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Bacterial Attachment and Biofilm Formation on Biomaterials
Published in Nihal Engin Vrana, Biomaterials and Immune Response, 2018
As the majority of different polymers is extensively used in other medical products like blood and urinal catheters, studies were made to determine to what extent indigenous bacteria, lactobacilli, could colonise prosthetic devices in vivo and in vitro and could attach to specific polymer surfaces in vitro. Intrauterine devices (IUDs) are such a class of medical devices, which are continuously exposed to periodic and extreme conditions, shifting from more to less acidic or anaerobic, and linked with the cervical and vaginal flora, whose composition and contamination level are hardly predictable [139]. “Normal” vaginal flora typically shows a predominance of Lactobacillus spp, believed to promote a healthy milieu by providing numerical dominance and by producing lactic acid to maintain an acid environment, inhospitable to many bacteria [140,141]. Lactobacilli also produce hydrogen peroxide (H2O2), antibiotic toxic hydroxyl radicals, bacteriocins and probiotics [142,143]. In one study, polyethylene IUDs in place for two years were removed from six women who were asymptomatic and free of signs of cervical or uterine infection [144]. Lactobacilli were found well attached to the IUDs, demonstrating that bacterial biofilms consisting of indigenous bacteria can occur on prosthetic devices without inducing a symptomatic infection. In vitro studies for polyethylene specimens found well-documented lactobacilli strains L. acidophilus T-13, L. casein GR-1, GR-2 and RC-17 and L. fermentum A-60. These organisms were found to adhere to IUDs and polymer urinary catheters within 24 hours.
Dendrimers as a Candidate for Microbicide in Prevention of HIV-1 Infection in Women: Steps toward Their Clinical Evaluation
Published in Costas Demetzos, Stergios Pispas, Natassa Pippa, Drug Delivery Nanosystems, 2019
Daniel Sepúlveda-Crespo, Jose Luis Jiménez-Fuentes, María Angeles Muñoz-Fernández
To determine the working concentrations for the different dendrimers, cell viability and 50% toxic concentration (TC50) will be measured using commercial assays. Two commercial reagents that use a colorimetric method for determining cell viability can be utilized. MTT and MTS assays require active mitochondria. Moreover, these assays measure the mitochondrial activity changing the yellow substrate that is cleaved by living cells to yield a dark-blue formazan product, not changing in case of cell toxicity. A second method to study the toxicity of the compound in the cells is using the 7-aminoactinomycin D (7-AAD) assay. 7-AAD is a fluorescent compound with a strong affinity for DNA that intercalates in double-stranded DNA. Such cells with compromised membranes will stain with 7-AAD, while in live cells with intact cell membranes the 7-AAD will not intercalate into the DNA. Another important point in the use of a vaginal microbicide is that the compound should not alter the normal vaginal flora or have spermicidal activity. Normal vaginal flora consists of different Lactobacillus species and other bacteria associated with fungal or bacterial vaginosis, like Candida albicans, Neisseria gonorrhoeae, or Gardnerella vaginalis [109]. It is important that the normal sperm survival is not altered by the use of the microbicide. The progressive motility of the sperm has to be measured using the sperm survival index, calculated from changes in progressive motility compared with a control condition. Finally, to the stability of the compounds, it is important that they can maintain their antiviral characteristics in an acidic medium, like that present in the human vagina (pH ≈ 4–5.8). An acid pH is necessary for natural protection in the vagina against pathogens. Thereby, it is important to dissolve the compounds in an acidic medium and treat different cell lines with it to probe its stability.
Protective effect of crop by-products on Lactobacillus gasseri H87 during freeze-drying and storage
Published in Drying Technology, 2023
YanJun Qu, ChangHao Yu, TianJun Gan, BaoQi Huang, ShuYuan Huang, Jing Yu, Ping Song
Therefore, the use of probiotics containing beneficial lactobacilli is a promising alternative to prevent or treat urogenital tract infections. Genital and urinary infections are related to the imbalance of vaginal flora, especially to dysbiosis of beneficial lactobacilli in the vagina.[6] Hence, probiotics containing beneficial lactobacilli can help keep the balance of vaginal microecology and maintain the dominant position of vaginal lactobacilli. This represents a promising alternative method to prevent or treat genital and urinary infections, which has been widely investigated in recent years.