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PubMed1999

Identification and characterization of two bacteriocin-producing bacteria isolated from garlic and ginger root.

Two bacteriocin-producing bacterial strains were isolated from garlic and ginger root by the agar overlay method. The bacteria were identified by 16S rRNA sequence analyses and fermentation patterns as Leuconostoc mesenteroides (garlic isolate) and Lactococcus lactis (ginger isolate). The bacteriocins were assigned the names leucocin BC2 and lactocin GI3, respectively. Physiochemical properties and antimicrobial spectra of the bacteriocins were determined by the spot-on-lawn method. Both bacteriocins were inhibited by proteolytic enzymes. Leucocin BC2 exhibited a narrow antimicrobial spectrum, inhibiting only Bacillus, Enterococcus, and Listeria species. Lactocin GI3 had a broader spectrum, inhibiting Bacillus, Clostridium, Listeria, Enterococcus, Leuconostoc, Pediococcus, and Staphylococcus species. Both bacteriocins remained active when heated at 90 degrees C for 15 min or 120 degrees C for 20 min. Leucocin BC2 assayed at 37 degrees C showed an inhibitory activity of 1,600 AU/ml, whereas at 8 degrees C the activity was 12,800 AU/ml. Conversely, lactocin GI3 activity was the same at both assay temperatures. Both bacteriocins remained active over a pH range of 2.0 to 9.0 and in various organic solvents. The activity of leucocin BC2 was increased when treated with 0.5% acetic acid and 0.5% lactic acid, whereas lactocin GI3 activity was decreased with either acid. The molecular mass values were 3.7 kDa for leucocin BC2 and 3.9 kDa for lactocin GI3. These results show that the inhibitory substances produced by the bacteria isolated from garlic and ginger are bacteriocins that appear to be different in some characteristics from previously reported bacteriocins.

Bacteria↗
PubMed2002

Competitive inhibition of Listeria monocytogenes in ready-to-eat meat products by lactic acid bacteria.

Forty-nine strains of lactic acid bacteria (LAB), isolated from commercially available ready-to-eat (RTE) meat products, were screened for their ability to inhibit the growth of Listeria monocytogenes at refrigeration (5 degrees C) temperatures on agar spot tests. The three most inhibitory strains were identified as Pediococcus acidilactici, Lactobacillus casei, and Lactobacillus paracasei by 16S rDNA sequence analysis. Their antilisterial activity was quantified in associative cultures in deMan Rogosa Sharpe (MRS) broth at 5 degrees C for 28 days, resulting in a pathogen reduction of 3.5 log10 cycles compared to its initial level. A combined culture of these strains was added to frankfurters and cooked ham coinoculated with L. monocytogenes, vacuum packaged, and stored at 5 degrees C for 28 days. Bacteriostatic activity was observed in cooked ham, whereas bactericidal activity was observed in frankfurters. Numbers of L. monocytogenes were 4.2 to 4.7 log10 and 2.6 log10 cycles lower than controls in frankfurters and cooked ham, respectively, after the 28-day refrigerated storage. In all cases, numbers of LAB increased by only 1 log10 cycle. The strain identified as P. acidilactici was possibly a bacteriocin producer, whereas the antilisterial activity of the other two strains was due to the production of organic acids. There was no significant difference (P > 0.05) in the antilisterial activity detected in frankfurters whether the LAB strains were used individually or as combined cultures. Further studies over a 56-day period indicated no impact on the quality of the product. This method represents a potential antilisterial intervention in RTE meats, because it inhibited the growth of the pathogen at refrigeration temperatures without causing sensory changes.

Animals↗
PubMed2002

Apparent antifungal activity of several lactic acid bacteria against Penicillium discolor is due to acetic acid in the medium.

Fifty-six dairy bacteria belonging to the genera Lactococcus, Lactobacillus, Pediococcus, Propionibacterium, Streptococcus, Enterococcus, Leuconostoc, and Brevibacterium were screened for antifungal activity against four species of fungi relevant to the cheese industry (Penicillium discolor, Penicillium commune, Penicillium roqueforti, and Aspergillus vesicolor). Most of the active strains belonged to the genus Lactobacillus, whereas Penicillium discolor was found to be the most sensitive of the four fungi investigated. Further studies on P. discolor showed antifungal activity only below pH 5. This effect of pH suggests that organic acids present in the culture could be involved in the detected activity. Determination of acid composition revealed lactic acid production for active dairy strains and the presence of acetic acid in active as well as inactive strains. It was demonstrated that the undissociated acetic acid originates from the bacterial growth medium. The synergistic effect of the acetic acid present and the lactic acid produced was likely the main factor responsible for the antifungal properties of the selected bacteria. These results could explain some discrepancies in reports of the antifungal properties of lactic acid bacteria, since the role of acetic acid has not been considered in previous studies.

