Resumen Siguiendo el hilo conductor de la historia económica reciente del Ecuador, este artículo pretende reflejar la evolución de los discursos ambientales en la región latinoamericana. Durante las últimas décadas del siglo veinte, la conciencia ambiental de la sociedad se combinó con la penetración del pensamiento ambiental en la formulación de las políticas estatales. En el Ecuador, este coctel resultó en el largo plazo en un discurso específico: el buen vivir, cuya dimensión socio-ecológica se fundamentó en la relación armónica entre la sociedad y la naturaleza. La materialización del buen vivir debió plasmarse en la iniciativa Yasuní-ITT, un plan para salvar parte de la Amazonía ecuatoriana de la actividad petrolera, renunciando a extraer una porción significativa de las reservas del país. El plan movilizó al Estado y a la sociedad, pero sucumbió a cuarenta años de dependencia del petróleo. La terminación de la iniciativa develó dos discursos ambientales antagónicos. Mientras el Estado justificaba la noción de los recursos naturales para la mercantilización, la sociedad defendió visiones alternativas de la naturaleza relacionadas con el patrimonio y el hábitat de grupos originarios. El divorcio previsible de los dos discursos reveló la polifonía del buen vivir y reanudó la lucha por un discurso ambiental predominante. El artículo argumenta también que una de las consecuencias de esa lucha es la construcción semiótica de distintos significados de desarrollo.

Abstract Following the guiding thread of recent Ecuadorian economic history, this paper aims to mirror the evolution of environmental discourses across the Latin American region. During the last decades of the twentieth century, increasing social environmental awareness added up to the penetration of environmental thinking into the states’ developmental policymaking. For Ecuador, this cocktail resulted in the long-run in a particular discourse: Buen vivir. Central to rationalize buen vivir was its socioecological dimension, founded on a harmonic relationship between society and nature. Buen vivir was meant to materialize in a plan to save part of the Ecuadorian Amazonia from oil drilling by leaving a significant portion of the country’s reserves under the ground in exchange for an international monetary compensation: The Yasuní-ITT initiative. Despite the fact that the plan mobilized state and society, it succumbed to forty-years of oil dependence of Ecuadorian economy, politics, and society. The termination of the initiative unveiled two antagonist environmental discourses. Whereas the state held the notion of natural resources available for commodification in the global market, society bet on alternative meanings of nature such as natural heritage and ancient peoples’ habitat and means of existence. As outcomes of the foreseeable divorce between the environmental discourses, buen vivir turned into a polyphonic concept and the struggle over a hegemonic environmental discourse resumed. It is argued that during the twenty-first century, one of the consequences of such a struggle is the construction of different meanings of development alike.

Background: Listeria monocytogenes is a foodborne pathogen that causes listeriosis, a disease that can present as febrile gastroenteritis or as an invasive form that has high mortality rates. So far, the genetic diversity of strains of L. monocytogenes isolated from patients, foods and environmental sources in Chile has been poorly studied. Aim: To characterize genetically L. monocytogenes strains received by the Institute of Public Health of Chile (ISP) between 2007 and 2014. Methods: We selected 94 strains of L. monocytogenes corresponding to 94 different pulsotypes identified by pulsed field gel electrophoresis (PFGE), DNA was extracted and serotyping was performed by polymerase chain reaction (PCR) and multilocus sequence typing (MLST). Results: The most common serotype was 4b (55.3%), followed by serotypes 1/2a (25.5%), 1/2b (17%) and 1/2c (2.2%). 32 sequence-type (ST) were identified, of which 4 were new, and the predominant ones were ST1 (28.7%) and ST2 (13.8%). All the strains of L. monocytogenes were grouped in Lineages I and II. Conclusions: A great genetic variability was observed in the strains of L. monocytogenes analyzed, being predominant the ST1 and ST2, both belonging to Lineage I. Our results contribute to know the population structure of this pathogen in Chile and its presence in clinical samples, food and the environment.

Resumen Introducción: Listeria monocytogenes es un patógeno transmitido por alimentos que causa listeriosis, una enfermedad que puede presentarse como gastroenteritis febril o en una forma invasora que tiene altas tasas de mortalidad. Hasta el momento, ha sido poco estudiada la diversidad genética de cepas de L. monocytogenes aisladas desde pacientes, alimentos y fuentes ambientales en Chile. Objetivo: Caracterizar genéticamente cepas de L. monocytogenes de estos tres orígenes recibidas por el Instituto de Salud Pública de Chile (ISP) entre los años 2007 y 2014. Material y Métodos: Se seleccionaron 94 cepas de L. monocytogenes correspondientes a 94 pulsotipos diferentes identificados por electroforesis en gel de campo pulsado (PFGE), se extrajo ADN y se realizó serotipificación mediante reacción de polimerasa en cadena (RPC) y tipificación de secuencias multilocus (MLST). Resultados: El serotipo más común fue 4b (55,3%), seguido de 1/2a (25,5%), 1/2b (17%) y 1/2c (2,2%). Se identificaron 32 secuencias tipo (ST), de las cuales cuatro fueron nuevas, y las predominantes fueron ST1 (28,7%) y ST2 (13,8%). La totalidad de las cepas se agrupó en los Linajes I y II. Conclusiones: Se observó una gran variabilidad genética en las cepas de L. monocytogenes analizadas, siendo predominantes las secuencias tipo ST1 y ST2, ambas pertenecientes al Linaje I. Nuestros resultados contribuyen a conocer la estructura poblacional de este patógeno en Chile y su presencia en muestras clínicas, alimentos y el medio ambiente.

