Effect of Four Essential Oils on Cells Release Membrane and Biofilm Formation of Clinical Bacterial Isolated From Oral Infection

Background: Bacterial biofilms forming are current resistant bacterial form to the treatment of oral diseases that colonizes in the gingival and sub-gingival regions of the mouth. The present study aims to screen the anti-biofilm potential and evaluate the effect of four essential oils on cells release membrane. Methods: Seven type isolate bacteria obtained during previous work were screen to select those who had ability to form biofilm using Congo Red Agar method, tube method and crystal violet method. The inhibitory parameter of biofilm forming was determine using microtiter plate method. The effect of essential oil on cell membrane release of each selected bacterial was put in evidence by measuring cellular material that absorb at 260 nm and 280 nm after 0 min, 30 min and 60 min of exposure and confirm by measuring DNA, RNA and proteins release by treated cells on extracellular medium using Nanodrop 1000 spectrophotometer. Results: The crystal violet method shows twelve (12) strong, five (05) moderate and five (05) weak biofilm forming bacteria. The anti-biofilm activity against the oral bacteria who shown that most of essentials oils have activity on different biofilm formation and the MICs ranged from 0.31 mg/mL to 1.25 mg/mL. Concentration of intracellular material released in extracellular medium ranged from 186,56 ± 2,35 ng/µL to 766,6 ± 2,84 ng/µL for DNA, 158,06 ± 1,87 ng/µL to 628,53 ± 2,05 ng/µL for RNA and 695,9 ± 2,11ng/µL to 1125,23 ± 2,15 ng/µL for proteins. Conclusion: This study demonstrates that the selected EOs have a significant anti-biofilm activity, acting on the cell surface and causing the disruption of the bacterial membrane. These EOs are interesting alternative to conventional antimicrobials for the control of oral microorganisms. Keywords: Anti-biofilm activity, Biofilm, oral disease

INVESTIGATING THE ANTIBACTERIAL, ANTIOXIDANT, AND ANTI-INFLAMMATORY ACTIVITIES OF AQUEOUS AND HYDROETHANOLIC EXTRACTS OF OCIMUM BASILICUM AND OCIMUM GRATISSIMUM ON SOME GERMS RESPONSIBLE FOR AEROBIC VAGINITIS

Objective: The present work evaluates the antibacterial, antioxidant, and anti-inflammatory activities of aqueous and hydroethanolic extracts of Ocimum basilicum and Ocimum gratissimum on germs responsible for aerobic vaginitis. Methods: University Teaching Hospital of Yaoundé and Central Hospital of Yaoundé provided the germ (Staphylococcus aureus) and isolates (Enterobacter cloacae and Providencia stuartii). The extracts were obtained by maceration of the plants in water and hydroethanolic system. Phytochemical screening was assessed using the standard method; sensitivity and inhibition tests were carried out on agar medium and microplates in liquid medium. The antioxidant activity of the extracts was evaluated using the 2,2-diphenyl-1-picrilhidrazil (DPPH), 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), ferric reducing antioxidant power assay (FRAP), and β-carotene assays; total polyphenols content was obtained by the Folin Ciocalteu assay; anti-inflammatory activity by denaturation of ovalbumin.  Results: Flavonoids, catechin, and tannins were abundant in the hydroethanolic extracts (56.65±3.89 and 228.94±8.42 mg EAA/g respectively). The extracts were bactericidal for S. aureus and bacteriostatic for P. stuartii and E. cloacae. The hydroethanolic extract of the leaves of O. gratissimum has the best anti-radical activity 23.08 ± 3.12, while that of the leaves of O. basilicum had the best-reducing power (388.36 ± 9.96). The anti-inflammatory activity was found to be significant in the leaf extracts studied with IC50 values ​​of 0.358 ± 0.013 mg/ml for O. basilicum to 0.269 ± 0.008 mg/ml for O. gratissimum, thus justifying their anti-inflammatory properties. The equivalent contents of primary and secondary antioxidants of the extracts were also obtained. Conclusion: The hydroethanolic extracts of Ocimum basilicum and Ocimum gratissimum have antibacterial, antioxidant, and anti-inflammatory properties

Systematic review and meta-analysis of the epidemiology of Lassa virus in humans, rodents and other mammals in sub-Saharan Africa.

Accurate data on the Lassa virus (LASV) human case fatality rate (CFR) and the prevalence of LASV in humans, rodents and other mammals are needed for better planning of actions that will ultimately reduce the burden of LASV infection in sub-Saharan Africa. In this systematic review with meta-analysis, we searched PubMed, Scopus, Africa Journal Online, and African Index Medicus from 1969 to 2020 to obtain studies that reported enough data to calculate LASV infection CFR or prevalence. Study selection, data extraction, and risk of bias assessment were conducted independently. We extracted all measures of current, recent, and past infections with LASV. Prevalence and CFR estimates were pooled using a random-effect meta-analysis. Factors associated with CFR, prevalence, and sources of between-study heterogeneity were determined using subgroup and metaregression analyses. This review was registered with PROSPERO, CRD42020166465. We initially identified 1,399 records and finally retained 109 reports that contributed to 291 prevalence records from 25 countries. The overall CFR was 29.7% (22.3-37.5) in humans. Pooled prevalence of LASV infection was 8.7% (95% confidence interval: 6.8-10.8) in humans, 3.2% (1.9-4.6) in rodents, and 0.7% (0.0-2.3) in other mammals. Subgroup and metaregression analyses revealed a substantial statistical heterogeneity explained by higher prevalence in tissue organs, in case-control, in hospital outbreak, and surveys, in retrospective studies, in urban and hospital setting, in hospitalized patients, and in West African countries. This study suggests that LASV infections is an important cause of death in humans and that LASV are common in humans, rodents and other mammals in sub-Saharan Africa. These estimates highlight disparities between sub-regions, and population risk profiles. Western Africa, and specific key populations were identified as having higher LASV CFR and prevalence, hence, deserving more attention for cost-effective preventive interventions