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1.
J Healthc Qual Res ; 38(2): 84-92, 2023.
Article in English | MEDLINE | ID: mdl-36175279

ABSTRACT

OBJECTIVE: To evaluate the access, development, and quality of consents forms for clinical practice within the Spanish Public Hospitals. METHOD: A cross-sectional study was conducted in a two-stage process (January 2018-September 2021). In stage 1, A nationwide survey was undertaken across all public general hospitals (n=223) in the Spanish Healthcare System. In stage 2, Data was taken from the regional health services websites and Spanish regulations. Health Regional Departments were contacted to verify the accuracy of the findings. Data was analyzed using a descriptive and inferential statistics (frequencies, percentages, Chi-square & Fisher's exact tests). RESULTS: The response rate was 123 (55.16%) of Spanish Public Hospitals. The results revealed a range of hospital departments involved in the development of consent documents and the absence of a standardized approach to consent forms nationally. Consent audits are undertaken in 43.09% hospitals and translation of written consents into other languages is limited to a minority of hospitals (35.77%). The validation process of consent documentation is not in evidence in 13% of Spanish Hospitals. Regional Informed Consent Committees are not place in the majority (70.7%) of hospitals. Citizens can freely access to consent documents through the regional websites of Andalusia and Valencia only. CONCLUSION: Variability is found on access, development and quality of written consent across the Spanish Public Hospitals. This points to the need for a national informed consent strategy to establish policy, standards and an effective quality control system. National audits at regular intervals are necessary to improve the consistency and compliance of consent practice.


Subject(s)
Consent Forms , Hospitals, Public , Humans , Cross-Sectional Studies , Informed Consent , Surveys and Questionnaires
2.
Pulm Circ ; 12(1): e12030, 2022 Jan.
Article in English | MEDLINE | ID: mdl-35506107

ABSTRACT

The post 3 kidney transplant course of pretransplant echocardiographically-defined pulmonary hypertension (PH) was reviewed in 115 patients. Of these 61 patients (the largest cohort reported to date), underwent 160 "for indication" echocardiograms posttransplant (mean echocardiograms per patient: 2.6 ± 2.3). Patients undergoing posttransplant echocardiograms demonstrated greater risks for worse outcomes than those without posttransplant echocardiograms; however, there was no difference in mortality, death-censored graft failure or the composite of death or graft failure between these two groups. Of patients tested, 36 (59%) showed resolution of PH at a median of 37.5 months. Six patients (16.7%) in whom PH resolved (at a median of 29 months), experienced recurrence of PH after an interval of 48 months. No pretransplant demographic or echocardiographic characteristics distinguished those in whom PH persisted versus resolved. Though there was no difference in the risk for mortality or death-censored graft loss between the two groups at 3 and 5 years, there was a higher risk for the composite of mortality or graft loss at three but not at five years in the group with persistent PH. In conclusion, echocardiographically defined PH resolved in 59% of patients following kidney transplantation; but irrespective of resolution there was no clear association with worse outcome.

4.
Food Microbiol ; 44: 185-95, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25084662

ABSTRACT

The purpose of this study was to determine the effect of enterocin AS-48, packaged under normal atmosphere (NA), vacuum (VP) or modified atmosphere (MAP) on the shelf life and safety of fresh sardines (Sardina pilchardus) stored at 5 °C. We studied the effect of these hurdles, alone or combined, on the relevant autochthonous bacterial populations. Total volatile basic nitrogen (TVB-N) content was used as indicative of freshness. Levels of biogenic amines cadaverine, putrescine, tyramine, and histamine were also determined. The application of AS-48 did not reduce the mesophilic, psychrotrophic, or Gram negative bacteria viable cell counts under any of the storage conditions tested. AS-48 did cause significant reductions in viable staphylococci counts, especially under VP. In sardines under NA treated with AS-48, the populations of histamine- and tyramine-forming total and lactic acid bacteria (LAB) showed no significant reductions. MAP or VP with AS-48 allowed reductions (significant at some storage times) in histamine- and tyramine-forming LAB. The TVB-N content was also reduced under normal atmosphere and, especially, in sardines stored under MAP. The most interesting results are those concerning the decrease (by several fold) in the levels of the biogenic amines cadaverine, putrescine, tyramine, and histamine determined after treatment with AS-48.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteriocins/pharmacology , Fish Products/analysis , Food Additives/analysis , Food Preservation/methods , Animals , Anti-Bacterial Agents/analysis , Bacteria/classification , Bacteria/drug effects , Bacteria/growth & development , Bacteria/isolation & purification , Bacteriocins/analysis , Fish Products/microbiology , Fishes , Food Additives/pharmacology , Food Safety , Food Storage
5.
Int J Food Microbiol ; 163(2-3): 136-45, 2013 May 15.
Article in English | MEDLINE | ID: mdl-23558197

