Enteroaggregative Escherichia coli O78:H10, the Cause of an Outbreak of Urinary Tract Infection

Abstract

eIn 1991, multiresistant Escherichia coli O78:H10 strains caused an outbreak of urinary tract infections in Copenhagen, Denmark. The phylogenetic origin, clonal background, and virulence characteristics of the outbreak isolates, and their relationship to nonoutbreak O78:H10 strains according to these traits and resistance profiles, are unknown. Accordingly, we extensively characterized 51 archived E. coli O78:H10 isolates (48 human isolates from seven countries, including 19 Copenhagen outbreak isolates, and 1 each of calf, avian, and unknown-source isolates), collected from 1956 through 2000. E. coli O78:H10 was clonally heterogeneous, comprising one dominant clonal group (61% of isolates, including all 19 outbreak isolates) from ST10 (phylogenetic group A) plus several minor clonal groups (phylogenetic groups A and D). All ST10 isolates, versus 25% of non-ST10 isolates, were identified by molecular methods as enteroaggregative E. coli (EAEC) (P < 0.001). Genes present in >90% of outbreak isolates included fimH (type 1 fimbriae; ubiquitous in E. coli); fyuA, traT, and iutA (associated with extraintestinal pathogenic E. coli [ExPEC]); and sat, pic, aatA, aggR, aggA, ORF61, aaiC, aap, and ORF3 (associated with EAEC). An outbreak isolate was lethal in a murine subcutaneous sepsis model and exhibited characteristic EAEC "stacked brick" adherence to cultured epithelial cells. Thus, the 1991 Copenhagen outbreak was caused by a tight, non-animal-associated subset within a broadly disseminated O78:H10 clonal group (ST10; phylogenetic group A), members of which exhibit both ExPEC and EAEC characteristics, whereas O78:H10 isolates overall are phylogenetically diverse. Whether ST10 O78:H10 EAEC strains are both uropathogenic and diarrheagenic warrants further investigation.

Characterization of Escherichia coli Isolates from Hospital Inpatients or Outpatients with Urinary Tract Infection

“…The prevalence of EAEC marker genes in urine isolates has also been reported in Brazil (39,57), and E. coli strains with a typical EAEC virulence marker content have been recently isolated from patients with prostatitis (58). Together with the recent documentation of an UTI outbreak caused by an EAEC O78:H10 strain (55,59), this demonstrates the high heterogeneity of this pathotype and underlines that some EAEC strains have the potential to be uropathogenic. Against the background that EAEC represents a highly heterogeneous pathotype (42,60,61), clinically relevant EAEC subtyping should be improved, and the uropathogenicity of EAEC isolates from UTI cases requires further analysis.…”

Prevalence and Characteristics of the Epidemic Multiresistant Escherichia coli ST131 Clonal Group among Extended-Spectrum Beta-Lactamase-Producing E. coli Isolates in Copenhagen, Denmark

“…Both isolates originated with patients with UTI admitted to emergency departments. We recently reported an outbreak of UTI in Copenhagen caused by a clonal group of E. coli O78:H10 that both fulfilled molecular criteria for EAEC and contained multiple ExPEC virulence genes (37). Intriguingly, the outbreak strain's EAEC-specific virulence factors were found to increase its uropathogenicity (38).…”

Recurrent urinary tract infection due to co‐infection with extended spectrum β‐lactamase‐producer uropathogenic Escherichia coli and enteroaggregative E. coli

“…EAEC-mediated extra-intestinal disease was first reported by Erik and colleagues in 2012 (Boll, 2012). EAEC has virulence factors that can cause symptomatic UTI (Herzog et al, 2013;Olesen et al, 2012). In Bangladesh, the true incidence of EAEC infections is unknown.…”