First isolation of Leptospira interrogans from Lycalopex griseus (South American gray fox) in Argentina shows new MLVA genotype.

To identify carriers of Leptospira spp. in Argentina, wild animals were trapped in Buenos Aires Province during three nights, capturing 12 Didelphis albiventris (white-eared opossum), six Chaetophractus villosus (big hairy armadillo), five Lycalopex griseus (South American gray fox), and two Conepatus chinga (Molina's hog-nosed skunk). All were tested by microscopic agglutination test, and five (two gray foxes, two armadillos, and one skunk) were positive for Leptospira interrogans serovars Canicola and Icterohaemorrhagiae, L. borgpetersenii serovar Castellonis, and L. kirschneri serovar Grippotyphosa, at titers of 1:50 and 1:100. Kidney tissue from all animals was cultured, and one isolate of L. interrogans from a gray fox was obtained. Hamsters inoculated with the isolate died after 6 days with no macroscopic lesions at necropsy. However, histologic examination revealed glomerulonephritis, interstitial nephritis, and pneumonia. The Leptospira strain from the South American gray fox was analyzed serologically and its pathogenicity was established. Genotyping through multiple-locus variable-number tandem repeat analysis showed that the strain was a new genotype related to the L. interrogans serogroup Icterohaemorrhagiae.

In vivo cell aggregations of a recent swine biofilm-forming isolate of Leptospira interrogans strain from Argentina.

Leptospirosis is a zoonosis of ubiquitous distribution caused by spirochetes. Leptospires exist either as saprophytic water-associated organisms or as animal pathogens that can survive in water. Previous works have demonstrated that both saprophytic and pathogenic leptospires are able to produce functional biofilms, which consist of a community of bacteria embedded in an extracellular matrix attached to a surface. This structure is believed to provide protection from environmental aggressiveness. In the present study, we analyzed the capacity of biofilm formation both of a a recent field isolate of Leptospira interrogans serovar Pomona obtained from an aborted swine fetus and of the saprophytic Leptospira biflexa serovar Patoc. We used light microscopy, immunofluorescence, and scanning electron microscopic examinations on glass and polystyrene plate models to evaluate the process in vitro. The ability to form bacterial aggregations in vivo was tested using pregnant guinea pigs infected with both strains. We obtained biofilms both on glass and plastic surfaces. Scanning electron microscopic analysis showed differences in the biofilm structure formed by both strains. L. interrogans serovar Pomona cell aggregations were observed in placental tissues by light microscopy. Biofilms and cell aggregations are consistent with the life of saprophytic strains in water and could help pathogenic strains to colonize the host and lead to abortion in pregnant animals.

In vivo cell aggregations of a recent swine biofilm-forming isolate of Leptospira interrogans strain from Argentina / Agregaciones celulares in vivo de Leptospira interrogans producidas por un aislamiento porcino capaz de formar biofilm

Leptospirosis is a zoonosis of ubiquitous distribution caused by spirochetes. Leptospires exist either as saprophytic water-associated organisms or as animal pathogens that can survive in water. Previous works have demonstrated that both saprophytic and pathogenic leptospires are able to produce functional biofilms, which consist of a community of bacteria embedded in an extracellular matrix attached to a surface. This structure is believed to provide protection from environmental aggressiveness. In the present study, we analyzed the capacity of biofilm formation both of a a recent field isolate of Leptospira interrogans serovar Pomona obtained from an aborted swine fetus and of the saprophytic Leptospira biflexa serovar Patoc. We used light microscopy, immunofluorescence, and scanning electron microscopic examinations on glass and polystyrene plate models to evaluate the process in vitro. The ability to form bacterial aggregations in vivo was tested using pregnant guinea pigs infected with both strains. We obtained biofilms both on glass and plastic surfaces. Scanning electron microscopic analysis showed differences in the biofilm structure formed by both strains. L. interrogans serovar Pomona cell aggregations were observed in placental tissues by light microscopy. Biofilms and cell aggregations are consistent with the life of saprophytic strains in water and could help pathogenic strains to colonize the host and lead to abortion in pregnant animals.

La leptospirosis es una zoonosis de amplia distribución causada por el género Leptospira. Las leptospiras existen de manera saprófita asociadas a ambientes acuáticos o como patógenos animales que también pueden sobrevivir en el agua. Trabajos previos demostraron que tanto las leptospiras saprófitas como las patógenas tienen la capacidad de formar biofilms, que consisten en una comunidad de bacterias embebidas en una matriz extracelular adherida a una superficie. Esta estructura tendría la función de proveer protección contra el medioambiente. En este estudio, analizamos la capacidad de formar biofilm en un aislamiento obtenido recientemente de un feto porcino abortado, caracterizado como Leptospira interrogans serovar Pomona, y en la bacteria saprófita Leptospira biflexa serovar Patoc. Se estudió la formación de biofilm en distintas superficies (vidrio y poliestireno), las que se evaluaron por microscopía óptica, inmunofluorescencia y microscopía electrónica de barrido. La capacidad de formar agregaciones bacterianas in vivo se evaluó utilizando un modelo de cobayas preñadas infectadas con ambas cepas. Se obtuvieron biofilms tanto en las superficies plásticas como de vidrio. La microscopía de barrido mostró diferencias en la estructura del biofilm formado entre ambas cepas. Se observaron agregaciones celulares en vasos placentarios de los animales infectados con L. interrogans serovar Pomona. Los biofilms y las agregaciones celulares son compatibles con la vida saprofítica en el agua y podrían favorecer a los microorganismos patógenos en la colonización del hospedador, lo que podría llevar al aborto en los animales preñados.

