[Infectious glomerulonephritis and pleuropneumonia due to Streptococcus pneumoniae. Pediatric clinical case]. / Glomerulonefritis infecciosa y pleuroneumonía por Streptococcus pneumoniae. Caso clínico pediátrico.

Acute glomerulonephritis caused by Streptococcus pneumoniae is a low prevalence pathology. There are several reports communicating different nephritogenic serotypes, however, 6C has been scarcely indicated as such. It is presented the case of a 4-year-old patient who entered Intensive Therapy Unit with pleuropneumonia due to Streptococcus pneumoniae serotype 6C and concomitantly developed edemas, arterial hypertension, hematuria, proteinuria, decreased glomerular filtration rate and C3 complement level. Acute glomerulonephritis was diagnosed. His evolution was satisfactory in a short time. This pathology is usually of a transitory and benign course; however, sometimes it can potentially complicate the evolution of a critically ill patient, so it is necessary to have it among the differential diagnoses to consider.

La glomerulonefritis aguda desencadenada por Streptococcus pneumoniae es una patología de baja prevalencia. Existen diversos reportes que comunican distintas cepas nefritogénicas; sin embargo, la 6C ha sido escasamente señalada como tal. Se presenta el caso de un paciente de 4 años, quien ingresó a Terapia Intensiva con pleuroneumonía por Streptococcus pneumoniae serotipo 6C y desarrolló, de modo concomitante, edemas, hipertensión arterial, hematuria, proteinuria, disminución del filtrado glomerular y del nivel de complemento C3. Se diagnosticó glomerulonefritis aguda. Su evolución fue satisfactoria en un breve plazo. Esta patología, por lo general, es de curso transitorio y benigno; sin embargo, en ocasiones, puede complicar la evolución de un paciente críticamente enfermo, por lo cual se hace necesario tenerla entre los diagnósticos diferenciales para considerar.

New trends in innovative vaccine development against Actinobacillus pleuropneumoniae.

Actinobacillus pleuropneumoniae is the etiological agent of porcine pleuropneumonia, a respiratory disease leading to severe economic losses in the swine industry. The most widely used commercial vaccines are bacterins comprising inactivated whole cells of A. pleuropneumoniae but these have only been partially effective in preventing disease. Innovative immuno-prophylactic preparations of A. pleuropneumoniae based on ApxI, ApxII, ApxIII, ApxIV toxins and outer membrane proteins, among others (i.e. RnhB, GalU, GalT, HflX, ComL, LolB, LppC), have high protective efficacy in mice and pigs. Some vaccine preparations have efficacy against homologous and heterologous A. pleuropneumoniae serovars, which constitute an important advance to control porcine pleuropneumonia. In this arena, subunit vaccines based on toxins are one of the most advanced and promising developments. Many research groups have focussed on the development of live attenuated vaccines comprising strains with inactivated Apx toxins and/or other virulence factors, their protective efficacy being determined in mouse and/or swine models. Other innovative approaches such as bacteria, yeast and plants as production and oral delivery platforms have been explored in animal models and the definitive host with encouraging results. In addition, further research into A. pleuropneumoniae-based DNA and nano-vaccines, as well as bioencapsulation of antigens in plants, is envisaged. Here, the recent findings and future trends in innovative vaccine development against A. pleuropneumoniae are reviewed and placed in perspective.

Actinobacillus pleuropneumoniae metalloprotease: cloning and in vivo expression.

The complete amino acid and nucleotide sequence of a secreted metalloprotease produced by Actinobacillus pleuropneumoniae serotype 1 is reported. A clone showing proteolytic activity in cell-free culture media was selected from a genomic library of A. pleuropneumoniae serotype 1 in pUC 19. The sequence obtained contained an open reading frame encoding a protein with 869 amino acids. This protein was identified as a zinc neutral-metalloprotease belonging to the aminopeptidase family, with a predicted molecular weight of approximately 101 kDa. This sequence showed high homology with other predicted or sequenced aminopeptidases reported for different Gram-negative bacteria. Expression of the protease was observed in lung tissue from pigs that died of porcine pleuropneumonia suggesting a role in pathogenesis.

