Strains Of Streptococcus Faecalis Research Articles

ISOLATION & FORMULATION OF POMEGRANATE JUICE BASED ON PROBIOTIC PROPERTIES

Probiotics are mainly living microorganisms that used to improve or restore gut flora when ingested. The consumption of probiotics is mainly regarded as safe.A strain of lactobacillus bacteria strain Streptococcus faecalis strains were isolated from bifilac probiotic medicine and identified by colony morphologies cultured on MRS (Man, Rogosa and Sharpe) media and biochemical testing were done in this study. Isolated bacteria were chosen for probiotic screening and further investigation was done based on biochemical properties and further screening. In this study, Gram staining, Catalase test, carbohydrate fermentation, protease test, starch hydrolysis test, motility test, urease, catalase, nitrate test, indole test, growth optimization (pH optimization, and temperature optimization) were all used . Based on the OD (Optical Density), isolated bacteria may thrive at pH 9.0 and at room temperature of 25 ℃, making them suitable for use as a probiotic.The shelf life of prepared health drink was also check by checking the growth of bacteria on to the EMB agar media. So, different test revealed that S. faecalis can used as a probiotic and also for the development of probiotic health drink. So Probiotics used in gut microbiota by eliciting an immune response that recognises them as beneficial and forms a protective barrier in the intestine against infections.

Screening of Antagonistic Activity of Lactic Acid Bacteria Strains in relation to Candida scotti for Optimal Conservation of Plant Juices

In a model experiment on juices of legumes with nine strains of lactic acid bacteria (LAB) of the genus Lactobacillus isolated from aboveground parts of the vegetating leguminous plants (RS1, RS3, RS4), their rhizosphere (RS5), plant juices (RS6 and RS7), and a corn silage (RS2), and also with the collection strain of Lactobacillus plantarum BS933 and commercial strain Streptococcus faecium 500, joint cultivation with Candida scotti was carried out. Change of standard indicators, such as PH of the medium, the ratio of lactic acid to fatty acid homologues, and microflora analysis of the juice demonstrated that yeast actively competes with LAB for nutrients in the environment and possesses an antibacterial effect that leads to silage deterioration. The results showed that only certain Lactobacillus strains (3 of 8) and also S. faecium 500 are capable of resisting negative consequences of yeast activity during conservation of plant juices.

Phototoxic Effect of Visible Light on Porphyromonas gingivalis and Fusobacterium nucleatum: An In Vitro Study¶†

AbstractThe antibacterial effect of visible light irradiation combined with photosensitizers has been reported. The objective of this was to test the effect of visible light irradiation without photosensitizers on the viability of oral microorganisms. Strains of Porphyromonas gingivalis, Fusobacteriurm nucleatum, Streptococcus mutans and Streptococcus faecalis in suspension or grown on agar were exposed to visible light at wavelengths of 400–500 nm. These wavelengths are used to photopolymerize composite resins widely used for dental restoration. Three photocuring light sources, quartz‐tungsten‐halogen lamp, light‐emitting diode and plasma‐arc, at power densities between 260 and 1300 mW/cm2 were used for up to 3 min. Bacterial samples were also exposed to a near‐infrared diode laser (wavelength, 830 nm), using identical irradiation parameters for comparison. The results show that blue light sources exert a phototoxic effect on P. gingivalis and F. nucleatum. The minimal inhibitory dose for P. gingivalis and F. nucleatum was 16–62 J/cm2, a value significantly lower than that for S. mutans and S. faecalis (159–212 J/cm2). Near‐infrared diode laser irradiation did not affect any of the bacteria tested. Our results suggest that visible light sources without exogenous photosensitizers have a phototoxic effect mainly on Gram‐negative periodontal pathogens.

