samples in Turkish women, respectively [49].…”

“…In Egypt, the biofilm capacity was observed in 58% of Candida albicans isolates from the chemotherapy patients. Also, the prevalence of ALS1 and HWP1 genes among the biofilmpositive C. albicans was 56.9% [48]. Inci et al showed the presence of ALS1 and HWP1 genes in 83.1% and 11.3%, respectively, of biofilm-producing isolates [49].…”

“…They also described that 58% of C . albicans were capable of biofilm production [ 48 ]. The prevalence of the ALS1 and HWP1 genes was detected in 48% and 3.9% of the strains isolated from vaginal samples in Turkish women, respectively [ 49 ].…”

Innate pathogenic traits in oral yeasts

“…As mentioned in the literature, normal flora can affect the health of the host by altering into a pathogenic organism [3]. Pathogenic species possess virulence factors that are associated with enhancing pathogenicity and resisting harsh conditions such as the implication of biofilm resulting in the resistance of yeasts to antifungal drugs [42,43].…”