RESUMEN
Current land use systems in the Amazon largely consist of extensive conventional productivist livestock operations that drive deforestation. Silvopastoral systems (SPS) support a transition to low carbon production if they intensify in sympathy with the needs of biophysical and socio-economic contexts. SPS have been promoted for decades as an alternative livestock production system but widespread uptake has yet to be seen. We provide a schema of associating factors for adoption of SPS based on past literature in tropical agriculture and apply this to a bespoke survey of 172 farms in the Caquetá region of the Colombian Amazon. We find a number of factors which do not apply to this region and argue for a context specific approach. The impact of managing increased market access and opportunities for SPS producers are crucial to avoiding additional deforestation. Further understanding of the underlying antecedents of common factors, such as perceptions of silvopastoral systems, would reduce the risk of perverse policy outcomes.
Asunto(s)
Agricultura , Políticas , Colombia , Granjas , Carbono , Conservación de los Recursos NaturalesRESUMEN
Shiga toxin (Stx) and hemolysin (Hly) of Escherichia coli O157:H7 produced an increase of reactive oxygen species (ROS) in normal human blood. In vitro assays showed that stimuli of ROS with these toxins oxidized proteins to carbonyls in plasma and raised the degradation of oxidized macromolecules, with the AOPP/carbonyl relationship also increasing. The oxidative stress generated by toxins during the Hemolytic Uremic Syndrome (HUS) produced oxidation of blood proteins with a rise in advanced oxidation protein products (AOPP) in children with HUS. There was a response from the antioxidant system in these patients, evaluated through the determination of the total antioxidant capacity of plasma by the Ferric Reducing Antioxidant Power (FRAP), which reduced the stimuli of ROS during in vitro incubation with Stx or Hly. The application of natural antioxidants was sufficient to reduce in vitro the oxidative stress provoked by both toxins in blood.
Asunto(s)
Antioxidantes/metabolismo , Proteínas Sanguíneas/metabolismo , Escherichia coli O157/patogenicidad , Proteínas de Escherichia coli/toxicidad , Proteínas Hemolisinas/toxicidad , Estrés Oxidativo/efectos de los fármacos , Toxina Shiga/toxicidad , Antioxidantes/farmacología , Biomarcadores/sangre , Biomarcadores/metabolismo , Niño , Escherichia coli O157/metabolismo , Proteínas de Escherichia coli/aislamiento & purificación , Frutas/química , Proteínas Hemolisinas/aislamiento & purificación , Síndrome Hemolítico-Urémico/sangre , Síndrome Hemolítico-Urémico/metabolismo , Humanos , Leucocitos/efectos de los fármacos , Leucocitos/metabolismo , Oxidación-Reducción , Extractos Vegetales/farmacología , Prosopis/química , Carbonilación Proteica/efectos de los fármacos , Especies Reactivas de Oxígeno/sangre , Toxina Shiga/aislamiento & purificación , Ziziphus/químicaRESUMEN
Tuberculosis continues to be a serious problem of public health causing nearly three million deaths per year all over the world. Despite technologic improvements in the diagnostic methods, it is not possible to control the disease in the absence of surveillance and treatment follow-up programs supervising the ending of treatments, and definitive cure of patients. The frequency of pulmonary and extrapulmonary tuberculosis, and simultaneous pulmonary and extrapulmonary tuberculosis localization among patients assisted at Tránsito Cáceres de Allende Hospital during thirteen years (1991-2003), was determined. The benefit of inoculating the specimens on Stonebrink medium for the best recuperation of Mycobacterium bovis was herein observed, and the contribution of Ziehl Neelsen staining in extrapulmonary materials was tested as well. Out of 790 cases of tuberculosis diagnosed, 723 were pulmonary, and 48 were extrapulmonary localization (pleural 31, renal 7, ganglionar 5, meningeal 2, genital 1, pericardial 1 and digestive 1), and 19 patients presented both, pulmonary and extrapulmonary tuberculosis. Out of the 723 pulmonary cases, 9 were caused by M. bovis. All M. bovis isolates grew on Stonebrink medium, and only one grew also on Lowenstein Jensen. Smear microscopy using Ziehl Neelsen staining resulted positive in 4 extrapulmonary specimens.
