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In South Tyrol the population of Scaphoideus titanus, the vector of Grapevine Flavescence dorée phytoplasma (FD), has been steadily increasing since 2010. The present work provides an overview of the monitoring activity of Scaphoideus titanus in South Tyrolean vineyards coupled with the description of a sensitive and reliable detection method of FD in the insect vector. We have developed an endogenous control of Scaphoideus titanus to be used in a multiplex real-time PCR, amplifying the map gene of FD phytoplasma. We present evidence on the performance of this new vector reference and its compatibility with FD detection., VITIS - Journal of Grapevine Research, Vol. 59 No. 2 (2020): Vitis

La utilización de las microalgas como fuente de energía para la obtención de aceite y biodiesel presenta muchas ventajas respecto a otras materias primas. Las microalgas tienen un alto rendimiento por superficie cultivada, diversifica el tipo de combustible a producir y no compite con la producción de alimentos, siendo clasificado como un biocombustible de tercera generación. En el presente trabajo seevalúa la influencia del rendimiento de biomasa microalgal bajo diferentes condiciones de cultivo. La microalga Chlorella vulgaris fue cultivada a escala de laboratorio utilizando 6 elermeyers de 250 mL siguiendo la metodología descrita en el medio de cultivo Watanabe modificado. Las condiciones de cultivo fueron 28°C ± 1°C con un pH aproximado entre 6 y 7. A partir del recuento celular mediante microscopía fue posible determinar la velocidad de crecimiento de la microalga en estudio con una duración de diez días; alcanzándose la máxima concentración de células en el cultivo con vitaminas y suministro de aire de 450.5×104 células/mL. A los cinco días los cultivos con vitaminas mostraron 8 veces mayor rendimiento, mientras que sin estas 7 veces. El mayor incremento se registró para el cultivo con vitaminas y suministro permanente de aire el cual incrementó su producción de biomasa 20 veces. Los resultados obtenidos en esta investigación de muestran el potencial que tiene la microalga Chlorella vulgaris para su uso con fines energéticos, encaminados fundamentalmente a la obtención de biodiesel.

Reducción alta, Univ. de Granada, Fctd. de Medicina

Resumen Introduccion:  - lactamasas de espectro extendido (BLEE) son enzimas plasmidiales que confi eren resis-tencia a multiples antimicrobianos. Las bacteriemias por enterobacterias productoras de BLEE restringen las opciones terapeuticas y aumentan la mortalidad. Objeti-vo : Realizar una descripcion clinica y molecular de las bacteriemias causadas por enterobacterias productoras de BLEE. Metodo : Se estudiaron retrospectivamente los casos de bacteriemia por Escherichia coli , Klebsiella pneumoniae y Proteus spp. confi rmadas para BLEE, en adultos ingresados en un hospital universitario durante los anos 2004-2007. Se revisaron los registros clinicos y de susceptibilidad. Se realizo tipifi cacion molecular por reaccion de polimerasa en cadena y estudio de clonalidad por electroforesis de campo pulsado. Resultados: Se iden-tifi co una prevalencia de BLEE de 9,8% en enterobacterias causantes de bacteriemias. Se observo susceptibilidad disminuida a quinolonas y aminoglucosidos, sin resisten-cia a carbapenemicos. Los tipos de BLEE predominantes fueron CTX-M (96%), TEM (62%) y GES (28%). El 79% de las cepas presento mas de un tipo de BLEE. El analisis clinico revelo alta frecuencia de patologias de riesgo, uso previo de antimicrobianos y uso de dispositivos invasores. No se encontro clonalidad signifi cativa.

Maestría en Educación Básica

Extended-spectrum-β-lactamases (ESBL) are plasmid-encoded enzymes that confer resistance to multiple antimicrobials. ESBL-producing enterobacteria that cause bacteremia limit therapeutic options and increase mortality.To perform a clinical and molecular description of bacteremia caused by ESBL-producing enterobacteria.We retrospectively studied the cases of bacteremia due to ESBL-producing Escherichia coli, Klebsiella pneumoniae and Proteus spp in adults admitted to a university hospital during the years 2004-2007. We reviewed the clinical records and antimicrobial susceptibility patterns. Molecular typing was performed by polymerase chain reaction and study of clonality by pulsed-field electrophoresis.We found a prevalence of 9.8% ESBL in enterobacteria causing bacteremia. Decreased susceptibility to quinolones and aminoglycosides was observed, without resistance to carbapenems. The predominant ESBL types were CTX-M (96%), TEM (62%) and GES (28%). 79% of the strains presented more than one type of ESBL. Clinical analysis revealed high prevalence of risk factors, previous use of antimicrobials and of invasive devices. There was no significant clonality.The presence of ESBLs in bloodstream infections is a clinical problem that must be considered when choosing empiric therapy.

