Escherichia coli patogênicas aviárias (APEC) causam infecções extraintestinais em aves, que podem ser localizadas ou sistêmicas, denominadas colibacilose. O patotipo de APEC não está definido, mas vários genes de virulência são associados a essas cepas, como os genes plasmidiais iroN, ompT, hlyF, iss e iutA, propostos, em 2008, como preditores da virulência de APEC. Além dos genes de virulência conhecidos, outros fatores podem estar associados à patogenicidade bacteriana, como as maquinarias de secreção protéica denominadas Sistemas de Secreção. O Sistema de Secreção do Tipo 6 (T6SS), descrito em 2006, tem sido associado à virulência de cepas APEC. Este trabalho divide-se em duas partes: a primeira teve como objetivo avaliar a frequência dos genes iroN, ompT, hlyF, iss e iutA em 401 cepas aviárias de E. coli e sua relação com a patogenicidade in vivo dessas cepas. A segunda parte teve como objetivos verificar a frequência de genes componentes do T6SS (clpV, vgrG, icmF e dotU), em uma coleção de 187 cepas APEC; e, em algumas cepas positivas para os genes, verificar a expressão de um fenótipo relacionado ao sistema, bem como a expressão do efetor vgrG e da ATPase do sistema clpV2, além da secreção de proteínas, no meio de cultura e durante contato com células eucarióticas. Os resultados da primeira parte indicam que cepas com dois ou mais dos genes analisados tem maior probabilidade de serem patogênicas do que cepas com apenas um ou nenhum dos genes. Já os da segunda parte mostram que várias cepas apresentaram duas cópias de pelo menos um dos genes testados, e algumas delas apresentaram resistência à predação por D. discoideum. Não foram encontradas diferenças entre a expressão dos genes vgrG (1 e 2) e clpV2 em cultura pura ou em contato com células eucarióticas. Este trabalho apresenta a triagem de genes plasmidiais em uma grande coleção de amostras de Escherichia coli, e a primeira triagem de genes do T6SS em uma coleção de isolados APEC. / Avian pathogenic Escherichia coli (APEC) causes extraintestinal infections in birds, which can be localized or systemic, known as colibacillosis. The APEC pathotype is still undefined, but several virulence genes are associated with these strains, as the plasmid-linked genes iroN, ompT, hlyF, iss and iutA, proposed in 2008 as APEC virulence predictors. Besides the known virulence genes, other factors may be associated with bacterial pathogenicity, such as the protein secretion machineries called Secretion Systems. Described in 2006, Type 6 Secretion System (T6SS) has been associated with virulence of APEC strains. This work is divided in two parts: the first aimed to evaluate the frequency of iroN, ompT, hlyF, iss and iutA genes in 401 avian strains of E. coli and its relationship with in vivo pathogenicity of these strains. The second part aimed to verify the frequency of T6SS genes (clpV, vgrG, icmF and dotU) in a collection of 187 APEC strains; and verify, in some positive strains, the expression of a phenotype related to the system, as well as the gene expression of effector vgrG and ATPase clpV2, besides the secretion of proteins into the culture medium and during contact with eukaryotic cells. The results of the first part of this study indicate that isolates harboring two or more of the genes analyzed were most likely to be pathogenic than strains harboring only one or none of the genes. The results of the second part show that several strains harbored two copies of at least one of the genes tested, and some of them were resistant to predation by D. discoideum. No differences were found between the expression of genes vgrG (1 and 2) and clpV2 in pure culture or in contact with eukaryotic cells. This work presents the screening of plasmidial genes in a large collection of Escherichia coli isolates, and the first screening of T6SS genes in a collection of APEC isolates.

