Resultado da pesquisa (34)

Termo utilizado na pesquisa virulence

#21 - Phenotypic and genotypic analysis of virulence in Staphylococcus spp. and its clonal dispersion as a contribution to the study of bovine mastitis, 33(2):161-170

Abstract in English:

ABSTRACT.- Marques V.F., Souza M.M.S., Mendonça E.C.L., Alencar T.A., Pribul B.R., Coelho S.M.O., Lasagno M. & Reinoso E. 2013. [Phenotypic and genotypic analysis of virulence in Staphylococcus spp. and its clonal dispersion as a contribution to the study of bovine mastitis.] Análise fenotípica e genotípica da virulência de Staphylococcus spp. e de sua dispersão clonal como contribuição ao estudo da mastite bovina. Pesquisa Veterinária Brasileira 33(2):161-170. Departamento de Microbiologia e Imunologia Veterinária, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ 23890-000, Brazil. E-mail: miliane@ufrrj.br Mastitis is an inflammation of one or more mammary glands caused mainly by bacteria, among which the genus Staphylococcus plays an important role. Bacteria belonging to this genus are known to express virulence factors which allow their persistence and spread in the host. This study aimed to evaluate the phenotypic and genotypic aspects of virulence factors in Staphylococci spp. isolates from bovine mastitis clinical cases. A total of 272 milk samples from 8 farms in the South-Fluminense region of Rio de Janeiro were analyzed. The samples underwent conventional bacterial identification, yielding 250 Staphylococci spp. isolates. These were tested for the phenotypic detection of slime production by the microplate and Congo Red Agar methods. The hemolysins production, hemolytic synergism, caseinase and DNase production were also evaluated. The isolates were then assayed through the Polymerase Chain Reaction method to detect genes associated with virulence factors such as: capsule (cap5, cap8), fibronectin (fnbA, fnbB), slime (icaA, icaD) and hemolysins (hla e hlb). Regarding the number of isolates assessed, 58% (145/250) were identified as coagulase-negative Staphylococcus spp. and 42% (105/250) as coagulase-positive Staphylococcus spp. The latter comprised 36.2% (38/105) of isolates identified as S. aureus, 11.4% (12/105) as S. intermedius and 3.8% (4/105) belonging to the SIG group. The hemolisin production was not significant, whereas only 6,4% (16/250) produced alfa hemolysis, 4,8% (12/250) produced beta hemolysis and 1,6% (4/250) was able to produce both. Caseinase production was observed in 66.4% (166/250) and slime production assayed through the microplate method was positive in 76,8% (192/250). DNAse was detected in coagulase-negative Staphylococcus spp. (38/145) and in S. aureus (14/38). Low association between genetic detection of icaA (38/250) and icaD (54/250) and slime phenotypic expression (192/250) suggest that others genetic markers can be involved in this expression. Regarding gene amplification, the isolates did not show significant correlation between the genetic detection of icaA (38/250) and icaD (54/250) and slime production (192/250), indicating that other genetic markers may be involved in this trait expression. The frequency of the occurrence of the others studied genes was of 4% (10/250) for cap5 and cap8, 32,8% (82/250) for fnbA, 4,4% (11/250) for fnbB, 19,2% (48/250) for hla and 18% (45/250) for hlb. The major circulating strain profile on the farms encompassed slime and caseinase producer strains. The spaA gene was found in all of the S. aureus isolates, presenting varying amplicons sizes, with 300bp being the prevalent size. The amplification of the coa gene showed nine polymorphic variants, with 600bp being the prevalent amplicon. The agr gene was also detected in every S. aureus isolate, with an amplicon of 200bp. It was noticed that the presence or absence of the virulence genes assayed in this study were not correlated with the 6 distinct electrophoretic profiles obtained by PFGE.

Abstract in Portuguese:

RESUMO.- Marques V.F., Souza M.M.S., Mendonça E.C.L., Alencar T.A., Pribul B.R., Coelho S.M.O., Lasagno M. & Reinoso E. 2013. [Phenotypic and genotypic analysis of virulence in Staphylococcus spp. and its clonal dispersion as a contribution to the study of bovine mastitis.] Análise fenotípica e genotípica da virulência de Staphylococcus spp. e de sua dispersão clonal como contribuição ao estudo da mastite bovina. Pesquisa Veterinária Brasileira 33(2):161-170. Departamento de Microbiologia e Imunologia Veterinária, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ 23890-000, Brazil. E-mail: miliane@ufrrj.br A mastite é uma inflamação da glândula mamária causada principalmente por bactérias, dentre as quais o gênero Staphylococcus ocupa um papel importante. Bactérias pertencentes a este gênero são caracterizadas por expressar fatores de virulência que permitem sua persistência e disseminação no hospedeiro. O presente trabalho teve por objetivo avaliar fenogenotipicamente os fatores de virulência de isolados de Staphylococcus spp. a partir de casos de mastite bovina. Foram analisadas 272 amostras de leite provenientes de oito propriedades da região Sul-Fluminense do Estado do Rio de Janeiro. Após identificação, obteve-se um total de 250 isolados de Staphylococcus spp. Estes foram submetidos às provas fenotípicas de detecção da produção de “slime” em microplaca e em ágar vermelho congo; produção de hemolisinas e sinergismo hemolítico; produção de caseinase e DNase. Posteriormente foram submetidos à técnica de PCR para detecção dos genes de produção de cápsula (cap5 e cap8), fibronectina (fnbA,e fnbB), “slime” (icaA e icaD) e hemolisinas (hla e hlb). Do total avaliado, 58% (145/250) foi identificado como Staphylococcus spp. coagulase-negativos e 42% (105/250) como Staphylococcus spp. coagulase-positivos, destes 36,2% (38/105) foram identificados como S. aureus, 11,4% (12/105) como S. intermedius e 3,8% (4/105) como pertencentes ao grupo SIG. Apenas 6,4% (16/250) dos isolados foram produtores de a-hemólise, 4,8% (12/250) de b-hemólise e, 1,6% (4/250) de a e b-hemólise. A produção de caseinase foi observada em 66,4% (166/250), e a produção de “slime” avaliada pela técnica da microplaca em 76,8% (192/250) dos isolados, respectivamente. A DNase foi detectada em ECNs (38/145) e S. aureus (14/38). Os marcadores genéticos avaliados para a produção de slime, icaA e icaD apresentaram nenhuma ou leve concordância com a produção fenotípica, respectivamente, utilizando o coeficiente Kappa. Tal dado parece indicar que outros marcadores genéticos podem estar envolvidos com a expressão desta característica. Os demais genes detectados com frequência de 4% (10/250) para cap5 e para cap8, 32,8% (82/250) para fnbA, 4,4% (11/250) para fnbB, 19,2% (48/250) para hla e 18% (45/250) para hlb. O perfil circulante nas propriedades foi o 1: isolado produtor de “slime” e caseinase. O gene spaA foi positivo em todos os S. aureus, apresentando amplicons de tamanhos variados, sendo o tamanho prevalente o de 300pb. A amplificação do gene coa apresentou nove tipos polimórficos distintos, sendo prevalente o amplicon de 600pb. O gene agr foi detectado em todos os S. aureus, com amplicon de 200pb. Foi observado que os genes de virulência estudados estavam distribuídos de modo aleatório entreos 6 distintos perfis eletroforéticos obtidos através da Eletroforese em Gel de Campo Pulsado (PFGE).


#22 - Detection of virulence-associated genes of Pasteurella multocida isolated from cases of fowl cholera by multiplex-PCR, 33(2):177-182

Abstract in English:

ABSTRACT.- Furian T.Q., Borges K.A., Rocha S.L.S., Rodrigues E.E., Nascimento V.P., Salle C.T.P. & Moraes H.L.S. 2013. Detection of virulence-associated genes of Pasteurella multocida isolated from cases of fowl cholera by multiplex-PCR. Pesquisa Veterinária Brasileira 33(2):177-182. Centro de Diagnóstico e Pesquisa em Patologia Aviária, Faculdade de Medicina Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 8824, Porto Alegre, RS 91540-000, Brazil. E-mail: thales.furian@ufrgs.br The current systems of breeding poultry, based on high population density, increase the risk of spreading pathogens, especially those causing respiratory diseases and those that have more than one host. Fowl Cholera (FC) is one such pathogen, and even though it represents one of several avian diseases that should be considered in the differential diagnosis of notifiable diseases that present with sudden death, the pathogenesis and virulence factors involved in FC are still poorly understood. The objective of this study was to investigate twelve genes related to virulence in 25 samples of Pasteurella multocida isolated from FC cases in the southern region of Brazil through the development of multiplex PCR protocols. The protocols developed were capable of detecting all of the proposed genes. The ompH, oma87, sodC, hgbA, hgbB, exBD-tonB and nanB genes were present in 100% of the samples (25/25), the sodA and nanH genes were present in 96% (24/25), ptfA was present in 92% (23/25), and pfhA was present in 60% (15/25). Gene toxA was not identified in any of the samples studied (0/25). Five different genetic profiles were obtained, of which P1 (negative to toxA) was the most common. We concluded that the multiplex-PCR protocols could be useful tools for rapid and simultaneous detection of virulence genes. Despite the high frequency of the analyzed genes and the fact that all samples belonged to the same subspecies of P. multocida, five genetic profiles were observed, which should be confirmed in a study with a larger number of samples.

Abstract in Portuguese:

