Effects of Microbiological and Physicochemical Properties of Cow’s Milk and Goat’s Milk Dadih Inoculated with Various Lactobacillus Species

Dadih is a dairy-based product and it is one of the most popular desserts among Malaysians and Indonesians. It is made from raw milk which naturally contains various types of microorganisms. This study was conducted to develop cultured dadih by inoculating various Lactobacillus species such as Lactobacillus acidophilus, Lactobacillus plantarum and Lactobacillus paracasei into dadih made from cow’s milk and goat’s milk. Prior to isolation of LAB from control dadih (dadih without inoculation with LAB), the dadih was stored at 4˚C for 48 hours. The microbiological (general microbial load, viability of and LAB, mould and yeast count) and physicochemical properties (pH, lactic acid content, total soluble solid, colour, texture and proximate composition) of dadih with different LAB strains and without LAB strain were determined. Results showed that L. paracasei spp. paracasei, Lactobacillus brevis, Lactobacillus casei were isolated from cow’s milk dadih while only L. paracasei spp. paracasei was isolated from goat’s milk dadih. The number of LAB ranged from 5.73 to 6.06 log10 CFU/g for cow’s milk dadih and 5.19 to 5.88 log10 CFU/g for goat’s milk dadih. Results revealed that dadih inoculated with LAB has lower pH and greater amount of lactic acid produced than control dadih. Total soluble solid for dadih with LAB also decreased. Hardness of dadih without LAB culture was higher compared to the inoculated dadih with LAB cultures. Proximate compositions (moisture, ash, crude fat, crude protein and total carbohydrate) showed variations due to differential formulations and incorporations of different LAB strains. Findings showed that L. acidophilus was chosen as the best starter culture for both types of dadih because it has significant effects on pH, titratable acidity, total soluble solid and texture of the dadih.

Age-related changes, influencing factors and crosstalk between vaginal and gut microbiota: a cross-sectional comparative study of pre- and postmenopausal women

Objective: The ideal vaginal environment is maintained by Lactobacillus species, which keep the vagina clean and free of infections, including sexually transmitted diseases and human papilloma virus infection. Other reported health benefits of Lactobacillus include a favorable impact on fertility and immunity, leading to a reduced risk of gynecological malignancies. Age-related decline in estrogen affects the population of Lactobacillus, leading to dominance of pathogenic flora and increased diversity in vaginal microbiota. In this study, we compared the differences between the vaginal microbiota of premenopausal and postmenopausal women. In addition, we examined the relationships between vaginal and gut microbiota, as well as their relationships to sex hormones and equol producing ability. Methods: This was a cross-sectional study of 35 premenopausal and 35 postmenopausal women, ranging from 27 to 76 years of age. We compared parameters such as the composition of the gut and vaginal microbiota, vaginal pH, sex hormones in the blood (estradiol and follicular stimulating hormone), and urinary equol concentration. Results: In the vaginal microbiota of premenopausal women, Lactobacillus species constituted approximately 71.98%, and pathogenic flora constituted approximately 16.87%. They were 10.08% and 26.78%, respectively, in the vaginal microbiota of postmenopausal women. Therefore, the proportion of Lactobacillus was significantly low, whereas microbial diversity and vaginal pH were significantly high (p<0.0001) in postmenopausal women. The compositions of the vaginal microbiota were significantly different in pre- and postmenopausal women. However, such differences were not noticeable in the gut microbiota. Urinary equol production had no significant correlation with vaginal microbiota, although it had significant relationships with gut microbiota in postmenopausal women. There were significant correlations among bacterial species in the gut and vaginal microbiota, especially in postmenopausal women. In both groups, the proportions of vaginal Lactobacillus were inversely correlated with vaginal microbial diversity and vaginal pH. Conclusion: Postmenopausal women had significantly low lactobacillus and high pathogenic flora in their vaginal flora, whereas such age-related differences were not identified in gut microbiota. There were significant correlations among the bacterial species inhabiting the gut and vaginal microbiota, especially in postmenopausal women, indicating potential crosstalk between each other.