El libro Cómo Aprovechar el APEC Perú 2008 en la Era de los TLC reúne a los seis mejores artículos presentados por estudiantes universitarios al V Concurso de Investigación Universitaria Juan Abugattás Abugattás. Este concurso es organizado por la Red Peruana para Estudios del Asia – Pacífico (REDAP), la cual reúne a las 12 universidades más prestigiosas del Perú con el objetivo de contribuir a la mejor inserción del Perú en el Asia Pacífico. La mayoría de los artículos presentes en este libro se han centrado en el fortalecimiento de las relaciones comerciales entre el Perú y las economías de la Región Asia Pacífico. Para ello, han desarrollado investigaciones sobre el rol de las redes de transporte en la competitividad y el aprovechamiento de los tratados de libre comercio celebrados entre las economías de APEC. Asimismo, se analizó las oportunidades que presenta la celebración de un acuerdo comercial en el futuro con Indonesia. En este marco, en el mes de febrero de 2012, bajo la Coordinación de la UPC, se convoca al V Concurso de Investigación Universitaria Juan Abugattás Abugattás «Cómo Aprovechar el APEC PERÚ 2008 en la era de los TLC» con el objeto de incentivar la investigación universitaria de alto nivel en torno a las relaciones del Perú con las economías miembro de APEC, en todos los campos académicos. Este concurso contó con el auspicio de la Embajada de la República de Indonesia, así como del Ministerio de Relaciones Exteriores y del Ministerio de Comercio Exterior y Turismo. Todo esto le da un gran respaldo a estos artículos que sin duda contribuye a la investigación universitaria de alto nivel.

<p>Antimicrobial resistant bacteria pose a serious threat to global public health. With the development of antibioticresistance far outpacing the discovery of new antibiotics, there is a need to  develop  alternative  strategies  to  control  bacterial  infections without increasing  antibiotic resistance. This study focused on developing bacteriophage therapy as a non-antibiotic means to control colibacillosis in poultry. Avian colibacillosis causes significant mortality and economic loss to poultry industries around the world. The etiological agent is Avian Pathogenic<em> E.  coli</em> (APEC), with serotypes are O78, O1, O2 and O5 most often associated with infections. Here, seven bacteriophages (AHP, MP1, MP2, AKA, MKA, AHC and MIA) were isolated from human and poultry wastewater samples to target these four APEC serotypes.</p> <p>The host-spectrum analysis of these phages revealed that all seven phages lysed at least two different APEC strains, with four phages lysing four or more distinct APEC serotypes. Taken together, the isolated phages covered 90% (9/10) of O-serotyped APEC strains targeted in our study. When co-cultured with the targeted APEC strain, bacterial concentrations in phage treated APEC cultures (average OD₆₀₀= 0.09) were significantly (P < 0.05) lower than those of untreated cultures  (average  OD₆₀₀=  1.22)  after  4  hr  incubation.  However,  exposure  of  the  phages  to simulated gastric fluid (pH 2.2–2.5) reduced viability of three of the seven phages by 2.35 –4.01 log PFU/mL after 90 min and to undetectable levels after 5 min for other four phages. In contrast, phage viability was not impacted by simulated intestinal fluid (SIF) with no reductions in phage concentrations after exposure to SIF for 3 hr. All seven bacteriophages were encapsulated in sodium  alginate  microcapsules  with  encapsulation  efficiencies  between  94.4%  to  98.9%.  In contrast to unprotected phages, viability of encapsulated phages was reduced by only0.74 –1.21  log PFU/mL when exposed to SGF for 90 min. Incubating the encapsulated phages sequentially in SGF (1 hr) and SIF (3 hr) indicated that 85% -90% of phages were released from the microcapsules after1 hr incubation in SIF with the maximum release of phages from the microcapsules occurring after 3 hr of incubation in SIF. To assess the in vivoefficacy of the phage treatment, broiler chicks were challenged with APEC and treated with a mixture of unprotected and encapsulated phages. Concentrations of the APEC in the ceca of phage treated birds (2.79 log CFU/g) were significantly lower (P < 0.05) than those of untreated birds (6.18 log CFU/g) by 4 d post-challenge. Additionally, in  most  cases,  APEC  was  not  recovered  from  the  lungs  of  phage  treated  birds  whereas concentrations of APEC in lungs of untreated birds was 4.81 log CFU/g. Hence, these results indicate that phage treatmenteffectively controlled APEC colonization and replication in the ceca and lungs of APEC-challenged chickens and provide further evidence of the viability of phage-based treatments as a non-antibiotic means of controlling bacterial infections in chickens.</p>