Introducción: β-lactamasas de espectro extendido (BLEE) son enzimas plasmidiales que confieren resistencia a múltiples antimicrobianos. Las bacteriemias por enterobacterias productoras de BLEE restringen las opciones terapéuticas y aumentan la mortalidad. Objetivo: Realizar una descripción clínica y molecular de las bacteriemias causadas por enterobacterias productoras de BLEE. Método: Se estudiaron retrospectivamente los casos de bacteriemia por Escherichia coli, Klebsiella pneumoniae y Proteus spp. confirmadas para BLEE, en adultos ingresados en un hospital universitario durante los años 2004-2007. Se revisaron los registros clínicos y de susceptibilidad. Se realizó tipificación molecular por reacción de polimerasa en cadena y estudio de clonalidad por electroforesis de campo pulsado. Resultados: Se identificó una prevalencia de BLEE de 9,8% en enterobacterias causantes de bacteriemias. Se observó susceptibilidad disminuida a quinolonas y aminoglucósidos, sin resistencia a carbapenémicos. Los tipos de BLEE predominantes fueron CTX-M (96%), TEM (62%) y GES (28%). El 79% de las cepas presentó más de un tipo de BLEE. El análisis clínico reveló alta frecuencia de patologías de riesgo, uso previo de antimicrobianos y uso de dispositivos invasores. No se encontró clonalidad significativa. Conclusión: La presencia de BLEE en bacteriemias constituye un problema clínico que debe ser considerado al elegir la terapia empírica.

¿Puede ser la administración electrónica una herramienta de inclusión digital? ¿Qué puede aportar la administración electrónica para avanzar en la inclusión digital? ¿Qué podemos hacer, cada uno desde nuestra actividad, para favorecer la inclusión digital? Estas son algunas de las preguntas que se formulaban los participantes en las III Jornadas sobre Derecho y Tecnología así como al XI Encuentro de Gobierno Electrónico e Inclusión Digital, celebrados en Zaragoza los días 23 y 24 de mayo de 2011. Cada uno, desde su perspectiva, trató de aportar ideas en esa línea que marcamos en la convocatoria del evento: «La administración electrónica como herramienta de inclusión digital». Estas aportaciones están recogidas en este libro, agrupadas en tres bloques diferentes. En el primero, bajo el título Políticas de inclusión digital desde la perspectiva de la administración electrónica, tienen cabida aquellas reflexiones sobre qué hacer para favorecer la inclusión digital desde la administración electrónica, con enfoques concretos en Brasil o Iberoamérica, o de tipo general, aplicable en cualquier país. En el segundo, el título Casos reales de inclusión digital desde la perspectiva de la administración electrónica reúne experiencias concretas llevadas a cabo en España y Brasil. Por último, y no menos importante, el título Inclusión digital desde las aulas universitarias recoge propuestas para fomentar la inclusión digital desde las aulas universitarias.

Streptococcus pneumoniae infections constitute a public health problem. In our country there is scarce information regarding isolates from bacteraemic episodes in adult population. The antibiotic susceptibility, serotypes and clonal relationship of 56 isolates of S. pneumoniae from adult patients with bacteraemic infections in Concepcion-Talcahuano, Bio-Bio Region, Chile, were studied. Resistance to tetracycline (21.4%), trimethoprim/ sulfamethoxazole (18%), erythromycin (18%), chloramphenicol (7%) and 1 penicillin resistant isolate from a meningeal focus (2%) was found. Also, all the isolates were susceptible to cefotaxime, levofloxacin, moxifloxacin and vancomycin. A wide variety of capsular serotypes was demonstrated, with predominance of serotypes 1, 5, 23F, 7F and 3. The macrorestriction analysis by pulse field electrophoresis revealed 31 electrophoretic patterns and 12 clonal groups, discarding a predominant clone. According to the results, at least, 80% of the S. pneumoniae serotypes isolated from bacteraemic adult patients are included in the available commercial vaccine.

Las infecciones ocasionadas por Streptococcus pneumoniae constituyen un problema de salud pública. En nuestro país existe escasa información sobre aislados de procesos bacteriémicos en población adulta. Se estudió la susceptibilidad, serotipos y relación clonal de 56 aislados de S. pneumoniae desde hemocultivos, entre enero 2005 y agosto 2006, de pacientes adultos de la intercomuna Concepción-Talcahuano, Región del Bío-Bío, Chile. Se encontró resistencia a tetraciclina (21,4%), cotrimoxazol (18%), eritromicina (18%), cloranfenicol (7%) y a penicilina en un solo aislado procedente de un foco meníngeo (2 %). La totalidad mostró susceptibilidad a cefotaxima, levofloxacina, moxifloxacina y vancomicina. Se demostró una amplia variedad de serotipos capsulares, con predominio de los serotipos 1, 5, 23F, 7F y 3. El análisis de macrorestricción y electroforesis en campo pulsado reveló 31 patrones electroforéticos con 12 grupos clona-les, descartando un clon predominante. De acuerdo a los resultados, al menos 80% de los serotipos de aislados de S. pneumoniae de procesos bacteriémicos están incluidos en la vacuna comercial disponible. Streptococcus pneumoniae infections constitute a public health problem. In our country there is scarce information regarding isolates from bacteraemic episodes in adult population. The antibiotic susceptibility, sero-types and clonal relationship of 56 isolates of S. pneumoniae from adult patients with bacteraemic infections in Concepcion-Talcahuano, Bio-Bio Region, Chile, were studied. Resistance to tetracycline (21.4%), trimethoprim/ sulfamethoxazole (18%), erythromycin (18%), chloramphenicol (7%) and 1 penicillin resistant isolate from a meningeal focus (2%) was found. Also, all the isolates were susceptible to cefotaxime, levofloxacin, moxifloxacin and vancomycin. A wide variety of capsular serotypes was demonstrated, with predominance of serotypes 1, 5, 23F, 7F and 3. The macrorestriction analysis by pulse field electrophoresis revealed 31 electrophoretic patterns and 12 clonal groups, discarding a predominant clone. According to the results, at least, 80% of the S. pneumoniae serotypes isolated from bacteraemic adult patients are included in the available commercial vaccine.