Phototoxic Effect of Visible Light on Porphyromonas gingivalis and Fusobacterium nucleatum: An In Vitro Study¶†

The antibacterial effect of visible light irradiation combined with photosensitizers has been reported. The objective of this was to test the effect of visible light irradiation without photosensitizers on the viability of oral microorganisms. Strains of Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus mutans and Streptococcus faecalis in suspension or grown on agar were exposed to visible light at wavelengths of 400-500 nm. These wavelengths are used to photopolymerize composite resins widely used for dental restoration. Three photocuring light sources, quartz-tungsten-halogen lamp, light-emitting diode and plasma-arc, at power densities between 260 and 1300 mW/cm2 were used for up to 3 min. Bacterial samples were also exposed to a near-infrared diode laser (wavelength, 830 nm), using identical irradiation parameters for comparison. The results show that blue light sources exert a phototoxic effect on P. gingivalis and F. nucleatum. The minimal inhibitory dose for P. gingivalis and F. nucleatum was 16-62 J/cm2, a value significantly lower than that for S. mutans and S. faecalis (159-212 J/cm2). Near-infrared diode laser irradiation did not affect any of the bacteria tested. Our results suggest that visible light sources without exogenous photosensitizers have a phototoxic effect mainly on Gram-negative periodontal pathogens.

Reduction of Bacillus subtilis, Bacillus stearothermophilus and Streptococcus faecalis in meat batters by temperature-high hydrostatic pressure pasteurization

People have a growing preference for fresh, healthy, palatable and nutritious meals and drinks. However, as food deterioration is a constant threat along the entire food chain, food preservation remains as necessary now as in the past. High pressure processing is one of the emerging technologies being studied as an alternative to the classical pasteurization and sterilization treatments of food. Samples of fried minced pork meat were inoculated with strains of Streptococcus faecalis and with sporulating microorganisms like Bacillus subtilis and stearothermophilus. The samples were subjected to several combined temperature-high pressure treatments predicted by the mathematical model applied in Response Surface Methodology. Using the “Box–Behnken” concept, the number of tests for a whole area of pressure–temperature–time-combinations (pressure variation: 50–400 MPa, temperature variation 20–80°C, time variation 1–60 min) could be limited to 15. In the center point of the model, the experimental combination was performed in triple to estimate the experimental variance. All the tests were executed in a randomized order to exclude the disturbing effect of environmental factors. Microbial analysis revealed for each microorganism an important reduction in total plate count, demonstrating a superior pressure resistance of the sporulating microorganisms in comparison with the most pressure resistant vegetative species Streptococcus faecalis. The effect of the medium composition could be neglected, showing little protective effect of, e.g. the fat fraction as seen in heat preservation techniques.

Ozone Inactivation of Microorganisms in Water: Gram positive Bacteria and Yeast

Inactivation kinetics of referent and isolate strains of Streptococcus faecalis. Staphylococcus aureus and Candida albicans towards ozone in water were analyzed in this paper. Water suspensions of 104 - 106 CFU/mL of Streptococcus faecalis ATCC 10541, Staphylococcus aureus ATCC 29213, Candida albicans ATCC 10231 and wild strains were prepared in sterile conditions and treated in a 100 mL bubble reactor with ozone, achieving concentrations from 0.3 to 2.5 mg of dissolved ozone / L of water, in contact with microorganisms. Inactivation kinetics of these bacterial strains was similar to gram-negative bacteria; first order inactivation kinetics respect to both the concentrations of ozone and microorganisms were found,. resulting an overall second order inactivation kinetics. Staphylococcus aureus isolate was more resistant than Streptococcus faecalis and Candida albicans strain. The longest time required to achieve total inactivation was 10 minutes.

Characterization of a Tn925-induced mutant of Staphylococcus aureus altered in exoprotein production.

An insertional mutant was isolated from a bovine Staphylococcus aureus strain after membrane-mating with a Streptococcus faecalis strain carrying conjugative plasmid pCF10::Tn925. This mutant, designated RC128, showed enhanced production of alpha-hemolysin and proteases and decreased production of coagulase, extracellular protein A, DNase, lipase and delta-hemolysin. No difference was found in the production of beta-hemolysin. Both, Southern blot analysis and transfer of the pleiotropic mutant phenotype by transduction, indicated that the mutation was originated from a single insertion of transposon Tn925. The LD50 determined by intraperitoneal administration in mice showed that mutant RC128 was slightly less virulent than its parental strain.