Les pays d'Asie du Sud-Est ont, très tôt dans leur période post-coloniale, envisagé de se regrouper pour former une organisation régionale : l’Association des nations d’Asie du Sud-Est, dénommée l’ANASE ou, plus communément appelée par son sigle anglais, ASEAN. En nous appuyant sur l’exemple de l’ASEAN, nous aborderons le concept d’intégration régionale économique sous son angle juridique, en cherchant notamment à le distinguer des vocables contigus de régionalisme, régionalisation ou encore de coopération économique. Quelles sont les caractéristiques d'une intégration régionale? Ses manifestations? En dépit de l'hétérogénéité des organisations régionales ayant pour objectif de construire une intégration économique dans une région donnée, quels sont les points communs qu’un juriste peut observer? Comment décrypter l’ASEAN grâce au processus d’intégration économique qu’elle conduit et à la stratégie qu’elle a choisie? Quelles sont ses particularités? Quels défis doit-elle relever pour atteindre ses objectifs d’intégration à travers les trois dimensions communautaires : économique, politico-sécuritaire et socio-culturelle? De quels soutiens externes l’ASEAN peut-elle bénéficier pour renforcer son processus d’intégration régionale ? Le rapprochement entre pays d’Asie du Sud-Est s’appuie sur l’intergouvernementalité et la sauvegarde absolue de la souveraineté de ses Etats membres qui conduisent à privilégier le recours au droit souple plutôt qu’au droit dur dans leur production normative. L’approche adoptée prendra soin de se différencier de celles de l'économiste, du politiste ou du spécialiste des relations internationales et ouvrira sur des points de vue extra-européens. Les spécificités de l’ASEAN et sa dimension interne seront abordées dans un premier temps, tandis que la seconde partie couvrira la dynamique externe de l’intégration économique de l’ASEAN à partir d’un choix sélectif de partenariats (UE, accords de libre-échange, Banque asiatique du développement, APEC). / The countries located in Southeast Asia have, very soon, during the postcolonial period, foreseen to regroup to forming a regional organization named “ASEAN” (Association of nations of Southeast Asia). We would like to address the concept of economic regional integration from a legal perspective based on the example of ASEAN. This will in particular lead us to distinguish such a concept with other terms similar or very closed, such as regionalism, regionalization and economic cooperation. What are the features of regional integration? What are its manifestations? Despite all the diversity of regional organizations the purpose of which is to build an economic integration within a specific region, what are the common features that a lawyer can observe? How to reveal the ASEAN regional organization through the economic integration process it has launched and strategies chosen by it? What are its peculiarities? What are the challenges it has to face to achieve its integration goals through the following three dimensions: the ASEAN Economic Community, the ASEAN Political &Security Community, and the ASEAN Socio-Cultural Community? What external support can ASEAN receive to strengthen its regional integration process? Southeast Asian countries look for a closer proximity between themselves on the basis of intergovernmentality and with the deep concern of recognition and protection of their sovereignty that lead to favor Soft law more than hard law in decision-making production. Our approach will be well differentiated from those adopted so far by the economists and political scientists or experts in international relations and will not be reductive to a Eurocentric viewpoint. The main features and the internal dimension of the ASEAN will be addressed in a first part, while the second part will be devoted to the external dynamic of the economic integration of the ASEAN based on a selective choice of partnerships (EU, free trade agreements, Asian Development Bank, APEC).

