Aislamiento de cepas de Enterococcus hirae productoras de enterocinas a partir del contenido intestinal de mejillón patagónico (Mytilus edulis platensis) Aislamiento de Enterococcus hirae de mejillón patagónico / Isolation of enterocin-producing Enterococcus hirae strains from the intestinal content of the Patagonian mussel (Mytilus edulis platensis)

Resumen Se aislaron del contenido intestinal del mejillón patagónico dos cepas de bacterias ácido lácticas y se caracterizaron por pruebas fenotípicas y moleculares. Los aislamientos se identificaron como Enterococcus hirae y fueron denominados E. hirae 463Me y 471Me. Por técnicas de PCR se identificó el gen de la enterocina P en ambas cepas, mientras que solamente en la cepa 471Me se detectó la enterocina hiracin JM79. Ambas cepas resultaron sensibles a los antibióticos clínicamente importantes y entre los rasgos de virulencia investigados mediante amplificación por PCR solo se pudieron detectar los genes cylL l y cylL s , sin embargo, no se observó actividad hemolítica en la prueba de agar sangre. Los sobrenadantes libres de células resultaron activos contra todas las cepas de Listeria y Enterococcus ensayadas, contra Lactobacillus plantarum TwLb 5 y contra Vibrio anguilarum V10. En óptimas condiciones de crecimiento, ambas cepas mostraron actividad inhibitoria contra Listeria innocua ATCC 33090 después de 2h de incubación. E. hirae 471Me alcanzó una actividad inhibitoria máxima de 163.840UA/ml después de 6h de incubación, mientras que el mismo valor se registró para E. hirae 463Me después de 8h. En ambos casos, la actividad antagonista alcanzó su máximo antes de lograr la fase estacionaria y permaneció estable hasta las 24h de incubación. En nuestro conocimiento, este es el primer informe de aislamiento de cepas bacteriocinogénicas de E. hirae de mejillón patagónico. La alta actividad inhibitoria y la ausencia de rasgos de virulencia indican que estos microorganismos podrían aplicarse en áreas biotecnológicas como la biopreservación de alimentos o las formulaciones probióticas.

Abstract Two bacteriocin-producing lactic acid bacterial strains were isolated from the intestinal content of the Patagonian mussel and characterized by phenotypic and molecular tests. The isolates were identified as Enterococcus hirae and named E. hirae 463Me and 471Me. The presence of the enterocin P gene was identified in both strains by PCR techniques, while enterocin hiracin JM79 was detected only in the 471Me strain. Both strains were sensitive to clinically important antibiotics and among the virulence traits investigated by PCR amplification, only cylL l and cylL s could be detected; however, no hemolytic activity was observed in the blood agar test. Cell free supernatants were active against all Listeria and Enterococcus strains tested, Lactobacillus plantarum TwLb 5 and Vibrio anguilarum V10. Under optimal growth conditions, both strains displayed inhibitory activity against Listeria innocua ATCC 33090 after 2h of incubation. E. hirae 471Me achieved a maximum activity of 163840AU/ml after 6h of incubation, while the same value was recorded for E. hirae 463Me after 8h. In both cases, the antagonist activity reached its maximum before the growth achieved the stationary phase and remained stable up to 24h of incubation. To our knowledge, this is first report of the isolation of bacteriocinogenic E. hirae strains from the Patagonian mussel. The high inhibitory activity and the absence of virulence traits indicate that they could be applied in different biotechnological areas such as food biopreservation or probiotic formulations.

Purification, characterization, mode of action, and enhanced production of Salivaricin mmaye1, a novel bacteriocin from Lactobacillus salivarius SPW1 of human gut origin

