Emergence of enteroaggregativeEscherichia coliwithin the ST131 lineage as a cause of extraintestinal infections

Abstract

26Escherichia coli sequence type 131 (ST131) is a major cause of urinary and bloodstream infections 27 and its association with extended-spectrum β-lactamases (ESBL) significantly complicates treatment. 28 Most notorious is its rapidly expanding H30-Rx clade (named for containing allele 30 of the type-1 29 fimbrial adhesin gene fimH and extensive antimicrobial resistance), which appears to have emerged 30 55 Escherichia coli sequence type 131 (ST131) is the dominant multidrug-resistant (MDR) 56 extraintestinal pathogenic E. coli (ExPEC) lineage worldwide, causing a wide range of infections 57 including bloodstream and urinary tract infections (BSIs/UTIs) (1-3). Its rise to global dominance 58 and pathogenicity is thought to have been primed by sequential acquisition of virulence-associated 59 genes followed by development of antibiotic resistance (4, 5). ST131 predominantly exhibits 60 serotype O25:H4 and is closely associated with fluoroquinolone resistance and the production of the 61 CTX-M-15 extended-spectrum β-lactamase (ESBL) (2, 6). The expansion of E. coli ST131 in the 62 United States has been driven mainly by a single clade, designated H30 because of its tight 63 association with allele 30 of the type-1 fimbrial adhesin gene, fimH. H30 has a prominent MDR-64 associated clade, H30R, which accounts for most fluoroquinolone resistance within ST131. H30R in 65 turn has two main sub-clades: H30R, which accounts for almost all ST131-associated CTX-M-14 66 and CTX-M-27 production (although most members are ESBL-negative), and H30Rx, which 67 accounts for almost all ST131-associated CTX-M-15 production (6). In addition to H30, other 68 distinct clades of ST131 are also circulating worldwide, most commonly associated to the 22 and 41 69 fimH alleles. While these non-H30 allelic variants are normally not associated with carriage of CTX-70 M-genes, cases of bla CTX-M-14 , bla CTX-M-15 and bla CTX-M-27 acquisition by ST131 lineages carrying 71 fimH22 or -H41 have been reported (4, 7). 72 ST131 isolates typically carry multiple ExPEC-associated virulence genes encoding 73 adhesins, toxins, and siderophores, whereas virulence genes typical of diarrheagenic E. coli (DEC) 74rarely have been reported (8, 9). However, we recently surveyed an international World Health 75 Organization (WHO) collection of historic E. coli for ST131 O25 isolates, assessing them for 76 temporal trends of antibiotic resistance and virulence traits. Among a total of 128 ST131 isolates we 77 found 12 (9%) that fulfilled molecular criteria for the enteroaggregative E. coli (EAEC) pathotype 78 (10). Pulsed-field gel electrophoresis (PFGE) analysis revealed a cluster comprising seven of these 79 6 EAEC isolates. Of these, sixincluding two urine isolates from patients with UTI, three fecal 80 isolates from patients with diarrhea, and one lower respiratory tract isolate (associated symptoms 81 unknown)were from Danish patients (1998)(1999)(2000), supporting the occurrence of an unrecognized 82 EAEC ST131-associated outbreak of UTI and po...

Origin and Evolution of Hybrid Shiga Toxin-Producing and Uropathogenic Escherichia coli Strains of Sequence Type 141

“…We believe that the presence of such melting pots is a phenomenon during pathogen evolution even more common than expected. Recent data from Boll et al (57) corroborate our hypothesis: they isolated ST131 E. coli, the most prevalent multidrug-resistant ExPEC lineage globally, from current community-acquired bacteremia and recurrent UTI cases in Denmark and found acquisition of the EAECdefining virulence plasmid pAA and of additional ExPEC genes, thereby enhancing the ability to successfully colonize and subsequently infect humans (57). We speculate that in-depth analysis of all available ST131 E. coli strains could reveal the existence of other hybrids within ST131 E. coli and further affirm our hypothesis that heteropathogenicity is a common phenomenon of pathogenic E. coli strains.…”

Whole genome sequence comparison of avian pathogenic Escherichia coli from acute and chronic salpingitis of egg laying hens

“…Poultry intestinal carriage of extra-intestinal pathogenic E. coli (ExPEC) which causes extra-intestinal disease in humans may be of epidemiological relevance and concern as the STs found are similar to the most prevalent STs from this study [40][41][42][43]. E. coli has been identified in both eggs and poultry meat [28,31,44,45] which may serve as a vector for E. coli Moreover it is suggested that certain lineages within ST131 have acquired traits which may favor intestinal colonization despite being characterized as ExPEC [46].…”

Genomic analysis of trimethoprim-resistant extraintestinal pathogenic Escherichia coli and recurrent urinary tract infections

“…These EAEC isolates were not previously described as hybrid strains and originated from cases of diarrhoeal disease in England [40]. However, hybrid EAEC/ExPEC strains are known to cause UTI outbreaks [119,120]. EAEC strains carry most of their virulence cargo on plasmids and are renowned for prolific biofilm formation [121].…”