Screening and Evaluation of a Potential Bacteriocin Producing Lactobacillus in Milk and Dairy Products Collected from Puducherry

In an array of identifying safe antimicrobial compounds, bacteriocin producing Lactobacillus strain have been investigated in this study from the daily consuming food resources of humans. Till now, the best studied bacteriocins are nisin A produced by Lactobacillus lactis and pedocin PA-1 synthesized by Pediococcus acidilactici which have been accredited as a preservative in the food industries by the World Health Organization (WHO). For this study, four different milk and dairy products viz., curd, cheese, yoghurt and butter were collected from the local markets of Karaikal region, Puducherry, India and were used for the isolation of Lactobacillus species using MRS agar. Totally, five morphologically distinct strains were collected and were initially named as MPD 1 to MPD 5. During the screening process of bacteriocin production, the strain MPD 5 showed maximum antimicrobial activity against Vibrio cholerae MTCC 3906 with 900AU/ml. This strain was molecular identified as Lactiplantibacillus plantarum MDP 5 based on 16S rRNA partial sequence method. This 16S rRNA partial sequence was submitted to the NCBI nucleotide GenBank and provided with the accession number, MW301154.1. Further, this strain revealed an enhanced production of bacteriocin using the standardized physicochemical factors such as pH 7, 35°C, 2% fructose and 1% peptone. Furthermore, these optimal conditions revealed more than 2-fold increase in the bacteriocin production. All the above information suggesting the possibilities of bacteriocin for the bioindustrial production using the L. plantarum MDP 5 of this study and its future prospects for the investigation of biocidal activities against many highly infectious pathogens of human and veterinary.

Determination of Molecular Weight and Antimicrobial Activities of a Purified Bacteriocin from Lactiplantibacillus plantarum MDP 5

Nowadays, unlimited use of antibiotics and preservatives have become a big concern regarding the human health which turn the interest of biotech industries into their research on biologically active molecules from probiotic microbes, since they are nontoxic and suitable for many safer applications. On this background, the present investigation focused on the characterization of a bacteriocin from a Lactobacillus strain. The characterization of a bacteriocin was done using a Lactiplantibacillus plantarum MDP 5 isolated from the local markets of Puducherry and production was performed under standardized cultural conditions. The study on the maximum recovery of bacteriocin using ammonium sulphate precipitation method revealed that the 60% saturation rate evidenced highest activity of 6500 AU/ml with 4.113g/L dry weight followed by the purification was done with RP-HPLC method using C18 column. The purified bacteriocin revealed a novel molecular weight of 22 kDa with the help of SDS-PAGE which has not been reported from Lactobacillus species. Further, the purified bacteriocin evidenced appreciable antimicrobial activities against all the tested human bacterial pathogens of this study. The highest antimicrobial activity was recorded against Escherichia coli MTCC 443 followed by Staphylococcus aureus MTCC 96, Vibrio parahemolyticus MTCC 451, Enterococcus faecalis MTCC 9845, Pseudomonas aeruginosa MTCC 741 and Klebsiella pneumoniae MTCC 109 in the concentrations of 8AU/ml, 16AU/ml, 32AU/ml, 64AU/ml, 256AU/ml and 512AU/ml, respectively. From the overall observation, this study explored a novel bacteriocin purified from a probiotic bacterium represented potential antimicrobial activities against many human pathogens which suggesting its possible use for the safe therapeutic applications.

Engineering of Vaginal Lactobacilli to Express Fluorescent Proteins Enables the Analysis of Their Mixture in Nanofibers

Lactobacilli are a promising natural tool against vaginal dysbiosis and infections. However, new local delivery systems and additional knowledge about their distribution and mechanism of action would contribute to the development of effective medicine. This will be facilitated by the introduction of the techniques for effective, inexpensive, and real-time tracking of these probiotics following their release. Here, we engineered three model vaginal lactobacilli (Lactobacillus crispatus ATCC 33820, Lactobacillus gasseri ATCC 33323, and Lactobacillus jensenii ATCC 25258) and a control Lactobacillus plantarum ATCC 8014 to express fluorescent proteins with different spectral properties, including infrared fluorescent protein (IRFP), green fluorescent protein (GFP), red fluorescent protein (mCherry), and blue fluorescent protein (mTagBFP2). The expression of these fluorescent proteins differed between the Lactobacillus species and enabled quantification and discrimination between lactobacilli, with the longer wavelength fluorescent proteins showing superior resolving power. Each Lactobacillus strain was labeled with an individual fluorescent protein and incorporated into poly (ethylene oxide) nanofibers using electrospinning, as confirmed by fluorescence and scanning electron microscopy. The lactobacilli retained their fluorescence in nanofibers, as well as after nanofiber dissolution. To summarize, vaginal lactobacilli were incorporated into electrospun nanofibers to provide a potential solid vaginal delivery system, and the fluorescent proteins were introduced to distinguish between them and allow their tracking in the future probiotic-delivery studies.