Background: Emergence of antibiotic resistance among pathogenic and food spoilage bacteria such as Staphylococcus aureus, Micrococcus luteus, Streptococcus pyogenes, Streptococcus sanguinis, Streptococcus mutans, Bacillus cereus, and Listeria monocytogenes triggered the search for alternative antimicrobials. An investigation aimed at purifying, characterizing, elucidating the mode of action, and enhancing the production of salivaricin from Lactobacillus salivarius of human gut origin was conducted. Results: Salivaricin mmaye1 is a novel bacteriocin purified from L. salivarius isolated from human feces. It is potent at micromolar concentrations and has a molecular weight of 1221.074 Da as determined by MALDI-TOF mass spectrometry. It has a broad spectrum of antibacterial activity. Salivaricin mmaye1 showed high thermal and chemical stability and moderate pH stability. The proteinaceous nature of salivaricin mmaye1 was revealed by the complete loss of activity after treatment with pepsin, trypsin, α-chymotrypsin, protease, and proteinase. Salivaricin mmaye1 is cell wall associated, and adsorption­desorption of the bacteriocin from the cell wall of the producer by pH modification proved successful. It exhibited a bactericidal mode of action mediated by pore formation. Its biosynthesis is regulated by a quorum sensing mechanism. Enhanced production of salivaricin mmaye1 was achieved in a newly developed growth medium. Conclusions: A novel, cell wall adhering, highly potent bacteriocin with a broad spectrum of inhibitory activity, membrane-permeabilizing ability, and enhanced production in a newly constituted medium has been isolated. It has a quorum sensing regulatory system and possesses interesting physicochemical characteristics favoring its future use in food biopreservation. These findings pave the way for future evaluation of its medical and food applications.

Interruptions of nurses' activities and patient safety: an integrative literature review / Interrupções de atividades de enfermeiros e a segurança do paciente: revisão integrativa da literatura / Interrupciones de actividades de enfermeros y la seguridad del paciente: revisión integradora de la literatura

OBJECTIVES: to identify characteristics related to the interruption of nurses in professional practice, as well as to assess the implications of interruptions for patient safety. METHOD: integrative literature review. The following databases were searched: Pubmed/Medline, LILACS, SciELO and Cochrane Library, using the descriptors interruptions and patient safety. An initial date was not established, but the final date was December 31, 2013. A total of 29 papers met the inclusion criteria. RESULTS: all the papers included describe interruptions as a harmful factor for patient safety. Data analysis revealed three relevant categories: characteristics of interruptions, implications for patient safety, and interventions to minimize interruptions. CONCLUSION: interruptions favor the occurrence of errors in the health field. Therefore, there is a need for further studies to understand such a phenomenon and its effects on clinical practice. .

OBJETIVOS: identificar características relacionadas à interrupção de enfermeiros em sua prática profissional, bem como avaliar as implicações para a segurança do paciente. MÉTODO: foi realizada revisão de literatura do tipo integrativa, com busca nas bases de dados Pubmed/Medline, LILACS, SciELO e Biblioteca Cochrane, utilizando os descritores interruptions e patient safety. A data inicial não foi limitada e a data final foi 31 de dezembro de 2013, identificando-se 29 artigos que atenderam aos critérios de inclusão. RESULTADOS: todos os artigos revisados descreveram a interrupção como fator prejudicial à segurança do paciente. A análise destes estudos revelou três categorias relevantes: características da interrupção, implicações da interrupção para a segurança do paciente e intervenções para minimizar as interrupções. CONCLUSÃO: a interrupção favorece a ocorrência de erros na saúde. Assim, notou-se necessidade de novas pesquisas para compreender tal fenômeno e seus efeitos na prática clínica. .

OBJETIVOS: identificar características relacionadas a la interrupción que sufren los enfermeros en su práctica profesional, así como evaluar las implicaciones para la seguridad del paciente. MÉTODO: fue realizada una revisión de literatura de tipo integradora, con búsqueda en las bases de datos Pubmed/Medline, LILACS, SciELO y Biblioteca Cochrane, utilizando los descriptores interruptions y patient safety. La fecha inicial no fue limitada y la fecha final fue 31 de diciembre de 2013, se identificaron 29 artículos que atendieran a los criterios de inclusión. RESULTADOS: todos los artículos revisados describieron la interrupción como un factor perjudicial a la seguridad del paciente. El análisis de estos estudios reveló tres categorías relevantes: características de la interrupción, implicaciones de la interrupción para la seguridad del paciente e intervenciones para minimizar las interrupciones. CONCLUSIÓN: la interrupción favorece la ocurrencia de errores en la salud. Así, se notó la necesidad de realizar nuevas investigaciones para comprender ese fenómeno y los efectos del mismo en la práctica clínica. .