Acetic Acid↗
PubMed2004

Isolation, identification, and selection of lactic acid bacteria from alfalfa sprouts for competitive inhibition of foodborne pathogens.

Several studies have investigated the control of pathogens on alfalfa sprouts, and some treatments have been shown to be effective in reducing pathogen populations. However, control methods investigated thus far only provide pathogen control at a given point in the sprouting process and can affect germination. Competitive inhibition of pathogens with lactic acid bacteria might provide pathogen control throughout the sprouting process and up to consumption. The purpose of this study was to isolate and identify lactic acid bacteria from alfalfa sprouts to inhibit the growth of foodborne pathogens. Fifty-eight lactic acid bacteria isolates were obtained from alfalfa seeds and sprouts. These isolates were evaluated for inhibitory action against Salmonella enterica, Escherichia coli O157:H7, and Listeria monocytogenes by agar spot tests. All pathogens were inhibited by 32 (55%) of the isolates, S. enterica by 56 (97%), E. coli O157:H7 by 49 (84%), and L. monocytogenes by 41 (71%). The isolates were identified by the Analytical Profile Index evaluation of carbohydrate utilization. Isolates obtained from a sample of alfalfa seeds and identified as Lactococcus lactis subsp. lactis showed zones of inhibition of 4.0 mm or greater for all pathogens. One of these isolates, Lactococcus lactis subsp. lactis (L7), and an isolate previously obtained, Pediococcus acidilactici (D3), were evaluated for competitive inhibition of S. enterica, E. coli O157:H7, and L. monocytogenes in deMan Rogosa Sharpe agar and broth. Pathogen populations were significantly reduced by day 5. The selected isolates will be further evaluated in future studies for inhibitory action toward S. enterica, E. coli O157:H7, and L. monocytogenes during sprouting.

Antibiosis↗
PubMed2004

Antimicrobial potential of immobilized Lactococcus lactis subsp. lactis ATCC 11454 against selected bacteria.

Immobilization of living cells of lactic acid bacteria could be an alternative or complementary method of immobilizing organic acids and bacteriocins and inhibit undesirable bacteria in foods. This study evaluated the inhibition potential of immobilized Lactococcus lactis subsp. lactis ATCC 11454 on selected bacteria by a modified method of the agar spot test. L. lactis was immobilized in calcium alginate (1 to 2%)-whey protein concentrate (0 and 1%) beads. The antimicrobial potential of immobilized L. lactis was evaluated in microbiological media against pathogenic bacteria (Escherichia coli, Salmonella, and Staphylococcus aureus) or Pseudomonas putida, a natural meat contaminant, and against seven gram-positive bacteria used as indicator strains. Results obtained in this study indicated that immobilized L. lactis inhibited the growth of S. aureus, Enterococcus faecalis, Enterococcus faecium, Lactobacillus curvatus, Lactobacillus sakei, Kocuria varians, and Pediococcus acidilactici. Only 4 h of incubation at 35 degrees C resulted in a clear inhibition zone around the beads that increased with time. With the addition of 10 mM of a chelating agent (EDTA) to the media, results showed growth inhibition of E. coli; however, P. putida and Salmonella Typhi were unaffected by this treatment. These results indicate that immobilized lactic acid bacteria strains can be successfully used to produce nisin and inhibit bacterial growth in semisolid synthetic media.

Alginates↗
PubMed2006

Lethality of commercial whole-muscle beef jerky manufacturing processes against Salmonella serovars and Escherichia coli O157:H7.