ABSTRACT

A set of 80 Lactobacillus strains (36 Lactobacillus plantarum and 44 Lactobacillus paracasei) isolated from Spanish farmhouse cheeses have been studied as to their functional and safety properties and their survival under gut-related conditions. None of these 80 Lactobacillus strains were able to hydrolyse starch. A high percentage of L. plantarum and L. paracasei strains were, however, capable of hydrolysing casein (86.1% and 68.2% respectively). For the other characteristics investigated, L. plantarum strains generally had more positive responses than L. paracasei. The latter strains tested negative for most of these characteristics, with the exception of stachyose hydrolysis, which was positive in six strains of L. paracasei. A high percentage (91.7%) of L. plantarum produced haemo-dependent catalase. Phytase was present in 10 L. plantarum and in 2 L. paracasei. Most L. plantarum (83.3%) but no L. paracasei hydrolysed bile salts. All strains were completely resistant to a challenge of pH3, but many showed a loss of viability after a subsequent exposure to 0.3% oxgall; in fact, only one L. paracasei strain and 33 L. plantarum strains (91.67%) were tolerant to both stresses. L. plantarum Mb25 and L. plantarum Mb26 were the most adherent to Caco-2 cells (adherence percentages of 36 and 7% respectively). These two strains were also the most adherent to HeLa 229 cells, with 19.3 and 16.0% adhesion respectively. The Mb26 strain inhibited the adhesion of Listeria monocytogenes to Caco-2 cells when added simultaneously to Listeria and also when added 1h before the pathogen (21.0% and 51.6% adhesion inhibition, respectively). Production of H2O2 was detected in 38.9% of L. plantarum strains and in 9.1% of L. paracasei. Twelve L. plantarum and eight L. paracasei strains produced bacteriocin-like inhibitors. PCR amplifications of several plantaricin genes suggest that all the bacteriocinogenic strains may produce plantaricin E/F and some may also manufacture the plantaricin J/K. The nine L. plantarum strains assayed for antibiotic resistance were resistant to ciprofloxacin (MIC>2 µg/ml), vancomycin (MIC>16 µg/ml), and teicoplanin (MIC>16 µg/ml). Moreover, some strains showed intermediate resistance to penicillin, tetracycline, rifampicin, and levofloxacin. We conclude that farmhouse cheeses are good sources of biotechnologically relevant lactobacilli and that the L. plantarum species shows better biotechnological properties than L. paracasei. This can be deduced from the finding of a high percentage of strains of L. plantarum that exhibit remarkable functional and inhibitory properties and high abilities to survive in gut-related conditions, which can be further developed for biotechnological applications.