Los sistemas multidrogas bacterianos contribuyen al desarrollo del fenotipo de multi-resistencia presentado por cepas de Acinetobacter baumannü, patógeno intrahospi-talario, que durante los últimos años ha incrementado su importancia por la creciente resistencia a carbapenémicos. El fenotipo de multi-resistencia está otorgado por la combinación de varios mecanismos de resistencia entre los cuales se encuentran estos sistemas de bombas de expulsión. El sistema multidroga AdeABC se ha detectado en muchas de estas cepas multi-resistentes de A. baumannü y, se ha relacionado con resistencia a diversos grupos de antimicrobianos, incluidos tigeciclina y meropenem. La inhibición de dichos sistemas multidrogas permitiría aumentar la eficacia de la terapia antimicrobiana. La siguiente revisión se enfoca en las bombas de expulsión multidrogas presentes en A. baumannü, con particular énfasis en el sistema AdeABC.

Sea urchins of the genus Diadema play an important role as controlers of algal growth in coral reef and rocky reef communities, but high densities cause bioerosion of the reef framework. Between January 2006 and February 2007 (except April, July and August), population densities and mean test diameter of Diadema mexicanum were determined at Isla Montosa, La Entrega, Isla Cacaluta and San Agustín, Bahías de Huatulco, Mexico. Mean density of the sea urchins was relatively constant through time at all localities: lowest at San Agustín (0.26±0.13 ind.m-2) and highest at La Entrega (4.17±1.4 ind.m-2). There were significant differences between La Entrega and other localities. Mean test diameter ranged between 4.41±0.88 cm (Isla Cacaluta) and 4.72±0.27 (San Agustin), and did no vary significantly between localities, but there were monthly variations. Test diameter agrees with other studies. The calculated amount of CaCO3 removed by D. mexicanum showed variations between localities. The lowest rate of bioerosion occurred at San Agustín (0. 25 kg.m-2.yr-1 ), and the highest at La Entrega (4 kg.m-2.yr-1). The recent urchin population decrease means a reduction in their removal of coral CaCO3: 5.55% to 2.36% at Isla Cacaluta, 5.08% to 1.40% at San Agustin and 16.59% to 3.08% at Isla Montosa. The only locality where bioerosion increased was La Entrega, from 27.04 % to 33.05 %. This reduction of urchin activities could be beneficial for coral reef growing and recovery from stress, nevertheless it could also signify an increase in algal biomass and competition with corals for light and space. We recommend a permanent monitoring and evaluation of population densities of D. mexicanum and fishes, as well as coral and algal cover at the area, to discern if changes in sea urchin densities in Bahias de Huatulco are a continuous phenomenon, or part of a natural cycle of increments and reductions. Rev. Biol. Trop. 56 (Suppl. 3): 255-263. Epub 2009 January 05. Los erizos del género Diadema desempeñan un papel importante como controladores del crecimiento algal en comunidades de arrecifes coralinos y rocosos. Si las densidades poblacionales se incrementan pueden causar bioerosión sobre la estructura del arrecife. Durante febrero 2006 y enero 2007 (excepto abril, julio y agosto), se determinaron las densidades poblacionales y diámetro promedio de testa de Diadema mexicanum en Isla Montosa, La Entrega, Isla Cacaluta y San Agustín en Bahías de Huatulco, México. La densidad media se mantuvo relativamente constante en el tiempo en todas las localidades. La más baja fue en San Agustín (0.26 ind.m-2) y la más alta en La Entrega (4.17 ind.m-2). Existieron diferencias significativas entre La Entrega y las demás localidades. El diámetro de la testa osciló entre 3.9 cm (La Entrega) y 4.72 cm (San Agustín) y no varió significativamente entre localidades, pero si hubo variaciones en el tiempo. La cantidad calculada de CaCO3 removido por D. mexicanum mostró variaciones entre localidades. La tasa mas baja de bioerosión ocurrió en San Agustín (0. 25 kg.m-2.yr-1), y la mas alta en La Entrega (4 kg.m-2.yr-1). En comparación con reportes previos, la reducción en el tamaño de las poblaciones de D. mexicanum significa una reducción en la remoción del CaCO3 producido, de 5.55 % a 2.36 % en Isla Cacaluta, 5.08 % a 1.40 % en San Agustín y 16.59 % a 3.08 % en Isla Montosa. La única localidad donde hubo incremento en la bioerosión fue La Entrega, de 27.04 % a 33.05 %. La reducción podría ser beneficiosa para el crecimiento y recuperación del arrecife, aunque podría ocurrir un incremento en la biomasa algal y competencia con los corales por luz y espacio. Se recomienda un monitoreo permanente de las densidades poblacionales de D. mexicanum y peces, así como la cobertura de corales y algas en Bahías de Huatulco, para discernir si los cambios en las poblaciones son un fenómeno continuo o parte de un ciclo de incrementos y reducciones.

