Imad Al Kassaa

Identification of Vaginal Lactobacilli with Potential Probiotic Properties Isolated from Women in North Lebanon

The aim of this work was to study the diversity of vaginal lactobacilli in Lebanese women and to evaluate the antagonism, hydrophobicity, and safety characteristics of these strains. This study was performed on samples from 135 women who visited a gynecology clinic in the north of Lebanon, between September 2012 and January 2013. From these samples, 53 different isolates of vaginal lactobacilli were collected from vaginal swabs and identified using biochemical and molecular methods. The use of genotypic Rep-PCR fingerprinting allowed for the organization of these isolates into 23 different groups. Seven of the isolated lactobacilli were antagonistic against the following vaginal pathogens: Gardnerella vaginalis CIP7074T, Staphylococcus aureus ATCC33862, Escherichia coli CIP103982, and Candida albicans ATCC10231. The antagonistic lactobacilli strains were then identified using 16S rDNA sequence. The data of this study show that the antagonistic lactobacilli were non-hemolytic, sensitive to most antibiotic tests, free of plasmid DNA, and exhibited interesting hydrophobicity and autoaggregation properties positioning them as potential candidates for probiotic design.

Identification of lactobacilli with inhibitory effect on biofilm formation by pathogenic bacteria on stainless steel surfaces

Two hundred and thirty individual clones of microorganisms were recovered from milk tanks and milking machine surfaces at two distinct farms (Bejaja City, Algeria). Of these clones, 130 were identified as lactic acid bacteria (LAB). In addition Escherichia coli, Salmonella, Staphylococcus aureus and Pseudomonas aeruginosa species were identified in the remaining 100 isolates-spoilage isolate. These isolates were assayed for ability to form biofilms. S. aureus, Lactobacillus brevis strains LB1F2, LB14F1 and LB15F1, and Lactobacillus pentosus strains LB2F2 and LB3F2 were identified as the best biofilm formers. Besides, these LAB isolates were able to produce proteinaceous substances with antagonism against the aforementioned spoilage isolates, when grown in MRS or TSB-YE media. During the screening, L. pentosus LB3F2 exhibited the highest antibacterial activity when grown in TSB-YE medium at 30 °C. Additionally, L. pentosus LB3F2 was able to strongly hamper the adhesion of S. aureus SA3 on abiotic surfaces as polystyrene and stainless steel slides. LAB isolates did not show any hemolytic activity and all of them were sensitive to different families of antibiotic tested. It should be pointed out that LB3F2 isolate was not cytotoxic on the intestinal cells but could stimulate their metabolic activity. This report unveiled the potential of LB1F2, LB14F1, LB15F1, LB2F2, and LB3F2 isolates to be used as natural barrier or competitive exclusion organism in the food processing sector as well as a positive biofilm forming bacteria.

Vaginal Lactobacillus gasseri CMUL57 can inhibit herpes simplex type 2 but not Coxsackievirus B4E2.

Abstract This study aimed at demonstrating the antiviral activity of Lactobacillus gasseri CMUL57 (L. gasseri CMUL57), L. acidophilus CMUL67 and L. plantarum CMUL140 against herpes simplex type 2 (HSV-2) and Coxsackievirus B4E2 (CVB4E2), which are enveloped and naked viruses, respectively. These lactobacilli were non-cytotoxic and were able to reduce the cytopathic effect induced by HSV-2 in Vero cell monolayers. However, lactobacilli were not active against CVB4E2. Tested lactobacilli displayed anti-HSV-2 activity when they were co-incubated with the virus prior to inoculating the mixture to Vero cell monolayers. The detection of HSV-2 DNA by PCR in pellets of bacteria/virus mixtures let us to hypothesize that anti-HSV-2 activity of lactobacilli resulted from the viruses’ entrapment. This study showed the capabilities of vaginal lactobacilli to inhibit enveloped viruses such as HSV-2.

