Nosocomial infections are important medical problems in neurosurgical patients. Among the nosocomial infections, meningitis and ventriculitis are fearful infections and can lead to severe complications even death. The reported incidence of postoperative meningitis is quite variable (0.5 – 8 %) [1–5]. The incidence of ventriculitis is even lower.
Post-neurosurgical intracranial infections are mostly caused by a wide array of microorganisms. It is reported that the most common organisms causing meningitis are non-fermentative Gram-negative bacteria (NFGNB) (27.3 %), followed by Pseudomonas aeruginosa (15.6 %) and Klebsiella species (12.6 %). A study of 18092 patients who underwent neurosurgical procedures at the department of neurosurgery, National Institute of Mental Health and Neurological Sciences, Bangalore, India during 2001 to 2007, showed that 415 patients developed infection such as meningitis. Only 9 patients of them developed to enterococcus meningitis [6]. Vancomycin-resistant Enterococcus (VRE) ventriculitis occurs extremely rare. So far there are no guidelines recommending an appropriate treatment.
Linezolid (LZD) is the first licensed member of the oxazolidinone class of antibiotics. It has good activity against almost all Gram-positive pathogens, including multidrug-resistant organisms such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) faecium [7]. The unique mechanism of linezolid, that involves inhibition of bacterial protein synthesis at a very early stage of the process, makes cross-resistance between linezolid and other classes of antibacterial agents unlikely [8]. Excellent tissue penetration and great oral bioavailability are notable properties of linezolid. Thus it allows sequential intravenous-to-oral administration without changing the drug or dosage regimen. It is approved in Europe and the USA for the treatment of nosocomial pneumonia, skin and soft tissue infections; and in the USA vancomycin-resistant Enterococcus (VRE) faecium and methicillin-resistant Staphylococcus aureus (MRSA) infections [9]. Linezolid is reported to have good penetration into the CNS [10]. A study in Japan showed the penetration of LZD into the CSF was 58.9 % of the peak value and 133 % of the trough value of serum concentrations following intravenous administration. And the penetration of LZD into the CSF was 82.9 % of the peak value and 145.6 % of the trough value of serum concentrations following oral administration [11]. For patients with a range of serious Gram-positive infections, including those caused by suspected or proven multidrug-resistant pathogens such as VRE or MRSA, linezolid can be an effective and generally well tolerated therapeutic option. In spite of this, gastrointestinal adverse effects are relatively common with linezolid and also associated with thrombocytopenia and myelosuppression [7]. Thus if the adverse effects occur, the doses and treatment period should be reduced.
In this case, the pathogen caused ventriculitis of the patient was vancomycin-resistant Enterococcus (VRE) faecium. It was resistant to many antimicrobials but sensitive to LZD. LZD administrated intravenously 600 mg q12h for half a month, followed by lumbar cistern drainage and VP shunt, led to an excellent outcome. Post-neurosurgical intracranial infections are critical severe events. The appropriate use of antibiotics is a key point. The antibiotics should be sensitive to pathogens and have good penetration into the CNS. The appropriate neurosurgical intervention is also very important, such as lateral ventricular puncture external drainage, lumbar cistern drainage, and VP shunt. Multiple methods led to the cure of post-neurosurgical vancomycin-resistant Enterococcus faecium ventriculitis in this case.