In vitro activity of flomoxef and cefazolin in combination with vancomycin

207 clinical isolates from strains of patients from the University Children's Hospital of Kiel were investigated for their in vitro activity with the agar dilution method against flomoxef and cefazolin (alone and partially in combination with vancomycin). Staphylococci were also tested with other cephalosporins (cefoxitin, cefamandole, cefotaxime, cefotetan and latamoxef). Flomoxef and cefazolin always acted more vigorously on staphylococci than the other cephalosporins. Resistance of Staphylococcus aureus strains against flomoxef and cefazolin did not occur but was found in 15 and 5 of 98 Staphylococcus epidermidis strains, respectively. Enterococcus faecalis strains were always resistant against both drugs; Streptococcus faecium strains were only moderately sensitive. Combined testing of flomoxef or cefazolin with vancomycin showed synergism in almost all staphylococcal strains. Synergism was stronger when S. epidermidis strains were only weakly sensitive to or resistant against flomoxef and cefazolin in comparison to highly sensitive strains. Flomoxef (or cefazolin) acted synergistically in combination with vancomycin on E. faecalis and S. faecium with the exception of two strains of E. faecalis which showed an additive effect of both drugs.

Thermal susceptibility of Streptococcus faecium strains isolated from frankfurters

The heat resistance of nine strains of Streptococcus faecium isolated from frankfurters was determined at 63 and 68 degrees C in brain heart infusion broth. Exponential-phase cultures (approximately 10(7) colonies/mL) were used as inoculants. The heat resistance of S. faecium DP2181, a moderately resistant isolate, was further examined in broth (55, 63, and 68 degrees C) and frankfurter emulsion (63 and 68 degrees C). The decimal reduction times (D values) were determined by regression. In broth, both time-temperature combinations resulted in a 3-4 log decline in bacterial numbers for the nine S. faecium strains tested. For S. faecium DP2181, the survivor curves deviated from the logarithmic order of death at all three heating temperatures. An initial slow period of death was evident at 55 degrees C and a resistant tail of organisms was observed at 55, 63, and 68 degrees C. The D55D63, and, D68 values for the logarithmic portion of the corresponding survivor curves were 105.6, 9.36, and 3.34 min, respectively. The survival of DP2181 was enhanced by the frankfurter emulsion. The results indicate that populations of S. faecium existed that were very heat resistant and could survive normal frankfurter processing if initially present in high numbers.

Growth characteristics of enterococci isolated from Laban Rayeb

Eleven strains of Enterococcus (Streptococcus) faecalis isolated from Laban Rayeb, a type of fermented milk, had been studied when grew in milk. Enterococcus (Streptococcus) faecalis strains 19 and 22 were the most active strains in the production of lactic acid, acetaldehyde and diacetyl. Both strains exhibited a high proteolytic activity besides a good clean flavour. Based on the obtained results, Enterococcus (Streptococcus) faecalis 19 and 22 could be used to bring about the lactic fermentation during the manufacture of some cultured dairy products.

Histamine formation by enterococci in goat cheese

Cheeses were made of heat-treated goat milk inoculated with large numbers of a histamine-producing strain of Streptococcus faecium or a non-histamine-producing strain of S. faecalis. Every second week during ripening (91 days) the cheeses were sampled for histamine analyses and bacteriological analyses. The numbers of enterococci remained high throughout the whole period of investigation and the maximum amount of histamine detected was 8.2 μg/g in one of the cheeses. The enterococci seem to have no relevance from a histamine intoxication point of view in cheeses of this kind.