Background: A progressive frequency of resistance to fluorquinolones is observed among Gram-negative bacilli. Aim: To investigate the mechanism of resistance to fluoroquinolones mediated by mutations affecting gyrA and gyrB genes in strains of Gram negative bacüli isolated from CMean hospitals. Material and method: Minimal inhibitory concentration of fluoroquinolones was determined in 91 randomly selected nalidixic acid-resistant strains of Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa, isolated from hospitals of 12 Chilean cities. Quinolone resistance determining region (QRDR) was amplified by PCR and mutations were determined by restriction fragment length polymorphism (RFLP) and DNA sequencing. Results: Strains with mutation in codon 83 of gyrA showed decreased susceptibility to ciprofloxacin with MICs ranging from 0.25 to 1024 fig/ml. The sequencing of PCR products for gyrA indicated amino acid changes in the QRDR region. One strain ofE. coli presented a double mutation, in codon 83 Ser to Leu as well as in codon 87 Asp to Asn. In strains ofK. pneumoniae, however, the change of codon 83 was Ser to Tyr, in A. baumannii was Ser to Leu and in P. aeruginosa was Thr to He. No strains with mutations affecting gyrB were found. Conclusions: Mutations in codon 83 of gyrA is a frequent genetic event involved in the mechanism leading to decreased susceptibility to fluoroquinolone in strains of Gram-negative bacilli

Minimal inhibitory concentration offluoroquinolones was determined in 91 randomly selected nalidixic acid-resistant strains of Escherichiacoli, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa, isolated fromhospitals of 12 Chilean cities. Quinolone resistance determining region (QRDR) was amplified by PCRand mutations were determined by restriction fragment length polymorphism (RFLP) and DNAsequencing.

Background: A progressive frequency of resistance to fluorquinolones is observed among Gram-negative bacilli. Aim: To investigate the mechanism of resistance to fluoroquinolones mediated by mutations affecting gyrA and gyrB genes in strains of Gram negative bacüli isolated from CMean hospitals. Material and method: Minimal inhibitory concentration of fluoroquinolones was determined in 91 randomly selected nalidixic acid-resistant strains of Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa, isolated from hospitals of 12 Chilean cities. Quinolone resistance determining region (QRDR) was amplified by PCR and mutations were determined by restriction fragment length polymorphism (RFLP) and DNA sequencing. Results: Strains with mutation in codon 83 of gyrA showed decreased susceptibility to ciprofloxacin with MICs ranging from 0.25 to 1024 fig/ml. The sequencing of PCR products for gyrA indicated amino acid changes in the QRDR region. One strain ofE. coli presented a double mutation, in codon 83 Ser to Leu as well as in codon 87 Asp to Asn. In strains ofK. pneumoniae, however, the change of codon 83 was Ser to Tyr, in A. baumannii was Ser to Leu and in P. aeruginosa was Thr to He. No strains with mutations affecting gyrB were found. Conclusions: Mutations in codon 83 of gyrA is a frequent genetic event involved in the mechanism leading to decreased susceptibility to fluoroquinolone in strains of Gram-negative bacilli

Background: Infectious diseases produced by Enterococcus spp, must be treated with a synergistic combination between a penicillin and an aminoglycoside. High level resistance to aminoglycosides is a serious therapeutic problem, since it predicts the loss of synergistic activity of this antimicrobial combination. Aim: To investigate the presence of genes encoding aminoglycoside-modifying enzymes (AMEs) among strains of Enterococcus spp with high level of resistance to aminoglycosides. Material and methods: The genes encoding some of the AMEs were investigated among 305 aminoglycoside-resistant strains of Enterococcus spp isolated in hospitals of the VIII region of Chile, by dot blot hybridization and Polymerase Chain Reaction (PCR). Results: High level resistance to some aminoglycosides was observed in 104 strains (34.1%) and 93 of these harbored at least one of the genes encoding the investigated AMEs. Three genes were detected: aac(6')Ieaph(2")Ia (14.8%) encoding for the enzyme AAC(6')Ie-APH(2'’)Ia (resistance to all aminoglycosides, except streptomycin); aph(3')IIIa (26%), and ant(6')Ia (28.5%) encoding for the phosphorylating enzymes APH(3')IIIa (resistance to kanamycin, amikacin and neomycin), and ANT(6')-Ia (resistance only to streptomycin), respectively. None of the strains harbored the gene ant (4') which encode for the enzyme ANT (4'). Conclusion: The low frequency of strains harbouring the bifunctional enzyme (

