Identification of the first bacteriocin isolated in Lebanon extracted via a modified adsorption-desorption method and its potential food application

Introduction: The raw goat milk is considered as a good source of novel bacteriocinogenic lactic acid bacteria (LAB) strains. Method: The bacteriocin, which named enterocin CMUL20-2 was secreted by Enterococcus faecium CMUL20-2. This bacterial strain was originally isolated from raw goat’s milk, was extracted by using a modified adsorption-desorption method and purified via RP-HPLC. antimicrobial activity was tested against several pathogenic and spoilage microbes. Results: The enterocin CMUL20-2 showed a strong adsorption on cell wall of producer strain even in acidic environment which facilitate its extraction in only two simple steps. The recovered purified enterocin has decreased procedure time and diminished the number of undesirable molecules present in Rogosa and Sharpe (MRS) broth. The recovered enterocin showed antimicrobial activity against several foodborne pathogenic and spoilage microbes. Conclusion:  The recovered enterocin was able to tolerate a variety of food chain conditions such as high temperature, pH and storage stability, and it can be a good candidate to protect food from spoilage microbes &nbsp

Functional and genomic characterization of ligilactobacillus salivarius TUCO-L2 isolated from lama glama milk: a promising immunobiotic strain to combat infections

Potential probiotic or immunobiotic effects of lactic acid bacteria (LAB) isolated from the milk of the South American camelid llama (Lama glama) have not been reported in published studies. The aim of the present work was to isolate beneficial LAB from llama milk that can be used as potential probiotics active against bacterial pathogens. LAB strains were isolated from llama milk samples. In vitro functional characterization of the strains was performed by evaluating the resistance against gastrointestinal conditions and inhibition of the pathogen growth. Additionally, the adhesive and immunomodulatory properties of the strains were assessed. The functional studies were complemented with a comparative genomic evaluation and in vivo studies in mice. Ligilactobacillus salivarius TUCO-L2 showed enhanced probiotic/immunobiotic potential compared to that of other tested strains. The TUCO-L2 strain was resistant to pH and high bile salt concentrations and demonstrated antimicrobial activity against Gram-negative intestinal pathogens and adhesion to mucins and epithelial cells. L. salivarius TUCO-L2 modulated the innate immune response triggered by Toll-like receptor (TLR)-4 activation in intestinal epithelial cells. This effect involved differential regulation of the expression of inflammatory cytokines and chemokines mediated by the modulation of the negative regulators of the TLR signaling pathway. Moreover, the TUCO-L2 strain enhanced the resistance of mice to Salmonella infection. This is the first report on the isolation and characterization of a potential probiotic/immunobiotic strain from llama milk. The in vitro, in vivo, and in silico investigation performed in this study reveals several research directions that are needed to characterize the TUCO-L2 strain in detail to position this strain as a probiotic or immunobiotic that can be used against infections in humans or animals, including llama.Fil: Quilodrán Vega, Sandra. Universidad de Concepción; ChileFil: Albarracín, Leonardo Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología; Argentina. Tohoku University; JapónFil: Mansilla, Flavia Ivana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Tohoku University; JapónFil: Arce, Lorena Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina. Tohoku University; JapónFil: Zhou, Binghui. Tohoku University; JapónFil: Islam, Md Aminul. Tohoku University; Japón. Bangladesh Agricultural University; BangladeshFil: Tomokiyo, Mikado. Tohoku University; JapónFil: Al Kassaa, Imad. Lebanese University. Faculty of Public Health; LíbanoFil: Suda, Yoshihito. Miyagi University; JapónFil: Kitazawa, Haruki. Tohoku University; JapónFil: Villena, Julio Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Tohoku University; Japó

Screening and characterization of antiviral and probiotic properties of novel lactic acid bacteria from human vaginal origin

