The present work demonstrates the antagonistic and antioxidant property of Lactobacillus gasseri LGS22 (MN258931), Lactobacillus gasseri MVS25(MN396621) isolated from human milk and Lactobacillus ...gasseri LBM220 (MN097539) isolated from exclusively breast-fed infant faeces. Antagonistic potential was assayed using agar well diffusion method against 17 food-borne and enteric pathogens. Further, in order to characterize the nature of inhibitory metabolites in culture supernatant, several preliminary experiments such as pH adjustment,treatment with protease, catalase and heat were performed. In addition, quantitative estimation of antimicrobial activity was performed using Time-kill assay against indicator pathogen Sh. flexneri type 2. Strains were further evaluated for antioxidant action such as scavenging of hydroxyl radical, DPPH radical and ABTS+ radical. The capacity to resist 0.4 mM, 0.8mM and 1 mM hydrogen peroxide for 16 h was also studied. Results report the efficient inhibitory potential of Lact. gasseri strains with zone sizes ranging from moderate to very strong inhibition (10-22 mm) against most of the indicator pathogens employed in the current study. Also, inhibitory action of cell-free culture supernatant of isolates LBM220 and MVS25 when adjusted to pH 6.5 was significantly reduced, elucidating the production of organic acids, while isolate LGS22 produced hydrogen peroxide as inhibitory metabolite. Lact. gasseri isolates were found to significantly scavenge free radicals, with scavenging potential in range of (80.687- 26.552%). It is concluded that these three Lact. gasseri isolates may be explored more for their bio-potential as food additive with antioxidant and antimicrobial activities. Keywords: Lactobacillus species, LAB, Infant faeces, Human milk, Antagonistic activity, Antioxidant activity
Importance of bifidobacteria as part of the infant intestinal microbiota has been highlighted. Their acquisition is influenced by the mode of birth and the feed regime afterwards, with a special role ...of the maternal microbiota. The presence of the same shared bifidobacterial strains between breast milk and infant faeces in 14 mother-infant pairs was assessed by means of pulsed-field gel electrophoresis (PFGE) genotyping. Four shared strains of Bifidobacterium breve (2), Bifidobacterium longum subsp. infantis and B. longum subsp. longum were found in breast milk-infant faeces pairs. Two years later, a second survey yielded four shared strains of the species Bifidobacterium adolescentis, Bifidobacterium bifidum, B. longum subsp. longum and Bifidobacterium pseudocatenulatum. Moreover, a B. bifidum strain was found to be shared by the infant faeces of the first study and the mother faeces tested two years later, pointing out a long term persistence. Some of the selected bifidobacterial strains showed probiotic potential due to their survival to gastrointestinal conditions and their ability to form biofilms.
The past decade has brought a significant rise in antimicrobial resistance, and the ESKAPE pathogens (
Enterococcus faecium
,
Staphylococcus aureus
,
Klebsiella pneumoniae
,
Acinetobacter baumannii
,
...Pseudomonas aeruginosa
and
Enterobacter
species) have considerably aggravated a threat to public health, causing nosocomial infections worldwide. The objective of the current study was to isolate novel probiotic strain with antimicrobial activity against multidrug-resistant ESKAPE pathogens. For this purpose, eighteen breastfed infant faeces were collected and lactic acid bacteria (LAB) with antagonistic activity were isolated. Out of 102 anaerobic LAB isolated, only nine exhibited inhibitory activity against all ESKAPE pathogens. These selected nine isolates were further characterized for their probiotic attributes such as lysozyme tolerance, simulated gastrointestinal tolerance, cellular auto-aggregation and cell surface hydrophobicity. Bile salt deconjugation and cholesterol-lowering capacity was also determined. Among all nine, isolate LBM220 was found to possess superior probiotic potential. Confirmatory identification of isolate LBM220 was done by both 16S rRNA sequence analysis and mass spectrometric analysis using MALDI-TOF. Based on BLAST result, isolate LBM220 was identified as
Lactobacillus gasseri.
Phylogenetic analysis of
Lactobacillus gasseri
LBM220 accession number MN097539 was performed. Also, detailed safety evaluation study of
Lact. gasseri
LBM220 showed the presence of intrinsic antibiotic resistance and the absence of hemolytic, DNase, gelatinase and toxic mucinolytic activity. Time kill assay was also performed to confirm the strong kill effect of
Lact. gasseri
LBM220 on all six multidrug resistant ESKAPE pathogens. Thus,
Lact. gasseri
LBM220 can be utilized and explored as potential probiotic with therapeutic intervention.
Few data are available to guide biological sample collection around the time of birth for large-scale birth cohorts. We are designing a large UK birth cohort to investigate the role of infection and ...the developing immune system in determining future health and disease. We undertook a pilot to develop methodology for the main study, gain practical experience of collecting samples, and understand the acceptability of sample collection to women in late pregnancy.
Between February-July 2014, we piloted the feasibility and acceptability of collecting maternal stool, baby stool and cord blood samples from participants recruited at prolonged pregnancy and planned pre-labour caesarean section clinics at University College London Hospital. Participating women were asked to complete acceptability questionnaires.
Overall, 265 women were approached and 171 (65%) participated, with ≥1 sample collected from 113 women or their baby (66%). Women had a mean age of 34 years, were primarily of white ethnicity (130/166, 78%), and half were nulliparous (86/169, 51%). Women undergoing planned pre-labour caesarean section were more likely than those who delivered vaginally to provide ≥1 sample (98% vs 54%), but less likely to provide maternal stool (10% vs 43%). Pre-sample questionnaires were completed by 110/171 women (64%). Most women reported feeling comfortable with samples being collected from their baby (<10% uncomfortable), but were less comfortable about their own stool (19% uncomfortable) or a vaginal swab (24% uncomfortable).