The gastrointestinal tract hosts around 10(14) bacterial microorganisms, in a constantly growing density from the stomach to the distal colon. This microbiota is composed by more than 500 species of bacteria, which are quickly acquired after birth, fairly stable during the host’s life, and essential for human homeostasis. These bacteria have important functions, such as stimulating the immune system, protecting the host from invading bacteria and viruses, and improving digestion, especially of complex carbohydrates. Also, the gut microbiota interacts directly with the immune system. However, the interaction of the intestinal epithelium and its microbiota with the immune system has yet to be fully understood. Secretory immunoglobulin A, produced by the plasma cells in Peyer’s patches and in the lamina propria, maintains non-invasive commensal bacteria and neutralize invasive pathogens. Dendritic cells migrate from the lamina propria of the secondary lymphoid organs to regulate gut immunity. They also have a key role maintaining luminal IgA and inducing the growth of regulatory T cells. Dendritic cells supervise the gut microenvironment too, keeping an immunological equilibrium and tolerance. The importance of the gut microbiota in regulating the immune system lies mostly in the homeostasis-or positive equilibrium. Thus, many diseases are a consequence of poor interactions or a loss of this equilibrium.

Abstract We report the first description of a rare catalase-negative strain of Staphylococcus aureus in Chile. This new variant was isolated from blood and synovial tissue samples of a pediatric patient. Sequencing analysis revealed that this catalase-negative strain is related to ST10 strain, which has earlier been described in relation to S. aureus carriers. Interestingly, sequence analysis of the catalase gene katA revealed presence of a novel nonsense mutation that causes premature translational truncation of the C-terminus of the enzyme leading to a loss of 222 amino acids. Our study suggests that loss of catalase activity in this rare catalase-negative Chilean strain is due to this novel nonsense mutation in the katA gene, which truncates the enzyme to just 283 amino acids.

Methicillin-resistant Staphylococcus aureus (MRSA) is widely distributed in hospital environments, causing serious infections, mainly the bloodstream, surgical site infection and pneumonia. Vancomycin (VAN) is the antibiotic of choice for treating severe MRSA infections; however, nowadays worldwide resistant strains (VRSA), with intermediate susceptibility (VISA) and decreased susceptibility or hetero-resistance to VAN (hVISA) have been reported, related to treatment failure and increased mortality. This report describes the first confirmed isolation of MRSA with hVISA phenotype in a public hospital in Chile.

Staphylococcus aureus resistente a meticilina (SARM) se encuentra ampliamente distribuido en ambientes hospitalarios, provocando infecciones graves, principalmente del torrente sanguíneo, infección de sitio quirúrgico y neumonía. Vancomicina (VAN) es el antimicrobiano de elección para tratar infecciones graves por SARM; sin embargo, actualmente en el mundo se han comunicado cepas resistentes (SARV), con susceptibilidad intermedia (SAIV) y susceptibilidad disminuida o con hetero-resistencia a VAN (SAIVh), relacionadas a falla terapéutica y aumento de la mortalidad. Describimos el primer aislado de SARM con fenotipo SAIVh en un hospital público de Chile.

Staphylococcus aureus is a known pathogen in pediatric patients that produces skin infections, cutaneous abscess, cellulitis and osteoarticular infections. Most of these infections are produced by a meticilin susceptible strain. The community associated methicillin resistant Staphylococcus aureus was published for the first time in 1993, ever since then is has been recognized as a cosmopolite pathogen. The first report in Latin America was published in 2003, and in Chile in 2008 from adult patients that have reported traveling to other countries. The following series describes four pediatric cases, all school-aged children, diagnosed since 2012 with clinical followups and molecular studies. Two cases presented as osteomyelitis of the lower extremity; and one presented as arm cellulitis. These three cases had Panton Valentine leukocidine (PV-L) negative strains from the clone complex 8. The last case presented a renal abscess, the strain was PV-L positive from the clone complex 30. This case series constitutes the first pediatric case report in Chile.

Staphylococcus aureus es un patógeno conocido como causa de infecciones de piel, tejidos blandos, osteoarticulares y celulitis en niños. Estas infecciones son principalmente causadas por cepas sensibles a meticilina. Staphylococcus aureus resistente a meticilina asociado a la comunidad fue publicado por primera vez en población australiana nativa en 1993 y desde entonces se ha transformado en un patógeno cosmopolita. En Latinoamérica se publicó el primer caso en 2003 y en Chile se comunicaron los primeros casos en 2008, casi todos adultos y con antecedentes de viaje al extranjero. Nuestra serie describe cuatro casos clínicos en niños escolares, pesquisados desde el 2012 con seguimiento clínico y estudio molecular. Dos casos se presentaron como una osteomielitis de extremidad inferior y uno como una celulitis de brazo. Los tres primeros casos correspondieron a cepas leucocidina Panton Valentine (PV-L) negativa, del complejo clonal 8. El último caso fue un absceso renal, cepa PV-L positiva, perteneciente al complejo clonal 30. Esta serie es el primer reporte de casos pediátricos en Chile.