Subject(s)
Cheese/microbiology , Food Microbiology , Gastrointestinal Tract/microbiology , Lactobacillus/physiology , Animals , Anti-Bacterial Agents/pharmacology , Bacteriocins/genetics , Caco-2 Cells , Goats , HeLa Cells , Humans , Hydrogen Peroxide/pharmacology , Lactobacillus/enzymology , Lactobacillus/genetics , Lactobacillus/isolation & purification , Listeria monocytogenes/drug effects , Microbial Sensitivity Tests , Microbial Viability
6.
Can J Microbiol ; 58(5): 596-604, 2012 May.
Article in English | MEDLINE | ID: mdl-22471967

ABSTRACT

The F420 strain, isolated from raw goat milk and identified as Enterococcus hirae, was selected because of its strong activity against gram-positive bacteria, including Listeria monocytogenes. Interestingly, the F420 strain lacks the virulence genes and decarboxylase activity of histidine, lysine, and ornithine, and it is susceptible to 11 of 14 tested antibiotics, including vancomycin. The antimicrobial compounds produced by E. hirae F420 strain showed high resistance to heat treatment and to acidic and basic pHs. The MALDI-TOF mass spectrometry analysis coupled with the sequence of peptide and structural gene analysis of one of the purified enterocins showed 100% identity with enterocin P (EntP), previously described in E. faecium strains. The structural gene for EntP is located on a plasmid of 65 kb. Other enterocins with molecular mass higher than 7 kDa were also detected. This is the first report of the production of EntP by E. hirae species naturally occurring in foods. The biotechnological characteristics of the F420 strain and its enterocins indicate their potential for application in the control of L. monocytogenes and other undesirable bacteria in food systems.


Subject(s)
Bacteriocins/biosynthesis , Drug Resistance, Bacterial , Enterococcus/isolation & purification , Food Microbiology , Milk/microbiology , Animals , Anti-Bacterial Agents/biosynthesis , Bacteriocins/genetics , Enterococcus/drug effects , Enterococcus/genetics , Enterococcus/pathogenicity , Goats/microbiology , Virulence
7.
Food Microbiol ; 30(1): 59-67, 2012 May.
Article in English | MEDLINE | ID: mdl-22265284

ABSTRACT

Enterococcus faecalis UGRA10, a new AS-48-producer strain, has been isolated from a Spanish sheep's cheese. The inhibitory substance produced by E. faecalis UGRA10 was purified and characterized using matrix-assisted laser desorption ionization-time of flight mass spectrometry, confirming its identity with AS-48 enterocin (7.150 Da). Subsequent genetic analysis showed the existence of the as-48 gene cluster on a plasmid of approximately 70-kb. The UGRA10 strain was examined for safety properties such as enterococci virulence genes, biogenic amine production, and antibiotic resistance. As for most E. faecalis strains, PCR amplification revealed the existence of gene encoding for GelE, Asa1, Esp, EfaA, and Ace antigens and for tyrosine decarboxylase. This strain was sensitive to most of the antibiotics tested, being resistant only to aminoglycosides, lincosamide, and pristinamicins. In addition, UGRA10 developed an ability to form biofilms and to adhere to Caco 2 and HeLa 229 cells. More interestingly, this strain shows a high ability to interfere with the adhesion of Listeria monocytogenes to Caco 2 cells. Altogether, the results suggest that this broad-spectrum bacteriocin-producing strain has biotechnological potential to be developed as a protective agent in food preservation and as a probiotic.


Subject(s)
Bacteriocins/isolation & purification , Cheese/microbiology , DNA, Bacterial/isolation & purification , Enterococcus faecalis/isolation & purification , Probiotics/metabolism , Aminoglycosides/metabolism , Animals , Bacterial Adhesion , Bacteriocins/pharmacology , Caco-2 Cells , Cheese/standards , Consumer Product Safety , Drug Resistance, Bacterial/drug effects , Enterococcus faecalis/genetics , Enterococcus faecalis/metabolism , Food Contamination/analysis , Food Microbiology/methods , HeLa Cells , Humans , Lincosamides/metabolism , Listeria monocytogenes/pathogenicity , Microbial Sensitivity Tests , Multigene Family , Sheep , Virulence
8.
Food Microbiol ; 27(1): 58-63, 2010 Feb.
Article in English | MEDLINE | ID: mdl-19913693