Asunto(s)
Tuberculosis Pulmonar/epidemiología , Tuberculosis/epidemiología , Adulto , Argentina/epidemiología , Comorbilidad , Infecciones por VIH/epidemiología , Hospitales/estadística & datos numéricos , Humanos , Mycobacterium bovis/aislamiento & purificación , Mycobacterium tuberculosis/aislamiento & purificación , Especificidad de Órganos , Prevalencia , Estudios Retrospectivos , Tuberculosis/microbiología , Tuberculosis Pulmonar/microbiologíaRESUMEN
A new aspect in the action of ampicillin and gentamicin was detected in Enterococcus faecalis. Reactive oxygen species (ROS) increased in sensitive strains during treatment with each antibiotic up to a certain concentration of antibiotic, above which ROS diminished as a consequence of oxidative stress. Tiron, a scavenger of the superoxide anion O(2)(-), counteracted the effect of the generated ROS. The oxidative stress was a consequence of an increase in ROS in the cytoplasm of bacteria, as observed by the nitroblue tetrazolium reaction. The viability of sensitive strains was significantly reduced at concentrations of antibiotics that increased the ROS, and this increment was parallel to the bactericidal effect. Sensitive E. faecalis strains showed an immediate increase of ATP in the presence of both antibiotics, thus an energy-dependent process had been triggered, indicating a bacterial reaction against the stress. The combination of both antibiotics augmented the effect of ROS, which helps to explain the synergism between ampicillin and gentamicin.
Asunto(s)
Ampicilina/farmacología , Antibacterianos/farmacología , Enterococcus faecalis/efectos de los fármacos , Gentamicinas/farmacología , Estrés Oxidativo/efectos de los fármacos , Oxígeno/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Sinergismo Farmacológico , Enterococcus faecalis/enzimología , Enterococcus faecalis/metabolismo , Estrés Oxidativo/fisiologíaRESUMEN
Tuberculosis continues to be a serious problem of public health causing nearly three million deaths per year all over the world. Despite technologic improvements in the diagnostic methods, it is not possible to control the disease in the absence of surveillance and treatment follow-up programs supervising the ending of treatments, and definitive cure of patients. The frequency of pulmonary and extrapulmonary tuberculosis, and simultaneous pulmonary and extrapulmonary tuberculosis localization among patients assisted at Tránsito Cáceres de Allende Hospital during thirteen years (1991-2003), was determined. The benefit of inoculating the specimens on Stonebrink medium for the best recuperation of Mycobacterium bovis was herein observed, and the contribution of Ziehl Neelsen staining in extrapulmonary materials was tested as well. Out of 790 cases of tuberculosis diagnosed, 723 were pulmonary, and 48 were extrapulmonary localization (pleural 31, renal 7, ganglionar 5, meningeal 2, genital 1, pericardial 1 and digestive 1), and 19 patients presented both, pulmonary and extrapulmonary tuberculosis. Out of the 723 pulmonary cases, 9 were caused by M. bovis. All M. bovis isolates grew on Stonebrink medium, and only one grew also on Lowenstein Jensen. Smear microscopy using Ziehl Neelsen staining resulted positive in 4 extrapulmonary specimens.
RESUMEN
Tuberculosis continues to be a serious problem of public health causing nearly three million deaths per year all over the world. Despite technologic improvements in the diagnostic methods, it is not possible to control the disease in the absence of surveillance and treatment follow-up programs supervising the ending of treatments, and definitive cure of patients. The frequency of pulmonary and extrapulmonary tuberculosis, and simultaneous pulmonary and extrapulmonary tuberculosis localization among patients assisted at Tránsito Cáceres de Allende Hospital during thirteen years (1991-2003), was determined. The benefit of inoculating the specimens on Stonebrink medium for the best recuperation of Mycobacterium bovis was herein observed, and the contribution of Ziehl Neelsen staining in extrapulmonary materials was tested as well. Out of 790 cases of tuberculosis diagnosed, 723 were pulmonary, and 48 were extrapulmonary localization (pleural 31, renal 7, ganglionar 5, meningeal 2, genital 1, pericardial 1 and digestive 1), and 19 patients presented both, pulmonary and extrapulmonary tuberculosis. Out of the 723 pulmonary cases, 9 were caused by M. bovis. All M. bovis isolates grew on Stonebrink medium, and only one grew also on Lowenstein Jensen. Smear microscopy using Ziehl Neelsen staining resulted positive in 4 extrapulmonary specimens.
