The conserved portion of the putative virulence region contributes to virulence of avian pathogenic Escherichia coli

Microbiology ◽  
2009 ◽  
Vol 155 (2) ◽  
pp. 450-460 ◽  
Author(s):  
Kelly A. Tivendale ◽  
Amir H. Noormohammadi ◽  
Joanne L. Allen ◽  
Glenn F. Browning
Keyword(s):  
Escherichia Coli ◽  
Systemic Disease ◽  
Complete Sequence ◽  
Avian Pathogenic Escherichia Coli ◽  
E Coli ◽  
Aerosol Exposure ◽  
Pathogenic Escherichia Coli ◽  
Extraintestinal Disease ◽  
Virulent Phenotype

Colibacillosis is a common systemic disease of worldwide economic importance in poultry, caused by Escherichia coli. E. coli are normally found in the intestines of poultry, but some strains are able to cause extraintestinal disease. Plasmid pVM01 is essential for virulence in avian pathogenic Escherichia coli (APEC) strain E3 in chickens after aerosol exposure and contains the virulence-associated genes iucA, iss and tsh in distinct regions. The determination of the complete sequence of this plasmid identified many ORFs that were highly similar to genes found in the APEC O1 plasmid, as well as many hypothetical ORFs. Truncated versions of pVM01 were constructed and introduced into avirulent APEC strain E3/2.4 and the pathogenicity of these strains was assessed by aerosol exposure. The function of the region of pVM01 that contains the genes for conjugation was confirmed. Strains carrying the truncated plasmids appeared to be of intermediate virulence compared to the wild-type APEC strain E3. The conserved portion of the putative virulence region was found to contribute to the colonization of and generation of lesions in the air sacs. Both the conserved and variable portions of the putative virulence region were shown to contribute to the colonization of the trachea, but the variable portion of the putative virulence region was not required for the strain to confer a virulent phenotype. These results reveal that deletion of the conserved portion of the putative virulence region, but not the variable portion of the putative virulence region, is associated with a decrease in virulence of APEC.

scholarly journals Complete DNA Sequence of a ColBM Plasmid from Avian Pathogenic Escherichia coli Suggests that It Evolved from Closely Related ColV Virulence Plasmids

2006 ◽  
Vol 188 (16) ◽  
pp. 5975-5983 ◽  
Author(s):  
Timothy J. Johnson ◽  
Sara J. Johnson ◽  
Lisa K. Nolan
Keyword(s):  
Escherichia Coli ◽  
Southern Blotting ◽  
Virulence Genes ◽  
Complete Sequence ◽  
Economic Losses ◽  
Avian Pathogenic Escherichia Coli ◽  
Prevalence Studies ◽  
E Coli ◽  
Virulence Plasmids ◽  
Pathogenic Escherichia Coli

ABSTRACT Avian pathogenic Escherichia coli (APEC), an extraintestinal pathogenic E. coli causing colibacillosis in birds, is responsible for significant economic losses for the poultry industry. Recently, we reported that the APEC pathotype was characterized by possession of a set of genes contained within a 94-kb cluster linked to a ColV plasmid, pAPEC-O2-ColV. These included sitABCD, genes of the aerobactin operon, hlyF, iss, genes of the salmochelin operon, and the 5′ end of cvaB of the ColV operon. However, the results of gene prevalence studies performed among APEC isolates revealed that these traits were not always linked to ColV plasmids. Here, we present the complete sequence of a 174-kb plasmid, pAPEC-O1-ColBM, which contains a putative virulence cluster similar to that of pAPEC-O2-ColV. These two F-type plasmids share remarkable similarity, except that they encode the production of different colicins; pAPEC-O2-ColV contains an intact ColV operon, and pAPEC-O1-ColBM encodes the colicins B and M. Interestingly, remnants of the ColV operon exist in pAPEC-O1-ColBM, hinting that ColBM-type plasmids may have evolved from ColV plasmids. Among APEC isolates, the prevalence of ColBM sequences helps account for the previously observed differences in prevalence between genes of the “conserved” portion of the putative virulence cluster of pAPEC-O2-ColV and those genes within its “variable” portion. These results, in conjunction with Southern blotting and probing of representative ColBM-positive strains, indicate that this “conserved” cluster of putative virulence genes is primarily linked to F-type virulence plasmids among the APEC isolates studied.

scholarly journals Avian pathogenic Escherichia coli: diagnosis, virulence and prevention.