ABSTRACT

Enterocin AS-48 is a cationic cyclic bacteriocin produced by Enterococcus faecalis with broad bactericidal activity. Currently we are assaying the efficacy of AS-48 as biopreservative in foods. In this work we have applied the spray drying process to different AS-48 liquid samples to obtain active dried preparations. We have also assayed different methods, heat, UV irradiation and filtration, to inactivate/remove the AS-48 producer cells from the samples. Best results were obtained for the sample from CM-25 cation exchange, for which it was also possible to completely eliminate/inactivate the producer cells by heat or UV irradiation without loss of activity. When added at 0.016% or 5% to Brain Heart Infusion broth or to skim milk, respectively, the AS-48 powder caused early and complete inactivation of Listeria monocytogenes. A partial inhibition of Staphylococcus aureus was achieved in broth and in skim milk supplemented with 2.5% and 10% AS-48 powder, respectively.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteriocins/pharmacology , Food Preservation/methods , Food Preservatives/pharmacology , Anti-Bacterial Agents/metabolism , Bacteriocins/metabolism , Enterococcus faecalis/metabolism , Enterococcus faecalis/radiation effects , Food Preservatives/metabolism , Listeria monocytogenes/drug effects , Staphylococcus aureus/drug effects
9.
J Exp Biol ; 212(Pt 22): 3621-6, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19880722

ABSTRACT

Among potential agents that might damage bird feathers are certain microorganisms which secrete enzymes that digest keratin, as is the case of the ubiquitous bacterium Bacillus licheniformis, present in both the feathers and skin of wild birds. It is therefore a good candidate for testing the effects of bird defences against feather-degrading microorganisms. One of these defences is the oil secreted by the uropygial gland, which birds use to protect their feathers against parasites. In previous studies we have shown how Enterococcus faecalis strains isolated from nestling hoopoes exert antagonistic effects against B. licheniformis, mediated by the production of bacteriocins. Consequently we hypothesized that this enterococcus and the bacteriocins it engenders might act as a defence against feather-degrading microorganisms in hoopoes. We investigated this hypothesis in a series of laboratory experiments and evaluated the extent to which the keratinolytic effects caused by B. licheniformis were reduced by the E. faecalis MRR10-3 strain, isolated from hoopoes, and its bacteriocins. In different treatments, feathers or pure keratin was incubated with B. licheniformis, B. licheniformis together with E. faecalis MRR10-3, and B. licheniformis together with the bacteriocins produced by E. faecalis MRR10-3. Our results were in accordance with the predicted effects on hoopoe feathers. There was a significant decrease both in pure keratin loss and in feather degradation in the presence of the symbiotic bacterium or its bacteriocin. These results suggest that by preening their feathers hoopoes benefit from their symbiotic relationship with bacteriocin-producing enterococci, which constitute a chemical defence against feather degradation.


Subject(s)
Bacillus/metabolism , Enterococcus faecalis/metabolism , Exocrine Glands/microbiology , Feathers , Symbiosis , Animals , Bacteriocins/metabolism , Birds , Feathers/metabolism , Feathers/microbiology , Feathers/pathology , Female , Keratins/metabolism , Male
10.
J Dairy Sci ; 92(6): 2514-23, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19447982

ABSTRACT

The use of high-intensity pulsed-electric field (HIPEF) and antimicrobial substances of natural origin, such as enterocin AS-48 (AS-48), nisin, and lysozyme, are among the most important nonthermal preservation methods. Thus, the purpose of this study was to evaluate the combined effect on milk inoculated with Staphylococcus aureus of the addition of AS-48 with nisin or lysozyme, or both, together with the use of HIPEF. Synergy was observed in the reduction of Staph. aureus counts with the following combination methods: i) addition of AS-48 and nisin, ii) addition of AS-48 plus use of HIPEF, and iii) addition of AS-48 and nisin plus use of HIPEF. Specifically, when 28 arbitrary units/mL of AS-48 and 20 IU/mL of nisin were added to the milk, and it was treated with HIPEF for 800 mus, over 6 log reductions were observed in the microorganism. In general, Staph. aureus inactivation was dependent on HIPEF treatment time, antimicrobial doses, and medium pH. During storage of the treated milk, survivor population was related to peptide concentration and temperature. Final cell viability was influenced by the sequence in which the treatments were applied: the addition of AS-48 or AS-48 and nisin was more effective before than after HIPEF treatment. The results obtained indicate that the combination of HIPEF and antimicrobials could be of great interest to the dairy industry, although it is necessary to study further the way in which the combined treatments act.