RESUMEN
Las micobacterias ambientales (MA) constituyen un importante grupo de especies bacterianas que se encuentran en el medio ambiente, pueden colonizar y ocasionalmente producir enfermedad enel hombre. En este trabajo se investigó la frecuencia de casos de micobacteriosis en relación con los de tuberculosis durante un período de diez años (1.991-2.000). Se estudiaron 16.700 muestras de 9.300 pacientes adultos de ambos sexos asistidos en el Hospital Regional de Tuberculosis de la Provincia de Córdoba, por consulta espontánea. Los aislamientos se realizaron por cultivo en los medios de Lowenstein Jensen y Stonebrink. Las colonias de bacilos ácidoalcohol resistentes (BAAR) se identificaron por pruebas bioquímicas y moleculares. El total de casos diagnosticados fue de 716, de los cuales 684 (95,5%) correspondieron a al complejo Mycobacterium tuberculosis y a micobacterias ambientales 32 (4,5%). Los casos de micobacteriosis se definieron por reiterados aislamientos con desarrollo representativo de una micobacteria ambiental, sospecha clínica y radiológica. De los 32 casos de micobacteriosis, el 75% del total correspondió aMycobacterium avium-intracellulare,15,6% a Mycobacterium fortuitum, 3,1% a Mycobacterium kansasii y 6,3% a Mycobacterium chelonae.Los casos de tuberculosis fueron 94,5% de localización pulmonar y 5,5% extrapulmonar.
Environmental mycobacteria (EM) constitute an important group of bacteria species found in the environment. They can colonize and occasionally produce disease in man. Sixteen thousand three hundred samples from 9300 adult symptomatic patients from the Hospital Regional of Tuberculosis in Cordoba were bacteriolocally investigated. The isolations were performed by culture on Lowenstein Jensen and Stonebrink culture media. The colonies of acid fast bacilli (AFB) were identified by biochemical and molecular tests. Among 716 culture positive cases, 684 (95.5%) were due to Mycobacterium tuberculosis complex and 32 to environmental mycobacteria.Serial samples allowed the confirmation of the etiologicalagent in culture and correlated with consistent clinical and radiological abnormalities. Seventy-five percente of these patients were affected by M. avium complex, 15.6% by M. fortuitum, 3.1% Mycobacterium kansasii and 6.3% Mycobacterium chelonae. Among tuberculosis cases, 94.5% and 5.5% had pulmonary and extrapulmonary disease respectively.
Asunto(s)
Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Infecciones por Mycobacterium/epidemiología , Tuberculosis/epidemiología , Argentina/epidemiología , Técnicas de Tipificación Bacteriana , Medios de Cultivo , Microbiología Ambiental , Hospitales Especializados/estadística & datos numéricos , Infecciones por Mycobacterium no Tuberculosas/epidemiología , Infecciones por Mycobacterium no Tuberculosas/microbiología , Infecciones por Mycobacterium/microbiología , Infecciones por Mycobacterium , Complejo Mycobacterium avium/aislamiento & purificación , Infección por Mycobacterium avium-intracellulare/epidemiología , Infección por Mycobacterium avium-intracellulare/microbiología , Infección por Mycobacterium avium-intracellulare , Mycobacterium tuberculosis/aislamiento & purificación , Mycobacterium/aislamiento & purificación , Micobacterias no Tuberculosas/aislamiento & purificación , Tuberculosis/microbiología , TuberculosisRESUMEN
Environmental mycobacteria (EM) constitute an important group of bacteria species found in the environment. They can colonize and occasionally produce disease in man. Sixteen thousand three hundred samples from 9300 adult symptomatic patients from the Hospital Regional of Tuberculosis in Cordoba were bacteriolocally investigated. The isolations were performed by culture on Lowenstein Jensen and Stonebrink culture media. The colonies of acid fast bacilli (AFB) were identified by biochemical and molecular tests. Among 716 culture positive cases, 684 (95.5%) were due to Mycobacterium tuberculosis complex and 32 to environmental mycobacteria. Serial samples allowed the confirmation of the etiological agent in culture and correlated with consistent clinical and radiological abnormalities. Seventy-five percent of these patients were affected by M. avium complex, 15.6% by M. fortuitum, 3.1% Mycobacterium kansasii and 6.3% Mycobacterium chelonae. Among tuberculosis cases, 94.5% and 5.5% had pulmonary and extrapulmonary disease respectively.