Dans ce travail, nous avons déterminé la composition de la flore vaginale d'un échantillon signatificatif de femmes Libanaises, puis évaluer l’effet antagoniste des souches lactiques notamment des lactobacilles contre certains pathogènes vaginales. Ainsi, sur les 135 prélèvements effectués, 53 isolats ont été identifiés par les méthodes de galerie API50 CH et pyroséquençage des régions variables (V1 et V2) du gène ADNr 16S. Les résultats obtenus ont montré une discordance entre les deux méthodes utilisées et sus-citées. Les résultats de l'effet antagoniste montrent que 7 souches sont antagonistes. L’identification des souches antagonistes a été confirmée par séquençage complet du gène ADNr 16S. En sus du potentiel antagoniste de ces lactobacilles, nous avons regardé d'autres propriétés biologiques de ces souches pouvant permettre une application probiotique. Trois isolats ont montré des propriétés intéréssantes d'hydrophobicité, d'autoaggrégation et dépourvues des caractères pathogènes. Afin d’évaluer l’effet antiviral de ces 3 isolats, des tests de cytotoxicité et d’adhésion sur une lignée cellulaire "Véro cell" ont été effectués. L’activité antivirale a été évaluée in vitro, vis-à-vis du virus herpétique de type-2 (VHS-2) et du virus non enevelopé CVBE4 comme virus contrôle. l'activité antivirale des lactobacilles a été evaluée dans 3 temps d'addition differents (Pre-infection, co-incubation et post-infection). On a choisi la souche qui a montré la meilleure activité anti-VHS-2, il s’agit de L. gasseri CMUL57. L’activité antivirale de cette souche (CMUL57) a été étudiée profondément afin d’expliquer le mécanisme de cette interaction bactérie/virus.The aim of this work is to determine the diversity of Lactobacillus species in vaginal flora in samples from Lebanese women and to evaluate the antagonistic effect of these strains against several vaginal pathogens in women. Thus, of the 135 samples collected, 53 isolates were isolated and identified by the gallery API50 CH (BioMerieux, France) and by pyrosequencing of the variable regions (V1 and V2) of the 16S rDNA gene. The results showed a large discrepancy between the two methods used. The antagonism results obtained showed the presence of 7 antagonistic strains against four pathogenic strains. The complete identification of these strains was confirmed by complete sequencing of the 16S gene (16S rDNA). Note that L. plantarum CMUL140 showed a strong anti-S. aureus activity and was used in a co-culture test. In addition to the potential antagonism of these lactobacilli, we looked at other features that can help in using these strains as probiotics. Therefore, we evaluated their probiotic and safe characteristics. To assess the antiviral effect of these three isolates, cytotoxicity and adhesion tests were performed on a "Vero cell" cell line. The results showed that none of three isolates were cytotoxic and carried a strong adhesion. Antiviral activity in vitro was evaluated against the herpes simplex virus type-2 (HSV-2) and CVBE4 as virus control. In order to investigate the anti-HSV-2 activity of lactobacilli, the strains were added to the infected cells at different intervals: pre-infection, co-incubation and post-infection. L.gasseri CMUL57 showed the strongest anti-HSV-2 activity and showed the capacity to trap HSV-2 on their cell wall

Antimicrobial activity and high thermostability of a novel BLIS secreted by Enterococcus Mundtii isolated from Lebanese cow’s milk

AL Kassaa, I., Safourim, N., Mostafa, N. and Hamze, M. Antimicrobial activity and high thermostability of a novel BLIS secreted by Enterococcus Mundtii isolated from lebanese cow’s milk. 2016. Lebanese Science Journal, 17(2): 166-176. Lactic acid bacteria (LAB) are used in many fields such as fermentation agents, increasing nutritional value and improving organoleptic quality of food. Also they are used as probiotics and preservatives against pathogens and spoilage microbes by producing antimicrobial substances such as bacteriocins. Fifty cow’s milk samples were collected and 175 LAB isolates were isolated and identified by using biochemical method. Fifteen isolates showed an antimicrobial activity against Listeria monocytogenes ATCC® 19115™. One strain, BL4 which showed the strongest activity, was chosen to extract and characterize its antimicrobial substance in order to evaluate its potential use as a new food protective agent. This strain was identified as Enterococcus mundtii by pyrosequencing method. The active substance was extracted using solvent method. This Bacteriocin like Inhibitory Substances “BLIS” can support a high temperature (121 ˚C) for a long time and resist pH variation. The BLIS BL4 can be considered as a peptide active against many food pathogen and food-spoilage microbes, such as Listeria monocytogenes and Penicillium spp. BLIS BL4 can be used in food application as bio-preservative to reduce food-spoilage and food-borne diseases in food products

