Enterococcus hirae Bacteremia in an Infant: Case Report and Review of the Literature

Enterococcus hirae is a gram-positive coccus that is rarely implicated in human disease and has not been reported in pediatric patients. We report a case of catheter-associated bloodstream infection and prolonged bacteremia in a 7-month-old infant dependent on total parenteral nutrition. The species was identified by the VITEK2 system and confirmed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The organisms was susceptible to ampicillin, vancomycin, and high-level gentamicin. The patient was treated with vancomycin and gentamicin with adjunctive vancomycin lock therapy but had persistent bacteremia. Therapy was changed to dual β-lactam therapy of ampicillin and ceftriaxone with synergistic gentamicin, which led to clearance of the enterococcal bacteremia. E hirae is an unusual species that may be difficult for the microbiology laboratory to identify. This is the first pediatric case and the second case of invasive E hirae in the United States.