RESUMO.- Furian T.Q., Borges K.A., Rocha S.L.S., Rodrigues E.E., Nascimento V.P., Salle C.T.P. & Moraes H.L.S. 2013. Detection of virulence-associated genes of Pasteurella multocida isolated from cases of fowl cholera by multiplex-PCR. [Pesquisa de genes associados à virulência em cepas de Pasteurella multocida isoladas em casos de cólera aviária através da técnica de multiplex-PCR.] Pesquisa Veterinária Brasileira 33(2):177-182. Centro de Diagnóstico e Pesquisa em Patologia Aviária, Faculdade de Medicina Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 8824, Porto Alegre, RS 91540-000, Brazil. E-mail: thales.furian@ufrgs.br Os atuais sistemas de criação na avicultura, baseados na alta densidade populacional, aumentam os riscos de disseminação de patógenos, especialmente das doenças respiratórias e daquelas cujos agentes etiológicos possuam mais de um hospedeiro. A Cólera Aviária (CA) apresenta estas características e apesar de representar uma das patologias aviárias que deve ser considerada para o diagnóstico diferencial de enfermidades com notificação obrigatória que cursam com morte súbita, a patogenia e os fatores de virulência envolvidos na CA ainda estão pouco elucidados. O objetivo deste trabalho foi pesquisar doze genes associados à virulência em 25 amostras de Pasteurella multocida isoladas de casos de CA na região sul do Brasil através do desenvolvimento de protocolos de multiplex-PCR. Os protocolos de multiplex-PCR desenvolvidos foram capazes de detectar todos os genes propostos. Os genes ompH, oma87, sodC, hgbA, hgbB, exBD-tonB, nanB estiveram presentes em 100% das amostras (25/25). Os genes sodA e nanH em 96% (24/25), o gene ptfA em 92% (23/25) e o gene pfhA em 60% (15/25). O gene toxA não foi identificado em nenhuma das amostras pesquisadas (0/25). Foram obtidos cinco diferentes perfis genéticos, sendo P1 (negativo para o gene toxA) o mais comum. Com este trabalho, concluiu-se que os protocolos de multiplex-PCR desenvolvidos tornam-se uma ferramenta bastante útil e rápida para a detecção simultânea dos genes de virulência. Apesar da alta frequência dos genes estudados e de todas as amostras pertencerem à mesma subespécie de P. multocida, foram observados cinco perfis genéticos, os quais devem ser confirmados em um estudo com um maior número de amostras.


#23 - Detection of virulence factors in Escherichia coli and analysis of Salmonella spp. in psittacines, 33(2):241-246

Abstract in English:

ABSTRACT.- Corrêa I.M.O, Flores F., Schneiders G.H., Pereira L.Q., Brito B.G. & Lovato M. 2013. [Detection of virulence factors in Escherichia coli and analysis of Salmonella spp. in psittacines.] Detecção de fatores de virulência de Escherichia coli e análise de Salmonella spp. em psitacídeos. Pesquisa Veterinária Brasileira 33(2):241-246. Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria, Av. Roraima 1000, Santa Maria, RS 97105-900, Brazil. E-mail: maristelalovato@gmail.com The enteric flora of psittacines is mainly composed of Gram positive bacteria. Gram negative bacteria, like Escherichia coli and Salmonella spp., have a high pathogenic potential and can be considerate as an indicative of management problems that may culminate in disease manifestation due to stress factors, poor diets and overcrowding, in combination with a high bacterial load on the environment. The objective of this study was evaluated the presence of Salmonella spp., Escherichia coli and the virulence genes iss and iutA from E. coli isolates. Forty-four samples were analyzed from psittacines living in captivity, which fifteen samples were from organs fragments of necropsied birds, and twenty-nine were from cloacal and crop swabs of red-spectacled parrots (Amazona pretrei) keeping in captivity. No samples were positive for Salmonella spp. In the samples in which E. coli was detected, both virulence factors (genes iss and iutA) were present.

Abstract in Portuguese:

RESUMO.- Corrêa I.M.O, Flores F., Schneiders G.H., Pereira L.Q., Brito B.G. & Lovato M. 2013. [Detection of virulence factors in Escherichia coli and analysis of Salmonella spp. in psittacines.] Detecção de fatores de virulência de Escherichia coli e análise de Salmonella spp. em psitacídeos. Pesquisa Veterinária Brasileira 33(2):241-246. Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria, Av. Roraima 1000, Santa Maria, RS 97105-900, Brazil. E-mail: maristelalovato@gmail.com A flora entérica dos psitacídeos é composta principalmente por bactérias Gram positivas. Bactérias Gram negativas, como Escherichia coli e Salmonella spp., apresentam elevado potencial patogênico, sendo consideradas indicativo de problemas de manejo, que poderão culminar em manifestação de doenças em decorrência de fatores estressantes, dietas deficientes e superlotação, combinados com alta carga bacteriana no ambiente. O objetivo deste trabalho foi avaliar a presença de Salmonella spp., Escherichia coli e os fatores de virulência dos genes iss e iutA dos isolados de E. coli. Analisou-se um total de 44 amostras provenientes de psitacídeos criados em cativeiro, sendo estas 15 fragmentos de órgãos de aves submetidas a exame de necropsia e também 29 amostras de swabs de cloaca e inglúvio de papagaios-charão (Amazona pretrei) criados em cativeiro. Nenhuma amostra foi positiva para Salmonella spp. Nas amostras de E. coli detectou-se ambos os fatores de virulência pesquisados.


