The causal relationship between O2:K7:H6 extra-intestinal pathogenic Escherichia coli (ExPEC) and native valve endocarditis: a case report

Background Native valves infective endocarditis due to Escherichia coli is still a rare disease and a particular virulence of some E.coli isolate may be suspected. Case presentation A 79-year-old woman presented during the post-operative period of an orthopedic surgery a urinary tract infection following obstructive ureteral lithiasis. E. coli was isolated from a pure culture of urine and blood sampled simultaneously. After evidence of sustained E.coli septicemia, further investigations revealed acute cholecystitis with the same micro-organism in biliary drainage and a native valve mitral endocarditis. E.coli was identified as O2:K7:H6, phylogenetic group B2, ST141, and presented several putative and proven virulence genes. The present isolate can be classified as both extra-intestinal pathogenic E.coli (ExPEC(JJ)) and uropathogenic E. coli (UPECHM). Conclusions The relationship between the virulent factors present in ExPEC strains and some serotypes of E. coli that could facilitate the adherence to cardiac valves warrants further investigation.