Aims: This study aimed to evaluate antidiabetic potential of indigenous Lactobacillus isolates by measuring the ability of α-glucosidase inhibitory (AGI) and antioxidant activity. The mechanism of probiotics as antidiabetic can occur through the AGI and antioxidant activity of LAB, which is able to suppress oxidative stress that causes chronic inflammation and pancreatic β cell apoptosis, and then through the ability to produce exopolysaccharide (EPS) and short chain fatty acids (SCFA). Methodology and results: MRS broth enriched with 10% glucose was selected as the growth medium for Lactobacillus. The growth medium was then centrifuged to obtain CFS and CFE was produced by extracting the medium with 96% ethanol as a solvent. The results showed that Lactobacillus pentosus MK42 had the highest AGI activity of 80.32 ± 2.20%. Antioxidant activity was not significantly different (P>0.05) among the tested Lactobacillus isolates. Lactobacillus paracasei RK41 produced the highest EPS (360.13 ± 50.01 mg/L), which was not significantly different (P>0.05) from Lactobacillus plantarum1 RB210. All Lactobacillus isolates were able to produce acetic acid, but not all were able to produce propionic and butyric acid. The highest propionic acid was produced by L. plantarum1 RB210 at 0.40 ± 0.31 mmol/L and the highest butyric acid was produced by L. plantarum1 MK2 at 0.22 ± 0.08 mmol/L. Conclusion, significance and impact of study The results show definitively that indigenous Lactobacillus isolates have considerable α-glucosidase inhibitor, antioxidant activity and the ability to produce of EPS and SCFA. This preliminary study suggests the use of indigenous Lactobacillus isolates which have the potential as antidiabetic agent, although the responsible compounds are unknown.
alpha-Glucosidases ; Antioxidants ; Lactobacillus--isolation & ; purification ; Hypoglycemic Agents

Lactobacillus sp., generally considered to be a harmless indigenous bacteria of the mucous membrane, occasionally causes serious infections. Lactobacillus endocarditis is a very rare disease, and no case has been reported in Korea. Gram-positive bacilli were isolated from blood cultures of a 41-year-old man with clinically suspected subacute bacterial endocarditis. The patient had a dental procedure 3 months prior to the infection. The isolate was identified as L. casei subsp. casei based on the cultural characteristics and gas liquid chromatography of metabolic products. The patient was treated with ampicillin and improved. When Lactobacillus is isolated from the blood of an endocarditis patient, the significance should be seriously considered. MeSH Terms:
Adult ; Endocarditis, Bacterial/*etiology ; Human ; Lactobacillus casei/*isolation & purification ; Male ; Septicemia/*etiology

BACKGROUNDThe normal microbial flora of the vagina plays an important role in preventing genital and urinary tract infections in women. Thus an accurate understanding of the composition and ecology of the ecosystem is important to understanding the etiology of these diseases. This study aimed to compare the characteristics of main lactobacillus species between healthy women and women with bacterial vaginosis (BV) by quantitative culture and PCR methods. Main lactobacillus species include L. crispatus, L. gasseri, L. jensenii and L. iners.

METHODSA total of 150 women attending Gynecology Outpatient Clinic of Beijing Friendship Hospital, were diagnosed as having BV because three or more of the following criteria were met (standard of Amsel's composite criteria): homogeneous discharge, elevated vaginal pH (pH > 4.5), production of amines, and presence of "clue" cells. Those with less than three of the criteria were considered as healthy. Simultaneously, smears were made of vaginal fluid and Gram stained, then were assessed qualitatively as normal (grade I), intermediate (grade II), or consistent with BV (grade III). Gardnerella vaginalis were identified by using Vitek 2 Compact and PCR methods. Lactobacillus species were identified by PCR methods. Gardnerella vaginalis and lactobacilli colony counts were determined by calculating the most number of colonies of each species in the appropriate plates (colonies between 10 and 300), corrected by the dilution of the sample in the plates, and multiplied by 10 (to account for plating 100 microl), in order to get colony forming units per milliliter of vaginal secretion.

RESULTSBV was diagnosed in 31% (46/150) patients using the composite criteria, the remainder being regarded as healthy. The majority of patients with BV had a smear assessed as grade III (91%, 42/46) and minority of them had a smear assessed as grade II (9%, 4/46). The majority of healthy women had a smear assessed as grade I (64%, 67/104). Smears assessed as grade II were found (36%, 37/104) among patients diagnosed as healthy, with less than three of the composite criteria. L. crispatus was cultured from 94% of healthy women and 83% of women with BV, with the former colonies count average value of 10(6) and the latter of 10(3). L. gasseri, L. iners, and L. jensenii were cultured from 85%, 68% and 43% of healthy women; and 28%, 89% and 44% of BV women, respectively.

CONCLUSIONSThe quantities of four lactobacillus species except L. jensenii had a significant difference between healthy women and women with BV. Our results provide support for the negative association between L. iners and L. gasseri. Although L. crispatus were existent both in healthy and BV positive women's vagina, the numbers of L. crispatus were significantly different for the dominant number in healthy women. Smears of vaginal fluid and Gram stain play an important guiding role in bacteria culture.