Asunto(s)
Infecciones por Mycobacterium/epidemiología , Tuberculosis/epidemiología , Adulto , Anciano , Anciano de 80 o más Años , Argentina/epidemiología , Técnicas de Tipificación Bacteriana , Medios de Cultivo , Microbiología Ambiental , Femenino , Hospitales Especializados/estadística & datos numéricos , Humanos , Masculino , Persona de Mediana Edad , Mycobacterium/aislamiento & purificación , Infecciones por Mycobacterium/diagnóstico por imagen , Infecciones por Mycobacterium/microbiología , Infecciones por Mycobacterium no Tuberculosas/epidemiología , Infecciones por Mycobacterium no Tuberculosas/microbiología , Complejo Mycobacterium avium/aislamiento & purificación , Infección por Mycobacterium avium-intracellulare/diagnóstico por imagen , Infección por Mycobacterium avium-intracellulare/epidemiología , Infección por Mycobacterium avium-intracellulare/microbiología , Mycobacterium tuberculosis/aislamiento & purificación , Micobacterias no Tuberculosas/aislamiento & purificación , Radiografía , Tuberculosis/diagnóstico por imagen , Tuberculosis/microbiologíaRESUMEN
Environmental mycobacteria (EM) constitute an important group of bacteria species found in the environment. They can colonize and occasionally produce disease in man. Sixteen thousand three hundred samples from 9300 adult symptomatic patients from the Hospital Regional of Tuberculosis in Cordoba were bacteriolocally investigated. The isolations were performed by culture on Lowenstein Jensen and Stonebrink culture media. The colonies of acid fast bacilli (AFB) were identified by biochemical and molecular tests. Among 716 culture positive cases, 684 (95.5
) were due to Mycobacterium tuberculosis complex and 32 to environmental mycobacteria. Serial samples allowed the confirmation of the etiological agent in culture and correlated with consistent clinical and radiological abnormalities. Seventy-five percent of these patients were affected by M. avium complex, 15.6
by M. fortuitum, 3.1
Mycobacterium kansasii and 6.3
Mycobacterium chelonae. Among tuberculosis cases, 94.5
and 5.5
had pulmonary and extrapulmonary disease respectively.
RESUMEN
The in vitro activities of benzenesulphonamide fluoroquinolones (BSFQs) I-III, new fluoroquinolones with a p-substituted benzenesulphonyl moiety attached to the C(7) piperazinyl ring of ciprofloxacin, were assessed in comparison with those of N-sulfanilylpiperazinyl fluoroquinolone (NSFQ)-105 and ciprofloxacin for 133 Gram-positive clinical isolates. NSFQ-105 and BSFQ-I were the most active drugs. They were 16- to 64-fold more active than ciprofloxacin against Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, including ciprofloxacin-resistant strains, and Streptococcus pneumoniae (eight- to 32-fold). A high degree of correlation was found between the MICs of the new compounds and ciprofloxacin for Staphylococcus spp. and E. faecalis. Staphylococci and enterococci exhibit cross-resistance to BSFQs and ciprofloxacin.