The Production of Vitamin B6 by Microorganisms in Corn Meal

Five microorganisms out of 22 cultures previously isolated from fermenting corn meal produced vitamin B6. These included Hansenula subpelliculosa (strain 1), Moraxella sp. (strain 4), and Bacillus licheniformis (strains 6, 9, and 10). Microorganisms not producing vitamin B6 were: Streptococcus faecalis (strains 3, 8, 25, and 34); Lactobacillus brevis (strains 11, 12, 14, 15, 16, 3, 38, 41, 43, 44, and 45); Agrobacter spp. (strains 22 and 23). B. licheniformis strains 6 and 10 were studied further to establish optimum conditions for vitamin B6 production in corn meal. For strain 6, optimal initial pH and temperature were 7 and 45°C, respectively. For B. licheniformis strain 10, there was no initial pH effect and the optimal temperature was also 45°C.

Evaluation of the combination effects of ampicillin or vancomycin combined with streptomycin, gentamicin, tobramycin or netilmicin against enterococci.

Seven strains of Streptococcus faecalis, of which two possessed high-level resistance to streptomycin (MIC greater than or equal to 2000 mcg/ml), and two strains of Streptococcus faecium were evaluated with respect to killing-effect and duration of post-antibiotic effect (PAE) of ampicillin and vancomycin in combination with streptomycin, gentamicin, tobramycin and netilmicin. No synergistic combination effects were seen with the two strains highly-resistant to streptomycin or with the two Streptococcus faecium strains to netilmicin and tobramycin. When these strains were excluded, no significant difference in average killing could be detected between the four aminoglycosides. The mean prolongation in recovery period of susceptible strains was significantly longer with combinations of ampicillin and netilmicin or streptomycin as compared with either gentamicin or tobramycin. A similar relationship was seen for combinations of vancomycin with the four aminoglycosides.

In-vitro activity of the new penems FCE 22101 and FCE 24362 alone or in combination with aminoglycosides against streptococci isolated from patients with endocarditis.

Seven strains of viridans streptococci isolated from patients with endocarditis were inhibited in vitro by 0.06-2 mg/l and 0.016-0.5 mg/l of the penems FCE 22101 and FCE 24362 respectively. The MBCs were the same or two-fold higher than the respective MIC with three exceptions. One strain of Streptococcus faecalis was only inhibited (8 mg/ml respectively 0.5 mg/l; MBC greater than 32 mg/l) and one strain of Str. faecium was resistant (MIC greater than or equal to 16 mg/l). When combined with gentamicin or netilmicin a bactericidal and synergistic killing was observed within 1-8 h in all strains except Str. faecium. Synergy could also be confirmed in all cases by following bacterial growth kinetics after elimination of antibiotics, by calculating the difference between the times required for bacteria exposed to antibiotic and unexposed bacteria to increase in numbers (PAE).

Further studies on post‐antibiotic effect and synergism in two strains of Streptococcus faecalis

The differences in the synergistic potential for either killing effect or increase in duration of post-antibiotic effect (PAE) seen with various beta-lactam-aminoglycoside combinations in two strains of Streptococcus faecalis were further studied to examine this relationship in more detail. It was seen that a strain which produced a synergistic increase in recovery period (PAE greater than or equal to 0.5 h), comparing the beta-lactam antibiotics alone and when combined with streptomycin, showed increased sensitivity (greater than or equal to 1 log10 reduction in viable counts) to a subinhibitory concentration of streptomycin added to a culture recovering from the PAE; this was not demonstrated with a strain showing no increase in PAE when briefly exposed to a combination therapy, although its corresponding killing curve was clearly synergistic. Moreover, it was seen that the differences in the synergistic prolongation of recovery period when combining various aminoglycosides at 1/4 x MIC with ampicillin were consistent with the different duration of PAE with the particular aminoglycoside alone at the MIC.