Subject(s)
Anti-Infective Agents/pharmacology , Antimicrobial Cationic Peptides/pharmacology , Electricity , Food Handling/methods , Food Preservation/methods , Milk/microbiology , Staphylococcus aureus/drug effects , Analysis of Variance , Animals , Bacterial Proteins/pharmacology , Muramidase/pharmacology , Nisin/pharmacology , Peptides/pharmacology , Regression Analysis
12.
Rev. chil. med. intensiv ; 23(2): 104-112, 2008. ilus, tab
Article in Spanish | LILACS | ID: lil-516236

ABSTRACT

La lesión digestiva aguda por caústicos es una patología que con cierta frecuencia se observa como motivo de consulta a los servicios de urgencias. Tiene un pronóstico reservado dada la cantidad de complicaciones quirúrgicas, médicas e infecciosas a las que están expuestos estos pacientes. Las secuelas que el paciente debe enfrentar en diferentes etapas de su evolución requieren de cuidados intensivos durante un tiempo prolongado además de muchos controles posteriores al alta para evaluar y tratar proiblemas de consideración, estenosis y otras lesiones faringo-esofágicas. Presentamos el caso de un adulto masculino que debido a un síndrome depresivo mayor cursa un intento suicida ingiriendo ácido muriático por boca con severa lesiones digestivas muy poco sintomáticas durante su evolución precoz, pero con un resultado fatal debido a sangrado digestivo agudo masivo.


The acute gastrointestinal injury by caustics is a condition that frequently is observed as a cause of consultations to emergency department. These patients have reserved prognosis given the number of surgical complications, medical and infections. The aftermath that the patient must face at different stages of their development require intensive care for a long time and post-discharge many patients required assess and treat problems, primarily stenosis and other injuries pharynx-esophageal. We report the case of an adult male with depressive syndrome and by suicide attempt with ingesting muriatic acid by mouth, he developed very little injuries digestive during his early trends, but with a fatal outcome due to acute massive gastrointestinal bleeding.


Subject(s)
Humans , Male , Adult , Hydrochloric Acid/adverse effects , Upper Gastrointestinal Tract/injuries , Caustics/adverse effects , Suicide, Attempted
13.
Lett Appl Microbiol ; 45(1): 19-23, 2007 Jul.
Article in English | MEDLINE | ID: mdl-17594455

ABSTRACT

AIMS: To determine the effectiveness of enterocin AS-48 on Staphylococcus aureus CECT 976 in combination with chemical preservatives at acidic and neutral pH. METHODS AND RESULTS: At pH 4.5, the activity of AS-48 increases in the presence of lactic acid (1.0%), acetic acid (0.5% and 1.0%), and citric acid (0.3% and 0.6%). This synergistic effect has also been observed during the first 8 h of incubation with benzoate (0.06% and 0.12%) and sorbate (2% and 3%). Interestingly, at pH 7, lactate (1%) increases the inhibitory effect of AS-48, reducing the S. aureus population by 6 log units compared with the control culture. At neutral pH, combinations of AS-48 and sodium tripolyphosphate, STPP (0.3% and 0.5%) also eliminate this pathogen after 24 h. CONCLUSIONS: These results indicate that enterocin AS-48 could be applied in combination with a range of chemical preservatives in order to increase its efficacy in inhibiting S. aureus. SIGNIFICANCE AND IMPACT OF THE STUDY: This study supports the potential use of enterocin AS-48 as a biopreservative to control S. aureus in combination with other food-grade chemical hurdles.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteriocins/pharmacology , Carboxylic Acids/pharmacology , Food Preservatives/pharmacology , Polyphosphates/pharmacology , Staphylococcus aureus/drug effects , Benzoates/pharmacology , Colony Count, Microbial , Drug Synergism , Enterotoxins/metabolism , Food Preservatives/chemistry , Humans , Hydrogen-Ion Concentration , Microbial Sensitivity Tests , Sorbic Acid/pharmacology , Staphylococcus aureus/growth & development , Staphylococcus aureus/metabolism
15.
J Appl Microbiol ; 102(5): 1350-61, 2007 May.
Article in English | MEDLINE | ID: mdl-17448170