The resistance of Acinetobacter baumannii to ss-lactam antibiotics is mainly due to the synthesis of ss-lactamases. From a clinical point of view, this bacteria and others, grouped under the acronym SPACE (S: Serratia, P: Pseudomonas, A: Acinetobacter, C: Citrobacter, E: Enterobacter) are essentially Amp-C ss-lactamases producers. There is no local information about ESBL presence in Acinetobacter. We studied ESBL production using the Ho and col. technique modified by adding cloxacillin as chromosomal ss-lactamases inhibitor. From 69 isolates, with resistance to at least one third generation cephalosporin, only 7 showed positive synergy test. Four of these amplified for TEM family gene, and one of these amplified also for the OXA family. Our study found a low ESBL production percentage, which agrees with the premise of Amp-C as the main mechanism of resistance to ss-lactam antibiotics in A. baumannii. However, the ESBL description in these bacteria emphasizes the capacity of expressing multiple resistance mechanisms.

La resistencia de Acinetobacter baumannii a antimicrobianos ß-lactámicos se debe fundamentalmente a la síntesis de ß-lactamasas. Del punto de vista clínico se considera que esta bacteria, y otras agrupadas en el acrónimo SPACE (Serratia, Pseudomonas, Acinetobacter, Citrobacter, Enterobacter), son predominantemente productoras de ß-lactamasas tipo AmpC. No hay información en nuestro país sobre presencia de ß-lactamasas de espectro extendido (BLEE) en Acinetobacter. Se estudió la producción de BLEE en cepas de Acinetobacter, mediante una modificación de la técnica de Ho y col adicionando cloxacilina como inhibidor de ß-lactamasas cromosomales. De 69 cepas con resistencia al menos a una cefalosporina de tercera generación, sólo siete presentaron sinergia positiva. Cuatro cepas amplificaron por RPC un fragmento intragénico de genes de familia TEM y una de ellas amplificó, además, para el gen de la familia OXA. Se evidenció un bajo porcentaje de producción de BLEE, lo que confirma que la producción de Amp-C es el principal mecanismo de resistencia de A. baumannii a ß-lactámicos. Sin embargo, la descripción de BLEE en esta bacteria, enfatiza su capacidad de albergar múltiples mecanismos de resistencia

La resistencia de Acinetobacter baumannii a antimicrobianos ß-lactámicos se debe fundamentalmente a la síntesis de ß-lactamasas. Del punto de vista clínico se considera que esta bacteria, y otras agrupadas en el acrónimo SPACE (Serratia, Pseudomonas, Acinetobacter, Citrobacter, Enterobacter), son predominantemente productoras de ß-lactamasas tipo AmpC. No hay información en nuestro país sobre presencia de ß-lactamasas de espectro extendido (BLEE) en Acinetobacter. Se estudió la producción de BLEE en cepas de Acinetobacter, mediante una modificación de la técnica de Ho y col adicionando cloxacilina como inhibidor de ß-lactamasas cromosomales. De 69 cepas con resistencia al menos a una cefalosporina de tercera generación, sólo siete presentaron sinergia positiva. Cuatro cepas amplificaron por RPC un fragmento intragénico de genes de familia TEM y una de ellas amplificó, además, para el gen de la familia OXA. Se evidenció un bajo porcentaje de producción de BLEE, lo que confirma que la producción de Amp-C es el principal mecanismo de resistencia de A. baumannii a ß-lactámicos. Sin embargo, la descripción de BLEE en esta bacteria, enfatiza su capacidad de albergar múltiples mecanismos de resistencia The resistance of Acinetobacter baumannii to ß-lactam antibiotics is mainly due to the synthesis of ß-lactamases. From a clinical point of view, this bacteria and others, grouped under the acronym SPACE (S: Serratia, P: Pseudomonas, A: Acinetobacter, C: Citrobacter, E: Enterobacter) are essentially Amp-C ß-lactamases producers. There is no local information about ESBL presence in Acinetobacter. We studied ESBL production using the Ho and col. technique modified by adding cloxacillin as chromosomal ß-lactamases inhibitor. From 69 isolates, with resistance to at least one third generation cephalosporin, only 7 showed positive synergy test. Four of these amplified for TEM family gene, and one of these amplified also for the OXA family. Our study found a low ESBL production percentage, which agrees with the premise of Amp-C as the main mechanism of resistance to ß-lactam antibiotics in A. baumannii. However, the ESBL description in these bacteria emphasizes the capacity of expressing multiple resistance mechanisms

Este artículo presenta la historia del proyecto de la Licenciatura en Economía y el debate en torno a los perfiles del profesional egresado de esta disciplina. El autor analiza un abierto abanico de posiciones que van desde Vasconcelos, Narciso Bassols, Lombardo Toledano y Jesús Silva Herzog (padre), hasta Gómez Morín y Cosío Villegas. Quienes coinciden en que la economía es una ciencia integral que tiene por objeto el bienestar del hombre en la sociedad.