Bacteriocins in S. mutans strains isolated from children with and without dental caries: biotypes and sensitivity to antibiotics

El objetivo de este estudio fue determinar la producción debacteriocinas en cepas de Streptococcus mutans aisladas de niños preescolares con y sin caries dental. Con este fin en sedeterminó el índice ceod y se tomó saliva no estimulada en 53 niños con edades entre 3 y 5 años. Las muestras de saliva se cultivaron en Agar Mitis Salivarius Bacitracina para el aislamiento selectivo y recuento de S. mutans, y se incubaron en anaerobiosis durante 2 días a 37°C. Las cepas de S. mutans aisladas se biotipificaron con el sistema enzimático Api-ZYM (bioMérieux; Marcy-lE´toile, Francia). La detección de bacteriocinas se realizó de acuerdo a la técnica de doble capa enagar infusión cerebro corazón y las concentraciones mínimas inhibitorias de los aislamientos fueron evaluados contra la penicilina, amoxicilina, cefazolina, eritromicina, clindamicina,imipenem y vancomicina, por el método de dilución en agar. La experiencia de caries dental en esta población fue de 66 por ciento (35/53) y el índice ceod promedio fue de 3.2 (rango 2-6).S. mutans fue aislado en 33 de los 53 niños incluidos en el estudio (62 por ciento). Las 33 cepas de S. mutans aisladas se agruparon en 10 biotipos. Ocho (24 por ciento) de las 33 cepas evaluadas produjeron bacteriocinas, 6 de estas cepas provinieron de pacientescon caries y las otras dos de pacientes sin caries. Todos los 33 aislamientos de S. mutans fueron altamente sensibles a los antibacterianos evaluados.

Antimicrobial spectrum, production and mode of action of staphylococcin 188 produced by staphylococcus aureus 188

Staphylococcus aureus 188 has been shown to produce bacteriocin-like inhibitory substance known as staphylococcin188. It has a broad-activity spectrum against Micrococcus luteus, Streptococcus pneumoniae, Streptococcus faecalis, Streptococcus viridans, Corynebacterium diphtheriae and several staphylococcus species. The arbitrary unit of staphylococcin 188 against Micrococcus luteus was 1280AU/mL. Its production with simultaneous measurement of activity was monitored and was found to produce maximum amount of staphylococcin after 7 hours of incubation. Mode of action of the staphylococcin 188 on the sensitive cells was bactericidal rather than bacterioloytic

Symbiotic effectiveness of bacteriocin producing and non-producing strains of Rhizobium in green gram (Vigna radiata).

Rhizobium strains nodulating green gram [Vigna radiata (L.) Wilczek] were found to produce bacteriocin on modified Bergersen's medium and inhibited the growth of homologous Rhizobium strains. Four bacteriocin producing and four bacteriocin non-producing strains were compared for their effect on nodulation, in planta nitrogenase activity and plant dry weight of green gram. The bacteriocin producers formed more nodules in comparison to non-bacteriocin producers. However, the symbiotic effectiveness of bacteriocin producers was less in terms of plant dry weight in comparison to non-bacteriocin producers.

Detection and characterization of bacteriocin-producing Lactococcus lactis strains

One hundred sixty strains of Lactococcus lactis were screened for bacteriocin production by well diffusion assay of GM17 agar. Fourteen (8.4 per cent) produced antimicrobial activity other than organic acids, bacteriophages or hydrogen peroxide. The frequency of bacteriocin production ranged from 2(per cent) in L.lactis subsp. cremoris up to 12(per cent) in L.lactis subsp.lactis. Antimicrobial activities were not observed in any strain of L.lactis subsp.lactis var.diacetylactis. Among thirteen bacteriocin-producing strains and two nisin-producing strains (L.lactis subsp.lactis ATCC 11454 and L.lactis subsp.lactis CNRZ 150), eight (53 per cent) were characterized as lactose-positive (Lac+) and proteinase-negative (Prt-). The bacteriocin-producing cultures were also characterized on the basis of plasmid content. All strains had 2 to 7 plasmids with molecular weights varying from 0.5 to 28.1 Mdal. Four strains (ITAL 435, ITAL 436, ITAL 437 and ITAL 438) showed identical profiles and the other were quite distinct.

Potential of streptococcus faecalis to produce bacteriocin [s] and its properties

Fifty-eight strains of Streptococcus faecalis isolated from ten samples of Mish cheese were screened for bacteriocin [S] production against each other and a range of bacterial species. Streptococcus faecalis 2 and Streptococcus faecalis 17 were found to produce inhibitory substances, which can prevent the growth of Streptococcus faecalis 17 and Listeria monocytogenes. Maximum production of bacteriocin [S] was observed in the late-log phase and its activity was eliminated by alpha-chymotrypsin, but it was less sensitive to trypsin and more resistant to rennet. Addition of 8% NaCl to the growth medium reduced the titer of bacteriocin [S]