Thermal processes used in making whole-muscle beef jerky include a drying step, which may result in enhanced pathogen thermotolerance and evaporative cooling that reduce process lethality. Several salmonellosis outbreaks have been associated with beef jerky. In this study, a standardized process was used to inoculate beef strips with five-strain cocktails of either Salmonella serovars or Escherichia coli O157:H7, to marinate the strips at pH 5.3 for 22 to 24 h at 5 degrees C, and to convert the strips to jerky using various heating and drying regimes. Numbers of surviving organisms were determined during and after heating and drying. Salmonella reductions of > or = 6.4 log CFU and similar reductions in E. coli O157:H7 were best achieved by ensuring that high wet-bulb temperatures were reached and maintained early in the process (51.7 or 54.4 degrees C for 60 min, 57.2 degrees C for 30 min, or 60 degrees C for 10 min) followed by drying at 76.7 degrees C (dry-bulb temperature). Processes with less lethality that reduced counts of both pathogens by > or = 5.0 log CFU were (i) heating and drying at 76.7 degrees C (dry bulb) within 90 min of beginning the process, (ii) heating for successive hourly intervals at 48.9, 54.4, 60, and 76.7 degrees C (dry bulb), and (iii) heating at 51.7 degrees C (dry bulb) and then drying at 76.7 degrees C (dry bulb), starting before the product water activity dropped below 0.86. In several trials, separate beef strips were inoculated with a commercial Pediococcus acidilactici starter culture as a potential surrogate for evaluating pathogen thermotolerance. The results of these trials suggested that this experimental approach may be useful for in-plant validation of process lethality.

Animals↗
PubMed1999

Prolonging cell-free protein synthesis with a novel ATP regeneration system.

A new approach for the regeneration of adenosine triphosphate (ATP) during cell-free protein synthesis was developed to prolong the synthesis and also to avoid the accumulation of inorganic phosphate. This approach was demonstrated in a batch system derived from Escherichia coli. Contrary to the conventional methods in which exogenous energy sources contain high-energy phosphate bonds, the new system was designed to generate continuously the required high-energy phosphate bonds within the reaction mixture, thereby recycling the phosphate released during protein synthesis. If allowed to accumulate, phosphate inhibits protein synthesis, most likely by reducing the concentration of free magnesium ion. Pediococcus sp. pyruvate oxidase, when introduced in the reaction mixture along with thiamine pyrophosphate (TPP) and flavin adenine dinucleotide (FAD), catalyzed the generation of acetyl phosphate from pyruvate and inorganic phosphate. Acetyl kinase, already present with sufficient activity in Escherichia coli S30 extract, then catalyzed the regeneration of ATP. Oxygen is required for the generation of acetyl phosphate and the H(2)O(2) produced as a byproduct is sufficiently degraded by endogenous catalase activity. Through the continuous supply of chemical energy, and also through the prevention of inorganic phosphate accumulation, the duration of protein synthesis is extended up to 2 h. Protein accumulation levels also increase. The synthesis of human lymphotoxin receives greater benefit than than that of chloramphenicol acetyl transferase, because the former is more sensitive to phosphate inhibition. Finally, through repeated addition of pyruvate and amino acids during the reaction period, protein synthesis continued for 6 h in the new system, resulting in a final yield of 0.7 mg/mL.

Adenosine Triphosphate↗
PubMed1999

Expanded bed adsorption as a unique unit operation for the isolation of bacteriocins from fermentation media.

Expanded bed adsorption using a strong cation exchanger allowed the direct isolation of amylovorin L471, a bacteriocin from Lactobacillus amylovorus DCE 471, from the fermentation medium. The pH of the loading and elution buffer were optimised in a packed bed with cell-free culture supernatant. Bound bacteriocin was eluted with 1.0 M NaCl. The highest recovery (30%) was obtained at the lowest pH (3.6). At higher pH values the recovery was lower, namely 12%, 15% and 7% at pH 4.5, 6.5 and 8.0, respectively. In expanded bed mode, direct isolation of the bacteriocin from the fermentation medium at pH 3.6 (loading and elution) initially resulted in a recovery of 12%. After optimisation of the pH (loading and elution at pH 3.6 and 6.5, respectively), the recovery for amylovorin L471 increased up to 30% and higher. Recovery of enterocin A from Enterococcus faecium CTC 492 fermentation medium averaged 15% (loading and elution at pH 3.6 and 6.0, respectively). With pediocin, produced by Pediococcus acidilactici ATCC 8042, 26% recovery was obtained at a pH of 6.5 during loading and elution. Low recoveries can be ascribed to non-optimal operation conditions (pH of loading and elution buffer), inactivation of the bacteriocin on a cationic resin, and the formation of more insoluble and less active, strongly hydrophobic bacteriocin aggregates upon further purification.

Adsorption↗
PubMedDate not supplied

Assay for citrovorum factor (NSC-3590) in the presence of methotrexate (NSC-740).

Treatment of certain malignancies with high-dose methotrexate/citrovorum factor rescue has recently been adopted as an effective regimen. A microbiologic assay capable of detecting citrovorum factor in the presence of massive amounts of methotrexate has been developed using a strain of Pediococcus cerevisiae resistant to methotrexate. The assay described in this paper is an inexpensive and rapid method of studying the distribution kinetics of citrovorum factor.

