Probiotic potential of Staphylococcus hominis MBBL 2-9 as anti-Staphylococcus aureus agent isolated from the vaginal microbiota of a healthy woman.

AIMS: To isolate and characterize an antagonist for use as probiotic agent in the biocontrol of Staphylococcus aureus. METHODS AND RESULTS: Bacteria that exhibited antimicrobial activity against Gram-positive bacteria including Staph. aureus were isolated from 12 healthy women, with Staphylococcus hominis MBBL 2-9 showing the strongest activity. The bacteriocin produced by Staph. hominis MBBL 2-9 was purified by 60% ammonium sulfate saturation, ultrafiltration, HLB cartridge and reverse-phase HPLC. The molecular weight was estimated as 2038.2 Da by MALDI-TOF mass spectrometry. The antagonist survived up to 2 h in artificial gastric juice (pH 2.5) and grew in the presence of 1% porcine bile extract. In addition, Staph. hominis MBBL 2-9 adhered effectively to HT-29 epithelial cell line. CONCLUSION: Staphylococcus hominis MBBL 2-9 exhibited desirable probiotic traits such as acid tolerance, bile resistance and adherence to epithelial cell line. The bacterium also produced a bacteriocin with unique molecular weight and high antimicrobial activity similar to traditional antibiotics. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first report of a bacteriocin-producing Staph. hominis MBBL 2-9 that has potential for use as a probiotic agent against Staph. aureus.

Purification and characterization of a lipopeptide produced by Bacillus thuringiensis CMB26.

AIMS: To isolate an antagonist for use in the biological control of phytopathogenic fungi including Colletotrichum gloeosporioides, then to purify and characterize the biocontrol agent produced by the antagonist. METHODS AND RESULTS: Bacteria that exhibited antifungal activity against the causative agent pepper anthracnose were isolated from soil, with Bacillus thuringiensis CMB26 showing the strongest activity. A lipopeptide produced by B. thuringiensis CMB26 was precipitated by adjusting the pH 2 with 3 n HCl and extracted using chloroform/methanol (2:1, v/v) and reversed-phase HPLC. The molecular weight was estimated as 1447 Da by MALDI-TOF mass spectrometry. Scanning electron and optical microscopies showed that the lipopeptide has activity against Escherichia coli O157:ac88, larvae of the cabbage white butterfly (Pieris rapae crucivora) and phytopathogenic fungi. The lipopeptide had cyclic structure and the amino acid composition was L-Glu, D-Orn, L-Tyr, D-allo-Thr, D-Ala, D-Val, L-Pro, and L-Ile in a molar ratio of 3:1:2:1:1:2:1:1. The purified lipopeptide showed the same amino acid composition as fengycin, but differed slightly in fatty acid composition, in which the double bond was at carbons 13-14 (m/z 303, 316) and there was no methyl group. CONCLUSION: A lipopeptide was purified and characterized from B. thuringiensis CMB26 and found to be similar to the lipopeptide fengycin. This lipopeptide can function as a biocontrol agent, and exhibits fungicidal, bactericidal, and insecticidal activity. SIGNIFICANCE AND IMPACT OF THE STUDY: Compared with surfactin and iturin, the lipopeptide from B. thuringiensis CMB26 showed stronger antifungal activity against phytopathogenic fungi. This lipopeptide is a candidate for the biocontrol of pathogens in agriculture.

FGF-1 affixation stimulates ePTFE endothelialization without intimal hyperplasia.

The affixation of FGF-1 to porous vascular grafts has been reported to stimulate capillary ingrowth and surface endothelialization. The current study further characterizes responses to fibroblast growth factor (FGF)-1 affixation to 30-cm-long grafts followed 140 days. ePTFE grafts (30 cm x 8 mm i.d.), 60 microns internodal distance, were impregnated with fibrin glue (FG) suspensions containing FGF-1 and heparin. Two negative control groups were treated either with FG with heparin alone or left untreated. Grafts were explanted from the canine thoracoabdominal aortic position after 10, 30, or 140 days (n = 3/time/group) 10 hr after im injection of tritiated thymidine (0.5 muCi/kg). Specimens were studied by light and electron microscopy, immunohistochemistry, morphometric analyses, and cross-sectional autoradiography. RNA preparations from inner capsule tissues were used for reverse transcription-polymerase chain reaction (RT-PCR) analyses of FGF-1, FGF-2, transforming growth factor-beta 1, (TGF-beta 1) and FGF receptor mRNA species. Inner capsule collagen was quantitated by hydroxyproline colorimetry. Histologic analyses of perianastomotic regions were performed for comparison purposes. All explants were patent and without intimal hyperplasia. Progressive capillarization of the internodal spaces occurred over time and was significantly more extensive in the FGF-1-treated group. Endothelialization of the luminal surface increased with time, at 140 days covering 86.7 +/- 11.6% of the FGF-1 explants vs 46.1 +/- 7.5% and 48.1 +/- 13.3% in the other groups, P < 0.007 and P < 0.04, respectively. Inner capsule thickness at 140 days differed significantly (P < 0.05) between the FGF-1 group (138.8 microns) vs either control group (93 and 67 microns, respectively), which did not significantly differ from each other. Cross-sectional autoradiography demonstrated an FGF-1-induced mitotic index increase at 30 days, 9.6 +/- 4.4% compared to 2.5 +/- 1.0 and 0 +/- 0%, respectively, with both myofibroblasts and endothelial cells incorporating the [3H]thymidine label. The mitotic index returned to quiescent levels at 140 days (< 1% in all groups). Collagen content increased with time in all groups, significantly greater in both FG groups vs untreated controls at 30 and 140 days. RT-PCR analyses revealed FGF-1, FGF-2, FGFR-1 (flg), and TGF-beta 1 mRNA in all samples without evidence of modulation by FGF-1 affixation. These data demonstrate FGF-1-induced graft capillarization and surface endothelialization without functionally significant intimal hyperplasia in this model.