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

Abstract

Introduction: Extraintestinal pathogenic Escherichia coli (ExPEC) is associated with various diseases such as urinary tract infections, neonatal meningitis and septicemia. There are many virulence factors (VF) encoded by genes in ExPEC, including papC, papG, ecpA, iroN, fyuA, iutA, ompTp, tsh, hlyF, hlyA and iss. These virulence genes may be present in pathogenicity islands (PAI) or plasmids. Methodology: In this study, we analyzed the presence of VF encoding genes, PAI sequences and phylogenetic groups of 96 ExPEC strains isolated from the urine and blood of patients at the University Hospital of Londrina, and we compared them with 50 faecal commensal strains from healthy individuals. Results: The VF fyuA (65.60%) was detected in pathogenic strains and commensal strains (46%). A comparison of the distribution of ExPEC and commensal strains in the phylogenetic groups showed that more ExPEC strains belonged to group B2 whereas more of the commensal isolates belonged to group A. The distribution of the seven PAI sequences between commensal strains and ExPEC strains showed that PAI IV 536 was common in both ExPEC and commensal isolates. Conclusions: These results showed that the ExPEC strains that belonged to group B2 had more PAI sequences compared to those of the other groups, especially group B1, which had virulence genes but the lowest percentage of PAI sequences, which leads us to conclude that the virulence of ExPEC strains characterized as B2 is likely attributed to PAI encoded genes, whereas the virulence of ExPEC strains belonging to phylogenetic group B1 is likely due to plasmid encoded virulence genes.

Characterization of auto-agglutinating and non-typeable uropathogenic Escherichia coli strains

“…Studies conducted in Mexico and other countries found that UPEC serogroup strains are integrated mainly in the virulent phylogroups (B2 and D) [17,25,[30][31][32]. In the phylogroup analysis, the PCR-GT-E. coli strains showed a higher frequency of strains in the virulent phylogroups (B2 and D) with significant differences (P < 0.05) when compared with PCR-NGT-E. coli strains.…”

Uropathogenic Escherichia coli pathogenicity islands and other ExPEC virulence genes may contribute to the genome variability of enteroinvasive E. coli

“…Besides PAI IV 536 no other PAIs from UPEC 536 were detected in this study. We have shown that EIEC also harbors multiple PAIs as described for UPEC [38]. However, the most predominant combination found in EIEC (PAIs I J96 and II CFT073 ) was not detected in UPEC [35, 38].…”

“…We have shown that EIEC also harbors multiple PAIs as described for UPEC [38]. However, the most predominant combination found in EIEC (PAIs I J96 and II CFT073 ) was not detected in UPEC [35, 38]. Except for PAI IV 536 the other three PAIs detected in this study did not correlate with the presence of the recognized virulence traits they are reported to encode namely: α-hemolysin, P-fimbriae, Prs-fimbriae, cytotoxic necrotizing factor 1, and aerobactin [35].…”

Three new serine-protease autotransporters of Enterobacteriaceae (SPATEs) from extra-intestinal pathogenic Escherichia coli and combined role of SPATEs for cytotoxicity and colonization of the mouse kidney

“…Tsh was the first SPATE identified in E. coli [49] and was shown to contribute to the development of respiratory lesions in the air sacs of chickens [22]. The tsh gene is located on ColV-type plasmids, was present in 50% of APEC strains [47], is less commonly associated with human ExPEC, but can be associated with certain human ExPEC strains [18,[50][51][52].…”