Biofilm formation of Candida Spp. isolated from the vagina and antibiofilm activities of lactic acid bacteria on the these Candida Isolates

Background: In this study, it was aimed to investigate the effects of bacterial cells and cell-free filtrates of Lactobacillus acidophilus 8MR7 and Lactobacillus paracasei subspecies paracasei 10MR8 on the biofilm formation of 3 Candida tropicalis, 3 C. glabrata and 12 C. albicans isolated from the vagina and identified their virulence factors. Methods: Haemolytic activities esterase activities, and phospholipase activities as virulence factors of Candida strains were determined. Biofilm formations of these isolates were determined by Congo Red agar and microtitration plate method. Anti-biofilm activities of bacterial cells and cell-free filtrates of L. acidophilus 8MR7 and L. paracasei subspecies paracasei 10MR8 on Candida isolates were determined by the microtitration plate method. Results: Bacterial cells of L. acidophilus 8MR7 and L. paracasei subspecies paracasei 10MR8 were not very effective in the in- hibition of biofilm, whereas it has been observed that the cell-free filtrates of these bacteria inhibit the formation of biofilms of Candida strains. Although the main mechanism for inhibiting the formation of Candida spp. biofilm is the competition for adhesion, it is concluded that the substances contained in the cell-free filtrates of lactic acid bacteria are also important. Conclusion: These isolates promise hope as potential bacteria that can be used for anti-adhesion purposes in health-care materials. Keywords: Lactobacillus acidophilus; L. paracesei subspecies paracesei; vagina; biofilm.

Miniaturized Fluorogenic Assays for Enumeration of E. coli and Enterococci in Marine Water

To detect E. coli, 4-methylumbelliferyl α-D-glucuronide (MUG) was incorporated into a modified Al-broth. To detect enterococci, 4-methylumbelliferyl α-D-glucoside (MUD) was incorporated into a selective medium. To each well of a sterile 96-well microtitration plate, 100 µl of media was added, air dried, covered with sterile tape and stored at 4°C. To enumerate the indicator bacteria using this method, 200 µ1 of diluted or undiluted water was added to wells with MUG and MUD media. The plates were incubated for 36-40 hours at 44°C and observed in the dark for fluorescence by UV light (366nm). Fifty subsurface marine waters from four areas were examined. The recovery rate of the fluorogenic assays is equal or superior to 3-tubes MPN and membrane filtration. The microtitration plate with MUG is more specific for E. coli than the membrane filtration. A 87.4 % confirmation rate was observed with the fluorogenic assay compared to a 31.7 % false-positive rate with membranes. For the enterococci, the analysis of 23 English Channel and North Sea samples indicated that the fluorogenic assay and the standard methods had the same specificity (<5 % of false-positive on 107 strains identified). In contrast, the microtitration plate with MUD showed, by far, the best specificity on 13 Mediterranean samples. A 100 % confirmation rate was observed with the fluorogenic assay while 44 % and 63 % false-positive rates were observed with 3 tubes MPN and MF respectively.