In der vorliegenden Arbeit wurde das Colicin V-codierende Plasmid p1ColV5155 des aviär pathogenen E. coli-Stammes (APEC) IMT5155 (O2:K1:H5) weitestgehend sequenzanalysiert und seine virulenzassoziierten Eigenschaften untersucht. Das ~ 180 kb große p1ColV5155 weist mit EitABC, EtsABCD, Salmochelin, SitABCD und Aerobaktin fünf ABC-Transportsysteme auf, deren Bedeutung für die Aufnahme von Eisenionen für die letztgenannten zwei Systeme mit Hilfe von Cosmidklonen (GB5155cD34, GB5155cD27) in einer Enterobaktin-negativen E. coli 1017-Transformante mittels CAS-Assays nachgewiesen werden konnte. Eine signifikante regulatorische Bedeutung von Eisenionen für die Expression plasmidcodierter virulenzassoziierter Faktoren konnte durch beta-Galaktosidase-Expressionsassays in einer IMT5155-Mutante (Iln) für das Serumresistenz steigernde Protein Iss, nicht jedoch für das Temperatursensitive Hämagglutinin (Tsh) nachgewiesen werden. Eine Aktivitätssteigerung beider Promotoren wurde durch eine gute Nährstoffversorgung bei einer Wachstumstemperatur von 37 °C erreicht. Insgesamt lassen die Studienergebnisse darauf rückschließen, dass der Promotor von tsh im Gegensatz zu iss sehr viel schwächer ist und spezifischer reguliert wird. In vivo-Versuche mit einer p1ColV5155-E. coli K12-Transformante (IMTp1D01) hatte weder Morbidität noch Mortalität der infizierten 5 Wochen alten SPF-Hühner zur Folge. Verschiedene in vitro-Versuche ergaben, dass das Plasmid nicht konjugationsfähig und über Generationen sehr stabil in der E. coli K12-Transformante nachzuweisen war. Das Plasmid vermittelte der Transformante eine erhöhte Resistenz beim Wachstum in Hühnerserum sowie eine erhöhte Tenazität in Makrophagen (Maus, J774). Damit weist das ColV-Plasmid eine Reihe genetischer Eigenschaften auf, die den APEC und anderen extraintestinal pathogenen E. coli-Stämmen sowohl eine Steigerung der Fitness in der Umwelt als auch ihre Vermehrung im Blut von Mensch und Tier ermöglichen. / In this study a high molecular weight, colicin V encoding plasmid p1ColV5155 of APEC strain IMT5155 (O2:K1:H5) was nearly complete sequenced and analysed. The most prevalent virulence traits of the ~ 180 kb plasmid are serum resistance (increased serum survival protein, Iss), adhesion (temperature-sensitive hemagglutinin, Tsh) and five different ABC-transport systems (EitABC, EtsABCD, salmochelin, SitABCD and aerobactin), the latter three being acquisition systems for iron. Studies with cosmids (GB5155cD34, GB5155cD27) which possess only sequences of p1ColV5155 salmochelin and aerobactin in an enterobactin-deficient E. coli1017, confirmed their importance for iron acquisition. The importance of iron in the regulation of the assumed virulence associated genes of the ColV-plasmid was tested especially for the promoter activity of iss and tsh. Expression studies in beta-galactosidase mutated strain of IMT5155 (Iln) corroborated the importance of environmental factors including source of sugar and a temperature of 37 °C of both promoter activities. The lack of iron decreases, and growth on serum increased the promoter activity of iss. In contrast the activity of the tsh promoter was much weaker and there was no indication found for iron-depending factors which regulate the promoter in a special way. Results of in vivo assays with a p1ColV5155-transformant of E. coli K12 (IMTp1D01) in five week old SPF-chickens did not result in disease. However, the presence of p1ColV5155 in the E. coli K12-strain was solid and increased the ability of the transformant to avoid destruction by bactericidal effects of macrophages (mouse, J774) and to survive in serum in vitro. In summary the ColV-plasmid seams to increase the fitness of the APEC and other extraintestinal pathogenic E. coli. Multiple iron acquisition and a potent defending system of the host serum help to remain to the environmental and in blood of human and animals alike.