Aislamiento e identificación de actinobacillus pleuropneumoniae en pulmones de cerdos con pleuroneumonóa crónica sacrificados en el rastro municipal de mérida, Yucatán, México / Isolation and identification of actinobacillus pleuropneumoniae in pigs lungs with chronic pleuropneumonia at the slaugterhouse of Merida, Yucatan, Mexico

Introducción. El objetivo del presente estudio fue estandarizar la técnica de siembra directa e implementar la prueba de aglutinación rápida en placa para el aislamiento e identificación de Actinobacillus pleuropneumoniae en pulmones de cerdos con pleuroneumonía crónica provenientes del rastro municipal de Mérida, Yucatán, México. Materiales y Métodos. De julio de 1996 a febrero de 1997 se tomaron en el rastro municipal de la ciudad de Mérida, 250 muestras de pulmones de cerdos con lesiones de plueroneumonía en los lóbulos caudales. Las muestras se sembraron en agar sangre con cepa nodriza de Staphylococcus aureus, posteriormente fueron incubadas a 37§C por 24 horas en aerobiosis. Las colonias que presentaron satelitismo, beta hemólisis y brillantes, fueron consideradas colonias sospechosas a A pleuropneumoniae. Para la confirmación de A pleuropneumoniae, se realizaron las pruebas bioquímicas de urea, glucosa, lactosa, mannitol, dulcitol, CAMP y NAD por el método de micrométodos. La prueba utilizada para la serotipificación de A pleuropneumoniae fue aglutinación rápida en placa. Resultados. En 129 (51.6 por ciento) pulmones se aisló A pleuropneumoniae. De las 129 muestras positivas a A pleuropneumoniae, en 113 (87.6 por ciento) muestras se obtuvo cultivo puro (sin la presencia de otras bacterias) y en 16 (12.4 por ciento) muestras A pleuropneumoniae estuvo acompañado de otras bacterias (15 con P multocida y 1 con A pyogenes). Los serotipos identificados de A pleuropneumoniae fueron: serotipo 1 en 88 (68.2 por ciento) cepas, serotipo 7 en 29 (22.5 por ciento) cepas, serotipo 5 en una (0.8 por ciento) cepa y 11 (8.5 por ciento) cepas tuvieron reacción cruzada entre los serotipos 1 y 7. Discusión. La selección de la muestra es uno de los factores más importantes para lograr el aislamiento de A pleuropneumoniae por medio de la técnica de siembra directa. La técnica de siembra directa para el aislamiento de A pleuropneumoniae en pulmones con pleuroneumonía crónica en cerdos de rastro puede ser utilizada para el diagnóstico de la enfermedad.

Efficacy of florphenicol premix in weanling pigs experimentally infected with Actinobacillus pleuropneumoniae.

The efficacy of a florfenicol premix was studied in weaning pigs experimentally inoculated with Actinobacillus pleuropneumoniae. Twenty five clinically healthy pigs were distributed into 3 groups; group A non-medicated, groups B and C orally medicated with 20 and 40 ppm of florfenicol respectively. The pigs were fed during 12 consecutive days and on day 5 all the groups were challenged with A. pleuropneumoniae serotype 1. All the animals in Group A developed clinical signs. Most of the pigs in the medicated groups maintained a good health status. Postmortem examination revealed severe pleuropneumonia in pigs from the control group and pneumonic lesions in 40% of the animals treated with 20 ppm of florfenicol. Development of pleuropneumonia was prevented in all the pigs medicated with 40 ppm of florfenicol. Actinobacillus pleuropneumoniae was recovered from the lungs of all control animals and from one pig of each of the medicated groups, however, the avidin biotin peroxidase (ABC-P) method detected the presence of the microorganism in all the animals. We demonstrated that medication with feed containing 40 ppm of florfenicol blocked efficiently the signs and lesions caused by A. pleuropneumoniae and increased the daily body weight gain.

Consumption of blood coagulation factors associated with Actinobacillus pleuropneumoniae infection

O efeito da infecçäo causada por Actinobacillus pleuropneumoniae no sistema da coagulaçäo do sangue de leitöes foi estudado. 25 leitöes desmamados isentos de organismos patogênicos específicos (IOPES) foram distribuídos de forma aleatória em 2 grupos. 10 leitöes firam infectados com 5x10(6) UFC de Actinobacillus pleuropneumoniae sorotipo 1, e 15 leitöes usados como controles negativos. Reduçöes significativas nas concentraçöes (Pó0.005) dos fatores de coagulaçäo do sangue IX, VIII, VII, X e V foram demonstradas. O tempo parcial ativado da tromboplastina aumentou enquanto que o tempo da protrombina (em porcentagem) diminuiu. A concentraçäo de antitrombina III diminui de forma significativa (Pó0.005). As alteraçöes observadas no tempo de trombina e na quantidade de fibrinogênio estäo relacionadas com a formaçäo de fibrina no processo de coagulaçäo sanguínea. Em consequência disso, a hemorragia pulmonar e a formaçäo de coágulos podem ser observados em pulmöes de leitöes infectados com Actinobacillus pleuropneumoniae

Pleuropulmonary tularemia: successful treatment with erythromycin.

A 64-year-old man had community-acquired pneumonia that was retrospectively diagnosed as pleuropulmonary tularemia. He was successfully treated with erythromycin. We review the case and briefly discuss the literature on this point.