Safety and persistence of orally administered human Lactobacillus sp. strains in healthy adults

Abstract

The aim of the study was to evaluate the safety and persistence of selected Lactobacillus strains in the gastrointestinal tract (GIT) of healthy adult volunteers after oral consumption of high doses of lactobacilli to identify potential candidates for probiotic and biotechnological applications. In the first phase of the study, nine individuals consumed capsules containing Lactobacillus gasseri 177 and E16B7, Lactobacillus acidophilus 821-3, Lactobacillus paracasei 317 and Lactobacillus fermentum 338-1-1 (each daily dose 1×1010 cfu) for 5 consecutive days. Data on gut health, blood parameters, and liver and kidney function were collected. The persistence of Lactobacillus strains was assessed by culturing combined with arbitrarily primed polymerase chain reaction (AP-PCR) and PCR-denaturing gradient gel electrophoresis (PCR-DGGE) on days 0, 5, 8, 10 and 20 from faecal samples. All strains survived gastrointestinal passage and were detected on the 5th day. L. acidophilus 821-3 was detected in four volunteers on the 8th day (4.3 to 7.0 log10 cfu/g) and in two on the 10th day (8.3 and 3.9 log10 cfu/g, respectively). In the second phase of the study, five additional volunteers consumed L. acidophilus 821-3 (daily 1×1010 cfu) for 5 consecutive days. The strain was subsequently detected in faeces of all individuals using real-time PCR on the 10th day (range 4.6-6.7; median 6.0 log10 cell/g) in both phases of the study for at least 5 days after discontinuation of consumption. The administration of high doses of different Lactobacillus strains did not result in any severe adverse effects in GIT and/or abnormal values of blood indices. Thus, the strain L. acidophilus 821-3 is a promising candidate for probiotic and biotechnological applications. Further studies will be performed to confirm the strain persistence and safety in a larger number of individuals.

Congruent Strain Specific Intestinal Persistence of Lactobacillus plantarum in an Intestine-Mimicking In Vitro System and in Human Volunteers

“…These data expand earlier in vitro observations of variation of GI-robustness among small numbers of L. plantarum strains [14], [15], towards an extensive cohort of strains of this species that were isolated from various geographical locations and diverse habitats [19]. Considerable variations between L. plantarum strains have been reported for other phenotypes as well, such as degradation of carbohydrates, growth at 45°C, and tolerance to NaCl or nisin in the growth medium [19].…”

“…by methods based on physiological characteristics like sugar utilization capacity [15]. Alternative discriminatory methods rely on molecular typing techniques like plasmid or genomic DNA profiling using restriction enzyme analysis (REA) [15], pulsed-field gel electrophoresis (PFGE) [47], [48], or PCR based fingerprinting techniques like random amplification of polymorphic DNA (RAPD) [49], arbitrarily primed PCR (AP-PCR) [14], PCR-denaturing gradient gel electrophoresis (PCR-DGGE) [14], internal transcribed spacer PCR (ITS-PCR) [47], or Real-Time PCR [14], [50]. Generally, these techniques are labor-intensive and cannot be applied in a high-throughput manner.…”

“…For example, 7% of the single administered L. plantarum NCIMB8826 reached the ileum alive, while of L. fermentum KLD and Lactococcus lactis MG1363 only 0.5 and 1.0% of the consumed bacteria could be recovered, respectively [13]. In addition, distinct persistence and survival characteristics of L. gasseri [14], L. reuteri [15], and L. plantarum [15] mixed with other species were reported. Moreover, several studies using 3 strains of L. reuteri illustrated the wide-range of GI persistence characteristics of these strains, which ranged from detection on 14 to 49 days following consumption by volunteers [16]–[18].…”

Mechanisms and therapeutic effectiveness of lactobacilli

“…13 Therefore, the ability of lactobacilli to adhere and colonise the GI tract mucosa has been investigated in the clinical setting and is summarised in table 1. [14][15][16][17] Antitumour activity…”

Dual-Color Bioluminescence Imaging for Simultaneous Monitoring of the Intestinal Persistence of Lactobacillus plantarum and Lactococcus lactis in Living Mice

“…lactis is similar to the persistence of each strain administered separately, illustrating that the strains are not competing with each other, even if they were colocalized in the cecum and colon as described previously (5). The survival and persistence of mixtures of LAB strains have been studied in mice and animals (15)(16)(17). However, to our knowledge, the comparison between the persistence of two coadministered LAB and the persistence of each strain administered separately has never been reported.…”