Aviäre pathogene E. coli (APEC) sind extraintestinale Pathogene, die beim Huhn systemische Infektionskrankheiten hervorrufen. Zur Identifizierung Gene, die an der Kolonisierung des Wirtes beteiligt sind, wurde ein Lungen-Infektionsmodell in 5 Wochen alten SPF Hühnern etabliert. In dem Modell wurden 1.800 mittels Signature-tagged-Mutagenese (STM) hergestellten Mutanten des APEC Stamms IMT5155 (O2:K1:H5; ST-Komplex 95) auf ihre Fähigkeit zur Kolonisierung getestet. Die Untersuchung führte zur Identifizierung Gene, einschließlich Adhäsin-, LPS- und Kapsel-bildenden Genen, sowie Genen mit putativer Funktion. Die STM-Analyse erlaubte zudem die Identifizierung eines zuvor nicht charakterisierten putativen Fimbrien-bildenden Adhäsins (Yqi). Das Genprodukt wurde vorläufig als ExPEC Adhäsin I (EA/I) bezeichnet. Eine Deletion des EA/I-Gens führte zu einer Reduzierung der Adhäsionsfähigkeit des Stammes IMT5155 in vitro und in vivo. Eine Komplementierung des EA/I-Gens in trans resultierte in einer Wiederherstellung des Adhäsions¬vermögens in vitro. Das EA/I-Protein (~39 kDa) wurde als Fusionsprotein in vitro exprimiert, und mittels SDS-PAGE und Western Blot nachgewiesen. Durch Überexpression des EA/I-Operons in dem Fimbrien-negativen E. coli-Stamm AAEC189 konnten mittels elektronenmikroskopischer Aufnahmen Fimbrien-bildende Strukturen auf der äußeren Membran dargestellt werden. Das Vorkommen des yqi in den untersuchten extraintestinal pathogenen E. coli (ExPEC), bei gleichzeitigem Fehlen in allen untersuchten intestinal pathogenen E. coli bestätigt die Bezeichnung ExPEC Adhäsin I. Die Prävalenz des EA/I-Gens war am stärksten assoziiert mit Stämmen der B2-Phylogenetische-Gruppe und des ST95-Komplexes des Multi-Lokus-Sequenz-Typisierungs (MLST)-Schemas. Sequenzanalysen ergaben zudem erste Hinweise auf eine positive Selektion des EA/I-Gens innerhalb dieses Komplexes. In der vorliegenden Arbeit gelang somit die Identifizierung und Charakterisierung des neuen ExPEC Adhäsin I. / The extraintestinal pathogen, avian pathogenic E. coli (APEC), known to cause systemic infections in chickens, is responsible for large economic losses in the poultry industry. To identify genes, involved adhesion and colonization, a lung colonization model of infection was established in 5-week old specific-pathogen free (SPF) chickens, and Signature-tagged mutagenesis (STM) was applied to this model by generating and screening a total of 1,800 mutants of an APEC strain IMT5155 (O2:K1:H5; ST complex 95). This led to the identification of new genes of interest, including adhesins, genes involved in capsule and LPS formation, and genes of putative function. Among the many genes identified was one coding for a novel APEC fimbrial adhesin (Yqi) not described for its role in APEC pathogenesis. Its gene product was temporarily designated ExPEC Adhesin I (EA/I). Deletion of the ExPEC adhesin I gene resulted in reduced colonization ability by APEC strain IMT5155 both in vitro and in vivo. Complementation of the adhesin gene restored its ability to colonize epithelial cells in vitro. The ExPEC adhesin I protein (~ 39 kDa) was expressed as a fusion protein in vitro as shown by SDS-PAGE and western blotting. Electron microscopy of an afimbriate strain E. coli AAEC189 over-expressed with the putative EA/I gene cluster revealed short fimbrial like appendages protruding out of the bacterial outer membrane. We observed that the adhesin coding gene yqi is prevalent among extraintestinal pathogenic E. coli (ExPEC) isolates and absent in all of the intestinal pathogenic E. coli strains tested, thereby validating the designation of the adhesin as ExPEC Adhesin I. In addition, prevalence of EA/I was most frequently associated with the E. coli phylogenetic group B2 and ST95 complex of the multi locus sequence typing (MLST) scheme, with evidence of a positive selection within this complex. This is the first report of the newly identified and functionally characterized ExPEC adhesin I.

中共從建政初期至冷戰期間，與國際組織接觸甚少，參與有限；改革開放後，特別是冷戰結束以來，中共參與國際組織步伐和範圍持續加速、擴大，且因其地處亞洲並自視為區域大國，亦逐步在亞太地區等周邊的國際組織或制度中，扮演建設性參與者乃至主導者的角色。從中共與國際組織的互動重心，由建政初期的尋求身分承認、維護主權與安全，到改革開放時期促進經濟發展利益，乃至冷戰結束迄今承擔「大國責任」，形塑負責任形象，並倡導建立和諧地區、和諧世界等演變軌跡顯示，中共自身發展的變化與需求，是其開展與國際組織互動關係最直接、最主要的影響因素與驅動力量；然在此互動過程中，國際組織的制度與規範亦逐漸改變中共對國家身分與利益的認知，並成為其內外政策調整的重要動力。對中共而言，伴隨國家實力、地位持續提升及利益範圍的擴大，未來如何在複雜多樣的國際組織與相關制度中，權衡本國利益與國際責任，維持在權力、利益和規範之間的平衡，根據自身發展需要注意對三者的取捨，將是中共持續面臨的課題。

