Bacillus cereus Bloodstream Infection in a Preterm Neonate Complicated by Late Meningitis

Central nervous system infections caused by Bacillus cereus have rarely been reported in infants. In this paper, the case of a 2-month-old low-birth-weight female who developed meningitis 45 days after resolution of a bloodstream infection (BSI) is described. The pulsed-field gel electrophoresis results revealed that the patterns of both B. cereus isolates responsible for the acute meningitis and for the prior bacteraemic episode were closely related. Although the source of the infection from within the patient was not clear, it is suggested that the B. cereus BSI developed in the neonate was complicated by acute meningitis. 1. Introduction Central nervous system (CNS) infections caused by Bacillus cereus are primarily of haematogenous origin and can complicate neuroinvasive procedures [1]. B. cereus rarely causes CNS infections in infants, but the mortality rate in such cases is high [2, 3]. Endospores of B. cereus are found in various environments, including healthcare settings. The occurrence of nosocomial B. cereus BSIs in hospitals and in neonatal intensive care units (NICUs) has been reported [4–6]. In the present paper, a case of acute meningitis caused by B. cereus that occurred long after B. cereus bloodstream infection (BSI) in an infant is described, and it is discussed whether the episode of meningitis related to the prior BSI or was new infection. 2. Case Presentation A 2-month-old low-birth-weight female (body weight, 0.8？kg) developed meningitis 45 days after resolution of a BSI. The BSI was not catheter related. The patient’s blood culture results were positive for B. cereus (006 and 007 on days 1 and 5, resp., from the onset of the BSI). B. cereus group was identified phenotypically as facultatively anaerobic, endospore-forming, gram-positive rods that yielded positive results for the egg-yolk reaction and utilized D-trehalose, using a 2% egg-yolk NGKG agar plate (NGKG agar base, Nissui Pharmaceutical, Tokyo, Japan) and a BBL crystal gram-positive identification system (Nippon Becton Dickinson, Tokyo, Japan). In the isolates 006 and 007, the minimum inhibitory concentrations (MICs) determined by the Etest method are shown in Table 1. Both isolates showed good susceptibility to imipenem, meropenem, gentamicin, clindamycin, vancomycin, linezolid, and levofloxacin. After treatment with adequate doses of vancomycin and meropenem—either singly or in combination—for a total of 10 and 16 days, respectively, the signs and symptoms of BSI completely resolved and the blood cultures were sterile within 20 days. However, 45 days after