Adult ; Female ; Gardnerella vaginalis ; isolation & purification ; Humans ; Lactobacillus ; isolation & purification ; Middle Aged ; Vagina ; microbiology ; Vaginosis, Bacterial ; microbiology

OBJECTIVETo develop a pulsed field gel electrophoresis (PFGE) method for molecular typing of Lactobacillus and Streptococcus thermophilus (S. thermophilus) and to apply it in identification and characterization of both bacteria isolated from yoghurt collected from Beijing supermarket.

METHODSThe five most useful restriction enzymes including Apa I, Not I, Sfi I, Xba I and Sma I were chosen to cut DNA of 52 strains of Lactobacillus, S. thermophilus as well as associated standard bacteria strains. The endonucleases and electrophoresis conditions for PFGE analysis were optimized and applied in molecular typing of Lactobacillus and S.thermophilus isolates. Cluster analysis based on the PFGE data was conducted. The identification results of PFGE were compared with those obtained in biochemical and 16s ribosomal RNA PCR identification tests.

RESULTSNot I was suitable for L. bulgaricus, L. fermentum and L. delbrueckii digestion. While Apa I was an appropriate endonuclease for S. thermophilus, L. acidophilus and L. casei digestion. The results of molecular typing indicated that 24 strains of L.bulgaricus and 15 strains of S. thermophilus were grouped into 8 types by PFGE method, respectively. While 7 strains of L.acidophilus were grouped into 3 types and 2 strains of L. delbrueckii were grouped into 2 different PFGE types.

CONCLUSIONThe results of PFGE analysis are in compliance with those of 16s rRNA PCR and biochemical identification. The PFGE method developed in this study is suitable for molecular characterization of both Lactobacillus and S. thermophilus.

Bacterial Typing Techniques ; methods ; Electrophoresis, Gel, Pulsed-Field ; methods ; Lactobacillus ; classification ; isolation & purification ; Streptococcus thermophilus ; classification ; isolation & purification

Cholesterol-lowering effect of lactic acid bacteria (LAB: Streptococcus, Lactobacillus and Bifidobacterium) is well-known. Thus, we investigated LAB isolated from human intestine on the cholesterol-lowering effect in vitro. Seven Streptococcus (61.1%), 11 Lactobacillus (71.8%) and 7 Bifidobacterium (27.9%) were isolated as acid (pH 2.5 and 3.0) and bile (0.3% oxgall) tolerant strains. Streptococcus HJS-1, Lactobacillus HJL-37 and Bifidobacterium HJB-4 were finally selected as probiotic strains to use through the bile salt hydrolase (BSH) activity assay by using MRS media added taurodeoxycholic acid (TDCA) and the cholesterol-lowering test by using soluble cholesterol containing MRS broth. These studies suggested that the isolated LAB had an excellent hypocholesterolemic effect.
Amidohydrolases/metabolism ; Bifidobacterium/*isolation&purification/physiology ; Cholesterol/*metabolism ; Feces/microbiology ; Female ; Humans ; Intestines/*microbiology ; Lactobacillus/*isolation&purification/physiology ; Male ; Probiotics/*therapeutic use ; Streptococcus/*isolation&purification/physiology ; Taurodeoxycholic Acid

BACKGROUNDOligosaccharides in human milk may protect infants by improving the intestinal micro-flora and fermentation. This study was to investigate effects of infant formula milk consisting of galacto-oligosaccharide (GOS) on intestinal microbial populations and the fermentation characteristics in term infants in comparison with that of human milk.

METHODSThe test formula (Frisolac H, Friesland, Netherland) was supplemented with GOS at a concentration of 0.24 g/dl. Human milk and another formula without oligosaccharides (Frisolac H, Friesland, Netherland) were used as positive and negative control respectively. Growth, stool characteristics, and side effects of the recruited infants were recorded after 3 and 6 months' follow-up, and the fecal species were collected for the analysis of intestinal micro-flora, short chain fatty acid (SCFA) and pH.

RESULTSAt the end of 3- and 6-month feeding period, intestinal Bifidobacteria and Lactobacilli were significantly increased in infants fed with GOS supplemented formula and human milk when compared with infants fed with negative control formula; however, there was no statistically significant difference between GOS supplemented formula and human milk groups. Stool characteristics were influenced by the supplement and main fecal SCFA (acetic), and stool frequency were significantly increased in infants fed with GOS supplemented formula and human milk, while the fecal pH was significantly decreased as compared with that of negative control (P < 0.05). Supplementation had no influence on incidence of side effects (including crying, regurgitation and vomiting).

CONCLUSIONSSupplementing infant formula with GOS at a concentration of 0.24 g/dl stimulates the growth of Bifidobacteria and Lactobacilli in the intestine and stool characteristics are similar to in term infants fed with human milk.