Adult↗
PubMed1975

Antimetabolites of pantothenic acid, ureido- and carbamoyl-derivatives.

Pantothenic acid analogs have been synthesized that contain alkyl and/or arylureido and carbamate functions in the beta-alanyl portion of the amide moiety of the vitamin. The analogs are inhibitory to growth of lactic acid bacteria at concentrations as low as 0.6 mug/ml, and the inhibitions are competitively reversed by supplements of pantothenic acid. The carbamate derivatives are more toxic to growth of Lactobacillus plantarum 8014 and Pediococcus cerevisiae 8042 than the ureido analogs, and chloro-substitutents on the aryl group significantly increase the toxicity of the analogs.

Bacteria↗
PubMed1999

[Studies on the lactate oxidase producing conditions by Edwardsiella tarda].

A bacterium producing lactate oxidase was re-screened from five strains based on previous researches. The lactate oxidase activity was the highest in strain L1 and this stain was chosen as the enzyme source. Morphological and physiological studies revealed that the bacterial strain L1 belongs to the Edwardsiella tarda Biogroup I. This stain is different from the reported strains Mycobacterium and Pediococcus, which produce lactate oxidase. The enzyme producing conditions were studied in shaking cultures, and the effects of initial pH, riboflavin, lactate and ammonia sulphate concentrations on the production were carried out respectively. The bacteria resource of enzyme is significant to pyruvate production by enzymatic method, and to the enzyme assay of lactate for medical diagnosis, and the application of enzyme electronic probe.

Culture Media↗
PubMed2004

Comparative composition of bacteria in the human intestinal microflora during remission and active ulcerative colitis.

Ulcerative colitis is a severe, relapsing and remitting disease of the human large intestine characterised by inflammation of the mucosa and submucosa. The main site of disease is the sigmoid/rectal region of the large bowel but the aetiology remains unknown. There is considerable evidence to indicate that the components of the resident colonic microflora can play an important role in initiation of the disease. The present study was aimed at characterising the faecal microflora of ulcerative colitis patients in remission and active phases to determine profile differences. Faecal samples were obtained from 12 patients, 6 with active colitis and 6 in remission. The samples were analysed for populations of lactobacilli, bifidobacteria, clostridia, bacteroides, sulphate-reducing bacteria (SRB) and total bacteria using culture independent fluorescence in situ hybridisation (FISH). Lactobacillus-specific denaturing gradient gel electrophoresis (DGGE) was then performed to compare the species present. Numbers of lactobacilli were significantly lower (p<0.05) during the active phase of the disease but the other populations tested did not differ. DGGE analysis revealed that Lactobacillus salivarus, Lactobacillus manihotivorans and Pediococcus acidilactici were present in remission, but not during active inflammation. These results imply that a reduction in intestinal Lactobacillus species may be important in the initiation of ulcerative colitis.

Adult↗
PubMed2005

[Gram-positive cocci as an opportunistic infection factor].

The frequency of opportunistic infections increased in the last years. The opportunistic infections are serious and very difficult to diagnose complication at patients with lower immunity. The following factors are conducive to develop infections caused by opportunistic bacteria: invasive research methods, medical treatments and immunological defects. The publication presents pathogenicity of bacteria of following types: Aerococcus, Kocuria, Kytococcus, Lactococcus, Leuconostoc, Micrococcus, Pediococcus. There are also mentioned diagnostic and treatment issues in the publication. The purpose of this study is to draw attention to infection caused by opportunistic bacteria, which are ingredients of physiological flora as well as diagnostic difficulties, which occur in case of isolation of this pathogens. Quick and correct diagnosis of etiological factor and applying of proper treatment can have very important impact on effectiveness of therapy and decrease of mortality in this kind of infections.

Gram-Positive Cocci↗
PubMed1987

[Extraintestinal isolation of Salmonella in chickens: epidemiologic study of 3 salmonellosis outbreaks after ingestion of raw eggs].

A taxonomic analysis of the malolactic microflora present in nine grape samples from different zones of Galicia, was carried out. Nineteen strains were isolated and identified as Lactobacillus plantarum (42%), L. brevis (10.6%), L. casei (5.25%), L. hilgardii (5.25%), Streptococcus cremoris (5.25%), Leuconostoc lactis (5.25%), L. oenos (10.6%), and Pediococcus acidilactici (15.8%).

Animals↗
PubMed1987

Bioavailability of high-dose oral leucovorin.