ABSTRACT

AIMS: Enterococcus faecalis produces a cationic and circular enterocin, AS-48, of 7149 Da, the genetic determinants of which are located within the pMB2 plasmid. We have compared enterocin AS-48 production by different enterococci species with that of other 'safe' lactic acid bacteris (LAB) (GRAS status) and looked into the subsequent application of this enterocin in food production. METHODS AND RESULTS: In an effort to exploit this system for the heterologous expression of enterocin AS-48, a number of vectors containing the as-48 cluster were constructed and used to transform several LAB strains (genera Enterococcus, Lactococcus and Lactobacillus) CONCLUSION: Heterologous production of enterocin AS-48 failed when bacteria other than those belonging to the genus Enterococcus were used as hosts, although expression of a partial level of resistance against AS-48 were always detected, ruling out the possibility of a lack of recognition of the enterococcal promoters. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results reveal the special capacity of species from the genus Enterococcus to produce AS-48, an enterocin that requires a post-transcriptional modification to generate a circular peptide with a wide range of inhibitory activity against pathogenic and spoilage bacteria. Preliminary experiments in foodstuffs using nonvirulent enterococci with interesting functional properties reveal the possibility of a biotechnological application of these transformants.


Subject(s)
Bacteriocin Plasmids/metabolism , Enterococcus faecalis/drug effects , Food Microbiology , Lactobacillaceae/metabolism , Anti-Bacterial Agents/biosynthesis , Bridged-Ring Compounds/metabolism , Culture Media , Food Preservation , Gene Expression , Plasmids
16.
J Appl Microbiol ; 101(2): 422-8, 2006 Aug.
Article in English | MEDLINE | ID: mdl-16882150

ABSTRACT

AIMS: To determine the activity of enterocin AS-48 against ropy-forming Bacillus licheniformis from cider. METHODS AND RESULTS: Enterocin AS-48 was tested on B. licheniformis LMG 19409 from ropy cider in MRS-G broth, fresh-made apple juice and in two commercial apple ciders (A and B). Bacillus licheniformis was rapidly inactivated in MRS-G by 0.5 microg ml(-1)AS-48 and in fresh-made apple juice by 3 microg ml(-1). Concentration-dependent inactivation of this bacterium in two commercial apple ciders (A and B) stored at 4, 15 and 30 degrees C for 15 days was also demonstrated. Counts from heat-activated endospores in cider A plus AS-48 decreased very slowly. Application of combined treatments of heat (95 degrees C) and enterocin AS-48 reduced the time required to achieved complete inactivation of intact spores in cider A to 4 min for 6 microg ml(-1) and to 1 min for 12 microg ml(-1). D and z values also decreased as the bacteriocin concentration increased. CONCLUSION: Enterocin AS-48 can inhibit ropy-forming B. licheniformis in apple cider and increase the heat sensitivity of spores. SIGNIFICANCE AND IMPACT OF THE STUDY: Results from this study support the potential use of enterocin AS-48 to control B. licheniformis in apple cider.