#24 - Molecular characterization of virulence factors in Aeromonas hydrophila obtained from fish, 32(8):701-706

Abstract in English:

ABSTRACT.- Oliveira S.T.L., Veneroni-Gouveia G. & Costa M.M. 2012. Molecular characterization of virulence factors in Aeromonas hydrophila obtained from fish. Pesquisa Veterinária Brasileira 32(8):701-706. Laboratório de Microbiologia e Imunologia Animal, Universidade Federal do Vale do São Francisco, Campus Ciências Agrárias, Colegiado Acadêmico de Zootecnia, Rodovia BR 407 Km 12, Lote 543, Projeto de Irrigação Nilo Coelho s/n, C1, Petrolina, PE 56300-000, Brazil. E-mail: mateus.costa@univasf.edu.br Multiple factors can be involved in the virulence processes of Aeromonas hydrophila. The objective of the present paper was to verify the presence of aerolysin, hidrolipase, elastase and lipase virulence genes through the polymerase chain reaction (PCR) in A. hydrophila isolates obtained from fish of the São Francisco River Valley, and to evaluate virulence according to the presence of these genes in Nile tilapia fingerlings. One hundred and fourteen isolates from the bacteria were used. DNA was heat extracted and PCR undertaken using specific primers described in the literature. For in vivo tests Nile tilapia fingerlings were used. From the PCR tests, negative isolates for all genes tested were selected, positive isolates for two genes (aerolysin and elastase) and positive for the four genes tested. These were inoculated at a concentration of 108 UFC/ml into the tilapias, considered as treatments; another group of animals was used as control (with inoculation of saline solution). In all, 12 distinct standards regarding the presence of virulence factors in isolates from A. hydrophila, were observed. Of the 114 isolates analyzed, 100 (87.72%) presented at least one of the virulence factors under study. The virulence factors were widely distributed among the A. hydrophila isolates. Aerolysin was the most frequent virulence factor present in the isolates analyzed. A. hydrophila led to the mortality of the Nile tilapia fingerlings, regardless of the absence or quantity of virulence genes tested.

Abstract in Portuguese:

RESUMO.- Oliveira S.T.L., Veneroni-Gouveia G. & Costa M.M. 2012. Molecular characterization of virulence factors in Aeromonas hydrophila obtained from fish. Pesquisa Veterinária Brasileira 32(8):701-706. Laboratório de Microbiologia e Imunologia Animal, Universidade Federal do Vale do São Francisco, Campus Ciências Agrárias, Colegiado Acadêmico de Zootecnia, Rodovia BR 407 Km 12, Lote 543, Projeto de Irrigação Nilo Coelho s/n, C1, Petrolina, PE 56300-000, Brazil. E-mail: mateus.costa@univasf.edu.br Múltiplos fatores podem estar envolvidos nos processos de virulência de Aeromonas hydrophila. O objetivo do presente trabalho foi verificar a presença dos genes de virulência aerolisina, hidrolipase, elastase e lipase, utilizando a reação em cadeia da polimerase (PCR), em isolados de Aeromonas hydrophila obtidos de peixes do Vale do São Francisco e, avaliar sua virulência de acordo com a presença desses genes de virulência em alevinos de tilápia do Nilo. Cento e quatorze isolados foram utilizados. O DNA foi termoextraído e a PCR realizada com a utilização de inciadores específicos descritos pela literatura. Para os testes in vivo alevinos de tilápia do Nilo foram utilizados. Segundo os resultados da PCR, foram selecionados isolados negativos para todos os genes de virulência testados, isolados positivos para dois genes de virulência, (aerolisina e elastase) e positivos para os quatro genes avaliados. Esses isolados foram inoculados na concentração de 108 UFC/ml nos alevinos e foram considerados como tratamentos e, um outro grupo de animais foi utilizado como grupo controle (com inoculação de solução salina). Ao final, 12 padrões distintos, em relação a presença dos fatores de virulência nos isolados de A. Hydrophila, foram observados. Dentre os 114 isolados analisados, 100 (87,72%) apresentaram pelo menos um dos genes de virulência sob estudo. Os fatores de virulência foram amplamente distribuídos entre os isolados de A. hydrophila. A aerolisina foi o fator de virulência mais frequente nos isolados analisados. A. hydrophila levou à mortalidade dos alevinos de tilápia do Nilo, independente da ausência ou quantidade de genes de virulência testados.


#25 - Serogroups and virulence genes of Escherichia coli isolated from psittacine birds, 31(10):916-921

Abstract in English:

ABSTRACT.- Knöbl T., Saidenberg A.B.S., Moreno A.M., Gomes T.A.T., Vieira M.A.M., Leite D.S., Blanco J.E. & Ferreira A.J.P. 2011. Serogroups and virulence genes of Escherichia coli isolated from psittacine birds. Pesquisa Veterinária Brasileira 31(10):916-921. Faculdade de Medicina Veterinária do Complexo Educacional FMU, Av. Santo Amaro 1239, São Paulo, SP 04505 002, Brazil. E-mail: tknobl@usp.br Escherichia coli isolates from 24 sick psittacine birds were serogrouped and investigated for the presence of genes encoding the following virulence factors: attaching and effacing (eae), enteropathogenic E. coli EAF plasmid (EAF), pili associated with pyelonephritis (pap), S fimbriae (sfa), afimbrial adhesin (afa), capsule K1 (neu), curli (crl, csgA), temperature-sensitive hemagglutinin (tsh), enteroaggregative heat-stable enterotoxin-1 (astA), heat-stable enterotoxin -1 heat labile (LT) and heat stable (STa and STb) enterotoxins, Shiga-like toxins (stx1 and stx2), cytotoxic necrotizing factor 1 (cnf1), haemolysin (hly), aerobactin production (iuc) and serum resistance (iss). The results showed that the isolates belonged to 12 serogroups: O7; O15; O21; O23; O54; O64; O76; O84; O88; O128; O152 and O166. The virulence genes found were: crl in all isolates, pap in 10 isolates, iss in seven isolates, csgA in five isolates, iuc and tsh in three isolates and eae in two isolates. The combination of virulence genes revealed 11 different genotypic patterns. All strains were negative for genes encoding for EAF, EAEC, K1, sfa, afa, hly, cnf, LT, STa, STb, stx1 and stx2. Our findings showed that some E. coli isolated from psittacine birds present the same virulence factors as avian pathogenic E. coli (APEC), uropathogenic E. coli (UPEC) and Enteropathogenic E. coli (EPEC) pathotypes.

