Evaluation of antibacterial effects of catechin and EDTA on planktonic and biofilm cells of Pseudomonas aeruginosa

Aims: Today, bacterial biofilms contribute to 65% of nosocomial infections worldwide. One of the most common pathogens that can form biofilm is Pseudomonas aeroginusa. Therefore, the present study was aimed to evaluate the antimicrobial effects of catechin and ethylenediaminetetraacetic acid (EDTA) on planktonic and biofilm cells of P.aeruginosa standard strain. Methodology and results: Standard strains of P. aeruginosa (ATCC 27853) were cultivated in nutrient agar medium for 24 h at 37 °C. The MICs values of EDTA, catechin and imipenem antibiotics on P. aeruginosa were determined with micro dilution test. Then, the biofilm of this bacterium was grown and finally the influences of these agents on biofilm inhibition were evaluated by colorimetric MTT and ATPase release assays. One way analyses of variance and then Fisher's least significant difference test were carried out to compare the different groups. The MIC values of catechin and EDTA on P. aeruginosa were 7.24 and 24.92 (μg/mL), respectively. Colorimetric assay with MTT showed that EDTA, and catechin inhibited biofilm formation significantly. ATPase assay indicated that the amount of released ATP from EDTA and catechin groups were significantly lower than the control group. Also, there was a significant difference between the EDTA and catechin groups with respect to the amount of the released ATP. Conclusion, significance and impact of study: Our findings showed that EDTA and catechin can inhibit the growth of planktonic and biofilm cells of P. aeruginosa. From the results of the present study, we suggest using these agents to reduce or inhibit bacterial contamination of medical devices.

[Expression of candida albicans ALS 2 and ALS 9 genes isolated from women with vaginal candidiasis by RT-PCR]

Approximately three-fourths of women experience an episode of vaginal candidiasis. Candida albicans[C. albicans] is the etiological agent in over 80% of cases. C. albicans has numerous virulence factors such as the agglutinin-like sequence [ALS] genes which code the large glycoprotein family that has a role in the adherence of Candida. The present study aims to evaluate expressions of the ALS 2, 9 genes in C. albicans which have been isolated from vaginal candidiasis. We collected 150 wet vaginal swabs from patients diagnosed with vaginal candidiasis. Samples were cultured on sabouraud dextrose and CHROMagar for morphological analysis. Then, DNA was extracted by glass bead and lysis buffer. We performed RFLP-PCR to confirm the presence of C. albicans. For investigation of semiquantitative expression of ALS2 and ALS9 genes, we performed RT-PCR by using specific primers. From 55 clinical isolates of C. albicans, 36.36% expressed both the ALS2 and ALS9 genes. There were 23 [41.81%] isolates that expressed only the ALS2 gene and 21 [38.1%] expressed the ALS9 gene. Expressions of the ALS9 [41.8%] and ALS 2 [38.1%] genes in Candida isolates may indicate that these genes play a critical role in adhesion and biofilm formation of vaginal infection. However the presence of both genes in 36.36% of the isolates suggests a positive role for these genes in augmentation of their activities.