Isolation of Actinobacillus pleuropneumoniae

Isolation of Actinobacillus pleuropneumoniae from tonsils of pigs 1 to 4 weeks  age commercial farm.

² Department of Biological Sciences, Faculty of Higher Cuautitlán, UNAM,   
³ FMVZ Autonomous University of Puebla

Introduction

Contagious swine pleuropneumonia is a worldwide disease caused by Actinobacillus pleuropneumoniae (APP) coccobacillary Gram negative bacteria. It is characterized by causing fibrin-necrotic pleuropneumonia because of the action of lipoprotein capsular even four different RTX toxins, called Apx (Apx Apx-I-IV) ^1.

 APP transmission occurs by direct contact or spray at close range,   through infected mothers or carrier pigs, allowing the colonization of the tonsils and alveolar epithelium.

The clinical presentation of the disease occurs when APP proliferates in lung tissue, supported by predisposing factors such as poor ventilation, heat stress, high microbial environmental burden, immunosuppression and circulation of viral or bacterial agents that damage the lungs and airways.

In the pathogenesis of lung tissue damage pleuropneumonia is a direct consequence of the Apx toxins,   generating alveolar epithelial injury with   cell necrosis and acute inflammatory response. Pulmonary endothelium is also injured blood vessels, causing thrombosis and infarctions and favors the formation of fibrinous exudate.  

The acute clinical course of the disease is characterized by fever, respiratory distress, cyanosis, abdominal breathing "jump", epistaxis and hemoptysis besides anorexia. Morbidity and mortality are usually greater than 10%.   The severity of the clinical picture may vary according to serotype, the microenvironmental conditions and primary stakeholders. Pigs that survive the acute process develop chronic course with persistent pneumonia, abdominal breathing and stunted.

 At necropsy the most characteristic lesions are cyanosis of the corpse, fibrinous pleuritis with pleural adhesions, fibrin-necrotic cranio-ventral or diffuse with red caudal lobes infarcts pneumonia. Recovered pigs have fibrous adhesions in pleura.   

The diagnosis is made ​​with data from clinical signs, morbidity and mortality, injuries at necropsy and histopathology, bacterial isolation and serology. For the serological diagnosis ELISA for detecting antibodies anti-Apx IV, which identifies clinically recovered pigs, and agglutination tests to detect carrier pigs and serotype that is infecting pigs is performed.

This study was conducted to isolate APP macerated tonsils of pigs 1-4 weeks of age of a commercial pig farm to determine the prevalence of infection and weeks of age to which colonization is detected.

Material and methods

The study was conducted on a farm of 2000 bellies, positive for infection with APP. Four groups of 15 dead pigs were established corresponding week   1 to 4   age, necropsy was performed and tonsil aseptically recovered. They were kept frozen at -20 ° C until planting.a maceration was performed with the tonsils and the supernatant was cultured on blood agar media with groove nurse Staphylococcus aureus   and BHI agar supplemented with NAD factor that helps in determining the dependence ofActinobacillus pleuropneumoniae   to this factor. Bacterial growth was purified and identified with biochemical primary and secondary testing.

Results

The isolation of Actinobacillus pleuropneumoniae was obtained from the first week of age, with 26% positive samples in the case of positivity in the 2nd, 3rd and 4th week was 20%, 33% and 46 % respectively  

Discussion
It was determined that APP is able to colonize the pigs from the first week of age, according to Fenwick ² Marsteller and indicates this possibility when pigs are infected in maternity.

It has been established that APP is a late colonizer. It is considered that a weaning age 10 days reduces the risk of colonization up to 90%,   and weaning at 16 days reduced by 50% the risk of encountering a colonized pig. These colonization rates may vary according to maternal immunity, but in this work July 30 positive samples total samples of the first two weeks of life were taken, representing a 23.3% prevalence.

In breastfeeding transmission of infection can be attributed to the mother pig, because it is the nearest source of contamination by direct contact of APP, especially if the divisions between a cage maternity and other are of a solid material. In the case of metal wire panel   transmission is possible among a litter of piglets to another. It should be considered an investigation into the possibility of spread of infection based on the variable construction material of the cage.

Even in the presence of maternal immunity colonization is observed, which determines the risk of sending infected sites 2 and 3, with the consequent possibility of developing the disease pigs.

These results force us to assess the segregated early weaning protocols that aim to eliminate APP. According to Muirhead and Alexander ²   not so premature settlements were developed, so the possibility of weaning of less than 21 days of lactation without the risk of transmission of infection is established, however our findings show us this possibility of early infection, so it is essential to have a medication protocol that meets this objective.