Klebsiella pneumoniae is an important pathogenic bacterium, frequently isolated from nosocomial samples, that exhibits wide antimicrobial resistance profiles, including third generation cephalosporins (3GC), aminoglycosides and quinolones. The resistance to 3GC is mainly due to the synthesis of extended spectrum beta lactamases (ESBL), encoded by conjugative plasmids.To investigate the potential transference of resistance to 3GC from nosocomial strains of K. pneumoniae to other clinical strains of various species of Enterobacteriaceae.The mating experiments were carried out in liquid media and three nosocomial strains of K. pneumoniae were used as donors. These strains were ESBL-producers and resistant to, at least, one of the 3GC assayed. One strain of Citrobacter freundii, Salmonella typhimurium, Serratia marcescens and Escherichia coli, isolated from clinical specimens, were used as recipients. The presence of bla genes was investigated by PCR.The three nosocomial strains of K. pneumoniae were able to transfer the resistance to 3GC and the genes encoding the ESBL to the susceptible recipient strains of enterobacteria. The frequency of transference was as high as 3.2 x 10-2 transconjugants/recipient cell when the strain of Citrobacter freundii was used as recipient. All transconjugants exhibited high level of resistance to the 3GC assayed.Strains of K. pneumoniae isolated from Chilean hospitals are able to disseminate the ESBL genes to clinical strains of others species of Enterobacteriaaceae.

Background: Klebsiella pneumoniae is an important pathogenic bacterium, frequently isolated from nosocomial samples, that exhibits wide antimicrobial resistance profiles, including third generation cephalosporins (3GC), aminoglycosides and quinolones. The resistance to 3GC is mainly due to the synthesis of extended spectrum beta lactamases (ESBL), encoded by conjugative plasmids. Aim: To investigate the potential transference of resistance to 3GC from nosocomial strains of K. pneumoniae to other clinical strains of various species of Enterobacteriaceae. Material and methods: The mating experiments were carried out in liquid media and three nosocomial strains of K. pneumoniae were used as donors. These strains were ESBL-producers and resistant to, at least, one of the 3GC assayed. One strain of Citrobacter freundii, Salmonella typhimurium, Serratia marcescens and Escherichia coli, isolated from clinical specimens, were used as recipients. The presence of bla genes was investigated by PCR. Results: The three nosocomial strains of K. pneumoniae were able to transfer the resistance to 3GC and the genes encoding the ESBL to the susceptible recipient strains of enterobacteria. The frequency of transference was as high as 3.2 x 10-2 transconjugants/recipient cell when the strain of Citrobacter freundii was used as recipient. All transconjugants exhibited high level of resistance to the 3GC assayed. Conclusions: Strains of K. pneumoniae isolated from Chilean hospitals are able to disseminate the ESBL genes to clinical strains of others species of Enterobacteriaaceae

Background: Klebsiella pneumoniae is an important pathogenic bacterium, frequently isolated from nosocomial samples, that exhibits wide antimicrobial resistance profiles, including third generation cephalosporins (3GC), aminoglycosides and quinolones. The resistance to 3GC is mainly due to the synthesis of extended spectrum beta lactamases (ESBL), encoded by conjugative plasmids. Aim: To investigate the potential transference of resistance to 3GC from nosocomial strains of K. pneumoniae to other clinical strains of various species of Enterobacteriaceae. Material and methods: The mating experiments were carried out in liquid media and three nosocomial strains of K. pneumoniae were used as donors. These strains were ESBL-producers and resistant to, at least, one of the 3GC assayed. One strain of Citrobacter freundii, Salmonella typhimurium, Serratia marcescens and Escherichia coli, isolated from clinical specimens, were used as recipients. The presence of bla genes was investigated by PCR. Results: The three nosocomial strains of K. pneumoniae were able to transfer the resistance to 3GC and the genes encoding the ESBL to the susceptible recipient strains of enterobacteria. The frequency of transference was as high as 3.2 x 10-2 transconjugants/recipient cell when the strain of Citrobacter freundii was used as recipient. All transconjugants exhibited high level of resistance to the 3GC assayed. Conclusions: Strains of K. pneumoniae isolated from Chilean hospitals are able to disseminate the ESBL genes to clinical strains of others species of Enterobacteriaaceae

The aminoglycoside-aminocyclitol antibiotics constitute one of the antibacterial agent families with greater activity upon aerobic Gram-negative bacilli. These compounds are formed by the combination of one amino-cyclic alcohol (aminocyclitol) and aminosaccharides (aminoglycosides) linked by glycosidic bonds. The strong bactericidal activity exhibited for these compounds is not only explained by their ability to inhibit the protein synthesis, but also by pleiotropic effect altering the permeability of cytoplasmatic membrane. The penetration of these antibiotics to the bacterial cells is mediated by three well defined phases, being the two latest dependant of the proton-motive force. This fact explains that this kind of compounds have no antibacterial activity upon anaerobic bacteria. Bacterial resistance to aminoglycosides is mainly due to aminoglycoside-modifying enzymes (AME), which are commonly encoded by extrachromosomal genetic elements as are plasmids and transposons. Nevertheless, new mechanisms of resistance and genetic elements participating in the resistance to these compounds have been identified. Thus, recently the methylation of the 16S rRNA binding the aminoglycosides has been described. On the other hand, the gene cassettes acquire an increasing importance, because they can host a varied of families of antibiotic resistance genes, including the aminoglycoside-aminocyclitols. These gene cassettes are associated to integrons, which are able to integrate and express these antibiotic resistance determinants.

