Microbiological quality and safety of commercialized thalassotherapy products based on marine mud and algae extracts in Tunisia.

A total of 15 samples of thalassotherapy products, distributed in Tunisia in their intact and final state of production, was analyzed to determine their microbiological safety status. The result shows the absence of pathogenic bacteria (Staphylococcus aureus, Candida albicans, Salmonella, Pseudomonas aeruginosa and coliforms). The incidence of contamination by Gram-positive Bacilli (mesophelic bacteria, aerobic and anaerobic spore forming bacteria, anaerobic sulphite-reducing bacteria) was found to be higher in products composed by mud and extract of alga. The biochemical and molecular identification of the major contaminant show that Bacilli were the most covered from 75% of the thalassotherapy products. Mineral analysis (organic matter, Fe, Mg, Ca, Na d K, Al, Si and Ti) shows strong composition on Aluminum and Silica. Cytotoxicity study of six thalassotherapy products and three essential oil extracts (Menthol, Clove and Eucalyptus) did not show any cytotoxic effect. Furthermore, antibacterial acitivity of 5 essentila oils, against 30 isolates of the genus Bacillus and 10 reference strains, has been characterized showing an interesting bactericidal potential of the extract of menthol and Eucalyptus.

The plant-growth-promoting actinobacteria of the genus Nocardia induces root nodule formation in Casuarina glauca.

Actinorhizal plants form a symbiotic association with the nitrogen-fixing actinobacteria Frankia. These plants have important economic and ecological benefits including land reclamation, soil stabilization, and reforestation. Recently, many non-Frankia actinobacteria have been isolated from actinorhizal root nodules suggesting that they might contribute to nodulation. Two Nocardia strains, BMG51109 and BMG111209, were isolated from Casuarina glauca nodules, and they induced root nodule-like structures in original host plant promoting seedling growth. The formed root nodule-like structures lacked a nodular root at the apex, were not capable of reducing nitrogen and had their cortical cells occupied with rod-shaped Nocardiae cells. Both Nocardia strains induced root hair deformation on the host plant. BMG111209 strain induced the expression of the ProCgNin:Gus gene, a plant gene involved in the early steps of the infection process and nodulation development. Nocardia strain BMG51109 produced three types of auxins (Indole-3-acetic acid [IAA], Indole-3-Byturic Acid [IBA] and Phenyl Acetic Acid [PAA]), while Nocardia BMG111209 only produced IAA. Analysis of the Nocardia genomes identified several important predicted biosynthetic gene clusters for plant phytohormones, secondary metabolites, and novel natural products. Co-infection studies showed that Nocardia strain BMG51109 plays a role as a "helper bacteria" promoting an earlier onset of nodulation. This study raises many questions on the ecological significance and functionality of Nocardia bacteria in actinorhizal symbioses.

Application of isolated Lactobacillus sakei and Staphylococcus xylosus strains as a probiotic starter culture during the industrial manufacture of Tunisian dry-fermented sausages.

For decades, lactic acid bacteria has been isolated and selected to be used as starter cultures in meat fermentation for standardization and management of quality of dry-fermented sausage which constitute a considerable challenge. The aim of this study was to evaluate the effect of Lactobacillus sakei strains, isolated from different origins, on qualities of dry-fermented sausages. These last, manufactured with different combinations of starter cultures (L. sakei + Staphylococcus xylosus), were ripened, using the same raw materials and conditions, for 45 days. Samples were collected during this period, and microbiological, physicochemical, fatty acid profile, and sensorial analyses determined. Lactic acid bacteria were the dominant flora during ripening. A desirable PUFA/SFA ratio, corresponding to 1:1.7 (0.6), was detected after 24 days of maturation in sausages inoculated by L. sakei BMG 95 and S. xylosus. Sensory analysis showed that fermented sausages manufactured with L. sakei and S. xylosus had a more desirable odor, flavor, and texture and consequently were preferred overall. In particular, sensory panellists preferred sausages produced with either L. sakei 23K or L. sakei BMG 95 when compared to fermented sausage produced with a commercial starter or no starter at all.

Diversity of Vaginal Lactic Acid Bacterial Microbiota in 15 Algerian Pregnant Women with and without Bacterial Vaginosis by using Culture Independent Method.

INTRODUCTION: Bacterial Vaginosis (BV) is the most common lower genital tract disorder among women of reproductive age (pregnant and non-pregnant) and a better knowledge of Lactobacillus species richness in healthy and infected vaginal microbiota is needed to efficiently design better probiotic products to promote the maintenance of normal flora which will help prevent bacterial vaginosis. AIM: To evaluate and compare the diversity of lactic acid bacterial species in pregnant women with and without BV. MATERIALS AND METHODS: A pilot study was carried out during November-2014 to March-2015 in University Badji Mokhtar, Annaba, Algeria. Vaginal swabs were collected from 15 pregnant women aged between 19 and 35 years (mean 27.6 years; n=15) living in the East of Algeria visiting Gynecology service, hospital Abdallah Nouaouria- El bouni, Annaba. Vaginal samples were gram-stained, and scored by the Nugent method. The cohort included cases of women with healthy "normal" vaginal flora, infected flora with bacterial vaginosis and women with "intermediate" flora. The vaginal LAB community from pregnant women was identified by culture independent method based on Denaturing Gradient Gel Electrophoresis (DGGE), with the 16S rRNA gene sequencing. RESULTS: A majority of LAB affiliated to the genus Lactobacillus was found in "normal" and "intermediate" flora (87.5% and 43.75% respectively), while a majority of LAB affiliated to the genus Enterococcus was identified in women with bacterial vaginosis and intermediate flora (60% and 46.75% respectively). Our results showed that the presence of Lactobacillus iners and Lactobacillus delbruekii promotes stability of the vaginal microbiota. CONCLUSION: This result confirms the findings of previous studies suggesting that the occurrence of predominant Lactobacillus negatively correlates with bacterial vaginosis incidence and their current use as probiotics. Lactobacillus iners and Lactobacillus delbruekii can be defined as critical for defense of the vagina. In addition, Enterococcus feacalis can be considered as an indicator of imbalance of the vaginal ecosystem.

Diversity and antimicrobial properties of lactic acid bacteria isolated from rhizosphere of olive trees and desert truffles of Tunisia.

A total of 119 lactic acid bacteria (LAB) were isolated, by culture-dependant method, from rhizosphere samples of olive trees and desert truffles and evaluated for different biotechnological properties. Using the variability of the intergenic spacer 16S-23S and 16S rRNA gene sequences, the isolates were identified as the genera Lactococcus, Pediococcus, Lactobacillus, Weissella, and Enterococcus. All the strains showed proteolytic activity with variable rates 42% were EPS producers, while only 10% showed the ability to grow in 9% NaCl. In addition, a low rate of antibiotic resistance was detected among rhizospheric enterococci. Furthermore, a strong antibacterial activity against plant and/or pathogenic bacteria of Stenotrophomonas maltophilia, Pantoea agglomerans, Pseudomonas savastanoi, the food-borne Staphylococcus aureus, and Listeria monocytogenes was recorded. Antifungal activity evaluation showed that Botrytis cinerea was the most inhibited fungus followed by Penicillium expansum, Verticillium dahliae, and Aspergillus niger. Most of the active strains belonged to the genera Enterococcus and Weissella. This study led to suggest that environmental-derived LAB strains could be selected for technological application to control pathogenic bacteria and to protect food safety from postharvest deleterious microbiota.