Asunto(s)
Antiinfecciosos/farmacología , Ciprofloxacina/farmacología , Farmacorresistencia Bacteriana , Cocos Grampositivos/efectos de los fármacos , Sulfonamidas/farmacología , Antiinfecciosos/química , Ciprofloxacina/análogos & derivados , Cocos Grampositivos/aislamiento & purificación , Humanos , Pruebas de Sensibilidad Microbiana/estadística & datos numéricos , Relación Estructura-Actividad , Sulfonamidas/química , BencenosulfonamidasRESUMEN
A leukotoxin purified from Enterobacter cloacae culture by saline precipitation, gel chromatography and HPLC was studied as a modulator of reactive oxidant species (ROS) produced by human neutrophils. Chemiluminescence showed that stimulation of ROS was achieved at a low leukotoxin concentration, but ROS production decreased when the toxin was applied at concentrations above 30 microg/mL. Also, the addition of 100 microg toxin/mL significantly reduced the activating effect of phorbol myristate acetate (PMA) and low doses of toxin did not produce an opposite effect toward the stimulation produced by PMA. Normal neutrophils showed a linear correlation between the inverse of ROS production and time, but the kinetic reaction changed when toxins were added to the cells and the ROS formation increased directly with time.
Asunto(s)
Exotoxinas/toxicidad , Neutrófilos/efectos de los fármacos , Neutrófilos/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Enterobacter cloacae , Exotoxinas/administración & dosificación , Exotoxinas/aislamiento & purificación , Humanos , Técnicas In Vitro , Mediciones Luminiscentes , Acetato de Tetradecanoilforbol/farmacologíaRESUMEN
A new toxin of Enterobacter cloacae able to lyse erythrocytes and leukocytes was found. Purification of the toxin was performed by salt precipitation, gel filtration, ion exchange and HPLC in C8 column. SDS-PAGE electrophoresis showed more than one bank corresponding to the leukotoxin able to form polymers and aggregate like some pore-forming cytotoxins (RTX). In culture supernatant the toxin showed 1 HU/ml (hemolytic unit) and 1.5 LU/ml (leukotoxic unit); after purification it reached 15 HU/ml and 20 LU/ml. The ratio between HU and percentage red cells affected the lytic capacity. E. cloacae toxin stimulated the oxidative metabolism of neutrophils, but over 50 microg toxin/ml the stimulus ceased as it was shown by NBT assay due to cell death. Chemiluminescence evidenced an increase in superoxide anion generation, but an excess of toxin interfered with this stimulus, as was previously observed in HlyA Escherichia coli toxin. Cross-reaction was found by immunoblotting with this HlyA. E. cloacae toxin presented higher amounts of proline, valine, aspartic and glutamic acids than HlyA. E. cloacae toxin was similar to HlyA in the prescence of a glycine-rich DNA sequence and in the observed effect of calcium on toxin activity. E. cloacae toxin did not cross-react by immunoblotting with hemolysin HmpA of Proteus.
Asunto(s)
Toxinas Bacterianas/química , Toxinas Bacterianas/toxicidad , Enterobacter cloacae/metabolismo , Eritrocitos/efectos de los fármacos , Toxinas Bacterianas/aislamiento & purificación , Calcio/farmacología , Relación Dosis-Respuesta a Droga , Eritrocitos/metabolismo , Hemólisis , Humanos , Técnicas In Vitro , Leucocitos/efectos de los fármacos , Leucocitos/metabolismo , Mediciones Luminiscentes , Neutrófilos/efectos de los fármacos , Neutrófilos/metabolismo , Oxidación-Reducción/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , TemperaturaRESUMEN
A leukotoxic and hemolytic toxin was purified from cultures of Enterobacter cloacae. Stimulation of oxidative stress was observed and the production of reactive oxidant species was measured in leukocytes treated with toxin by means of nitroblue tetrazolium and chemiluminescence assays. Molecular weight of toxin was estimated by chromatography and SDS-PAGE. Two protean peaks with toxic activity were found in Sephadex G-100 (P1, 42.0 kDa; and P2, 13.3 kDa). The relative amounts between the peaks (P1/P2 = 0.36) changed when 2-mercaptoethanol was employed (P1/P2 = 0.59). When Sephadex G-200 chromatography was performed, a protean peak of Ve = 113 mL (100 kDa) was found; its was dissociated with 3 M urea in toxic proteins of lower mass: 42, 27, and 13.3 kDa. SDS-PAGE (15%) showed a single toxin band of purified monomer (13.3 kDa), but electrophoresis of a 42-kDa toxin with urea presented three bands of trimer, dimer, and monomer. An increase of casein hydrolysate and albumin molecular weight was observed by chromatography after incubation with toxin due to the binding of both proteins with toxin.
