No description available.

No description available.

No description available.

Mannheimia haemolytica is the principal bacterial agent associated with bovine respiratory disease (BRD). It has a significant economic impact on the beef feedlot industry. The current methods for BRD prevention and treatment have various problems and limitations, especially with reports of increased antimicrobial resistance in M. haemolytica. Bacteriophage therapy presents a novel method to mitigate M. haemolytica. This study aimed to isolate strictly lytic M. haemolytica-specific bacteriophages from bovine nasopharyngeal swabs and feedlot trough water. This was accompanied by an extensive characterization of temperate bacteriophages induced from representative strains of a M. haemolytica collection. Phage morphology, host specificity, genomic diversity, and comparative genomics were determined. Even though temperate bacteriophages are not ideal candidates for phage therapy, they can be engineered or modified to serve this function. Genome sequences of selected temperate bacteriophages also provide a foundation for future studies on the biology of these microorganisms. / viii, 107 leaves : ill. ; 29 cm

Mannheimia haemolytica is an opportunistic pathogen in cattle and the main bacterial agent in bovine respiratory disease. Despite its economic importance, few studies have characterized the genetic diversity of M. haemolytica, particularly from feedlots. Three genotyping techniques (BOX-PCR, (GTG)5-PCR and PFGE) were compared to discriminate M. haemolytica and strains from the family Pasteurellaceae. PFGE was the most discriminating and repeatable, although BOX-PCR was most accurate in clustering isolates together according to species. Mannheimia haemolytica was isolated from nasal swab samples collected from cattle upon entry and exit from two feedlots in southern Alberta. These were characterized by PFGE and antimicrobial susceptibility using a disk-diffusion assay. Select gene determinants were screened for using PCR. PFGE analysis revealed the isolates to be highly diverse. Ten percent of the isolates exhibited resistance. At present, the development and spread of antimicrobial resistance in M. haemolytica observed within the feedlots examined appears to be low. / xi, 116 leaves : ill. ; 29 cm

Submitted by Simone Souza (simonecgsouza@hotmail.com) on 2018-05-02T17:09:56Z No. of bitstreams: 1 DISS_2015_Mayara Inácio Vincenzi da Silva.pdf: 1467868 bytes, checksum: 1589e777267d83f74d5b55da57e6a5db (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2018-05-16T15:13:07Z (GMT) No. of bitstreams: 1 DISS_2015_Mayara Inácio Vincenzi da Silva.pdf: 1467868 bytes, checksum: 1589e777267d83f74d5b55da57e6a5db (MD5) / Made available in DSpace on 2018-05-16T15:13:07Z (GMT). No. of bitstreams: 1 DISS_2015_Mayara Inácio Vincenzi da Silva.pdf: 1467868 bytes, checksum: 1589e777267d83f74d5b55da57e6a5db (MD5) Previous issue date: 2015-08-07 / CAPES / Ferro (Fe) é um elemento essencial e a capacidade de adquiri-lo in vivo têm sido descrita em diversos agentes patogênicos através de fatores de virulência. Análises globais de transcritos durante a privação de ferro tem sido descritos através da técnica de “microarray”, entretanto através da técnica de RNA-seq recentemente tem demonstrado resultados superiores. O isolado de Pasteurella multocida (Pm 16759) altamente patogênica em suínos foi cultivado em duas condições com diferentes concentrações de Fe (controle e privação) com o objetivo de analisar transcritos diferencialmente expressos. O RNA total das duas condições foi extraído e sequenciado através da plataforma de nova geração Ion Torrent. Os dados foram analisados no Software Ion Reporter™ e processados no programa Rockhopper. Foram obtidas 1.341.615 leituras com tamanho médio de 81pb, com 96% de alinhamento com o genoma de Pasteurella multocida subsp. multocida 3480 e 98,8% de acurácia. No mapeamento das leituras das duas condições, observou-se 2,652 transcritos e destes, 177 (6,7%) foram diferencialmente expressos, sendo 93 na condição controle (Fe+) e 84 na condição de privação (Fe-). Na condição de privação de ferro, o perfil de transcritos foram associados a função de transporte celular (fbpABC, high-affinity Fe2+/Pb2+ permease e periplasmic protein probably involved in hight-affinity Fe2+), reguladores transcricionais e proteínas hipotéticas. O perfil na condição controle (Fe+) apresentou transcritos diferencialmente expressos associados ao RNAs anti-sense (asRNA) e genes do metabolismo energético (fructose-1,6-bisfosfatase). A técnica de RNA-seq mostrou-se eficiente na identificação de transcritos diferencialmente expressos por P. multocida em condições de privação de Fe, o que pode auxiliar nos estudos de patogenicidade. / Iron (Fe) is an essential element and the ability to acquire it, in vivo, have been described in several pathogens such as virulence factors. Global analyses of transcripts during iron deprivation have been described by microarray studies, however, recently RNA-seq analysis shows superior results. The high pathogenic swine strain of Pasteurella multocida (BRMSA 1113) was grown in the two conditions with different concentrations of Fe (control and deprivation) in order to analyze the differentially expressed transcripts. The total RNA of the two conditions was extracted and sequenced by new generation Ion Torrent plataform. Data were analyzed in Ion Reporter ™ Software and processed in Rockhopper software. Sequence analysis shows 1,341,615 readings with median length of 81pb, with 96% of alignment to the reference genome Pasteurella multocida strain 3489, and 98.8% accuracy. Reads mapping to genome of P. multocida in these two conditions, detected 2,652 transcripts, which , 177 (6.7%) were differentially expressed, with 93 in the control condition (Fe +) and 84 provided with iron deprivation condition (Fe-). In condition (Fe-), differential expressed transcript profile were associated to function of cellular transport (fbpABC,, high-affinity Fe2+/Pb2+ permease and periplasmic protein probably involved in hight-affinity Fe2+), transcptional regulators and hypothetical proteins. The control condition (Fe+) shows differential expressed transcripts profile associated to RNA anti-sense (asRNA) energetic metabolism genes (fructose-1,6-bisphosphatase). The technique of RNA-seq proved effective in identifying novel differentially expressed transcripts by P. multocida (BRMSA 1113) under conditions of Fe deprivation, which can assist in pathogenicity studies.