2019 ◽  
Vol 11 (2) ◽  
pp. 21-31 ◽  
Author(s):  
Maja Velhner ◽  
Ljiljana Suvajdžić ◽  
Dalibor Todorović ◽  
Dubravka Milanov ◽  
Gordana Kozoderović
Keyword(s):  
Escherichia Coli ◽  
Management Practice ◽  
Disease Process ◽  
Multidrug Resistant ◽  
Avian Pathogenic Escherichia Coli ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
Good Management Practice ◽  
Resistant Strains

Avian pathogenic Escherichia coli (APEC) causes colibacillosis within poultry flocks all around the world. There is a number of virulence mechanisms involved in the disease process in poultry and determination of some of the responsible genes is important for diagnosis of colibacillosis. In this work, research data regarding diagnostics of APEC and how certain clonal lineages could cause infection in different hosts is presented. In order to determine virulence genotype of APEC, multiplex polymerase chain reaction, based on a published sequence of seven pairs of primers (iroN, ompT, hlyF, iss, iutA, elitC and cvaC), was used in our laboratory. It was established in the research of other scientists that isolates with two or more of these genes can develop pathogenic phenotype, while isolates with one or none of the genes are mostly commensal E. coli. Additionally, virulence mechanisms in APEC were also briefly described. It was emphasized that resistance genes and virulence genes are sometimes co-located on the same plasmid and that such plasmids could be shared among related or unrelated bacteria species. Since APEC often confers resistance to antibiotics, the therapy is less effective in poultry with multidrug resistant strains. It was concluded that good management practice, treatment with probiotics and/or vaccination are necessary to reduce colibacillosis outbreaks. This approach is even more pronounced since APEC resides in intestine of healthy poultry and could cause disease if poultry is exposed to various stressors.

scholarly journals Avian Pathogenic Escherichia coli (APEC): An Overview of Virulence and Pathogenesis Factors, Zoonotic Potential, and Control Strategies

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 467
Author(s):  
Dipak Kathayat ◽  
Dhanashree Lokesh ◽  
Sochina Ranjit ◽  
Gireesh Rajashekara
Keyword(s):  
Escherichia Coli ◽  
Current Status ◽  
Neonatal Meningitis ◽  
Clear Understanding ◽  
Zoonotic Potential ◽  
Secretion Systems ◽  
Avian Pathogenic Escherichia Coli ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
Tract Infections

Avian pathogenic Escherichia coli (APEC) causes colibacillosis in avian species, and recent reports have suggested APEC as a potential foodborne zoonotic pathogen. Herein, we discuss the virulence and pathogenesis factors of APEC, review the zoonotic potential, provide the current status of antibiotic resistance and progress in vaccine development, and summarize the alternative control measures being investigated. In addition to the known virulence factors, several other factors including quorum sensing system, secretion systems, two-component systems, transcriptional regulators, and genes associated with metabolism also contribute to APEC pathogenesis. The clear understanding of these factors will help in developing new effective treatments. The APEC isolates (particularly belonging to ST95 and ST131 or O1, O2, and O18) have genetic similarities and commonalities in virulence genes with human uropathogenic E. coli (UPEC) and neonatal meningitis E. coli (NMEC) and abilities to cause urinary tract infections and meningitis in humans. Therefore, the zoonotic potential of APEC cannot be undervalued. APEC resistance to almost all classes of antibiotics, including carbapenems, has been already reported. There is a need for an effective APEC vaccine that can provide protection against diverse APEC serotypes. Alternative therapies, especially the virulence inhibitors, can provide a novel solution with less likelihood of developing resistance.

scholarly journals Resistência antimicrobiana e perfil plasmidial de Escherichia coli isolada de frangos de corte e poedeiras comerciais no Estado de Pernambuco