Background: Klebsiella pneumoniae is a pathogenic bacterium frequently isolated from nosocomial samples, specially the subspecie pneumoniae, with extensive antibiotic resistance profiles, including third generation cephalosporins, aminoglycosides and quinolones. This is specially true for those strains producing extended spectrum beta lactamases (ESBL). Aim: To investigate the susceptibility to gentamicin, amikacin and ciprofloxacin and the presence of some aminoglycoside modifying enzyme (AMEs) among nosocomial strains of K pneumoniae subspecie pneumoniae producing ESBL. Material and methods: The antibiotic resistant patterns and the level of resistance (minimal inhibitory concentration, MIC) of 100 strains, isolated from several hospitals of different Chilean cities, were determined. The presence of some aminoglycosides modifying enzyme (AMEs) was investigated by PCR. Results: Sixty five percent of strains were resistant to gentamicin, 47% were resistant to amikacin and 29% were resistant to ciprofloxacin. The most frequent AMEs genes detected were the aac(6')-Ib gene (6'N-Acetyltransferase type Ib enzyme) in 69% of strains, conferring resistance to amikacin, kanamycin, tobramycin, and neomycin, and the gene aac(3)-IIa (3-Acetyltransferase type 3-IIa enzyme), in 36% of strains, conferring resistance to gentamicin. Conclusions: Among nosocomial strains of K pneumoniae subspecie pneumoniae isolated from Chilean hospitals, there is an association between the production of ESBL and the resistance to others antimicrobial agents, especially aminoglycosides. Nevertheless, 71% of isolates are susceptible to ciprofloxacin (Rev Med Chile 2004; 132: 1173-8). (Key Words: Aminoglycosides; Antibiotic resistance, bacterial; Klebsiella pneumoniae)

Background: Klebsiella pneumoniae is a pathogenic bacterium frequently isolated from nosocomial samples, specially the subspecie pneumoniae, with extensive antibiotic resistance profiles, including third generation cephalosporins, aminoglycosides and quinolones. This is specially true for those strains producing extended spectrum beta lactamases (ESBL). Aim: To investigate the susceptibility to gentamicin, amikacin and ciprofloxacin and the presence of some aminoglycoside modifying enzyme (AMEs) among nosocomial strains of K pneumoniae subspecie pneumoniae producing ESBL. Material and methods: The antibiotic resistant patterns and the level of resistance (minimal inhibitory concentration, MIC) of 100 strains, isolated from several hospitals of different Chilean cities, were determined. The presence of some aminoglycosides modifying enzyme (AMEs) was investigated by PCR. Results: Sixty five percent of strains were resistant to gentamicin, 47% were resistant to amikacin and 29% were resistant to ciprofloxacin. The most frequent AMEs genes detected were the aac(6')-Ib gene (6'-N-Acetyltransferase type Ib enzyme) in 69% of strains, conferring resistance to amikacin, kanamycin, tobramycin, and neomycin, and the gene aac(3)-IIa (3-Acetyltransferase type 3-IIa enzyme), in 36% of strains, conferring resistance to gentamicin. Conclusions: Among nosocomial strains of K pneumoniae subspecie pneumoniae isolated from Chilean hospitals, there is an association between the production of ESBL and the resistance to others antimicrobial agents, especially aminoglycosides. Nevertheless, 71% of isolates are susceptible to ciprofloxacin (Rev Méd Chile 2004; 132: 1173-8)

Bacteria have developed sophisticated and successful genetic mechanisms to evade the action of antimicrobials. Bacterial multiresistance has caused serious problems in the treatment of nosocomial infections. Integrons and gene cassettes are considered the main genetic elements in the evolution of plasmids and transposons that actively participate in the mobilization of genes, codifying different bacterial resistance mechanisms. This article reviews the historical and structural aspects of integrons and resistance gene cassettes and the presence of these structures in Gram negative bacteria isolated from Chilean hospitals in the last ten years (Rev Méd Chile 2004; 132: 619-26).

Bacteria have developed sophisticated and successful genetic mechanisms to evade the action of antimicrobials. Bacterial multiresistance has caused serious problems in the treatment of nosocomial infections. Integrons and gene cassettes are considered the main genetic elements in the evolution of plasmids and transposons that actively participate in the mobilization of genes, codifying different bacterial resistance mechanisms. This article reviews the historical and structural aspects of integrons and resistance gene cassettes and the presence of these structures in Gram negative bacteria isolated from Chilean hospitals in the last ten years (Rev Méd Chile 2004; 132: 619-26).