In vivo cell aggregations of a recent swine biofilm-forming isolate of Leptospira interrogans strain from Argentina / Agregaciones celulares in vivo de Leptospira interrogans producidas por un aislamiento porcino capaz de formar biofilm

Leptospirosis is a zoonosis of ubiquitous distribution caused by spirochetes. Leptospires exist either as saprophytic water-associated organisms or as animal pathogens that can survive in water. Previous works have demonstrated that both saprophytic and pathogenic leptospires are able to produce functional biofilms, which consist of a community of bacteria embedded in an extracellular matrix attached to a surface. This structure is believed to provide protection from environmental aggressiveness. In the present study, we analyzed the capacity of biofilm formation both of a a recent field isolate of Leptospira interrogans serovar Pomona obtained from an aborted swine fetus and of the saprophytic Leptospira biflexa serovar Patoc. We used light microscopy, immunofluorescence, and scanning electron microscopic examinations on glass and polystyrene plate models to evaluate the process in vitro. The ability to form bacterial aggregations in vivo was tested using pregnant guinea pigs infected with both strains. We obtained biofilms both on glass and plastic surfaces. Scanning electron microscopic analysis showed differences in the biofilm structure formed by both strains. L. interrogans serovar Pomona cell aggregations were observed in placental tissues by light microscopy. Biofilms and cell aggregations are consistent with the life of saprophytic strains in water and could help pathogenic strains to colonize the host and lead to abortion in pregnant animals.(AU)

La leptospirosis es una zoonosis de amplia distribución causada por el género Leptospira. Las leptospiras existen de manera saprófita asociadas a ambientes acuáticos o como patógenos animales que también pueden sobrevivir en el agua. Trabajos previos demostraron que tanto las leptospiras saprófitas como las patógenas tienen la capacidad de formar biofilms, que consisten en una comunidad de bacterias embebidas en una matriz extracelular adherida a una superficie. Esta estructura tendría la función de proveer protección contra el medioambiente. En este estudio, analizamos la capacidad de formar biofilm en un aislamiento obtenido recientemente de un feto porcino abortado, caracterizado como Leptospira interrogans serovar Pomona, y en la bacteria saprófita Leptospira biflexa serovar Patoc. Se estudió la formación de biofilm en distintas superficies (vidrio y poliestireno), las que se evaluaron por microscopía óptica, inmunofluorescencia y microscopía electrónica de barrido. La capacidad de formar agregaciones bacterianas in vivo se evaluó utilizando un modelo de cobayas preñadas infectadas con ambas cepas. Se obtuvieron biofilms tanto en las superficies plásticas como de vidrio. La microscopía de barrido mostró diferencias en la estructura del biofilm formado entre ambas cepas. Se observaron agregaciones celulares en vasos placentarios de los animales infectados con L. interrogans serovar Pomona. Los biofilms y las agregaciones celulares son compatibles con la vida saprofítica en el agua y podrían favorecer a los microorganismos patógenos en la colonización del hospedador, lo que podría llevar al aborto en los animales preñados.(AU)

Necrotic enteritis in young calves.

Non-enterotoxin (CPE)-producing Clostridium perfringens type A has been associated with enteritis in calves. Recent evidence has suggested that a novel toxin, named beta2 (CPB2), is implicated in the pathogenesis of this disease, although there is little evidence supporting this. In the current study, the role of C. perfringens type A in an outbreak of enteritis in calves was studied. Two 20-day-old dairy calves exhibiting apathy and reluctance to eat, with paresis of the anterior limbs, were euthanized for postmortem examination. Gross and histological changes compatible with acute enteritis, rumenitis, meningitis, and pneumonia were seen in both calves. Clostridium perfringens type A non-CPE, non-CPB2 was isolated from the abomasum and the small intestine. Escherichia coli ONTH8 (with cdtBIII and f17 virulence genes detected by polymerase chain reaction) was also isolated from the brain, abomasum, and intestine from both calves. All the samples were negative for Salmonella spp. When the C. perfringens strain was inoculated into bovine ligated small and large intestinal loops, cell detachment, erosion, and hemorrhage of the lamina propria were observed, predominantly in the small intestine. The results suggest that non-CPE, non-CPB2 C. perfringens type A is able to induce pathologic changes in the intestine of calves, probably enhanced by other pathogens, such as some pathogenic E. coli strains.

Upper alimentary tract papillomas in calves related to papillomavirus infection.

This study reports 3 cases of spontaneous papillomavirus infection in 1-week-old calves. Thickening of the omasum and abomasum wall, with acute inflammation, necrosis, ulceration, and neoplastic changes were seen in 1 calf. In the other 2, small papillomas were observed in the omasal mucosa, exhibiting proliferation of the parakeratinized epithelium. Papillomavirus antigens were detected by immunohistochemistry and virus-like particles were seen through electron microscopy.

[Adaptation of an immunohistochemistry protocol for the detection of Leptospira spp. in samples of formaldehyde-fixed tissue]. / Adaptación de un protocolo de inmunohistoquímica para la detección de Leptospira spp. en muestras de tejido fijado en formaldehído.

The immunohistochemistry technique was evaluated in tissue samples fixed in formaldehyde saline solution 10 % and included in paraffin to be used as a lab method allowing to identify leptospires in tissues. Samples obtained from the experimental inoculation of 8 guinea pigs carriers of L. interrogans Pomona isolated from a clinical case were used. The disease was reproduced in a lab model. The histologic sections of the kidneys of the animals inoculated were subjected to histopathological studies, immunofluorescence, Warthin-Starry stain, and immunohistochemistry technique using formaldehyde-fixed samples. This technique proved to be an efficient tool for the diagnosis of leptospirosis.