2012 ◽  
Vol 32 (5) ◽  
pp. 405-410 ◽  
Author(s):  
Mércia R. Barros ◽  
Wanderley D, da Silveira ◽  
Janete M. de Araújo ◽  
Elizianne P. Costa ◽  
Andrea Alice da F. Oliveira ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Avian Pathogenic Escherichia Coli ◽  
E Coli ◽  
Pathogenic Escherichia Coli

Embora existam linhagens de Escherichia coli não patogênicas para aves, muitas outras possuem a capacidade de causar sérios danos à saúde das mesmas, sendo capazes de ocasionar diferentes tipos de processos infecciosos. As linhagens patogênicas são denominadas Avian Pathogenic Escherichia coli (APEC), possuindo genes relacionados ao processo de patogênese em epissomos (plasmídios) ou no cromossomo. A presença de plasmídios, contendo genes de resistência a antibióticos em linhagens aviárias, patogênicas ou não, indicam a possibilidade de transferência gênica lateral entre diferentes tipos de linhagens facilitando também a transferência de genes de patogenicidade ou virulência. Objetivou-se com este estudo avaliar o perfil de sensibilidade a antibióticos (13) de diferentes amostras (35) de E. coli isoladas de aves comerciais do Estado de Pernambuco apresentando, ou não, sinais clínicos de processos infecciosos e correlacionar esta resistência com a presença de plasmídios. Os testes utilizados demonstraram que 94,28% dos isolados foram resistentes a três ou mais antibióticos, com a lincomicina apresentando o maior percentual de resistência (100%). Na Concentração Inibitória Mínima (CIM) observou-se multirresistência a vários antimicrobianos. A presença de plasmídios foi detecada em 80,0% (28/35) dos isolados, com 16 isolados apresentando plasmídios com peso molecular aproximado de 88 MDa. Também foi verificada a presença de linhagens apresentando plasmídios de vários tamanhos. Concluiu-se que isolados de E. coli resistentes a antimicrobianos utilizados na avicultura estão presentes no Estado de Pernambuco, tanto em frangos de corte quanto em poedeiras comerciais. A presença de plasmídios detectados na maioria dos isolados pode estar associada à resistência aos antimicrobianos e sugere a presença de possíveis genes relacionados à patogenicidade. Monitorar a resistência a antibióticos em bactérias isoladas de animais torna-se um fator determinante para eleição e êxito do tratamento, bem como a possibilidade de eliminação daquelas que possuem plasmídios para se evitar a transferência de genes relacionados à patogenicidade.

scholarly journals Sequencing and Functional Annotation of Avian Pathogenic Escherichia coli Serogroup O78 Strains Reveal the Evolution of E. coli Lineages Pathogenic for Poultry via Distinct Mechanisms

2012 ◽  
Vol 81 (3) ◽  
pp. 838-849 ◽  
Author(s):  
Francis Dziva ◽  
Heidi Hauser ◽  
Thomas R. Connor ◽  
Pauline M. van Diemen ◽  
Graham Prescott ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Core Genome ◽  
Systemic Disease ◽  
Genomic Islands ◽  
Content Type ◽  
E Coli ◽  
Group 4 ◽  
Pathogenic Escherichia Coli ◽  
Transposon Mutants ◽  
Avian Disease

ABSTRACTAvian pathogenicEscherichia coli(APEC) causes respiratory and systemic disease in poultry. Sequencing of a multilocus sequence type 95 (ST95) serogroup O1 strain previously indicated that APEC resemblesE. colicausing extraintestinal human diseases. We sequenced the genomes of two strains of another dominant APEC lineage (ST23 serogroup O78 strains χ7122 and IMT2125) and compared them to each other and to the reannotated APEC O1 sequence. For comparison, we also sequenced a human enterotoxigenicE. coli(ETEC) strain of the same ST23 serogroup O78 lineage. Phylogenetic analysis indicated that the APEC O78 strains were more closely related to human ST23 ETEC than to APEC O1, indicating that separation of pathotypes on the basis of their extraintestinal or diarrheagenic nature is not supported by their phylogeny. The accessory genome of APEC ST23 strains exhibited limited conservation of APEC O1 genomic islands and a distinct repertoire of virulence-associated loci. In light of this diversity, we surveyed the phenotype of 2,185 signature-tagged transposon mutants of χ7122 following intra-air sac inoculation of turkeys. This procedure identified novel APEC ST23 genes that play strain- and tissue-specific roles during infection. For example, genes mediating group 4 capsule synthesis were required for the virulence of χ7122 and were conserved in IMT2125 but absent from APEC O1. Our data reveal the genetic diversity ofE. colistrains adapted to cause the same avian disease and indicate that the core genome of the ST23 lineage serves as a chassis for the evolution ofE. colistrains adapted to cause avian or human disease via acquisition of distinct virulence genes.

