1,721,068 research outputs found
Lactobacilli as Anti-biofilm Strategy in Oral Infectious Diseases: A Mini-Review
Full text linkThe spread of biofilm-related diseases in developed countries has led to increased mortality rates and high health care costs. A biofilm is a community of microorganisms that is irreversibly attached to a surface, behaving very differently from planktonic cells and providing resistance to antimicrobials and immune response. Oral diseases are an excellent example of infection associated with the formation of highly pathogenic biofilms. It is generally accepted that, when the oral homeostasis is broken, the overgrowth of pathogens is facilitated. Among them, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans are the main etiological agents of periodontitis, while Streptococcus mutans is strongly associated with the onset of dental caries. Other microorganisms, such as the fungus Candida albicans, may also be present and contribute to the severity of infections. Since the common antibiotic therapies usually fail to completely eradicate biofilm-related oral diseases, alternative approaches are highly required. In this regard, the topical administration of probiotics has recently gained interest in treating oral diseases. Thus, the present mini-review focuses on the possibility of using Lactobacillus spp. as probiotics to counteract biofilm-mediated oral infections. Many evidence highlight that Lactobacillus living cells can impede the biofilm formation and eradicate mature biofilms of different oral pathogens, by acting through different mechanisms. Even more interestingly, lactobacilli derivatives, namely postbiotics (soluble secreted products) and paraprobiotics (cell structural components) are able to trigger anti-biofilm effects too, suggesting that they can represent a novel and safer alternative to the use of viable cells in the management of biofilm-related oral diseases
THE HEALTH-PROMOTING EFFECT OF EXTRACELLULAR VESICLES RELEASED BY VAGINAL LACTOBACILLI
No full textLactobacilli (LB) species dominate the vaginal microflora performing a first line defence against infections (1).
Lactobacilli metabolites mediate the health-promoting effect acting as antimicrobials or are used for quorum-sensing
and cross-talk communication (2). In this sense, extracellular vesicles (EVs) from LB demonstrate an antimicrobial
activity (3,4), modulate host’s nervous and immune system (5) and induce apoptosis in cancerous liver
cells (6). Notably, EVs derived from vaginal LB isolates reduce HIV-1 infection (7). Here, we investigate the
health-promoting activity of EVs produced by two strains of LB isolated from human vagina (L. gasseri BC12
and L. crispatus BC5) in terms of anti-adhesive effect on pathogens and pro-adhesive effect on LB. EVs were
recovered from LB cultures by ultracentrifuge cycles and yield (1010 EVs/mL), size (90-150 nm diameter) and
protein content were characterized. Adhesion assays, performed on HeLa cells monolayer, demonstrated that
LB-EVs were able to reduce at least 25% the adhesion of all pathogens tested: Escherichia coli, Staphylococcus
aureus, Enterococcus faecalis and Streptococcus agalactiae. Moreover, LB-EVs stimulated more than 26%
the adhesion of all LB strains, including the same producer strains and two other vaginal isolates belonging to
the same species (L. gasseri BC9, BC13 and L. crispatus BC1, BC3). L. gasseri BC12 EVs demonstrated the
best health-promoting profile. These results highlighted that the barrier effect exerted by lactobacilli can be
mediated by EVs released in the vaginal environment. This opens to the hypothesis of using postbiotics from
human vaginal bacteria as a new strategy to prevent/treat human infections
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Biotechnological Valorization of Brewer's Spent Grains and Grape Pomace to Obtain Functional Ingredients for Food Formulations
No full textGenotypic and phenotypic characterization of Lactobacillus strains with antipathogenic activities
No full textLactobacillus crispatus BC5 and Lactobacillus gasseri BC12 possess antipathogenic activities that makes them good candidates as probiotics. Indeed, it has been demonstrated that these Lactobacilli can carry out a fungistatic and fungicidal activities against Candida albicans, inhibit the Chlamydia trachomatis infectivity, reduce the Neisseria gonorrhoeae viability and inhibit HIV-1 replication.
The aim of this study is to characterize L. crispatus and L. gasseri from genotypic and phenotypic point of views.
Whole genome sequencing was performed followed by gene annotation, genome comparison and single gene analysis, with a specific focus on genes involved in antibiotic resistance and production of antimicrobial compounds. Phenotypic characterization was performed using Phenotype Microarray, revealing carbon and nitrogen sources used by these two strains as well as their specific sensitivity to several drugs and chemical compounds. Functional assays demonstrated the capacity of Lactobacillus biosurfactants to eradicate and inhibit the biofilm formation of methicillin resistant S. aureus (MRSA). Taken together, these results demonstrate that L. crispatus and L. gasseri having possible biotechnological applications, in particular, for the treatment and/or prevention of pathogen infections
Development of soy-yoghurts, containing functional vaginal lactobacilli and their investigation after digestion using postmenopausal donors
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Lactobacillus crispatus interferes with Chlamydia trachomatis infectivity through modulation of integrin exposure in cervical cells
No full textIn women, urogenital CT infections are often asymptomatic, thus remaining unnoticed and untreated. This can lead to complications and sequelae including pelvic inflammatory disease, tubal infertility and ectopic pregnancy (1, 2). A normal vaginal microbiota, dominated by lactobacilli, is crucial for the prevention of several urogenital and sexually transmitted infections, including Chlamydia (3, 4, 5). This aspect is strengthened by the demonstration that in case of bacterial vaginosis, a clinical condition characterized by the depletion of lactobacilli, a higher risk of STI transmission and acquisition is reported (6).
This study aimed to elucidate the molecular bases of the interaction among lactobacilli, Chlamydia trachomatis and epithelial cells. We evaluated the capacity of lactobacilli cells and supernatants to interfere with C. trachomatis infectivity in HeLa cells, by means of competition, exclusion and displacement mechanisms. Lactobacilli cells were the most active fraction, by means of an exclusion strategy. We investigated the potential mechanism of protection in Lactobacillus crispatus BC5 (model strain), and we demonstrated that the incubation of HeLa cell line with BC5 cells induces important modifications al the level of the epithelial plasma membrane, by altering lipid composition and α5 integrin subunit exposure. When α5 integrin subunits were masked by a specific blocking antibody, Chlamydia infection was precluded. α5 integrin subunit is thus crucial for the pathogen penetration into HeLa cells, and the anti-Chlamydia activity of BC5 can be directly linked to membrane properties modifications in epithelial cells. In conclusion, we identified a potential molecular mechanism at the basis of the protection exerted by Lactobacillus against the sexually transmitted pathogen Chlamydia trachomatis, getting insights into the role of the vaginal microbiota for the woman’s health
Exopolysaccharides released by vaginal Lactobacillus strains: chemical characterization and modulation of biofilm formation.
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