Fifteen adult subjects comprised the study group; 2 were colon cancer patients. Total leucovorin (citrovorum factor; CF) doses of 200, 400, 800, and 1600 mg were equally subdivided and administered at 0, 1, 2, and 3 hours. Three of the subjects were fasting and the other 12 were not. Quantitation of serum L-CF by Pediococcus cerevisiae and total reduced folates (TRF) by radio-assay were performed in 10 samples from each subject drawn over a 12-hour period after initiation of CF dosing. The mean serum levels of L-CF remained greater than 0.1 microM at 3 hours and the TRF 3.5 microM at 5 hours, respectively, after termination of CF dosing in all subjects treated at the 800- and 1600-mg dose schedule. At all CF dosage schedules employed, peak serum concentrations were reached within 4 and 6 hours after initiation of oral CF. Peak TRF concentrations at the 200-, 400-, 800-, and 1600-mg doses were 3.42 +/- 0.65, 4.05 +/- 1.04, 4.81 +/- 0.14, and 5.11 +/- 1.81 microM, respectively. Peak L-CF levels at 200, 400, 800, and 1600 were 0.15 +/- 0.11, 0.21 +/- 0.14, 0.23 +/- 0.11, and 0.34 +/- 0.16 microM. Based upon these observations, the following conclusions were reached: 1) no significant differences were observed in serum concentrations of folates between the 800- and 1600-mg dose schedules; 2) at these doses serum concentrations of L-CF and TRF were achieved that warrant a phase I investigation of high-dose oral CF with standard dose FUra in patients with advanced colorectal carcinoma.

Administration, Oral↗
PubMed1995

Microflora of murcha: an amylolytic fermentation starter.

Murcha is a traditional starter, used commonly in Darjeeling hills and Sikkim in India to ferment a variety of starchy substrates in order to produce sweet-sour alcoholic beverages, called jnards. Murcha cakes are mildly acidic (pH 5.2) and contain 13% w/w moisture and 0.7% w/w ash (dry weight basis). A total of 194 bacterial, 190 yeast and 80 mould strains were isolated from 30 samples of murcha. The counts (cfu/g fresh weight) of micro-organisms in the samples were 2.0 x 10(7) to 4.2 x 10(8) for Pediococcus pentosaceus, 4.0 x 10(7) to 6.8 x 10(8) for Saccharomycopsis fibuligera, 2.0 x 10(6) to 7.2 x 10(7) for Pichia anomala, 1.0 x 10(6) to 4.1 x 10(7) for Mucor circinelloides and < 10 to 1.0 x 10(6) for Rhizopus chinensis. While all the species were prevalent in 100% of the samples, R. chinensis was detected in only 50% of them. Both the moulds but one yeast species, S. fibuligera had amylolytic activity.

Amylases↗
PubMed1994

Inhibition of spoilage and food-borne pathogens by lactic acid bacteria isolated from fermenting tef (Eragrostis tef) dough.

A study was carried out at the Department of Biology, Addis Abeba University, in 1991 to determine the inhibitory potential of fermenting tef and the lactic acid bacteria isolated from fermenting tef dough on Salmonella spp., Pseudomonas aeruginosa, Klebsiella spp., Bacillus cereus and Staphylococcus aureus. The test bacteria grew in the fermenting tef uptill 30 hr or till the pH dropped to 4.7. Thereafter, growth was inhibited and decreases in population were apparent. The results showed that the spent media from all of the four lactic acid bacterial isolates, namely, Lactobacillus spp., Pediococcus spp., Leuconostoc spp. and Streptococcus spp. inhibited the test bacteria. Acidity on its own was not responsible for the inhibition of the test bacteria. The spent medium from Streptococcus spp. showed the best inhibitory activity amongst the lactic acid bacteria.

Bread↗
PubMed1994

Survival and growth of selected pathogens in fermented kocho (Ensete ventricosum).

A study was conducted to investigate the antagonistic potential of fermented kocho, aqueous extract of fermented kocho and spent media from lactic acid bacteria (LAB) isolated from it on Salmonella sp, Pseudomonas aeruginosa, Klebsiella sp, Bacillus cereus and Staphylococcus aureus. Fermented kocho (pH 4.3) inhibited growth of the test bacteria soon after their introduction into the food. The spent media from all of the four LAB, isolated from fermented kocho, namely Pediococcus sp, Leuconostoc sp, Lactobacillus sp and Streptococcus sp prevented the survival and growth of the test bacteria. The spent medium from Streptococcus sp showed the best antagonistic effect amongst all the LAB isolates. In all cases the inhibitory effects were independent of pH.

Bacteria↗