Pyelonephritis Caused Solely by Escherichia hermanii

In contrast with Escherichia coli, the association of E. hermanii with urinary tract infections has not been described.

In this case, E. hermanii was the sole isolate recovered from urine specimens of a pyelonephritis patient. The organism was found to be susceptible to piperacillin-tazobactam, ceftazidime, cefazolin, cefixime, aztreonam, gentamicin, tobramycin, imipenem, meropenem and amikacin, and resistant to amoxicillin. Antibiotic treatment was initiated with oral cefixime (400 mg every 24 hours). The symptoms were relieved within 72 hours after therapy. A urine sample was taken seven days after antibiotic therapy. E. hermanii was no longer isolated.

The present case demonstrates that the uropathogenic E. hermanii clone can cause destruction of the kidneys. During asymptomatic bacteriuria or cystitis, the bacteria remain in the urinary tract. Even when pyelonephritis develops, inflammatory response of the host is still restricted to the urinary tract. These signs mean that uropathogenic E. hermanii may be not very virulent.