scholarly journals Specific Roles of the iroBCDEN Genes in Virulence of an Avian Pathogenic Escherichia coli O78 Strain and in Production of Salmochelins

2008 ◽  
Vol 76 (8) ◽  
pp. 3539-3549 ◽  
Author(s):  
Mélissa Caza ◽  
François Lépine ◽  
Sylvain Milot ◽  
Charles M. Dozois
Keyword(s):  
Escherichia Coli ◽  
Respiratory Infections ◽  
Mass Spectrometry Analysis ◽  
Liquid Chromatography Mass Spectrometry ◽  
Avian Pathogenic Escherichia Coli ◽  
Prevalence Studies ◽  
Spectrometry Analysis ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
Negative Mutant

ABSTRACT Avian pathogenic Escherichia coli (APEC) strains are a subset of extraintestinal pathogenic E. coli (ExPEC) strains associated with respiratory infections and septicemia in poultry. The iroBCDEN genes encode the salmochelin siderophore system present in Salmonella enterica and some ExPEC strains. Roles of the iro genes for virulence in chickens and production of salmochelins were assessed by introducing plasmids carrying different combinations of iro genes into an attenuated salmochelin- and aerobactin-negative mutant of O78 strain χ7122. Complementation with the iroBCDEN genes resulted in a regaining of virulence, whereas the absence of iroC, iroDE, or iroN abrogated restoration of virulence. The iroE gene was not required for virulence, since introduction of iroBCDN restored the capacity to cause lesions and colonize extraintestinal tissues. Prevalence studies indicated that iro sequences were associated with virulent APEC strains. Liquid chromatography-mass spectrometry analysis of supernatants of APEC χ7122 and the complemented mutants indicated that (i) for χ7122, salmochelins comprised 14 to 27% of the siderophores present in iron-limited medium or infected tissues; (ii) complementation of the mutant with the iro locus increased levels of glucosylated dimers (S1 and S5) and monomer (SX) compared to APEC strain χ7122; (iii) the iroDE genes were important for generation of S1, S5, and SX; (iv) iroC was required for export of salmochelin trimers and dimers; and (v) iroB was required for generation of salmochelins. Overall, efficient glucosylation (IroB), transport (IroC and IroN), and processing (IroD and IroE) of salmochelins are required for APEC virulence, although IroE appears to serve an ancillary role.

scholarly journals Virulence gene profiles of avian pathogenic Escherichia coli isolated from chickens with colibacillosis in Bulawayo, Zimbabwe

2015 ◽  
Vol 82 (1) ◽  
Author(s):  
Joshua Mbanga ◽  
Yvonne O. Nyararai
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Economic Losses ◽  
Avian Pathogenic Escherichia Coli ◽  
Pcr Assay ◽  
E Coli ◽  
Gene Profiles ◽  
Pathogenic Escherichia Coli ◽  
Polymerase Chain

Colibacillosis, a disease caused by avian pathogenic Escherichia coli (APEC), is one of the main causes of economic losses in the poultry industry worldwide. This study was carried out in order to determine the APEC-associated virulence genes contained by E. coli isolates causing colibacillosis in chickens. A total of 45 E. coli isolates were obtained from the diagnostics and research branch of the Central Veterinary Laboratories, Bulawayo, Zimbabwe. These isolates were obtained from chickens with confirmed cases of colibacillosis after postmortem examination. The presence of the iutA, hlyF, ompT, frz, sitD, fimH, kpsM, sitA, sopB, uvrY, pstB and vat genes were investigated by multiplex polymerase chain reaction (PCR) assay. Of the 45 isolates, 93% were positive for the presence of at least one virulence gene. The three most prevalent virulence genes were iutA (80%), fimH (33.3%) and hlyF (24.4%). The kpsM, pstB and ompT genes had the lowest prevalence, having been detected in only 2.2% of the isolates. All 12 virulence genes studied were detected in the 45 APEC isolates. Virulence gene profiles were constructed for each APEC isolate from the multiplex data. The APEC isolates were profiled as 62.2% fitting profile A, 31.1% profile B and 6.7% profile C. None of the isolates had more than seven virulence genes. Virulence profiles of Zimbabwean APEC isolates are different from those previously reported. Zimbabwean APEC isolates appear to be less pathogenic and may rely on environmental factors and stress in hosts to establish infection.

