La pleuroneumonía en el contexto del complejo respiratorio porcino

La faceta investigadora del autor se ha centrado principalmente en los microorganismos de origen bacteriano que producen enfermedades respiratorias en el cerdo. Por esta razón ha seleccionado este tema como eje de su conferencia. En la actualidad, estos agentes patógenos respiratorios ya no son considerados de forma individual, sino formando parte de entidades complejas, responsables del establecimiento de las denominadas enfermedades polimicrobiana

El "libro de libros": a propósito de animales, microorganismos, enfermedades y zoonosis

La Biblia es el "libro de los libros". El término latino (biblía), que procede del griego βιβλία, significa precisamente libros. Su origen etimológico nos remite también a la ciudad de Biblos, destacado mercado de papiros de la antigüedad. Los animales aparecen como símbolos en diversas ocasiones, no solo en la Biblia, sino en todas las representaciones de origen judeocristiano. Conceptos como Dios, Jesús, la Iglesia o Satanás son expresados en forma de sencillas figuras como peces, águilas, leones, corderos, serpientes, machos cabríos..., entre otros muchos animales. Resulta peculiar el criterio de división que establece el Antiguo Testamento entre las especies animales: se refiere de modo reiterado a animales, a aves (como si no lo fueran), a todo ser viviente que se mueve en las aguas (como si tampoco) y a todo ser que se arrastra sobre la tierra (reptil, en otras ocasiones). Paradójicamente, en un libro tan inabarcable como la Biblia no se cita demasiado el término "enfermedad" , mientras que resulta más frecuente el vocablo "plaga". En el "libro de libros" se hace escasa referencia a médicos (doce veces, repartidas entre Antiguo y Nuevo Testamento) o sanadores (tan solo en dos ocasiones en el Antiguo Testamento), labor que era efectuada dentro de las primeras comunidades judías por los sacerdotes (término que figura trescientas veces únicamente en el Pentateuco), que completaban su atención espiritual con la sanitaria. No en vano, la cultura hebrea que abarca el Antiguo Testamento seguía creyendo, al igual que la mesopotámica, que la enfermedad se encontraba relacionada con un castigo divino, como manifestación externa del pecad

Evaluation of different API systems for identification of porcine Pasteurella multocida isolates

4 p.An exhaustive biochemical characterisation of 60 porcine Pasteurella multocida clinical isolates recovered from lesions indicative of pneumonia, previously confirmed by PCR and all belonging to the capsular serogroup A, was performed by means of four commercial systems. The API 20NE correctly identified almost all isolates (95%), but only 60% could be ascribed to this species by the API 20E method. The high diversity exhibited by the API 50CHB/E system, with six different patterns, does not advise its use as additional system for a definitive identification at the species level, but this method could be a potential tool for characterising P. multocida isolates below this level. The more uniform reactions yielded by the API ZYM test make this system helpful in the confirmatory identification of this organism. The high variability (20 profiles) obtained when the four systems are taken together also suggests their usefulness for epidemiological purposes in order to sub-type P. multocida isolatesS

Value of Indirect Hemagglutination and Coagglutination Tests for Serotyping Haemophilus parasuis

P. 880-882An indirect hemagglutination test (IHA) and a coagglutination test (CA) were evaluated using saline, boiled, and autoclaved extracts for serotyping Haemophilus parasuis. CA showed several cross-reactions, whereas IHA gave rise to specific reactions, with minor exceptions. IHA was further compared with the immunodiffusion test (the “gold standard”) for the serotyping of 67 field isolates. As a conclusion, IHA is recommended as a useful method for sensitive and specific serotyping of H. parasuisS

Haemophilus parasuis serovar 5 Nagasaki strain adheres and invades PK-15 cells

7 p.Haemophilus parasuis is the agent responsible for causing Gla¨ sser’s disease, which is characterized by fibrinous polyserositis, polyarthritis and meningitis in pigs. The purpose of this study was to investigate the in vitro ability of two H. parasuis serovars of different virulence (serovar 5, Nagasaki strain, highly virulent, belonging to serovar 5, and SW114 strain, nonvirulent, belonging to serovar 3) to adhere to and invade porcine kidney epithelial cells (PK-15 line). Nagasaki strain was able to attach at high levels from 60 to 180 min of incubation irrespective of the concentrations compared (107–1010 CFU), and a substantial increase of surface projections could be seen in PK-15 cells by scanning electron microscopy. This virulent strain was also able to invade effectively these epithelial cells, and the highest invasion capacity was reached at 180 min of infection. On the contrary, nonvirulent SW114 strain hardly adhered to PK-15 cells, and it did not invade these cells, thus suggesting that adherence and invasion of porcine kidney epithelial cells could be a virulence mechanism involved in the lesions caused by H. parasuis Nagasaki strain in this organS

Nucleotide sequence and transfer properties of two novel types of Actinobacillus pleuropneumoniae plasmids carrying the tetracycline resistance gene tet(H)

17 p.The aim of this study is to analyze the sequence and transfer properties of two tetracycline resistance plasmids found in clinical isolates of Actinobacillus pleuropneumoniae in order to assert their role in the spread of tetracycline resistenceS