Background: The resistance of Shigella flexneri to antimicrobial agents can be associated to the presence of integrons that may contain and express antimicrobial resistance gene cassettes. Aim: To study antimicrobial resistance and the presence of integrons and antimicrobial gene cassettes in Shigella flexneri strains. Material and methods: In vitro susceptibility to 27 antimicrobials was studied in twenty four Shigella flexneri strains isolated from stools. The presence of integrons class 1, 2 and 3 and antimicrobial resistance gene cassettes was investigated by polymerase chain reaction (PCR) using specific primers for each gene. Results: Most strains were resistant to one of the following antimicrobials: ampicillin, sulphonamide, trimethoprim, tetracycline, streptomycin, sulfamethoxazole-trimethoprim or chloramphenicol. Twenty nine percent were simultaneously resistant to all these antimicrobials. Integrons class 1 and 2 were found in 19 strains (79%). Class 3 integrons were not found. Gene cassettes dfrA1 and ant(3")I were associated to integrons class 2 in most strains (15/20, 75%). Genes cat, tetB and blarTEM were detected in 18/24 (75%), 7/24 (29%) and 4/24 (17%) of the strains, respectively and were not associated to any of the studied integrons. Genes that codify enzymes AAC(6')Ib and APH(3')VI were not detected in any strain. Conclusions: The high frequency of integrons found in the studied strains, could partly explain the increasing antimicrobial resistance of Shigella flexneri strains, isolated in Chile (Rev Méd Chile 2003; 131: 727-33)

La activi-dad de estas enzimas esta dirigida especifica-mente a la hidrolisis de la union β-lactama delanillo β-lactamico, provocando la produccionde un compuesto acido carente de actividadantibacteriana. El uso de una importante canti-dad de nuevos antibioticos β-lactamicos contri-buyo, a traves de varias decadas, a la seleccionde bacterias Gram positivas y Gram negativasque producen una o mas de estas enzimas.Una importante proporcion de las β-lactama-sas descritas hasta este momento es codificadapor genes de ubicacion plasmidial. Especifica-mente, en bacilos Gram negativos, las β-lactamasas de los grupos TEM (especialmenteen

La resistencia bacteriana a los agentes antimicrobianos ha aumentado durante las últimas décadas. De particular importancia es la descripción de aislamientos de Enterococcus resistente a vancomicina (EVR), de reciente y progresiva descripción en nuestro país. Comunicamos el aislamiento de dos cepas de E. faecium resistentes a vancomicina de pacientes colonizados por este microorganismo en el Hospital Clínico Regional de Concepción. El estudio feno y genotípico fue positivo para vanB, además ambos aislamientos presentaron similitud genética en un estudio de tipificación molecular por rep-PCR. Interesantemente el aislamiento de estas cepas precedió al aislamiento de EVR según el protocolo ministerial. Esta diferencia puede explicarse por los factores de riesgo que presentaron los pacientes estudiados.

Background: Enterococcus is a bacterial genus with low virulence. However, in the last years, the importance of some enterococcus species as nosocomial pathogens has increased, specially due to their resistance to some antimicrobial. Aim: To identify enterococcus strains using classical biochemical techniques and genomic amplification with Polymerase Chain Reaction (PCR). Material and methods: Three hundred and five enterococcus strains, isolated between 1996 and 1999, from different clinical specimens in hospitals and other centers of the VIIIth Region of Chile, were studied. The isolates were identified, to the species level, according to the scheme proposed by Carvalho et al. Identification of some strains was confirmed by PCR. Results: Eighty nine percent of isolates were identified as E faecalis, 10.2% as E faecium and 3.3% as other species. Conclusions: PCR is a fast and promising technique, useful in the identification of Enterococcus species (Rev Med Chile 2002; 130: 45-49)

La resistencia bacteriana a los agentes antimicrobianos ha aumentado durante las últimas décadas. De particular importancia es la descripción de aislamientos de Enterococcus resistente a vancomicina (EVR), de reciente y progresiva descripción en nuestro país. Comunicamos el aislamiento de dos cepas de E. faecium resistentes a vancomicina de pacientes colonizados por este microorganismo en el Hospital Clínico Regional de Concepción. El estudio feno y genotípico fue positivo para vanB, además ambos aislamientos presentaron similitud genética en un estudio de tipificación molecular por rep-PCR. Interesantemente el aislamiento de estas cepas precedió al aislamiento de EVR según el protocolo ministerial. Esta diferencia puede explicarse por los factores de riesgo que presentaron los pacientes estudiados. The antibiotic resistance among bacteria has increased during the last decades. Of particular importance was the report of vancomycin-resistant Enterococcus isolates (VRE), recently described in our country. In this work we report the isolation of two strains of E. faecium resistant to vancomycin from colonized patients admitted to the Hospital Regional de Concepción. The phenotyping and genotyping studies gave positive results for VanB type of vancomycin resistance. Both strains showed genetic similarity when were molecular typed by rep-PCR. Interestingly, the isolation of this strains was previous to the isolation of VRE according to the protocols delineated by the Health Ministry. This difference may be explained by the risk factors exhibited by the colonized patients.