Asunto(s)
Toxinas Bacterianas/toxicidad , Neutrófilos/efectos de los fármacos , Estrés Oxidativo , Toxinas Bacterianas/química , Dimerización , Enterobacter cloacae/metabolismo , Humanos , Neutrófilos/metabolismo , Unión ProteicaRESUMEN
A plague (Yersinia pestis) epizootic spread through Gunnison's prairie dogs (Cynomys gunnisoni), and possibly other rodent species, in the Moreno Valley in north-central New Mexico between winter 1984-1985 and autumn 1987. We observed the progress of the epizootic and subsequent population recovery at four prairie dog towns within the valley during this period. At two towns (Midlake and Val Verde) the prairie dogs were marked prior to the epizootic. At two additional towns (Vega and South Entrance) prairie dogs were marked following the epizootic. In 1988, a second epizootic occurred at Vega. One hundred thirty-nine serum samples were collected from prairie dogs and other rodents and 1,750 fleas were collected from animals and burrows. Fleas infected with Y. pestis were collected from prairie dogs, deer mice (Peromyscus maniculatus), and thirteen-lined ground squirrels (Spermophilus tridecemlineatus). Prairie dog fleas included Oropsylla hirsuta, O. labis and O. tuberculata, deermouse associated fleas were Aetheca wagneri and Rhadinopsylla sectilis, and Oropsylla bacchi was associated with thirteen-lined ground squirrels. All of the above flea species were collected from prairie dog burrows. All rodent species shared some flea species. Thirteen-lined ground squirrels disappeared shortly before plague was identified in prairie dogs at Midlake. Meadow voles were rare following the epizootic at Vega in 1986, became abundant in 1987, and disappeared at the time of the second prairie dog epizootic in summer 1988. Although we collected serum from Gunnison's prairie dogs, thirteen-lined ground squirrels, deer mice, and meadow voles (Microtus pennsylvanicus), we identified elevated serum titers against Y. pestis only in Gunnison's prairie dogs. Prairie dog mortality at all towns affected by plague was in excess of 99%. Serum antibody titers indicate that more than 40% of the few prairie dogs left to establish colonies following epizootics survived plague infection.
Asunto(s)
Brotes de Enfermedades/veterinaria , Peste/veterinaria , Enfermedades de los Roedores/epidemiología , Sciuridae , Animales , Arvicolinae/parasitología , Infestaciones Ectoparasitarias/parasitología , Infestaciones Ectoparasitarias/veterinaria , Femenino , Insectos Vectores/microbiología , Masculino , New Mexico/epidemiología , Peromyscus/parasitología , Peste/epidemiología , Sciuridae/parasitología , Siphonaptera/microbiología , Yersinia pestis/aislamiento & purificaciónRESUMEN
Leukotoxic activity was assayed in clinical isolates of Enterobacter cloacae. Two strains were selected out of 38 by their greater hemolytic activity in blood agar plates. Leukotoxin was purified by salt precipitation, dialysis, chromatography by gel filtration, and high pressure liquid chromatography (HPLC). Human leukocytes, when incubated with purified E. cloacae toxin, showed high percentages of death and lysis, with time and dose dependence. The chromatographic profile of gel filtration presented three protein peaks and toxic activity was detected in the second peak. After HPLC, leukotoxin coeluted with the hemolytic activity and both activities were detected only after 2-mercaptoethanol treatment. Coomassie-stained sodium dodecyl sulfate--polyacrylamide gels showed a single band. This band was estimated to represent a protein of 13300 Da on the basis of both sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration chromatography.