Abstract in Portuguese:

RESUMO.- Knöbl T., Saidenberg A.B.S., Moreno A.M., Gomes T.A.T., Vieira M.A.M., Leite D.S., Blanco J.E. & Ferreira A.J.P. 2011. Serogroups and virulence genes of Escherichia coli isolated from psittacine birds. [Sorogrupos e genes de virulência em Escherichia coli isoladas de psitacídeos.] Pesquisa Veterinária Brasileira 31(10):916-921. Faculdade de Medicina Veterinária do Complexo Educacional FMU, Av. Santo Amaro 1239, São Paulo, SP 04505 002, Brazil. E-mail: tknobl@usp.br Amostras de Escherichia coli isoladas de 24 psitacídeos doentes foram sorogrupadas e investigadas para a presença de genes que codificam os seguintes fatores de virulência: attaching e effacing (eae), plasmídeo EAF (EAF), pili associado à pielonefrite (pap), fímbria S (sfa), adesina afimbrial (afa), cápsula K1 (neu), curli (crl, csgA), hemaglutinina termosensível (tsh), enterotoxina termo-estável 1 de E. coli enteroagregativa (astA), toxina termolábil (LT) e toxina termoestável (STa e STb), Shiga-like toxinas (stx1 e stx2), fator citotóxico necrotizante 1 (cnf1), hemolisina (hly), produção de aerobactina (iuc) e resistência sérica (iss). Os resultados mostraram que os isolados pertenciam a 12 sorogrupos: O7; O15; O21; O23; O54; O64; O76; O84; O88; O128; O152 e O166. Os genes de virulência encontrados foram: crl em todos os isolados, pap em 10 isolados, iss em sete isolados, csgA em cinco isolados, iuc e tsh em três isolados e eae em dois isolados. A combinação dos genes de virulência revelou 11 perfis genotípicos distintos. Todas as amostras foram negativas para os genes que codificam EAF, EAEC, K1, sfa, afa, hly, cnf, LT, STa, STb, stx1 e stx2. Estes resultados demonstraram que algumas amostras de E. coli isoladas de psitacídeos apresentam os mesmos fatores de virulência presentes nos patotipos de E. coli patogênicas para aves (APEC), uropatogênicas (UPEC) e E. coli enteropatogênicas (EPEC).


#26 - Virulence factors of avian pathogenic Escherichia coli (APEC), p.479-486

Abstract in English:

ABSTRACT.- Nakazato G., Campos T.A., Stehling E.G., Brocchi M. & Silveira W.D. 2009. Virulence factors of avian pathogenic Escherichia coli (APEC). Pesquisa Veterinária Brasileira 29(7):479-486. Departamento de Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Cidade Universitária Zeferino Vaz s/n, Cx. Postal 6109, Barão Geraldo, Campinas, SP 13081-862, Brazil. E-mail: wds@unicamp.br Avian pathogenic Escherichia coli (APEC) strains cause a great diversity of diseases in birds and are responsible for great economic losses in the avian industry. To date, several studies have been carried out to better understand the APEC pathogenesis for a possible development of tools which could prevent the economics losses caused by these strains. This review discusses the virulence factors described do date to be expressed by these strains and the advances made to understand and identify virulence determinants present in APEC.

Abstract in Portuguese:

RESUMO.- Nakazato G., Campos T.A., Stehling E.G., Brocchi M. & Silveira W.D. 2009. Virulence factors of avian pathogenic Escherichia coli (APEC). [Fatores de virulência de Escherichia coli aviária patogênica (APEC).] Pesquisa Veterinária Brasileira 29(7):479-486. Departamento de Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Cidade Universitária Zeferino Vaz s/n, Cx. Postal 6109, Barão Geraldo, Campinas, SP 13081-862, Brazil. E-mail: wds@unicamp.br Linhagens de Escherichia coli patogênicas para aves (APEC) causam uma grande diversidade de doenças em aves e são responsáveis por grandes prejuízos na indústria aviária. Nos últimos anos, vários estudos foram realizados para melhor entender a patogênese de linhagens APEC e para desenvolver ferramentas que podem prevenir as perdas econômicas causadas por estas linhagens. Esta revisão discute os fatores de virulência descritos nestas linhagens e os avanços realizados para entender e identificar os determinantes de virulência presentes em APEC.