Antimicrobial susceptibility patterns of Haemophilus parasuis from pigs in the United Kingdom and Spain

18 p.A total of 30 British and 30 Spanish Haemophilus parasuis isolates were tested for their susceptibility to 19 of the antimicrobials currently used in swine practice with a broth microdilution method in order to know the emergence of resistance against these compounds in this porcine pathogen. All the British isolates were susceptible to penicillin, ceftiofur, erythromycin, tilmicosin, enrofloxacin, and florfenicol, and most of them were susceptible to the remaining antimicrobials (the highest resistance rate found was of 20% to neomycin). In contrast, all the Spanish isolates were susceptible exclusively to florfenicol, and high proportions of resistance were encountered for penicillin, ampicillin, oxytetracycline, erythromycin, tilmicosin, tiamulin and trimethoprim + sulphamethoxazole; in addition, a bimodal or multimodal distribution, or tailing of Spanish isolates over the MIC range was observed for clindamycin, sulphonamides and tylosine tartrate, suggesting the development of acquired resistance. In addition, several multiresistance patterns were found among the Spanish isolates, 23.3% of them being resistant to at least eight antimicrobials, the same rate as that encountered for those being susceptible to all antimicrobials tested. This study showed that in general British H. parasuis isolates are susceptible to antimicrobial agents routinely used for treatment of porcine respiratory diseases; however, the Spanish isolates need a more continuous surveillance of their susceptibility patternsS

Distribution of Tetracycline Resistance Genes in Actinobacillus pleuropneumoniae Isolates from Spain

P. 702-708Actinobacillus pleuropneumoniae is the etiological agent of porcine pleuropneumonia. Tetracycline is used for therapy of this disease, and A. pleuropneumoniae carrying the tet(B) gene, coding for an efflux protein that reduces the intercellular tetracycline level, has been described previously. Of the 46 tetracycline-resistant (Tcr) Spanish A. pleuropneumoniae isolates used in this study, 32 (70%) carried the tet(B) gene, and 30 of these genes were associated with plasmids. Eight (17%) isolates carried the tet(O) gene, two (4%) isolates carried either the tet(H) or the tet(L) gene, and all these genes were associated with plasmids. This is the first description of these tet genes in A. pleuropneumoniae. The last two Tcr isolates carried none of the tet genes examined. Except for tet(O)-containing plasmids, the other 34 Tcr plasmids were transformable into an Escherichia coli recipient. Two plasmids were completely sequenced. Plasmid p11745, carrying the tet(B) gene, was 5,486 bp and included a rep gene, encoding a replication-related protein, and two open reading frames (ORFs) with homology to mobilization genes of Neisseria gonorrhoeae plasmid pSJ7.4. Plasmid p9555, carrying the tet(L) gene, was 5,672 bp and, based on its G C content, consisted of two regions, one of putative gram-positive origin containing the tet(L) gene and the other comprising four ORFs organized in an operon-like structure with homology to mobilization genes in other plasmids of gram-negative bacteriaS

Characterization of a recombinant transferrin-binding proteinA (TbpA) fragment fromHaemophilus parasuis serovar 5

9 p.Haemophilus parasuis, the etiological agent of Gl¨asser’s disease in pigs, possesses iron acquisition pathways mediated by a surface receptor that specifically bind porcine transferrin. This receptor is composed of transferrin-binding protein A (TbpA) and TbpB. As it has been reported for other gram-negative organisms, H. parasuis TbpA could be useful as a candidate target for H. parasuis vaccination. In this study, a 600-bp tbpA fragment of the gene encoding TbpA from H. parasuis serovar 5, the Nagasaki strain, was amplified by PCR and cloned into a pBAD/ Thio-TOPO expression vector, generating the pBAD-Thio-TbpA-V5-His (TbpAHis) construction. Escherichia coli LMG194-competent cells were transformed with this construction, followed by the induction of protein expression with arabinose. A band (38.5 kDa) corresponding to a 200-amino acid recombinant TbpA (rTbpA) fragment was seen on the sodium dodecyl sulfate polyacrylamide gel electrophoresis and confirmed by immunoblotting. Polyclonal antibodies raised against this fragment were specific for H. parasuis and Actinobacillus pleuropneumoniae, reacted at the cell surface with H. parasuis, and a significant bactericidal activity was also detected. Therefore, this rTbpA fragment induces an immunological response and might be useful as an antigen for vaccination against Gl¨asser’s diseaseS

Autoevaluación en línea y otras metodologías sencillas en el fomento del rendimiento académico de “Microbiología”

P. 41-42La “Microbiología” (6,0 créditos ECTS) se integra en la asignatura de “Biología y Microbiología” (10,5 créditos ECTS), la de mayor extensión del Grado en “Ciencia y Tecnología de los Alimentos” de la Universidad de León (ULE), impartida en el primer semestre. Transcurridos cinco años desde su implantación, nuestra experiencia revela que los estudiantes adolecen de falta de motivación, ya que sus contenidos han sido abordados parcialmente en el instituto, y por la propia génesis de la asignatura, que reúne Zoología, Botánica y Microbiología, dado que las dos primeras materias no podían ser impartidas independientemente, al no alcanzar los 6 créditos mínimos preceptivosS