Subject(s)
Alcoholic Beverages , Bacillus/physiology , Bacteriocins/pharmacology , Food Preservation , Food Technology , Malus , Consumer Product Safety , Hot Temperature , Spores, Bacterial
17.
Food Chem Toxicol ; 44(10): 1774-81, 2006 Oct.
Article in English | MEDLINE | ID: mdl-16831501

ABSTRACT

The enterococcal bacteriocin (enterocin) AS-48 is a broad-spectrum cyclic peptide. Enterocin AS-48 was tested against Bacillus coagulans in three vegetable canned foods: tomato paste (pH 4.64), syrup from canned peaches (pH 3.97), and juice from canned pineapple (pH 3.65). When vegetative cells of B. coagulans CECT (Spanish Type Culture Collection) 12 were inoculated in tomato paste supplemented with 6 microg/ml AS-48 and stored at different temperatures, viable cell counts were reduced by approximately 2.37 (4 degrees C), 4.3 (22 degrees C) and 3.0 (37 degrees C) log units within 24 h storage. After 15-days storage, no viable cells were detected in any sample. Strain B. coagulans CECT 561 showed a poor survival in tomato paste, but surviving cells were also killed by AS-48. The bacteriocin was also very active against B. coagulans CECT 12 vegetative cells in juice from canned pineapple stored at 22 degrees C, and slightly less active in syrup from canned peaches. In food samples supplemented with 1.5% lactic acid, enterocin AS-48 (6 microg/ml) rapidly reduced viable counts of vegetative cells below detection limits within 24 h storage. Addition of glucose and sucrose (10% and 20%) significantly increased bacteriocin activity against vegetative cells of B. coagulans CECT 12. Enterocin AS-48 had no significant effect on B. coagulans CECT 12 spores. However, the combined application of AS-48 and heat (80-95 degrees C for 5 min) significantly increased the effect of thermal treatments on spores.


Subject(s)
Bacillus/drug effects , Bacteriocins/pharmacology , Food Preservation/methods , Fruit/microbiology , Vegetables/microbiology , Bacillus/growth & development , Carbohydrates , Food Microbiology , Hot Temperature , Lactic Acid
18.
J Appl Microbiol ; 99(6): 1364-72, 2005.
Article in English | MEDLINE | ID: mdl-16313409

ABSTRACT

AIMS: To determine the effects of outer membrane (OM) permeabilizing agents on the antimicrobial activity of enterocin AS-48 against Escherichia coli O157:H7 CECT 4783 strain in buffer and apple juice. METHODS AND RESULTS: We determined the influence of pH, EDTA, sodium tripolyphosphate (STPP) and heat on E. coli O157:H7 CECT 4783 sensitivity to enterocin AS-48 in buffer and in apple juice. Enterocin AS-48 was not active against intact cells of E. coli O157:H7 CECT 4783 at neutral pH. However, cells sublethally injured by OM permeabilizing agents (EDTA, STPP, pH 5, pH 8.6 and heat) became sensitive to AS-48, decreasing the amount of bacteriocin required for inhibition of E. coli O157:H7 CECT 4783. CONCLUSIONS: The results presented indicate that enterocin AS-48 could potentially be applied with a considerably wider range of protective agents, such as OM permeabilizing agents, with increased efficacy in inhibiting E. coli O157:H7. SIGNIFICANCE AND IMPACT OF THE STUDY: Results from this study support the potential use of enterocin AS-48 to control E. coli O157:H7 in combination with other hurdles.


Subject(s)
Anti-Bacterial Agents/pharmacology , Escherichia coli O157/drug effects , Food Microbiology , Food Preservation/methods , Beverages , Bridged-Ring Compounds/pharmacology , Cell Membrane Permeability/drug effects , Chelating Agents/pharmacology , Colony Count, Microbial , Food Contamination , Hot Temperature , Hydrogen-Ion Concentration , Malus
19.
J Appl Microbiol ; 99(1): 141-50, 2005.
Article in English | MEDLINE | ID: mdl-15960674