Vaginal health in women and the possibility of predicting preterm birth through microbiome analysis

Background: With the recent development of next-generation sequencing technology, the microbiome in the body is being revealed in detail. It is also possible to describe the normal vaginal microenvironment and, more specifically, any changes in pregnancy. Moreover, we present the hypothesis that the microbiome is a contributing factor to preterm birth (PTB).Current Concepts: High estrogen status stimulates the maturation and proliferation of vaginal epithelial cells and the accumulation of glycogen, which promotes lactic acid production and maintains the vaginal environment at an acidic pH. The vaginas of most premenopausal women are predominantly colonized by Lactobacillus which plays an important role in local defense. Recently, it has also been reported that there are several specific types of Lactobacillus species, while other anaerobes, including Gardnerella and Atopobium also coexist in the vagina. Vaginal dysbiosis is defined as various expressions of microorganisms, secretion of specific metabolites, and changes in pH. During pregnancy, a multitude of microbiome changes occur in the oral cavity, gut, vagina, and placenta. The risk of PTB increases if the microbiome changes to one of dysbiosis. It is possible to analyze the characteristic microbiome composition related to PTB and to develop biomarkers predicting PTB. It is necessary to educate patients based on these findings.Discussion and Conclusion: Microbiome analysis has contributed significantly to understanding the association between women’s vaginal health and PTB. Continued research will also contribute to public health by assisting in the prediction and prevention of PTB.

Cholesterol-lowering Potential and Exopolysaccharide Biosynthesis of Lactobacillus spp. isolated from Human Milk

Recent research generated information that human milk is not only a valuable source of nutrition, but it also provides a complex microbial community, containing especially Lactobacillus species - the major components of a great number of commercial probiotics. New findings on potential applications of Lactobacillus species revealed that these bacteria have abilities to produce anti-microbial exopolysaccharides (EPS) and to reduce cholesterol in culture broth. In this study, we successfully isolated and screened for Lactobacillus bacteria from human milk samples, and finally obtained four strains, including L. plantarum BM7.13, L. plantarum BM29.7, L. acidophilus BM10.8 and L. rhamnosus BM30.4. Researching the probiotic activities of these strains showed that all strains were tolerant to the low pH (3.0) and 0.3% bile salts. Characterization of the probiotic properties indicated that all selected Lactobacillus isolates had ESP (125-326 mg/L) and exhibited strong antimicrobial activities against pathogenic microbes, such as Escherichia coli, Staphylococcus aureus, Shigella flexneri and Salmonella typhimurium. Our results also indicated that all strains displayed cholesterol assimilation capabilities in culture broth with the maximum figure recorded for L. plantarum BM7.13.

The correlations between gut microbiota of Muslim Thai lactating women and their dietary intake and gut microbiota of breastfed infants

Introduction: Foods and nutrients are essential not only for human health, but also for the balance of gut microbiota. This research aimed to correlate the gut microbiota of lactating women with their food/ nutrient intakes, as well as with their infants’ gut microbiota. Methods: A cross-sectional study was conducted in 27 pairs of mothers and their exclusively breastfed infants. For lactating women, the dietary assessment was conducted by 24-hour recall, and food groups were assessed following the Food and Agriculture Organization’s guidelines, while nutrient intake was analysed using INMUNCAL V3 programme. Gut microbiota of mothers and infants were measured in stool samples using fluorescent in situ hybridisation technique. Results: It was found that energy intake of mothers was only 66% of the recommended Thai Dietary Reference Intakes (DRIs). Most micronutrient and dietary fibre intakes were below the Thai DRIs. Vitamin A (VA)-rich fruits and vegetables food group correlated positively with Lactobacillus species (spp). The association between gut microbiota and nutrient intake of lactating women showed that total protein, phosphorus, and VA were positively correlated with Bifidobacterium spp.; while β-carotene and vitamin C were also positively correlated with Lactobacillus spp. In contrast, consumption of eggs and calcium correlated negatively with Clostridium spp./ Enterobacter spp. Bifidobacterium spp. and Lactobacillus spp. of lactating women and breastfed infants showed strong correlations. Conclusion: Food and nutrient intakes of lactating women were correlated with their Clostridium spp./Enterobacter spp., Bifidobacterium spp. and Lactobacillus spp. Furthermore, Bifidobacterium spp. and Lactobacillus spp. of mothers and breastfed infants showed strong correlations.