Members of the Lactobacillus Genus Complex (LGC) as Opportunistic Pathogens: A Review

Abstract

Microorganisms belonging to the Lactobacillus genus complex (LGC) are naturally associated or deliberately added to fermented food products and are widely used as probiotic food supplements. Moreover, these bacteria normally colonize the mouth, gastrointestinal (GI) tract, and female genitourinary tract of humans. They exert multiple beneficial effects and are regarded as safe microorganisms. However, infections caused by lactobacilli, mainly endocarditis, bacteremia, and pleuropneumonia, occasionally occur. The relevance of Lactobacillus spp. and other members of the LGC as opportunistic pathogens in humans and related risk factors and predisposing conditions are illustrated in this review article with more emphasis on the species L. rhamnosus that has been more often involved in infection cases. The methods used to identify this species in clinical samples, to distinguish strains and to evaluate traits that can be associated to pathogenicity, as well as future perspectives for improving the identification of potentially pathogenic strains, are outlined.

Characterization of a bacterial strain Lactobacillus paracasei LP10266 recovered from an endocarditis patient in Shandong, China

“…To the best of our knowledge, this is the first study based on the whole-genome comparative analysis of a L. paracasei strain isolated from an IE patient conducted to comprehensively assess the pathogenicity both in vivo and in vitro . Generally, lactobacilli isolated from blood are overlooked due to their low virulence perceived [ 18 ]. Endocarditis induced by L. paracasei is relatively rare [ 19 , 20 ].…”

Beneficial Propionibacteria within a Probiotic Emmental Cheese: Impact on Dextran Sodium Sulphate-Induced Colitis in Mice

“…Briefly, chromosomal DNA samples were prepared according to Gautier et al [32] and digested using Xba I. Electrophoresis was run at 14 • C on a 1% agarose gel on a Chef DR II system (Bio-rad, Richmond, UK) with the following parameters: initial time 2s, final time 20s, migration time migration 20h, voltage 6V.cm −1 = 200V. For thermophilic lactobacilli, parameters were: enzyme AscI [34], initial time 1s, final time 10s, migration time 16h, Voltage: 6V.cm −1 = 200V. For thermophilic streptococci, parameters were: enzyme SmaI [35], initial time 2s, final time 20 s, migration time 24h, Voltage: 6V.cm −1 = 200V.…”

Paraprobiotics and Postbiotics of Probiotic Lactobacilli, Their Positive Effects on the Host and Action Mechanisms: A Review

“…The genus Lactobacillus is the largest genus among lactic acid bacteria (LAB), consisting of more than 237 species (1), with continuous new species discoveries, such as Lactobacillus metriopterae (2) and Lactobacillus timonensis (3). Some Lactobacillus species are among the most widely used probiotics (4).…”