Rough and smooth morphotypes isolated from Lactobacillus farciminis CNCM I-3699 are two closely-related variants.

This study focused on a pleomorphic strain Lactobacillus farciminis CNCM I-3699 known as probiotic for animal applications. On plating, this strain was characterized by the presence of rough and smooth morphotypes depending on experimental conditions. Dominant smooth (S) form, bright white, having smooth edges with moist, ropy, and creamy along with rough (R) form, pale white, having irregular edges and a dry and granular aspect were always obtained from the parent strain under aerobic culture conditions. In anaerobic conditions, only S form growth was observed. Biochemical dosage of capsular exopolysaccharides showed a significant difference between S and R forms (p<0.01), in agreement with a ropy or non ropy phenotype for the S or R form, respectively. These differences were confirmed by transmission electronic microscopy. The auto-aggregation profile revealed major differences in cultural behaviors. The R morphotype presented a highly auto-aggregative ability contrary to the S morphotype. However, biochemical and molecular analyses revealed that R and S morphotypes: 1) shared the same sugar fermentation pattern; 2) belonged to L. farciminis species using 16S rDNA sequencing; 3) had identical PFGE patterns using NotI and ApaI endonucleases; and 4) had identical CRISPR loci but different from those of other L. farciminis strains. Furthermore, the novelty and uniqueness of CRISPR spacer sequences in CNCM I-3699 provides a genetic support for the development of a molecular tracking tool for CNCM I-3699 and its variants. In conclusion, L. farciminis CNCM I-3699 is a pleomorphic strain giving reproducibly rise to two phenotypically distinct morphotypes R and S. This phenomenon may explain survival and growth abilities in in vitro fluctuating aerobic-anaerobic conditions along with modulation of exopolysaccharide synthesis and autoaggregation profile.

Genome Sequence of Lactobacillus plantarum Strain UCMA 3037.

Nucleic acid of the strain Lactobacillus plantarum UCMA 3037, isolated from raw milk camembert cheese in our laboratory, was sequenced. We present its draft genome sequence with the aim of studying its functional properties and relationship to the cheese ecosystem.

In vitro characterization of aggregation and adhesion properties of viable and heat-killed forms of two probiotic Lactobacillus strains and interaction with foodborne zoonotic bacteria, especially Campylobacter jejuni.

Bacterial aggregation and/or adhesion are key factors for colonization of the digestive ecosystem and the ability of probiotic strains to exclude pathogens. In the present study, two probiotic strains, Lactobacillus rhamnosus CNCM-I-3698 and Lactobacillus farciminis CNCM-I-3699, were evaluated as viable or heat-killed forms and compared with probiotic reference Lactobacillus strains (Lb. rhamnosus GG and Lb. farciminis CIP 103136). The autoaggregation potential of both forms was higher than that of reference strains and twice that of pathogenic strains. The coaggregation potential of these two beneficial micro-organisms was evaluated against several pathogenic agents that threaten the global safety of the feed/food chain: Escherichia coli, Salmonella spp., Campylobacter spp. and Listeria monocytogenes. The strongest coaggregative interactions were demonstrated with Campylobacter spp. by a coaggregation test, confirmed by electron microscopic examination for the two forms. Viable forms were investigated for the nature of the bacterial cell-surface molecules involved, by sugar reversal tests and chemical and enzymic pretreatments. The results suggest that the coaggregation between both probiotic strains and C. jejuni CIP 70.2(T) is mediated by a carbohydrate-lectin interaction. The autoaggregation potential of the two probiotics decreased upon exposure to proteinase, SDS or LiCl, showing that proteinaceous components on the surface of the two lactobacilli play an important role in this interaction. Adhesion abilities of both Lactobacillus strains were also demonstrated at significant levels on Caco-2 cells, mucin and extracellular matrix material. Both viable and heat-killed forms of the two probiotic lactobacilli inhibited the attachment of C. jejuni CIP 70.2(T) to mucin. In conclusion, in vitro assays showed that Lb. rhamnosus CNCM-I-3698 and Lb. farciminis CNCM-I-3699, as viable or heat-killed forms, are adherent to different intestinal matrix models and are highly aggregative in vitro with pathogens, especially Campylobacter spp., the most commonly reported zoonotic agent in the European Union. This study supports the need for further in vivo investigations to demonstrate the potential food safety benefits of Lb. rhamnosus CNCM-I-3698 and Lb. farciminis CNCM-I-3699, live or heat-killed, in the global feed/food chain.