RESUMO
This study proposes an ecological approach for preventing respiratory tract infections caused by Bordetella bronchiseptica in mammals using a mixture of carbohydrates. In an in vivo study, 51-day-old New Zealand rabbits were treated with a solution containing 1 × 107 CFUs of B. bronchiseptica and 250 µg of one of the following carbohydrates: N acetylglucosamine (GlcNAc), N acetylgalactosamine (GalNAc), alpha methyl mannose (AmeMan), alpha methyl glucose (AmeGlc) and sialic acid (Neu5AC). Positive (B. bronchiseptica) and negative (Physiological Saline Solution (PSS)) controls were included. Animals treated with GlcNAc or AmeGlc showed no clinical signs of infection and exhibited a significant reduction (p < 0.05) in the severity of microscopic lesions evaluated in the nasal cavity and lung compared with the positive controls. Additionally, the presence of bacteria was not detected through microbiological isolation or PCR in the lungs of animals treated with these sugars. Use of a mixture of GlcNAc and AmeGlc resulted in greater inhibition of microscopic lesions, with a significant reduction (p < 0.05) in the severity of these lesions compared to the results obtained using individual sugars. Furthermore, the bacterium was not detected through microbiological isolation, Polymerase Chain Reaction (PCR) or indirect immunoperoxidase (IIP) in this group.
Assuntos
Infecções por Bordetella , Bordetella bronchiseptica , Mucosa Respiratória , Animais , Coelhos , Bordetella bronchiseptica/efeitos dos fármacos , Infecções por Bordetella/veterinária , Infecções por Bordetella/microbiologia , Mucosa Respiratória/efeitos dos fármacos , Mucosa Respiratória/microbiologia , Aderência Bacteriana/efeitos dos fármacos , Carboidratos/farmacologia , Acetilglucosamina/farmacologia , Infecções Respiratórias/veterinária , Infecções Respiratórias/microbiologia , Infecções Respiratórias/tratamento farmacológico , Pulmão/microbiologia , Pulmão/efeitos dos fármacos , Pulmão/patologiaRESUMO
In order to characterize the in vivo lesions in the nasal cavities and lungs, twenty-eight rabbits were intranasally instilled with lipopolysaccharide (LPS) from P. multocida and then divided into seven groups according to euthanasia time. The nasal cavities and the lungs were processed for light microscopy, lectin histochemistry and transmission electron microscopy. Increased goblet cell activation and neutrophil infiltration were relevant changes in the nasal cavity. A predominantly interstitial pattern of diffuse alveolar damage and bronchopneumonic foci were the main lesions found in the lungs. LPS was found in the cytoplasm of ciliated cells, goblet cells, glandular cells, venular endothelial cells and neutrophils in the nasal cavity and in club cells, capillary endothelial cells and neutrophil in the lung. This study demonstrates that the LPS is able to cause lesions in the upper and lower respiratory tract, it binds to and is internalized by respiratory epithelial cells. Furthermore, it also traverses the intercellular spaces to reach the blood vessels, where it binds to and is internalized by neutrophil and red blood cells. These cells may then travel to the lungs where the LPS induces typical diffuse alveolar damage. This route of lung interstitial damage, to our knowledge, has not been described for this molecule or any known pathogen.
Assuntos
Infecções por Pasteurella , Pasteurella multocida , Coelhos , Animais , Infecções por Pasteurella/patologia , Infecções por Pasteurella/veterinária , Lipopolissacarídeos/toxicidade , Células Endoteliais , Pulmão/patologiaRESUMO
Pathogenic bacteria are responsible for several diseases in humans and in a variety of hosts. Detection of pathogenic bacteria is imperative to avoid and/or fight their potential harmful effects. This work reports on the first amperometric biosensor for the rapid detection of Streptococcus agalactiae (S. agalactiae). The biosensor relies on a single biotinylated antibody that immobilizes the bacteria on a screen-printed carbon electrode while is further linked to a streptavidin-conjugated HRP reporter. The biotinylated antibody provides selectivity to the biosensor whereas serves as an anchoring point to the reporter for further amplification of the electrochemical signal. The resultant immunosensor is simple, responds rapidly, and allows for the selective and highly sensitive quantification of S. agalactiae cells in a concentration range of 101-107CFUml-1, with a detection limit of 10CFUml-1. The approach not only enables a rapid detection and quantification of S. agalactiae in environmental samples but also opens up new opportunities for the simple fabrication of electrochemical immunosensors for different target pathogens.
Assuntos
Anticorpos Imobilizados/química , Técnicas Biossensoriais/métodos , Doenças dos Peixes/diagnóstico , Infecções Estreptocócicas/veterinária , Streptococcus agalactiae/isolamento & purificação , Tilápia/microbiologia , Microbiologia da Água , Animais , Técnicas Biossensoriais/economia , Técnicas Eletroquímicas/economia , Técnicas Eletroquímicas/métodos , Eletrodos , Doenças dos Peixes/microbiologia , Imunoensaio/economia , Imunoensaio/métodos , Limite de Detecção , Infecções Estreptocócicas/diagnóstico , Infecções Estreptocócicas/microbiologiaRESUMO
Rickettsial organisms are well-known fish pathogens in both natural and culture environments. This study reports an outbreak of disease in red tilapia larvae caused by piscirickettsia-like organisms (PLOs), which lasted from June until October 2009. Severe mortality was recorded almost exclusively in larvae and postlarvae aged 1-22 days old. Although clinical or gross findings were not evident in diseased fish, histopathology revealed severe necrosis of the epidermis and gill epithelium, with concomitant changes in the underlying skeletal muscle as being the most relevant microscopic lesions. Although PLOs were visible with the routine hematoxylin eosin technique, they were better observed with Giemsa and toluidine blue stains. Transmission electron microscopy revealed that the bacterium was located within the cytoplasm and phagolysosoma-like structures of epithelial cells from the gills and the skin. The bacteria measured 0.9 ± 0.2 µm × 2.1 ± 0.6 µm and had a double cell membrane (the outer one having undulating projections), with variable electron-dense and electron-lucent areas. Ultrastructurally, abundant myelin figures surrounded the microorganisms within host cell cytoplasm. Results indicated that Piscirickettsia-like organisms can cause massive epithelial cell damage associated with concomitant alteration of the electrolyte balance.