Production of bacteriocin lactobacilli

Nine strains of Lactobacillus casei and four strains of Lactobacillus plantarum isolated from Domiati cheese were tested for bacteriocin production against each other, also different species of bacteria were used as indicator strains. Lactobacillus plantarum 22 was found to produce an inhibitory substance[s] against L.plantarum 19, streptococcus lactis spp. cremoris CNRZ 117 and streptococcus faecium 82. The inhibitor substance [s] was sensitive to proteolytic enzymes but retained full activity after treating with catalase. Addition of NaCl to the growth medium lowered the titre of bacteriocin. L.plantarum 22 [Bacteriocin positive] contains six plasmids [33, 9.1, 5.3, 5.1, 3.4 and 1.1 M dal.] while its derivatives [Bacteriocin negative] 22 S[1] and 22 S[2] and loosed a 9.1 M dal

Production of bacteriocins by streptococci

Production of inhibitory substance [s] was investigated by using 8 strains of Streptococcus lactis ssp. lactis and 6 strains of Streptococcus lactis ssp. cremoris isolated from Domiati cheese samples. Among the strains tested, Streptococcus lactis spp. lactis 5 and 7 were found to inhibit the growth of S. lactis spp. lactis 1, 3 and 6, S. lactis spp., cremoris 11, 14, 19, 20 and CNRZ 117, Leuconostoc mesenteroides ssp. mesenteroids 1, Lactobacillus delbrueckii ssp. bulgaricus CNRZ 1188, 1183 and Lactobacillus plantarum 19. In contrast, strains of S. lactis ssp. cremoris tested did not inhibit the growth of indictor strains used. The inhibitor substance [s] was completely inactivated by alpha chemotrypsin, but it was less sensitive to trypsin and pronase. The optimum pH for the activity of antibacterial agent was 4.5-5. Addition of 4% NaCl to the growth medium of the producer strain reduced the titer of bacteriocin

Physical demonstration of a high molecular weight bacteriocin plasmid in Vibrio cholerae by genetic transformation process.

Bacteriocinogeny was transferred at high frequencies from bacteriocinogenic (Bac+) V. cholerae strains to non-bacteriocinogenic (Bac-) recipients in the in situ genetic transformation system on agar surface. DNA extracted from samples of growth of bacteria transformed to Bac+ were obtained at 2 h intervals following contact with the sterile agar surface where the donor had grown previously. This showed acquisition of a high molecular weight plasmid which could be physically demonstrated best in the 6 h sample of the Bac+ transformants; their 4 h samples failed to show this specific plasmid, while it was demonstrable only as a faint band in the 8 h samples.

Production of a bacteriophage, a phage tail-like bacteriocin and an antibiotic by Bacillus azotofixans

Twenty-two nitrogen-fixing Bacillus azotofixans strains shown to produce an inhibition zone against themselves in plate assays. The B. azotofixans type strain P3L-5, chosen for further studies, produced inhibition zones against various Bacillus strains and other bacterial genera. This antibacterial substance was also produced in liquid medium and its production was enhanced in semisolid medium (0.4% agar) after 3 to 5 days of incubation. The substance was suggested to be an antibiotic and its preliminary characterization showed resistance to heat (100§ C, 15 minutes), to trypsin, pronase, deoxyribonuclease I, ribonuclease A, phospoholipase C, ethanol, acetone, and ether, and sensitivity to strong alkali treatment. Its molecular weight was estimated to be between 3500 to 6000. After induction of B. azotofixans P3L-5 with mitomycin C or ultraviolet light, two types of particles were detected in the lysate: one similar to a phage tail and the other, less frequent, similar to a complete bacteriophage. Lysates containing these particles showed a killing effect in some but not all B. azotofixans strains, but neither the other Bacillus species nor Micrococcus were inhibited by these lysates

Incidence of klebocinogeny using two indicator systems.

The incidence of bacteriocinogeny among 117 clinical isolates of Klebsiella pneumoniae was examined using two systems of indicators-K. pneumoniae WC indicator and the Abbott-Shannon set of indicators. None of the isolate tested produced bacteriocin active on K. pneumoniae WC while 23 per cent positivity was observed with the Abbott-Shannon indicators. Most of the bacteriocin producers were urinary isolates (53.8%) followed by 15.3 and 30.7 per cent respectively of faecal and miscellaneous isolates. Our results indicate the advantages of using a set of indicators over a single indicator strain.