The mashing process of tonsillar tissue is a suitable method for the isolation of APP   usually used in experimental studies 3 and in this paper was applied to pigs that are part of routine maternity mortality, so it is a useful diagnostic strategy for research and development   on APP on commercial farms.  

References

1. Gottschalk M., Taylor DJ, Actinobacillus pleuropneumoniae, in: BE Straw, JJ Zimmerman, S. D'Allaire, Taylor DJ (Eds.), Diseases of swine, Blackwell Publishing Professional, Ames, Iowa, USA, 2006 pp. 563-576.

2. Marstseller TA ,. Fenwick, B: Actinobacillus pleuropneumoniae disease and serology. Swine Health Prod 1999 (7):. 161-165.

3. MR Muirhead, Alexander TJL: Managing and treating disease in the weaner, grower and finishing periods.   In Managing Pig Health and the Treatment of Disease, 2007; p. 294. Sheffield: 5M Enterprises Ltd.  

·

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QUE ES LA MEDICINA ORTOMOLECULAR?

               QUE ES LA MEDICINA ORTOMOLECULAR?

La medicina ortomolecular o nutrición ortomolecular o terapia de las megavitaminas es una terapia alternativa que recomienda el uso de cantidades de biomoléculas (de vitaminas por ejemplo) por encima de los umbrales marcados por la Organización Mundial de la Salud y la Administración de Drogas y Alimentos, pudiendo causar hipervitaminosis y otras enfermedades cuando se usan dosis extremadamente altas.

Es considerada por la comunidad científica como una pseudociencia, ya que no existe evidencia alguna que la apoye. El término y la base teórica formal fue en 1968, acuñada por Linus Pauling. Su interés por las vitaminas nació, como él mismo lo cuenta en sus papeles (que pueden consultarse on Line en la U.S. National Library of Medicina) [1] debido a una enfermedad incurable que le fue diagnosticada al rededor de los 40 años. Fue tal su interés por los nutrientes esenciales y su eficacia lo que le llevó a dejar todos los demás campos de investigación a los que dedicaba su vida para dedicarse por completo al estudio y desarrollo de la medicina ortomolecular, a la cual dedicó los últimos veinte años de su vida.

A menudo, el médico ortomolecular emplea múltiples sustancias vitales (aminoácidos, enzimas, nutrientes no esenciales, hormonas, vitaminas, minerales, etc.) en un esfuerzo terapéutico de restaurar éstos (o sustancias derivadas de ellos) a los niveles estadísticamente normales en personas jóvenes sanas. La comunidad científica la considera como PELIGROSA debido a las cantidades de vitaminas y minerales, además de otras sustancias alimenticias, que la medicina ortomolecular administra a sus pacientes, puede causar hipervitaminosis. Los investigadores ortomoleculares exponen que sólo existen 27 casos probados de muerte debido al exceso de vitaminas en 10 años, pero eso no implica que el exceso de vitaminas no pueda ser perjudicial para la salud, ya que puede ser causa de hipercalcemia, cefaleas y náuseas.

Según un estudio, la terapia de megavitaminas era la novena terapia de CAM más generalizada (2.8%) en los Estados Unidos durante 2002.³
En conformidad con estudios anteriores, este encontró que la mayoría de los individuos (54.9%) utilizaban terapias de CAM conjuntamente con la medicina convencional
El hecho de que solamente el 11.8% de adultos buscaran los cuidados de un médico alternativo licenciado o certificado sugiere que la mayoría de los individuos que utilizan terapias alternativas se autorrecetan o automedican.
Cuidado con los charlatanes

Referencias

·  Edzard Ernst and Simon Singh. «Trick Or Treatment: The Undeniable Facts about Alternative Medicine». Bantam Press. ISBN 0593061292.

·  ·  R. Rizzoli, C. Stoermann, P. Ammann, J.-P. Bonjour. «Hypercalcemia and hyperosteolysis in vitamin D intoxication: Effects of clodronate therapy». ScienceDirect.

Wikipedia

@Rdzg Carlos     Este blog esta protegido con una licencia Creative Commons 4 Internacional

LA PLAGA QUE NOS ESTÁ DEJANDO SIN NARANJAS.  

Estados Unidos y varios países productores de naranjas en América Latina -entre los que se encuentran México y Brasil- luchan desde hace años una guerra sin cuartel contra una enfermedad proveniente de Asia que está poniendo en riesgo la industria de los cítricos.