Probiotics: Role in the Prevention of Chronic Viral Diseases

Viral infections are the most critical among infectious diseases, especially those that can lead to chronic diseases. The control and the prevention of chronic diseases represent a challenge for public health organizations. These chronic diseases are the major cause of death worldwide. To achieve the greatest impact, public health campaigns should focus on creating novel treatment and prevention strategies against chronic viral diseases. Probiotics are defined as live microorganisms with beneficial effects for humans. Probiotic strains have shown antiviral activity against a variety of infectious viruses such as respiratory and enteric viruses. In this chapter, we discuss the possible role of probiotic strains in chronic viral infections and their benefits in therapy strategies against such diseases. Data from numerous studies has shown that the use of probiotic as therapeutic agents is safe and inexpensive and can avoid the need for invasive treatment for several chronic viral infections caused by HIV, HCV, HTLV, HPV, CVB4, etc. The principal mechanisms of the antiviral activity of the probiotic strains studied until now were the production of antiviral compounds, the immunomodulatory effect, and virus trapping by the probiotic cell wall.

Methods and Techniques to Evaluate the Antiviral Activity of a New Probiotic Strain

The “antiviral probiotic” term is not yet used in science nor approved by FDA and WHO. Indeed, the evaluation of antiviral activity of probiotic strains needs to be standardized and approved. Until now, “antiviral probiotics” are not used either in the medical or food sectors. Furthermore, this type of probiotic is not widely recognized by health organizations such as the WHO and FDA. However, antiviral probiotics (AvPrs) have shown an efficient antiviral effect in the prevention and treatment of several viral infections. In last decade, many studies have been conducted to evaluate the antiviral activity of some probiotic strains. Few studies have showed the mechanisms behind such activity. The needs and the importance of antiviral probiotics have encouraged researchers to deeply investigate the antiviral mechanism. A probiotic strain needs to be tested and evaluated by many experiment to be recognized and approved as antiviral probiotics. Besides cytotoxicity, probiotic characteristics and immunomodulation effect of probiotic strain, choosing cell line, indicator virus and addition time of bacterial cells are the essential criteria for this selection.

The Antiviral Activity of Probiotic Metabolites

One of the most important characteristics of lactic acid bacteria (LAB) is the production of a large variety of active substances, such as acids, active ribosomal proteins, non-ribosomal peptide synthetase (NRPS), hydrogen peroxide, and other metabolites. In recent decades, several studies have evaluated the importance of these active substances in both the medical and food sectors. LAB have been used for several years in food fermentation to give good taste and protect the food against spoilage and pathogenic microorganisms. In this chapter, we focus on the antiviral activity of LAB metabolites.

Antiviral Probiotics: A New Concept in Medical Sciences

In recent decades, probiotics have shown beneficial effects on animal and human health. Probiotics can protect the host against several health threats, including infectious diseases. Before 1995, researchers believed that the effect of probiotics was only on gut microbiota which can restore the gut flora and thus prevent pathogenic bacteria from triggering gastroenteritis. Recent studies have shown that the immunomodulatory activity is the most important mechanism of action of probiotics. From this information, researchers started to evaluate the effect of some immunobiotics, not only on pathogenic bacteria but also on viruses, including enteric and respiratory viruses. Several studies have confirmed the potential antiviral activity of some probiotics due to the immunomodulatory effect. These studies were conducted on humans (clinical trials) and in animal models. In this chapter, probiotics with antiviral effect against respiratory and enteric viruses will be presented and discussed, as well as their mechanisms of action.In recent decades, probiotics have shown beneficial effects on animal and human health. Probiotics can protect the host against several health threats, including infectious diseases. Before 1995, researchers believed that the effect of probiotics was only on gut microbiota which can restore the gut flora and thus prevent pathogenic bacteria from triggering gastroenteritis. Recent studies have shown that the immunomodulatory activity is the most important mechanism of action of probiotics. From this information, researchers started to evaluate the effect of some immunobiotics, not only on pathogenic bacteria but also on viruses, including enteric and respiratory viruses. Several studies have confirmed the potential antiviral activity of some probiotics due to the immunomodulatory effect. These studies were conducted on humans (clinical trials) and in animal models. In this chapter, probiotics with antiviral effect against respiratory and enteric viruses will be presented and discussed, as well as their mechanisms of action.