Inflammatory bowel disease (IBD), comprises Crohn’s disease (CD) and ulcerative colitis (UC), and is a chronic relapsing inflammation of gastrointestinal tract without any known cause or cure. Currently, it is accepted that IBD is a result of a dysfunctional immune response to commensal bacteria in a genetically susceptible host, and that environmental factors can trigger the onset or reactivation of the disease. This thesis considers the possibility of a specific pathogenic agent as well as an imbalance in the composition of the normal microflora in the pathogenesis of IBD. Gut biopsy tissues were taken from a population-based case-control tissue bank held at the University of Manitoba. Automated ribosomal intergenic spacer analysis (ARISA) and terminal restriction fragment length polymorphisms (T-RFLP) were employed to assess the diversity of gut microbiota. The phylogenetic, virulence and biochemical characteristics of Escherichia coli isolated from IBD biopsies were examined using multi-locus sequence typing (MLST), DNA microarray technology and API 20E system. Utilizing ARISA and T-RFLP, a remarkable increase in the order of unclassified Clostridia was detected in inflamed tissues, particularly in CD patients (P < 0.05). Moreover, species richness and diversity were the highest in non-inflamed IBD biopsies. Culture-based quantification detected a significantly higher number of E. coli in IBD tissues (P < 0.05). Phylogenetic analysis revealed the tendency of E. coli isolated from IBD patients to be grouped into separate clonal clusters based on their allelic profiles (P = 0.02). A link was detected between uropathogenic E. coli (UPEC) CFT073 and strains isolated from IBD, with regards to gene distribution and virulence, using microarray technology. Amino acid substitutions N91S and S99N in FimH, the adhesive subunit of E. coli type I fimbria, were significantly associated to IBD (P < 0.05). This study demonstrated an increase in the microbial diversity of non-inflamed IBD tissues and suggested a recruitment phase of bacterial adherence and colonization, before the inflammation sets in. Furthermore, E. coli isolated from IBD tissues were distinct from commensal strains in both clonal and virulence characteristics and shared remarkable traits with extraintestinal pathogenic E. coli. Features involved in bacterial adhesion to epithelial cells may hold the key to E. coli pathogenesis in IBD.

Inflammatory bowel disease (IBD), comprises Crohn’s disease (CD) and ulcerative colitis (UC), and is a chronic relapsing inflammation of gastrointestinal tract without any known cause or cure. Currently, it is accepted that IBD is a result of a dysfunctional immune response to commensal bacteria in a genetically susceptible host, and that environmental factors can trigger the onset or reactivation of the disease. This thesis considers the possibility of a specific pathogenic agent as well as an imbalance in the composition of the normal microflora in the pathogenesis of IBD. Gut biopsy tissues were taken from a population-based case-control tissue bank held at the University of Manitoba. Automated ribosomal intergenic spacer analysis (ARISA) and terminal restriction fragment length polymorphisms (T-RFLP) were employed to assess the diversity of gut microbiota. The phylogenetic, virulence and biochemical characteristics of Escherichia coli isolated from IBD biopsies were examined using multi-locus sequence typing (MLST), DNA microarray technology and API 20E system. Utilizing ARISA and T-RFLP, a remarkable increase in the order of unclassified Clostridia was detected in inflamed tissues, particularly in CD patients (P < 0.05). Moreover, species richness and diversity were the highest in non-inflamed IBD biopsies. Culture-based quantification detected a significantly higher number of E. coli in IBD tissues (P < 0.05). Phylogenetic analysis revealed the tendency of E. coli isolated from IBD patients to be grouped into separate clonal clusters based on their allelic profiles (P = 0.02). A link was detected between uropathogenic E. coli (UPEC) CFT073 and strains isolated from IBD, with regards to gene distribution and virulence, using microarray technology. Amino acid substitutions N91S and S99N in FimH, the adhesive subunit of E. coli type I fimbria, were significantly associated to IBD (P < 0.05). This study demonstrated an increase in the microbial diversity of non-inflamed IBD tissues and suggested a recruitment phase of bacterial adherence and colonization, before the inflammation sets in. Furthermore, E. coli isolated from IBD tissues were distinct from commensal strains in both clonal and virulence characteristics and shared remarkable traits with extraintestinal pathogenic E. coli. Features involved in bacterial adhesion to epithelial cells may hold the key to E. coli pathogenesis in IBD.