#27 - Virulence factors and antimicrobial resistance in Staphylo-coccus aureus isolated from bovine mastitis in Rio de Janeiro, p.369-374

Abstract in English:

ABSTRACT.- Coelho S.M.O., Reinoso E., Pereira I.A., Soares L.C., Demo M., Bogni C & Souza M.M.S. 2009. Virulence factors and antimicrobial resistance in Staphylo-coccus aureus isolated from bovine mastitis in Rio de Janeiro. Pesquisa Veterinária Brasileira 29(5):369-374. Departamento de Microbiologia e Imunologia Veterinária, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ 23890-000, Brazil. E-mail: miliane@ufrrj.br The study was conducted to characterize pheno-genotypically the virulence factors and resistance pattern of Staphylococcus aureus isolates from milk samples of cows with subclinical mastitis. All hemolytic isolates presented beta-hemolysin, and 38% of the non-hemolytic isolates were able to express hemolysins in the presence of a beta-hemolytic strain. The amplification of the coa-gene displayed four different size polymorphisms with about 400 bp, 600 bp, 700 bp and 900 bp. The spaA gene that encodes the IgG-binding region of protein A revealed sizes of 700 bp and 900 bp. The amplification of region X from spaA yielded a single amplicon for each isolate with the prevalent amplicon size being of 180 bp. Amplification of sae gene yielded an amplicon size of 920 bp in 71% of the isolates. Antibiotic resistance pattern revealed that 42% S. aureus were susceptible to all antimicrobials tested. Seven different antibiotic patterns were observed. Our results indicated that 47% and 25% of S. aureus strains exhibited resistance to penicillin and oxacillin respectively. All oxacillin-resistant isolates were mecA-positive.

Abstract in Portuguese:

ABSTRACT.- Coelho S.M.O., Reinoso E., Pereira I.A., Soares L.C., Demo M., Bogni C & Souza M.M.S. 2009. Virulence factors and antimicrobial resistance in Staphylo-coccus aureus isolated from bovine mastitis in Rio de Janeiro. Pesquisa Veterinária Brasileira 29(5):369-374. Departamento de Microbiologia e Imunologia Veterinária, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ 23890-000, Brazil. E-mail: miliane@ufrrj.br The study was conducted to characterize pheno-genotypically the virulence factors and resistance pattern of Staphylococcus aureus isolates from milk samples of cows with subclinical mastitis. All hemolytic isolates presented beta-hemolysin, and 38% of the non-hemolytic isolates were able to express hemolysins in the presence of a beta-hemolytic strain. The amplification of the coa-gene displayed four different size polymorphisms with about 400 bp, 600 bp, 700 bp and 900 bp. The spaA gene that encodes the IgG-binding region of protein A revealed sizes of 700 bp and 900 bp. The amplification of region X from spaA yielded a single amplicon for each isolate with the prevalent amplicon size being of 180 bp. Amplification of sae gene yielded an amplicon size of 920 bp in 71% of the isolates. Antibiotic resistance pattern revealed that 42% S. aureus were susceptible to all antimicrobials tested. Seven different antibiotic patterns were observed. Our results indicated that 47% and 25% of S. aureus strains exhibited resistance to penicillin and oxacillin respectively. All oxacillin-resistant isolates were mecA-positive.


#28 - Occurrence of virulence-related sequences and phylogenetic analysis of commensal and pathogenic avian Escherichia coli strains (APEC), p.533-540

Abstract in English:

ABSTRACT.- Campos T.A., Lago J.C., Nakazato G., Stehling E.G., Brocchi M., Castro A.F.P. & Silveira W.D. 2008. Occurrence of virulence-related sequences and phylogenetic analysis of commensal and pathogenic avian Escherichia coli strains (APEC). Pesquisa Veterinária Brasileira 28(10):533-540. Departamento de Microbiologia e Immunologia, Instituto de Biologia, Unicamp, Cidade Universitrária Zeferino Vaz s/n, Campinas, SP 13081-862, Brazil. E-mail: wds@unicamp.br The presence of iron uptake (irp-2, fyuA, sitA, fepC, iucA), adhesion (iha, lpfAO157/O141, lpfAO157/O154, efa, toxB) and invasion (inv, ial-related DNA sequences and assignment to the four main Escherichia coli phylogenetic groups (A, B1, B2 e D) were determined in 30 commensal E. coli strains isolated from healthy chickens and in 49 APEC strains isolated from chickens presenting clinical signs of septicemia (n=24) swollen head syndrome (n=14) and omphalitis (n=11) by PCR. None of the strains presented DNA sequences related to the inv, ial, efa, and toxB genes. DNA sequences related to lpfAO157/O154, iucA, fepC, and irp-2 genes were significantly found among pathogenic strains, where iucA gene was associated with septicemia and swollen head syndrome and fepC and irp-2 genes were associated with swollen head syndrome strains. Phylogenetic typing showed that commensal and omphalitis strains belonged mainly to phylogenetic Group A and swollen head syndrome to phylogenetic Group D. Septicemic strains were assigned in phylogenetic Groups A and D. These data could suggest that clonal lineage of septicemic APEC strains have a multiple ancestor origin; one from a pathogenic bacteria ancestor and other from a non-pathogenic ancestor that evolved by the acquisition of virulence related sequences through horizontal gene transfer. Swollen head syndrome may constitute a pathogenic clonal group. By the other side, omphalitis strains probably constitute a non-pathogenic clonal group, and could cause omphalitis as an opportunistic infection. The sharing of virulence related sequences by human pathogenic E. coli and APEC strains could indicate that APEC strains could be a source of virulence genes to human strains and could represent a zoonotic risk.

