Publications by authors named "M S Chadfield"

Host-pathogen interactions of Pasteurella multocida isolates of different origin were studied in a mouse model, focusing on pathology, bacterial load and expression of the metalloproteinase MMP9 and its inhibitor TIMP1. Intranasal inoculation with one of three doses (10(6), 10(4), 10(2)CFU) of an isolate from porcine pneumonia or fowl cholera showed marked differences between the two isolates. The avian isolate was highly pathogenic with severe signs of necrotizing pneumonia, liver necrosis and high bacterial load in lung and liver.

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Background: The importance of flagella and chemotaxis genes in host pathogen interaction in Salmonella enterica is mainly based on studies of the broad host range serovar, S. Typhimurium, while little is known on the importance in host specific and host adapted serovars, such as S. Dublin.

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Fifty-five clinical isolates of avian pathogenic Escherichia coli (APEC) from seven outbreaks of acute haemorrhagic septicaemia in turkeys were characterized by serotyping, plasmid profiling including restriction analysis with HindIII, ribotyping with EcoRI and HindIII, multilocus sequence typing (MLST) and virulence profiling. A clonal relationship was demonstrated for each outbreak according to serotype, plasmid profiling, ribotyping, and MLST. In addition, isolates demonstrated highly similar virulence profiles, as all isolates were positive for F11 pili and possessed genes encoding aerobactin (iucD), increased serum survival (iss), temperature-sensitive haemagglutinin (tsh) and colicin V plasmid operon genes (cva/cvi).

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Pasteurella multocida is a major cause of porcine pneumonia, but the pathogenesis of the disease is poorly defined. The aim of this study was to further understand the host response to infection by use of a mouse model of P. multocida pneumonia.

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The genus Streptococcus consists of more than 60 species, but only Streptococcus equi subspecies zooepidemicus, Streptococcus gallolyticus ssp. gallolyticus, Streptococcus gallinaceus, Streptococcus dysgalactiae, Streptococcus mutans and Streptococcus suis have been isolated from poultry. During investigations of the aetiology of increased mortality in broiler parent stock at the end of production, pure cultures of streptococcal-like organisms that could not be classified among these six species were obtained from 24 cases of septicaemia or valvular endocarditis and septicaemia.

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