Escherichia coli patogênica aviária (APEC) é a causa de doenças extra-intestinais em aves, que se manifestam na forma de doenças localizadas ou infecções sistêmicas, gerando grandes perdas econômicas para a indústria aviária. O objetivo desse trabalho foi estudar isolados de APEC do sul do Brasil em relação à resistência a agentes antimicrobianos; a prevalência de fatores associados à virulência; a tipagem filogenética e o perfil filogenético. Na avicultura, os agentes antimicrobianos são muito utilizados na prevenção de infecções e na forma de promotores de crescimento. Foram utilizadas 41 isolados de E. coli obtidos de infecções sistêmicas e 144 isolados de celulite, utilizando o método de difusão com discos. Isolados APEC apresentaram baixos níveis de resistência, com excessão da tetraciclina e das sulfonamidas; e para isolados de colissepticemia, também foi observado uma resistência aos antimicrobianos que atuam na parede celular (ampicilina, cefalotina, bacitracina e ceftiofur). Vários fatores de virulência têm sido investigados em cepas APEC, os que têm sido mais frequentemente associados com a patogenicidade são as fímbrias de aderência F1 e Tsh (hemaglutinina sensível à temperatura); o sistema sideróforo aerobactina, a proteína iss (increased serum survival), a cápsula K e a produção de colicina V. Foram realizadas reações da polimerase em cadeia multiplex (PCR), testando um total de 33 fatores nos isolados APEC. Os fatores relacionados a adesão, sideróforos e resistência ao soro foram presentes em todas as amostras. Os fatores que apresentaram maior prevalência nas amostras foram, fimC, ompA, crlA e traT. A tipagem filogenética foi realizada através do método descrito por Clermont et al., (2000), que permite separar os isolados em 4 grupos filogenéticos principais (A, B1, B2 e D). Observamos a maior presença de isolados APEC pertencentes ao grupo D, tanto para celulite quanto para colissepticemia. A análise do perfil filogenético foi realizada pelo método ARDRA, que é baseado na variação da região do espaçamento intergênico (ISR) na região 16S-23S do DNA ribossômico. Os resultados foram analisados formando um dendrograma que mostra a proximidade filogenética dos isolados, indicando que não foi possível separar os clones de celulite dos de colissepticemia e não existem clones endêmicos nas regiões analisadas. Os resultados obtidos no presente estudo, fornecem um panorama geral da resistência aos agentes antimicrobianos, prevalência dos fatores de virulência, tipagem filogenética e perfil filogenético encontrados nos isolados de E. coli aviária do sul do Brasil de infecções de colissepticemia e celulite. / extra-intestinal infections in poultry, called colibacilose, and cause great economic losses to the poultry industry. The aim of this work was to examine APEC strains, isolated from avian cellulitis and colisepticemic chickens from South Brazil, for antibiotic resistance, presence of virulence-associated genes (VAGs), phylogenetic typing and phylogenetic analyses. In poultry, antibiotics are routinely used to prevent infection and promote growth. We analyzed the susceptibility to 15 antibiotics in 144 E. coli isolates collected from cellulitis lesions and in 41 isolates from septicemic chickens. APEC isolates have shown low levels of resistance excepting tetracycline and sulphonamides, and colisepticemic isolates were resistant to antibiotics that act in the cell wall, such as ampicilin, cephalotin, ceftiofur and bacitracin. The virulence factors most frequently associated with APEC pathogenicity are the adhesins F1 and Tsh (Temperature sensitive hemagglutinin), the iron acquisition system aerobactin, the protein Iss (increased serum survival), K1 capsule and production of colicin V. To investigate the presence of VAGs in the isolates, we performed multiplex polymerase chain reactions to test 33 virulence factors. Virulence factors related to adhesion, iron acquisition and serum resistance were present in almost all strains. The factors fimC, ompA, crlA and traT were the most frequent in APEC isolates. The phylogenetic typing were done using the Clermont et al. (2000) method, which classifies E. coli strains into four main phylogenetic groups (A, B1, B2, and D). Our phylogenetic typing has shown that cellulitis and colisseptisemic isolates were more related to group D. Amplified ribossomal restriction analysis (ARDRA) was performed in colissepticemic and celullitis isolates from broiler chickens from Southern Brasil. The similarity among isolates were observed with a dendrogram based on the band pattern. Our results have shown that clones of celullitis and colissepticemic isolates could not be distinguished and there is no endemic clones in regions observed analised. The results of the present work give us a panorama of the susceptibility to antibiotics, virulence factors, phylogenetic typing and phylogenetic analyses currently found in APEC isolates from severe lesions of cellulites and colibacillosis in south Brazil. Besides that, these analyses could be helpful for monitoring and preventing outbreakes of colibacilosis. Controling the first stages of the disease and detecting more prevalent clones in this region may reduce the incidence of the disease.