Abstract in Portuguese:

ABSTRACT.- Campos T.A., Lago J.C., Nakazato G., Stehling E.G., Brocchi M., Castro A.F.P. & Silveira W.D. 2008. Occurrence of virulence-related sequences and phylogenetic analysis of commensal and pathogenic avian Escherichia coli strains (APEC). Pesquisa Veterinária Brasileira 28(10):533-540. Departamento de Microbiologia e Immunologia, Instituto de Biologia, Unicamp, Cidade Universitrária Zeferino Vaz s/n, Campinas, SP 13081-862, Brazil. E-mail: wds@unicamp.br The presence of iron uptake (irp-2, fyuA, sitA, fepC, iucA), adhesion (iha, lpfAO157/O141, lpfAO157/O154, efa, toxB) and invasion (inv, ial-related DNA sequences and assignment to the four main Escherichia coli phylogenetic groups (A, B1, B2 e D) were determined in 30 commensal E. coli strains isolated from healthy chickens and in 49 APEC strains isolated from chickens presenting clinical signs of septicemia (n=24) swollen head syndrome (n=14) and omphalitis (n=11) by PCR. None of the strains presented DNA sequences related to the inv, ial, efa, and toxB genes. DNA sequences related to lpfAO157/O154, iucA, fepC, and irp-2 genes were significantly found among pathogenic strains, where iucA gene was associated with septicemia and swollen head syndrome and fepC and irp-2 genes were associated with swollen head syndrome strains. Phylogenetic typing showed that commensal and omphalitis strains belonged mainly to phylogenetic Group A and swollen head syndrome to phylogenetic Group D. Septicemic strains were assigned in phylogenetic Groups A and D. These data could suggest that clonal lineage of septicemic APEC strains have a multiple ancestor origin; one from a pathogenic bacteria ancestor and other from a non-pathogenic ancestor that evolved by the acquisition of virulence related sequences through horizontal gene transfer. Swollen head syndrome may constitute a pathogenic clonal group. By the other side, omphalitis strains probably constitute a non-pathogenic clonal group, and could cause omphalitis as an opportunistic infection. The sharing of virulence related sequences by human pathogenic E. coli and APEC strains could indicate that APEC strains could be a source of virulence genes to human strains and could represent a zoonotic risk.


#29 - Genes associated with pathogenicity of avian Escherichia coli (APEC) isolated from respiratory cases of poultry, p.183-186

Abstract in English:

ABSTRACT.- Rocha A.C.G.P., Rocha S.L.S., Lima-Rosa C.A.V., Souza G.F., Moraes H.L.S., Salle F.O., Moraes L.B. & Salle C.T.P. 2008. Genes associated with pathogenicity of avian Escherichia coli (APEC) isolated from respiratory cases of poultry. Pesquisa Veterinária Brasileira 28(3):183-186. Centro de Diagnóstico e Pesquisa em Patologia Aviária, Departamento de Medicina Animal, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 8824, Porto Alegre, RS 91540-000, Brazil. E-mail: ana.crocha@terra.com.br The virulence mechanisms of avian pathogenic Escherichia coli (APEC) have been continually studied and are believed to be multi-factorial. Certain properties are primarily associated with virulent samples and have been identified in avian isolates. In this study a total of 61 E. coli, isolates from chicken flocks with respiratory symptomatology, were probed by Polimerase Chain Reation (PCR) for the presence of genes responsible for the adhesion capacity, P fimbria (papC) e F11 fimbria (felA), colicin production (cvaC), aerobactin presence (iutA), serum resistance (iss), temperature-sensitive hemagglutinin (tsh), and presence of K1 and K5 capsular antigens (kpsII). The iss gene was detected in 73,8%, tsh in 55,7%, iutA in 45,9%, felA in 39,3%, papC in 24,3%, cvaC in 23% and kpsII in18%.