Ahora, un equipo de investigadores descubrió cómo una bacteria, que se cree es la causa de esta plaga, optimiza su expansión alterando la conducta de los insectos que se encargan de contagiar la enfermedad entre las plantas.

Según el estudio, llevado a cabo por la Universidad de Florida y publicado en la revista PLOS ONE, los psílidos asiáticos (los insectos que esparcen la enfermedad) vuelan más lejos y con más frecuencia después de alimentarse de plantas infectadas.
Se cree que este aumento en su movilidad incrementa sus posibilidades de transmitir la bacteria.
Esta enfermedad, llamada Huanglongbing o enverdecimiento de los cítricos, destruye la apariencia y valor económico de los árboles de cítricos, y afecta el sabor de la fruta.

Las hojas de las plantas enfermas se van llenando de manchas.

"Las hojas comienzan a ponerse amarillas, les salen manchas, las ramas empiezan a morir, el sistema de raíces se seca y finalmente el árbol decae y se muere", le dijo a la BBC Kirsten Pelz Stelinski, coautora del estudio.
"Es un problema global en términos de producción de cítricos en todo el mundo. Sólo para darles un ejemplo, en Florida, es una industria que mueve US$9.000 millones al año".
"Por el impacto de la enfermedad se han perdido miles de trabajos y miles de millones de dólares. En muchas partes de Florida tenemos el 100% de los árboles infectados”.
En Estados Unidos la situación es tal, que muchos se preguntan si la enfermedad no acabará con las naranjas, cuyo jugo es parte fundamental del desayuno de muchos.

La enfermedad está causada por un grupo de bacterias relacionadas. El estudio se centró en una de las cepas conocida como Candidatius Liberibacter asiaticus (o CLas).

Tras alimentarse de una planta infectada, los insectos buscan otras porque reconocen que el valor nutritivo de ésta es bajo.

La bacteria se duplica dentro de la planta, en la savia que transporta los nutrientes.
Para pasar de planta a planta, la bacteria necesita a un insecto llamado psilido asiático.
El insecto se alimenta de la planta insertándole una trompa en la hoja para chuparle la savia.
La investigación de la Universidad de Florida pone de manifiesto cómo la bacteria desarrolló una suerte de estrategia maquiavélica para aumentar sus chances de supervivencia.
"Cuando las plantas tienen la bacteria producen salicilato de metilo, (un compuesto orgánico) que los psílidos encuentran muy atractivo", explicó Pelz Stelinski.

En el momento en que llegan grupos de psílidos a alimentarse, la planta con la bacteria produce más de este compuesto, algo que a los hambrientos psílidos les resulta imposible de resistir. Pero esta atracción no dura mucho.
"Cuando la bacteria está presente, los psílidos se alimentan y la planta libera el compuesto, pero los insectos se dan cuenta de que la planta puede no ser la mejor anfitriona, y eso es porque las plantas infectadas suelen tener una calidad nutritiva más baja", explica la investigadora.
"Entonces los psílidos abandonan la planta infectada para buscar una nueva y cuando lo hacen, se llevan algunas bacterias, por eso (podemos decir) que las bacterias están promoviendo su propia expansión", añade.
Pero la manipulación no termina allí.

La enfermedad se originó en Asia y llegó a América por el comercio global.

Aunque se estima que los insectos infectados viven menos tiempo, la evidencia sugiere que tienen más descendencia. Y las poblaciones más grandes benefician a la bacteria al ofrecer más opciones para su dispersión.
El estudio también señala que la bacteria afecta otros aspectos de la conducta del insecto para aumentar sus posibilidades de transmisión.
Según señala Pelz Stelinksi, los hace moverse con más frecuencia o volar por un lapso de tiempo mayor.

"Aumenta de hecho su tendencia al movimiento. Así que en ese sentido también extiende su radio, "manipulando su vehículo".
Los investigadores esperan que el estudio contribuya a hallar una solución para frenar el avance de la enfermedad.

Referencias:

BBC UK/Ciencia 

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Helicobacter pylori

                                  Helicobacter pylori

Cientists isolate the component of the bacterium that causes ulcers

Almost half the world's population is infected with the gastrointestinal tract bacteria Helicobacter pylori, a causative agent of gastritis, ulcers and stomach cancer. A Japanese research team has found the component of the bacterium that causes ulcers directly (a protein called cow), and also the stomach cells that serve as a gateway VacA (VacA receptor). The VacA protein can now be used to create a vaccine, and its natural receptor variants allow predict which people are most at risk.
The discovery in 1984 of the Helicobacter bacterium common in the human stomach, was a causative agent of gastritis, ulcers and stomach and duodenal cancer opened an unsuspected route of treatment (or prevention) of diseases that were thought to be associated with meals spicy and stress. Today we know that most ulcers can be cured with antibiotics combined two weeks of killing Helicobacter stomach colony.