Estudo da inibiçäo de Staphilococcus aureus por Streptococcus lactis produtor de bacteriocina / Inhibition of Staphylococcus aureus by Streptococcus lactis producer of bacteriocin

Quatro cepas de S.lactis produtoras de bacteriocina foram avaliadas quanto à sua capacidade em inibir o desenvolvimento de 30 cepas de S. aureus provenientes de várias fontes. As técnicas utilizadas foram teste de inibiçäo, sendo que duas cepas de S. lactis (Sl5 e Sl51) apresentaram percentual de inibiçäode 41 e 58% respectivamente. No teste de crescimento associativo em leite, observou-se acentuada inibiçäo de três das cepas de S. aureus utilizadas (Sa16, Sa21 e Sa39), frente ao S. lacts (Sl51). A percentagem da populaçäo de S. aureus inibida após 9 horas de fermentaçäo variou de 87,5 a 96,6%

Klebocinas K6 y K150: producción y actividad en diferentes condiciones experimentales / Klebocins K6 y K150: production and activity in various experimental conditions

Se investigó la produción de bacteriocina en cepas de Klebsiella pneumoniae aisladas de pacientes con diversas infecciones. Mediante el método de estrías cruzadas se encontraron dos cepas capaces de inhibir el crecimiento de un alto número de bacterias de la misma especie. La Klebocina K150 presentó mayores halos de inhibición y un espectro de Klebsielas sensibles más amplio que la K6. Ambas se produjeron en medios complejos pero no se pusieron en evidencia en los medios de cultivo sintéticos empleados; la cepa 150 fue incapaz de elaborar bacteriocina en agar nutritivo, triptosa-extracto de carne y eosina-azul de metileno, mientras que la cepa 6 sintetizó la klebocina en todos excepto en triptosa-extracto de carne. Laa K150 es más susceptible al tratamiento con calor que la K6. Se estimó el peso molecular de las bacteriocinas como inferior a 10.000 D. Laa producción de bacteriocina se presentó asociada a la capacidad de hemolizar glóbulos rojos y a la actividad de lipasa. Además las cepas Klebocina-positivas se caracterizaron por un espectro de multiresistencia a antimicrobianos que las diferenció de otras cepas, resistentes

Association of R plasmids of Klebsiella pneumoniae with resistance to heavy metals, klebocin and beta lactamase production and lactose fermentation.

One hundred and fifty clinical isolates of Klebsiella pneumoniae were studied for beta lactamase production, Klebocin production and resistance to antibiotics and metals. 97.3 and 82.7 per cent strains produced beta-lactamase and klebocin respectively. Resistance to arsenite, antimony, tellurite, mercury and silver was observed in 91,66,6, 47.7, 44.8 and 33.3 per cent respectively and to ampicillin, tetracycline and nalidixic acid in 93.3,60, 41.3, 34.4, 28.2, and 1.3 per cent respectively. Forty eight antibiotic and metal resistant strains were then conjugated with Escherichia coli 711 F-Lac-Nxr. Transferable drug resistance, metal ion resistance, beta lactamase production, klebocin production and lactose fermentation was seen in 30, 21, 10, 11 and 5 isolates respectively.

Bacteriocinogenia, un sistema de antagonismo bacteriano / Bacteriocinogenia, a system for bacterial antagonism

Bacterial antagonism depends on many factors. Among others, for example we have competition for an essential nutrient, the production of toxic metabolites or the release of antibiotic substances. The production of bacteriocines by "killer" strains correspons to the latrer, being determined by plasmidial or chromosomal genes. On the other hand, the susceptibility to a given bacteriocine depends on the presence of surface recptors that are codified by the cellular DNA. The bacteriocine particles correspond to protein conglomerates which are sometimes associated with glucolipids. With the death of the productive cell, these particles are livated motivated by synthesis. The similarities which they share with the bacteriophage are many. However, their fundamental differences are that they lack nuclic acid and their incapcity to transmit themselves. Cellular death caused by the action of the bacteriocine is extremely quck, acting on the permeability of the plasmatic membrane, on the macromolecular syntesis (DNA, RNA an proteins) and on cellular oxidation. The wide range of bacteriocine and their respective spectre of action over the more or less related strains are excellent parameters to detect, identify and classify the productive bacteria and the susceptible ones. With only a few exceptions, the bacteriocines not lethal to their own productive cell nor to taxonomically distant species. This has led to intersting ecological and epidemiological outlooks. The amplitude of this phenomenon in Gram+ and Gram- bacteria has led to the study of fine mechanisms which have triggered the genetic expression to elaborate bacteriocines, determining the one responsible for this are the genes and localized signals in transmissible episomes or in chromosomal operons