PRÉVALENCE DE LISTERIA MONOCYTOGENES DANS LE LAIT CRU DE VACHE AU LIBAN NORD

Al Kassaa Imad, Khaled el Omari, Marwa Saati, Bachar Ismail and Monzer Hamze. 2016. Prevalence of Listeria monocytogenes in raw cow milk in north Lebanon. Lebanese Science Journal, 17(1): 39-45. Listeriosis, although a zoonosis, is an invasive disease that can affect newborns, pregnant women and immunocompromised adults. Clinical manifestations can be expressed by febrile gastroenteritis, invasive forms including severe sepsis, meningitis, rhombencephalitis, prenatal infections and abortions. Species of Listeria bacteria are ubiquitous and adaptable to the environment in animal and plant foods. This study aimed to determine the prevalence of Listeria monocytogenes in 100 samples of fresh cow milk collected from different areas of North Lebanon. Listeria monocytogenes was detected by using the Grand VIDAS technique (Biomérieux France). The results obtained revealed the absence of Listeria monocytogenes in all analyzed samples

Detection of pathogenic bacteria in diarrheal stool collected from children in North Lebanon by using conventional stool culture and microarray technique « CLART® Enterobac »

Bechara, R., Hosny, M., AL-Kassaa, I., Dabboussi, F., Mallat, H. and Hamze, M. 2016. Detection of pathogenic bacteria in diarrheal stool collected from children in north lebanon by using conventional stool culture and microarray technique « clart® enterobac ». Lebanese Science Journal, 17(2): 233-239. Illness caused by enteropathogens represents an important economic and health burden worldwide. The majority of enteropathogens causes gastrointestinal infections which have a great impact on public health both in developing and developed countries. The aim of this study is to detect and identify the main enteropathogens in Lebanese diarrheal stool from children under 15 years old. The detection was performed by using both conventional method and microarray technique CLART® EnteroBac (Genomica-Spain). Five enteric pathogens, Salmonella spp, Shigella spp, Clostridium difficile B, Enteropathogenic E. coli, Campylobacter jejuni were detected in 80 diarrheal stools, from children under 15 years old. The results showed that CLART® EnteroBac technique have detected enteropathogens in 19% of samples, whereas 1% returned positive using stool culture methods

Prevalence of anti-hepatitis E virus IgG antibodies in sera from hemodialysis patients in Tripoli, Lebanon.

Hepatitis E virus (HEV) is an important global public health concern. Several studies reported a higher HEV prevalence in patients undergoing regular hemodialysis (HD). In Lebanon, the epidemiology of HEV among HD patients has never been investigated previously. In this study, we examine the seroprevalence of HEV infection among 171 HD patients recruited from three hospital dialysis units in Tripoli, North Lebanon. Prevalence of anti-HEV IgG antibodies was evaluated in participant's sera using a commercial enzyme-linked immunosorbent assay (ELISA). The association of socio-demographic and clinical parameters with HEV infection in patients was also evaluated. Overall, 96 women and 75 men were enrolled in this study. Anti-HEV IgG antibodies were found positive in 37/171 HD patients showing a positivity rate of 21.63%. Among all examined variables, only the age of patients was significantly associated with seropositivity (P = 0.001). This first epidemiological study reveals a high seroprevalence of HEV infection among Lebanese HD patients. However, further evaluations that enroll larger samples and include control groups are required to identify exact causative factors of the important seropositivity rate in this population

Applications des bactériocines et bactéries lactiques dans le contrôle des pathogènes alimentaires

International audienc

LABiocin database: A new database designed specifically for Lactic Acid Bacteria bacteriocins

International audienceBacteriocins from lactic acid bacteria (LAB) are successfully applied as natural alternatives to food preservation and to antibiotics; however, information on these antimicrobial peptides (AMPs) is scattered through the literature and databases. Therefore, we developed the LABiocin database, a specialized database on LAB bacteriocins. The database was stored and compiled using MySQL with NetBeans IDE as the platform. Important data are compiled, including bacteriocin name, class, amino acids and nucleic acid sequences, if available. Target microorganisms, origin, status of the producing strains and their culture conditions and extraction and purification methods are also included in this new database. A phylogenetic tree for the mature peptide bacteriocin sequences has also been created.LABiocin is an interactive database with a user-friendly interface that integrates several tools and services and comprises up to 517 LAB bacteriocins. Besides data searching tools, a BLAST tool was integrated into the database to enable the user to perform a homology search against mature peptide sequences. Users can be linked to other databases that contain additional information, particularly about predicted bacteriocin structure and mechanisms of action.The LABiocin database enables comprehensive functional analysis of this special group of AMPs. This would be useful in food preservation and food safety applications and would also have substantial implications for development of new drugs for medical use. LABiocin database is available at labiocin.net