Host-pathogen relationships among Escherichia coli isolates recovered from men with febrile urinary tract infection

Background. Host-pathogen relationships in men with febrile urinary tract infection ( FUTI) are poorly understood. Methods. Phylogenetic background, extended virulence genotypes, and serotypes were determined for 70 Escherichia coli isolates recovered from urine samples obtained from men with FUTI for comparison with available data for 70 E. coli rectal isolates recovered from uninfected men. Bacterial traits were assessed in relation to underlying host characteristics ( age, compromise status, and history of urinary tract infection) and acute manifestations (bacteremia, flank pain, and serum prostate-specific antigen [PSA] level). Results. Compared with rectal isolates, FUTI isolates exhibited a significantly higher prevalence of virulence-associated phylogenetic groups, serotypes, and extraintestinal virulence genes. The latter included traditional prostatitis-associated traits ( e. g., hemolysin and cytotoxic necrotizing factor), as well as unconventional traits, such as outer membrane protease T. These bacterial traits occurred largely independent of host age, urological compromise status, urinary tract infection history, and acute manifestations. However, certain traits were less prevalent in association with use of urinary tract instrumentation and significantly predicted elevated PSA levels. Conclusions. Considerable virulence capability may be required for an E. coli strain to cause FUTI in men, regardless of whether most compromising conditions are present. Bacterial traits that promote prostatic invasion may be relevant for the pathogenesis of FUTI, even among men without classic manifestations of acute prostatitis.