ABSTRACT

AIMS: Characterization of Ent F-58 produced by Enterococcus faecium strain F58 isolated from Jben, a soft, farmhouse goat's cheese manufactured without starter cultures. METHODS AND RESULTS: E. faecium strain F58 was isolated because of its broad inhibitory spectrum, including activity against food-borne pathogenic and spoilage bacteria. The antimicrobial substance was produced during the growth phase, with maximum production after 16-20 h of incubation at 30 degrees C, and was stable over a wide pH range (4-8) and at high temperatures (5 min at 100 degrees C). The enterocin was purified to homogeneity using cation exchange and hydrophobic interaction on C-18 and reverse-phase high-performance liquid chromatography. The activity was eluted as two individual active fractions (F-58A and F-58B) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis showed masses of 5210.5 and 5234.3 Da respectively. Both peptides were partially sequenced by Edman degradation, and amino-acid sequencing revealed high similarity with enterocin L50 (I). PCR-amplified fragments containing the structural genes for F-58 A and B were located in a 22-kb plasmid harboured by this strain. We verified that it also holds the structural gene for P-like enterocin. CONCLUSION: E. faecium strain F58 from Jben cheese, a producer of enterocin L50, exerts an inhibitory effect against strains of genera such as Listeria, Staphylococcus, Clostridium, Brochothrix and Bacillus. Enterocin was characterized according to its functional and biological properties, purification to homogeneity and an analysis of its amino acid and genetic sequences. SIGNIFICANCE AND IMPACT OF THE STUDY: E. faecium strain F58 is a newly discovered producer of enterocin L50, the biotechnological characteristics of which indicate its potential for application as a protective agent against pathogens and spoilage bacteria in foods.


Subject(s)
Bacteriocins/chemistry , Cheese/microbiology , Enterococcus faecium/isolation & purification , Food Microbiology , Amino Acid Sequence , Animals , Anti-Bacterial Agents/chemistry , Bacteriocin Plasmids/analysis , Blotting, Southern/methods , Bridged-Ring Compounds/analysis , Culture Media , Goats , Hot Temperature , Hydrogen-Ion Concentration , Microbial Sensitivity Tests , Molecular Weight , Morocco , Polymerase Chain Reaction/methods
20.
Int J Food Microbiol ; 104(3): 289-97, 2005 Oct 25.
Article in English | MEDLINE | ID: mdl-15979752

ABSTRACT

Alicyclobacillus acidoterrestris is a spoilage-causing bacterium in fruit juices. Control of this bacterium by enterocin AS-48 from Enterococcus faecalis A-48-32 is described. Enterocin AS-48 was active against one A. acidocaldarius and three strains of A. acidoterrestris tested. In natural orange and apple juices incubated at 37 degrees C, vegetative cells of A. acidoterrestris DSMZ 2,498 were inactivated by enterocin AS-48 (2.5 microg/ml) and no growth was observed in 14 days. In commercial fruit juices added of AS-48 (2.5 microg/ml) and inoculated with vegetative cells or with endospores of strain DSMZ 2,498, no viable cells were detected during 90 days of incubation at temperatures of 37 degrees C, 15 degrees C or 4 degrees C, except for apple, peach and grapefruit juices inoculated with vegetative cells and incubated at 37 degrees C which were protected efficiently for up to 60 days. Remarkably, in all commercial fruit juices tested, no viable cells were detected as early as 15 min after incubation with the bacteriocin. Endospores incubated for a very short time (1 min) with increasing bacteriocin concentrations were inactivated by 2.5 microg/ml AS-48. Electron microscopy examination of vegetative cells and endospores treated with enterocin AS-48 revealed substantial cell damage and bacterial lysis as well as disorganization of endospore structure.


Subject(s)
Bacteriocins/pharmacology , Beverages/microbiology , Food Preservation/methods , Food Preservatives/pharmacology , Gram-Positive Endospore-Forming Rods/drug effects , Colony Count, Microbial , Dose-Response Relationship, Drug , Fruit , Gram-Positive Endospore-Forming Rods/growth & development , Gram-Positive Endospore-Forming Rods/ultrastructure , Temperature , Time Factors
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