Colonization of the Respiratory Tract by a Virulent Strain of Avian
            <i>Escherichia coli</i>
            Requires Carriage of a Conjugative Plasmid

Ginns, Carol A.; Benham, Michelle L.; Adams, Louise M.; Whithear, Kevin G.; Bettelheim, K. A.; Crabb, Brendan S.; Browning, Glenn F.

doi:10.1128/iai.68.3.1535-1541.2000

Cited by 48 publications

(53 citation statements)

References 54 publications

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“…Strains E3, E30, and E956 were the most virulent strains, causing morbidity in 75, 59, and 88% of exposed birds, respectively, while the less virulent strains, E133, E1043, and E1292, caused morbidity in 25, 9, and 31% of experimentally exposed birds, respectively. Strain E3/2.4, a plasmid-cured derivative of E3, caused morbidity in 12% of exposed birds (11). PCR products were analyzed on an agarose gel and can be seen in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The E. coli strains used in this study were field isolates E3, E30, E133, E956, and E1043 (10) and E1292 (9) and derivatives of field isolate E3 with different combinations of plasmids (11). The pathogenicity of five of the field isolates and the plasmid-cured derivatives of E3 had been determined previously using an aerosol challenge method (10).…”

Section: Methodsmentioning

confidence: 99%

“…Plasmid curing by subculturing at high temperatures led to the derivation of a series of strains with different plasmid combinations. Using aerosol exposure (10) to test the pathogenicity of plasmid-cured E3 strains, it was found that the loss of the largest plasmid, pVM01, was correlated with the loss of virulence and an inability to colonize the respiratory tract (11). The introduction of a TnphoAtagged pVM01 plasmid into the plasmid-cured, avirulent strain E3/2.4 restored the virulent phenotype (11).…”

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Association of iss and iucA , but Not tsh , with Plasmid-Mediated Virulence of Avian Pathogenic Escherichia coli

et al. 2004

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Avian pathogenic Escherichia coli (APEC) is an economically important respiratory pathogen of chickens worldwide. Factors previously associated with the virulence of APEC include adhesins, iron-scavenging mechanisms, the production of colicin V (ColV), serum resistance, and temperature-sensitive hemagglutination, but virulence has generally been assessed by parenteral inoculation, which does not replicate the normal respiratory route of infection. A large plasmid, pVM01, is essential for virulence in APEC strain E3 in chickens after aerosol exposure. Here we establish the size of pVM01 to be approximately 160 kb and show that the putative virulence genes iss (increased serum survival) and tsh (temperature-sensitive hemagglutinin) and the aerobactin operon are on the plasmid. These genes were not clustered on pVM01 but, rather, were each located in quite distinct regions. Examination of APEC strains with defined levels of respiratory pathogenicity after aerosol exposure showed that both the aerobactin operon and iss were associated with high levels of virulence in APEC but that the possession of either gene was sufficient for intermediate levels of virulence. In constrast, the presence of tsh was not necessary for high levels of virulence. Thus, both the aerobactin operon and iss are associated with virulence in APEC after exposure by the natural route of infection. The similarities between APEC and extraintestinal E. coli infection in other species suggests that they may be useful models for definition of the role of these virulence genes and of other novel virulence genes that may be located on their virulence plasmids.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Association of iss and iucA , but Not tsh , with Plasmid-Mediated Virulence of Avian Pathogenic Escherichia coli

et al. 2004

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“…Of particular interest in recent years has been the role that plasmid-located genes may play in the virulence of the E. coli causing disease in poultry, and several accounts linking large aerobactin-or ColV-encoding plasmids to avian E. coli virulence are found in the literature (8,9,10,14,15). Interestingly, it has been Fig.…”

Section: Discussionmentioning

confidence: 99%

Multiple Antimicrobial Resistance Region of a Putative Virulence Plasmid from an Escherichia coli Isolate Incriminated in Avian Colibacillosis

2004

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Infections due to Escherichia coli have been costly to the poultry industry, but the exact virulence mechanisms used by these organisms to cause disease in birds remain undefined. Several factors have been shown to contribute to the virulence of avian E. coli, and many of the genes encoding these factors have been found on large conjugative plasmids. Because of the occurrence of antimicrobial resistance genes on these same plasmids, it is possible that the use of antimicrobial agents may select for persistence of E. coli containing such plasmids. In the present study, a subclone of one of these plasmids was identified as likely containing some virulence and antimicrobial resistance genes. In an effort to better understand the relationship between virulence and resistance in these plasmids, this subclone was sequenced and the sequence analyzed. Analysis of this 30-kilobase (kb) region of plasmid pTJ100 revealed a mosaic of virulence genes, insertion sequences, antimicrobial resistance cassettes, and their remnants. Many of the resistance genes found in this region were expressed under laboratory conditions, indicating that certain antimicrobial agents, including disinfectants, antibiotics, and heavy metals, could promote selection of E. coli containing such plasmids in the production environment. Also, analysis of the G + C content of this clone indicated that it is the likely consequence of a complex evolution with components derived from various sources. The occurrence of many mobile elements in conjunction with antimicrobial resistance and virulence genes in this 30-kb region may indicate that the genetic constitution of the clone is quite plastic. Although further study will be required to better define this plasmid's role in avian E. coli virulence, the sequence described here is, to our knowledge, the longest known contiguous sequence of a ColV plasmid yet presented. Analysis of this sequence indicates that this clone and its parent plasmid may be important to the pathogenesis of avian colibacillosis and the evolution of avian E. coli virulence. KeywordsEscherichia coli, avian colibacillosis, antimicrobial resistance, disinfectant resistance, heavy metal resistance, virulence, R plasmid, poultry, Tn21, pTJ100 SUMMARY. Infections due to Escherichia coli have been costly to the poultry industry, but the exact virulence mechanisms used by these organisms to cause disease in birds remain undefined. Several factors have been shown to contribute to the virulence of avian E. coli, and many of the genes encoding these factors have been found on large conjugative plasmids. Because of the occurrence of antimicrobial resistance genes on these same plasmids, it is possible that the use of antimicrobial agents may select for persistence of E. coli containing such plasmids. In the present study, a subclone of one of these plasmids was identified as likely containing some virulence and antimicrobial resistance genes. In an effort to better understand the relationship between virulence and resistance in these plasm...

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“…Exchange of large amounts of genetic material can be expected in strains that carry a variety of plasmids, including conjugal plasmids, which contribute to virulence and fitness. One such possible case is the presence of genes encoding aerobactin in an unclassified, non-ColV plasmid (Ginns et al, 2000). In pathogenic strains, the mobility of plasmids and genes is probably a driving evolutionary force that accelerates their adaptation to new ecological niches as well as their resistance to antibacterial agents and the immune response.…”

Section: Discussionmentioning

confidence: 99%

A novel ColV plasmid encoding type IV pili

Gophna

Parket

Häcker³

et al. 2003

Microbiology

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Colonization of the Respiratory Tract by a Virulent Strain of Avian Escherichia coli Requires Carriage of a Conjugative Plasmid

Cited by 48 publications

References 54 publications

Association of iss and iucA , but Not tsh , with Plasmid-Mediated Virulence of Avian Pathogenic Escherichia coli

Association of iss and iucA , but Not tsh , with Plasmid-Mediated Virulence of Avian Pathogenic Escherichia coli

Multiple Antimicrobial Resistance Region of a Putative Virulence Plasmid from an Escherichia coli Isolate Incriminated in Avian Colibacillosis

A novel ColV plasmid encoding type IV pili

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