Abstract in Portuguese:

ABSTRACT.- Rocha A.C.G.P., Rocha S.L.S., Lima-Rosa C.A.V., Souza G.F., Moraes H.L.S., Salle F.O., Moraes L.B. & Salle C.T.P. 2008. Genes associated with pathogenicity of avian Escherichia coli (APEC) isolated from respiratory cases of poultry. Pesquisa Veterinária Brasileira 28(3):183-186. Centro de Diagnóstico e Pesquisa em Patologia Aviária, Departamento de Medicina Animal, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 8824, Porto Alegre, RS 91540-000, Brazil. E-mail: ana.crocha@terra.com.br The virulence mechanisms of avian pathogenic Escherichia coli (APEC) have been continually studied and are believed to be multi-factorial. Certain properties are primarily associated with virulent samples and have been identified in avian isolates. In this study a total of 61 E. coli, isolates from chicken flocks with respiratory symptomatology, were probed by Polimerase Chain Reation (PCR) for the presence of genes responsible for the adhesion capacity, P fimbria (papC) e F11 fimbria (felA), colicin production (cvaC), aerobactin presence (iutA), serum resistance (iss), temperature-sensitive hemagglutinin (tsh), and presence of K1 and K5 capsular antigens (kpsII). The iss gene was detected in 73,8%, tsh in 55,7%, iutA in 45,9%, felA in 39,3%, papC in 24,3%, cvaC in 23% and kpsII in18%.


#30 - Pathogenicity of Rhodococcus equi in mice, isolated from environment, human and horse clinical samples

Abstract in English:

ABSTRACT.- Costa M.M., Machado S.A., Krewer C.C., Ilha M.R.S., Graça D.L., Guaraldi A.L.M. & Vargas A.C. 2006. Pathogenicity of Rhodococcus equi in mice, isolated from environment, human and horse clinical samples. Pesquisa Veterinária Brasileira 26(3):167-170. Laboratório de Bacteriologia, Departamento de Medicina Veterinária Preventiva, Centro de Ciências Rurais, Universidade Federal de Santa Maria, Avenida Roraima 1000, Santa Maria, RS 97105-900, Brazil. E-mail: agueda@ccr.ufsm.br Rhodococcus equi is a facultative intracellular pathogen associated with bronchopneumonia, mesenteric lymphadenitis and enterocolitis in foals. Although R. equi is likely to be found in every horse-breeding farm, the clinical disease is unrecognized in most of them. Capsule components, equi factor, micolic acid and some products encoded by the large 85-90Kb plasmid were described as virulence factors. However, the pathogenesis of R. equi infections and the sensibility of foals are not completely understood. The aim of this study was evaluate the virulence of R. equi isolated from human, horses and environment for mices. Nine strains carrying the 85-90Kb plasmid isolated from foal clinical specimens, one from immunodeficient human patient and six plasmidless strains (four isolated from feces, one from pasture and one from immunodeficient human patient) were inoculated in cyclophosphamide immunossuppressed mice. The pathological changes and viability of R. equi cells in the liver of mice was verified after the 3rd, 6th an 10th day after inoculation for horse and environmental isolates and for R. equi isolates from human patients on the 1st, 3rd and 6th day. During the necropsy procedures, infiltrate of macrophages and pyogranulomatous lesions were detected after the sixth pos-inoculation day in the liver and spleen. In horse isolates, only plasmid positive strains were virulent, but in human isolates both strains (plasmid positive e plasmid negative) were virulent. Both groups of the immunossupressed mice inoculated with R. equi isolated from environment showed pathological changes. All R. equi strains were unable to kill non imunossuppressed mice.

Abstract in Portuguese:

ABSTRACT.- Costa M.M., Machado S.A., Krewer C.C., Ilha M.R.S., Graça D.L., Guaraldi A.L.M. & Vargas A.C. 2006. Pathogenicity of Rhodococcus equi in mice, isolated from environment, human and horse clinical samples. Pesquisa Veterinária Brasileira 26(3):167-170. Laboratório de Bacteriologia, Departamento de Medicina Veterinária Preventiva, Centro de Ciências Rurais, Universidade Federal de Santa Maria, Avenida Roraima 1000, Santa Maria, RS 97105-900, Brazil. E-mail: agueda@ccr.ufsm.br Rhodococcus equi is a facultative intracellular pathogen associated with bronchopneumonia, mesenteric lymphadenitis and enterocolitis in foals. Although R. equi is likely to be found in every horse-breeding farm, the clinical disease is unrecognized in most of them. Capsule components, equi factor, micolic acid and some products encoded by the large 85-90Kb plasmid were described as virulence factors. However, the pathogenesis of R. equi infections and the sensibility of foals are not completely understood. The aim of this study was evaluate the virulence of R. equi isolated from human, horses and environment for mices. Nine strains carrying the 85-90Kb plasmid isolated from foal clinical specimens, one from immunodeficient human patient and six plasmidless strains (four isolated from feces, one from pasture and one from immunodeficient human patient) were inoculated in cyclophosphamide immunossuppressed mice. The pathological changes and viability of R. equi cells in the liver of mice was verified after the 3rd, 6th an 10th day after inoculation for horse and environmental isolates and for R. equi isolates from human patients on the 1st, 3rd and 6th day. During the necropsy procedures, infiltrate of macrophages and pyogranulomatous lesions were detected after the sixth pos-inoculation day in the liver and spleen. In horse isolates, only plasmid positive strains were virulent, but in human isolates both strains (plasmid positive e plasmid negative) were virulent. Both groups of the immunossupressed mice inoculated with R. equi isolated from environment showed pathological changes. All R. equi strains were unable to kill non imunossuppressed mice.


Colégio Brasileiro de Patologia Animal SciELO Brasil CAPES CNPQ UNB UFRRJ CFMV