Bifidobacterium ; isolation & purification ; Dietary Supplements ; Galactose ; administration & dosage ; Humans ; Infant ; Infant Formula ; Infant, Newborn ; Intestines ; microbiology ; Lactobacillus ; isolation & purification ; Oligosaccharides ; administration & dosage

OBJECTIVETo investigate the relationship between Mutans streptococcus (MS), Lactobacilli (LB), pH value and buffer capacity of saliva and early childhood caries (ECC).

METHODSA total of 178 children aged from 42 to 54 months were recruited from 14 urban kindergartens in Beijing. The ECC group contained 87 children with more than 5 decayed teeth, and the control group was composed of 91 caries-free children. Unstimulated (UWS, 2 ml) and stimulated (SWS, 2 ml) whole saliva were collected in each subject. The pH value and buffer capacity of saliva were measured using an electro-acidimeter (+/- 0.01pH).

RESULTSMS and LB were isolated from 96.6% and 79.3% of children with ECC, which were significantly higher than those (63.7%, 27.5%) of caries-free children (P < 0.05) respectively. The counts of MS and LB in children with ECC were approximately 10 times higher than that in caries-free children. Initial pH value and buffer capacity of SWS were significantly higher than that of UWS (P < 0.001) in both groups. The pH value and buffer capacity of both UWS and SWS in ECC children were significantly higher than caries-free children (P < 0.05). There were no significant correlations between MS, LB and pH value and buffer capacity of saliva in caries-free children. Significant correlation (r = 0.249, P < 0.05) was found between the numbers of MS and buffer capacity of stimulated saliva in ECC children.

CONCLUSIONSMS and LB were important pathogens for ECC. Lower initial pH value and buffer capacity of saliva may be an important factor of ECC.

Buffers ; Child, Preschool ; Dental Caries ; metabolism ; microbiology ; Female ; Humans ; Hydrogen-Ion Concentration ; Lactobacillus ; isolation & purification ; Male ; Saliva ; chemistry ; microbiology ; Streptococcus mutans ; isolation & purification

OBJECTIVETo study the effect of a low level of galacto-oligosaccharides (GOS) on intestinal bifidobacteria and lactobacilli, and fermentation characteristics in term infants by comparing with human milk and a standard infant formula without GOS.

METHODSA total of 371 term infants from four hospitals of China were enrolled. The infants started with breast feeding. After 1-2 weeks, some of the infants were changed to feeding with formula milk and then were randomly assigned to two formula-feeding groups: with or without GOS supplementation (2.4 g/L). Growth, stool characteristics, and side effects were recorded in a 3-month-follow-up. Faecal samples were collected for analysis of intestinal bacteria (culture technique), acetic acid (gas chromatography) and pH (indicator strip) at postnatal 3 months.

RESULTSCompared with the formula-feeding group without GOS, the contents of bifidobacteria, lactobacilli and acetic acid and stool frequency increased, and faecal pH decreased significantly in the GOS-formula-feeding and the human milk group. There were no significant differences between the GOS-formula-feeding and the human milk groups. Supplementation with GOS did not lead to an increase in the incidence of crying, regurgitation and vomiting.

CONCLUSIONSA supplementation of low levels of GOS in infant formula seemed to improve stool frequency, decrease faecal pH, and stimulate intestinal bifidobacteria and lactobacilli up to levels as found in breast-fed infants.

Bifidobacterium ; isolation & purification ; Dietary Supplements ; Galactose ; administration & dosage ; Humans ; Hydrogen-Ion Concentration ; Infant Formula ; Infant, Newborn ; Intestines ; microbiology ; Lactobacillus ; isolation & purification ; Oligosaccharides ; administration & dosage

The application potential of rep-PCR in typing beer-spoilage isolates was studied. The effects of different factors, including DNA templates and primers, on the quality and reproducibility of fingerprints were investigated. The CTAB protocol was shown to be the feasible method for DNA extraction. Primers BOXA1R and (GTG)5 were used in rep-PCR, and the PCR products were sequenced to identify strains isolated from two breweries. Rep-PCR fingerprint profiles were obtained by using GelCompar II software. Cluster analysis showed that the isolates belonging to Lactobacillus brevis, L. buchneri, L. casei/paracasei, L. plantarum are divided into 2 or 3 subgroups. In addition, the two rep-PCR fingerprint profiles complemented with each other in typing these isolates. Combining the similarity coefficient cut-off (SCC) of species, 9 unknown isolates were identified rapidly by using both fingerprint databases. The results indicate that rep-PCR is a simple, reliable and promising method for rapid identification of beer-spoilager.
Beer ; microbiology ; Cluster Analysis ; DNA Fingerprinting ; methods ; DNA, Bacterial ; genetics ; isolation & purification ; Databases, Genetic ; Lactobacillus ; genetics ; isolation & purification ; physiology ; Polymerase Chain Reaction ; methods ; Sequence Analysis, DNA ; Time Factors

China ; Drug Resistance, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Fast Foods ; microbiology ; Lactobacillus ; isolation & purification ; physiology ; Microbial Sensitivity Tests ; RNA, Ribosomal, 16S ; genetics ; Streptococcus ; isolation & purification ; physiology ; Yogurt ; microbiology