Comparison of virulence factors and expression of specific genes between uropathogenic Escherichia coli and avian pathogenic E. coli in a murine urinary tract infection model and a chicken challenge model

Abstract

Avian pathogenic Escherichia coli (APEC) and uropathogenic E. coli (UPEC) establish infections in extraintestinal habitats of different hosts. As the diversity, epidemiological sources and evolutionary origins of extraintestinal pathogenic E. coli (ExPEC) are so far only partially defined, in the present study,100 APEC isolates and 202 UPEC isolates were compared by their content of virulence genes and phylogenetic groups. The two groups showed substantial overlap in terms of their serogroups, phylogenetic groups and virulence genotypes, including their possession of certain genes associated with large transmissible plasmids of APEC. In a chicken challenge model, both UPEC U17 and APEC E058 had similar LD 50 , demonstrating that UPEC U17 had the potential to cause significant disease in poultry. To gain further information about the similarities between UPEC and APEC, the in vivo expression of 152 specific genes of UPEC U17 and APEC E058 in both a murine urinary tract infection (UTI) model and a chicken challenge model was compared with that of these strains grown statically to exponential phase in rich medium. It was found that in the same model (murine UTI or chicken challenge), various genes of UPEC U17 and APEC E058 showed a similar tendency of expression. Several iron-related genes were upregulated in the UTI model and/or chicken challenge model, indicating that iron acquisition is important for E. coli to survive in blood or the urinary tract. Based on these results, the potential for APEC to act as human UPEC or as a reservoir of virulence genes for UPEC should be considered. Further, this study compared the transcriptional profile of virulence genes among APEC and UPEC in vivo.

Genes of Virulence and Phylogenetic Group in Isolates of Avian Pathogenic Escherichia coli

“…In this study, the ColV plasmid was detected in 91% of the isolates, in other studies it has been reported from 53 to 67% [2,26,27]. The combined detection of the tsh, iss, iroN and cvaC genes suggests the presence of ColV plasmids; in this study the iss, iroN and cvaC combination was 69.5%, while iss, tsh and cvaC decreased to 34.7%.…”

“…In this work, ibeA it was detected in 8% of the isolates, while Rodríguez-Siek et al [2] and Zhao et al [26], reported a frequency of 14.7% and 17% respectively. The participation of ibeA in APEC is related to the formation of biofilms in vitro and to the capacity of invasion in APEC strains, although the exact mechanism by which ibeA contributes to the development of colibacillosis is unknown.…”

“…In addition, the number of virulence genes was similar in both groups with an average of seven genes, which is not in agreement with that described for group B1, which is mainly formed by commensal strains. Zhao et al [26], reported that 40% of APEC isolates analyzed belong to group A, which has also been classified as commensal strains and IPEC; likewise, Jeong et al [23] found high percentages of APEC isolates within groups A and B. Under this, it is assumed that the classification of E. coli in phylogenetic groups per se, does not allow differentiating the commensal strains of the ExPEC strains and suggests that the phylogenetic origin of the APEC isolates is diverse.…”

Presence of virulence genes and pathogenicity islands in extraintestinal pathogenic Escherichia coli isolates from Brazil

“…It is necessary to perform antimicrobial susceptibility testing because the E. coli strains show ExPEC are known to produce several virulence factors, contributing to their survival in the host urinary tract, blood, and other tissues. Among the eleven tested virulence genes, all of them were detected in some of the ExPEC strains and faecal commensal isolates, as shown by others [4,25]. The gene most commonly found in both ExPEC and commensal samples was ecpA (94.8% and 96%, respectively).…”

Distribution of serotypes and virulence-associated genes in pathogenicEscherichia coliisolated from ducks

“…Also, recent reports have suggested APEC strains are linked with human diseases, such as urinary tract infection and neonatal meningitis, mostly caused by extraintestinal pathogenic E. coli (Rodriguez-Siek et al, 2005a;Ewers et al, 2007;Moulin-Schouleur et al, 2007;Mellata et al, 2009;Zhao et al, 2009). Moreover, Shiga-toxinproducing E. coli (STEC) has been demonstrated to exist in chickens or other birds, suggesting that poultry are a reservoir of STEC for humans (Parreira & Gyles, 2002;Grossmann et al, 2005).…”