But while half of people are infected with Helicobacter, only a small fraction develops ulcers, and stomach cancer alone. Scientists suspect that the discrepancy was due to natural variations in the virulence of some other strains of Helicobacter and, on the one hand and individual susceptibility to the disease on the other. The Japanese have found the most likely basis for both power range.
The study, published today in Nature Genetics, is a collaboration between the National Institute for Basic Biology in Okazaki, and the Universities of Kobe, Shinshu, Nagasaki and Tokyo. The results refer to mice, but the bacterium is the same in rodents and humans, and receiver mouse stomach cells exists in our species.
The attack of Helicobacter to gastric mucosa is executed by bacterial VacA protein. It binds to a specific receptor on the surface of the cells lining the stomach. VacA binding to its receptor activates a biochemical cascade that causes cells to become detached from the mucosa, inner fragile tissues exposing the corrosive action of gastric acid. So ulcer originates.

Why not all those infected develop ulcer? On the one hand, because Helicobacter is very diverse. The gene that makes the VacA protein (the gene vacA) exists in all strains, but is highly variable, and some strains are much more active VacA protein. It's a matter of luck which strain touch us. Significant that one of the most active variants of VacA (s2) is much more common in ulcer than those with only gastritis.
Variable genes
The other factor contributing to the discrepancy (between the many and the few infected ulcer) is the variability in certain human genes, and work identifies two strongest candidates. VacA receptor (called Ptprz) is not in the stomach cells to facilitate the attack of Helicobacter (evolution is blind, but not stupid). It is for detecting other human molecule (the pleiotropin) to finely modulate various aspects of the biology of the gastric mucosa.

Japanese scientists have found that pleiotropin administered in high amounts, can produce obvious signs of ulcer. Individuals, therefore, may differ in their susceptibility to attack of Helicobacter due to natural variability in the gene that produces the receptor VacA, or manufactured by the pleiotropin, or both. Of course, you can not rule out other sources of variability.
Gastroenterologist Richard Peek, of the School of Medicine at Vanderbilt University (Tennessee, USA), also points out today in Nature Genetics: "Understanding the role in the origin of the ulcer of the determinants of the virulence of Helicobacter pylori can contribute the development of a vaccine. " One obvious possibility is to generate antibodies against cow. Peek added that the finding VacA receptor "can allow the identification of infected individuals increased risk of disease." Helicobacter Since many tumors also causes stomach, it may be one of the first cases where a cancer is reached prevent some doses of antibiotics. The discovery that stomach ulcers and gastritis caused them a lot of bacteria, Helicobacter pylori, not only won them a Nobel (and infection) with their authors, Barry J. Marshall and J. Robin Warren. Also completely it changed the way to treat the disease: surgery and painkillers to combinations of antibiotics. In the case of an infection, the next step is to find a vaccine. And it is the Chinese team has published their findings in The Lancet, with promising efficacy of currently 72%.

The trial is a classic exercise of comparison between vaccinated and unvaccinated people (the control group) in which no one knows who is getting the drug and who is not, which is avoided or equals the placebo effect. This form of testing is called double-blind because no one, neither the volunteers nor the health to serve them know why you are taking each.
For work to 4,464 boys were selected 6 to 15 years in the province of Jiangsu, of which 4,403 were under control three years later. They were chosen to ensure that young people had not been in contact with the bacteria. With these two groups, one receiving the vaccine and another that took (the vaccine is oral) placebo were formed.
The result is that, in all, 64 cases were recorded helicobacter infection. Of these, 50 were in the group that did not take the drug, and the remaining 14 in the of those who are actually vaccinated. Taking the raw numbers, this represents a reduction of cases (protection rate) of 72%. When data is adjusted and the time variable in the trial were all introduced, low efficiency slightly, to 71.8%.

Less than 1% of the participants in the two groups (12 in total, of which five had been vaccinated) had to leave for health reasons, but the authors rule out adverse effects were related to immunization.
The trial authors themselves admit that the time has passed (three years) is not enough, and we have to wait to confirm or exclude that the protective effect of the drug is maintained, but indicate a breakthrough for protecting people of this disease. The beneficiaries are potentially hundreds of millions: it is estimated that between 5% and 15% of the population has complications from a gastric ulcer at least once in your life

References:

Javier Sampedro.

 Nature Journal

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