Roultella ornithinolytica infection in infancy: a case of febrile urinary tract infection.

Raoultella ornithinolytica is a Gram-negative, non-motile, encapsulated, aerobic bacillus belonging to the Enterobacteriaceae family. R. ornithinolytica is a not very common, but emergent causal agent of human infection, and its expression of beta-lactamase provides resistance to commonly used antibiotics. The pathogenetic potential of R. ornithinolytica isolates in human disease has become increasingly important. Several cases of hospital-acquired infection, mostly associated with invasive procedures, or in patients with co-morbidity caused by R. ornithinolytica, have been previously reported in the adult population. In pediatric population, two cases in immunocompromised children, one case in an infant with visceral heterotaxy and one case of catheter-related bacteraemia are described. Here, we present the first case of febrile urinary tract infection due to R. ornithinolytica in an 8-month-old infant, recovered from a previous febrile UTI caused by E. coli and without co-morbidity. The empiric therapy with ceftriaxone, followed by cefpodoxime proxetil, resolved symptoms: the clinical condition of the infant improved rapidly and the treatment eradicated urine from the R. ornithinolytica infection. Since other pathogens rather than R. ornithinolytica are usually identified in children with urinary tract infections, including Escherichia coli, Proteus, Klebsiella and Pseudomonas, the identification of this microorganism in our patient's urine was also unexpected.