scholarly journals Transcription Regulator YgeK Affects the Virulence of Avian Pathogenic Escherichia coli

Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3018
Author(s):  
Jian Tu ◽  
Dandan Fu ◽  
Yi Gu ◽  
Ying Shao ◽  
Xiangjun Song ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Transcriptional Regulator ◽  
Avian Pathogenic Escherichia Coli ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
System 2 ◽  
Important Regulator ◽  
Alignment Analysis ◽  
Responsible Pathogen

Avian pathogenic Escherichia coli (APEC) is the responsible pathogen for colibacillosis in poultry, and is a potential gene source for human extraintestinal pathogenic Escherichia coli. Escherichia coli type III secretion system 2 (ETT2) is widely distributed in human and animal ExPEC isolates, and is crucial for the virulence of ExPEC. Transcriptional regulator YgeK, located in the ETT2 gene cluster, was identified as an important regulator of gene expression in enterohemorrhagic E. coli (EHEC). However, the role of YgeK in APEC has not been reported. In this study, we performed amino acid alignment analysis of YgeK among different E. coli strains and generated ygeK mutant strain AE81ΔygeK from clinical APEC strain AE81. Flagellar formation, bacterial motility, serum sensitivity, adhesion, and virulence were all significantly reduced following the inactivation of YgeK in APEC. Then, we performed transcriptome sequencing to analyze the functional pathways involved in the biological processes. Results suggested that ETT2 transcriptional regulator YgeK plays a crucial role in APEC virulence. These findings thus contribute to our understanding of the function of the ETT2 cluster, and clarify the pathogenic mechanism of APEC.

scholarly journals Virulence Characteristic of Avian Pathogenic Escherichia coli (APEC) Isolates

2020 ◽  
Vol 38 (1) ◽  
pp. 61
Author(s):  
Sruti Listra Adrenalin ◽  
Lynda Nugrahaning Imanjati ◽  
Ima Fauziah ◽  
Vinsa Cantya Prakasita ◽  
Sitarina Widyarini ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Respiratory Disease ◽  
High Mortality ◽  
Specific Pathogen Free ◽  
Avian Pathogenic Escherichia Coli ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
High Virulence ◽  
Specific Pathogen ◽  
Costs Of Treatment

Avian pathogenic Escherichia coli (APEC) is a cause of colibacillosis in poultry, one of the respiratory disease that causes serious problems in the poultry industry. The APEC can cause high mortality and culling, decreased production, and high costs of treatment. Manifestations of colibacillosis are airsacculitis, perihepatitis, and pericarditis. The APEC serotypes that are widely identified in the field are O1K1, O2K1, and O78K80. Embryo lethality assay (ELA) is a method for determine the virulence of APEC serotypes. The aim of this study was to determine the virulence characteristic of APEC isolates. Five APEC serotypes O1K1, O2K1, O78K80, O157H7, and unknown serotype were used for ELA method by inoculated E. coli into chorioallantoic of specific pathogen free 12-days old embryos. Each group of 10 embryos, inoculated E. coli dose of 100-500 CFU/ 0,1 ml. Candling was carried out for 6 days (18-days old embryo) to determined the mortality and pathological lesions. The percentage of embryo mortality post-inoculated with APEC O1K1, O2K1, unknown serotypes were 100% (10/10), O78K80 serotype was 90% (9/10), and O157H7 serotype was 70% (70%). Lesions of all embryos were cranial and extremity hemorrhage. In this study, E. coli isolates had high virulence. 

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