Synergism and mechanism of subinhibitory concentration of streptomycin on Streptococcus faecalis

The influence of various incubation conditions on synergism with cell wall-active agents combined with streptomycin was studied in a Streptococcus faecalis strain. It could be shown that both a synergistic increased killing effect and a synergistic prolongation of post-antibiotic effect (PAE) were not dependent on an active process, as they occurred both in an anaerobic atmosphere and when an electron transport inhibitor (sodium azide) was added to the media. Moreover, it was demonstrated that if a drug, alone or in combination with streptomycin, had a PAE, there was an increased susceptibility to a subinhibitory concentration of streptomycin (1/4xMIC) when added to a culture recovering from its PAE. These findings confirm the commonly held belief in a mechanistic mechanism of synergism: That cell wall-active agents modify in some way the cell-envelope, thereby enhancing aminoglycoside uptake and killing in Streptococcus faecalis.

Evaluation of Four Media for Recovery of Heat-Stressed Streptococci

Two strains of Streptococcus faecium and one strain of Streptococcus faecalis were subjected to heat stress in a ham broth and recovered on all purpose tween agar; deMan, Rogosa, Sharpe agar; tryptone-dextrose-yeast extract-meat extract-peptone agar; and tryptic soy agar. Survival curves for the organisms recovered on each agar were constructed and D values (death rates) were calculated. Differences in death rates were noted for each organism between different media. The greatest recovery of cells that had received sub-lethal heat treatment occurred using all purpose tween agar.

Ammonium lactate from deproteinized alfalfa juice byStreptococcus faecium

Deproteinized alfalfa juice is a by-product of the mechanical fractionation of alfalfa to obtain protein. In this work the juice was used as the substrate for the production of ammonium lactate (l-lactic acid) by a strain ofStreptococcus faecium. Batch fermentation with a constant pH of 5.8 gave 27.2 g/l of lactic acid (90% conversion and 1.1 g/l/h productivity) and 6×1012 cells/l after 24 h. Semicontinuous fermentation allowed the conversion of 3-times the volume of deproteinized juice after 44 h, finally giving 29.7 g/l of ammonium lactate (99% conversion and 2.5 g/l/h productivity) and 4–6×1012 cells/l.

Further Studies on the Thermal Resistance of Streptococcus faecium and Streptococcus faecalis in Pasteurized Ham

Strains of Streptococcus faecium and Streptococcus faecalis were inoculated into raw ham and subjected to heating conditions simulating the industrial processing of cured, pasteurized ham. Thermal resistance characteristics including survival curves, phantom thermal death time curves, D values and z values were determined. Streptococcus faecium P-1A was the most heat resistant organism tested, showing a D value of 29.04min at 66°C. Streptococcus faecium E-20 showed a D value of 13.69min at this temperature and Streptococcus faecalis P-2A was the least heat resistant organism with a D value of 1.69min at 66°C. It was demonstrated that these three organisms showed greater thermal resistance in the raw ham than in Sorenson's buffer or ham broth, as determined in a previous study. The derived z values for the raw ham suggest that the use of the z value in determining pasteurization process parameters be carefully reconsidered.

Synergistic effect of ampicillin or vancomycin in combination with decreasing concentrations of streptomycin against enterococci.

The extent of synergistic killing and duration of the post-antibiotic effect (PAE) was evaluated in streptomycin-susceptible strains of Streptococcus faecalis and Streptococcus faecium with 20 mcg/ml of ampicillin or 10 mcg/ml of vancomycin in combination with decreasing concentrations of streptomycin (20, 10, 5, 2, 1, 0.5 mcg/ml). The bactericidal activity or duration in recovery period declined progressively in a linear pattern with decreasing concentrations of streptomycin. One log10 or greater reduction in viable counts was seen with streptomycin concentrations of 2 mcg/ml or higher with both ampicillin and vancomycin. A synergistic increase in recovery period (PAE greater than or equal to 0.5 h) of ampicillin or vancomycin was observed with concentrations of streptomycin in excess of 2 mcg/ml and 1 mcg/ml, respectively. These results suggest that lower dosage of streptomycin in the therapy of enterococcal infections will probably result in a higher relapse rate.