It is possible to collect a range of biological samples from women around the time of delivery, and this was acceptable for most women. These data inform study design and protocol development for large-scale birth cohorts.
Aims: This study aimed to characterize new isolates of human bifidobacteria, evaluate some of their probiotic potential and to screen these isolates for their effectiveness at inhibiting Listeria ...monocytogenes in vitro.
Methods and Results: Thirty‐four Bifidobacterium isolates from infant faeces were identified by fructose‐6‐phosphate phosphoketolase and PCR. Six isolates, coded RBL67, RBL68, RBL69, RBL70, RBL85 and RBL86, showed higher antagonistic activity against L. monocytogenes. Neutralized culture supernatants of these strains did not inhibit L. monocytogenes when tested by agar diffusion method. However, the concentration of supernatant by speed‐vac resulted in the formation of an inhibitory effect with supernatants from strains RBL67, RBL68 and RBL70. This effect was shown to be related to heat‐stable proteinaceous compound(s) which were resistant to heating at 100°C for 5 min but not to pronase‐E, proteinase‐K or trypsin. The extraction of the inhibitory compounds by methanol–acetone extraction procedure indicated that four strains (RBL67, RBL68, RBL69 and RBL70) were mostly soluble in acetone. However, strain RBL85 produced inhibitory substances that were soluble in methanol.
Conclusion: Infant bifidobacterial isolates produce heat‐stable proteinaceous compounds active against L. monocytogenes.
Significance and Impact of the Study: Production of antibacterial substances by bifidobacteria would improve intestinal bacterial ecology and inhibit intestinal pathogens.
In this research, 21 strains of lactobacilli were isolated from newborn infant faeces.
Lactobacillus rhamnosus (seven strains),
L. paracasei ssp.
paracasei (four strains),
L. fermentum (four ...strains),
L. buchneri (two strains),
L. brevis (one strain),
L. curvatus (one strain) and
Lactobacillus sp. (two strains) isolated from infant faeces were analysed for acid production, antibiotics resistances, H
2S productions and antimicrobial activities.
Inhibition activity of bacteriocins and/or bacteriocin-like substances of the lactobacilli against some food contaminants and pathogenic bacteria (
Escherichia coli,
Staphylococcus aureus ATCC 28213,
S. aureus ATCC 2392,
Yersinia enterocolitica and
Bacillus cereus) were determined by the agar diffusion method.
An enzyme-based assay was developed for the detection of bifidobacteria in infant faeces. Ninety-five samples from 51 breast-fed infants in the age between 3 and 276 days were investigated. ...Bifidobacteria and other bacterial groups were determined by cultivation and fluorescence in situ hybridisation (FISH). Faecal samples were examined for the activity of fructoso-6-phosphate phosphoketolase (F6PPK) and for other enzymatic reactions using the API-ZYM kit.
Twenty-nine infants had high numbers of bifidobacteria (usually higher than 9 log CFU/g) in their faeces. Seventeen infants (35%) did not contain detectable amounts of bifidobacteria in their faecal samples. The remaining five individuals had low counts of bifidobacteria (3–6 log CFU/g). Most negative infants possessed major amounts of clostridia in their faecal flora. There were no significant differences among bifidobacterial counts obtained by cultivation and FISH, detection of F6PPK, α-galactosidase and α-glucosidase activities could routinely be used for the rapid and simple detection of bifidobacteria in infant faecal samples. Bifidobacterial colonies were identified using enzymatic tests and PCR procedure based on 16S rRNA gene sequences species-specific primers. In 14 samples, the identifications of individual isolates were compared with direct analyses of faeces using the nested PCR-denaturing gradient gel electrophoresis (nested DGGE) procedure. The results obtained in several cases are not identical.
Bifidobacterium longum and
Bifidobacterium breve were most frequently identified. Bifidobacteria-positive samples had high activities of α-galactosidase and α-glucosidase. On the contrary, negative samples missed either one or both of these enzymatic activities. While all positive samples tested showed distinctive fructose-6-phosphate phosphoketolase activity (F6PPK), none of the negative samples expressed F6PPK activity.
This study was conducted to obtain a good probiotic strain of L. acidophilus from infant feces which have the acid and bile tolerance. The selection criteria for the strain included antimicrobial ...activity, serum cholesterol reduction, resistance to the hydrogen peroxide, angiotensin converting enzyme (ACE) inhibition activity and iron solubility. To this end, five probiotic Lactobacillus strains have been isolated from infant feces. Especially, L. acidophilus SD 105 had strong antimicrobial activity against Listeria sp., high deconjugation activity in the medium which contained 0.5% of glycocholate (GCA) and high resistance to the hydrogen peroxide. L. acidophilus SD 102 showed the highest ACE inhibition activity among the tested cultures and L. acidophilus SD 103 showed iron solubility of more than 70%.
Objective: To isolate and identify Lactobacillus gasseri from 125 fecal samples of healthy infants, and to evaluate its safety and antimicrobial activity. Methods: In this study, fecal samples of ...1-month-old healthy infants were taken, and the strains were separated by MRS medium, Gram staining, biochemical identification and 16S rRNA sequencing technology were used to strain identification. Subsequently, the hemolysis of the isolated L. gasseri was evaluated by blood agar. The drug sensitivity of antibiotics was determined by micro broth dilution method, and the safety of the isolated strains were evaluated. Finally, the inhibitory effects of the 15 isolated L. gasseri strains on E. coli ATCC 25922 and S. aureus ATCC 25923 were detected by Oxford cup method. Results: Fifteen strains of L. gasseri were successfully isolated from 125 fecal samples of healthy infants. Hemolysis test results showed that 14 strains of them was hemolytic negative. The 15 tested strains were highly sensitive to tetracycline, vancom
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