Intraventricular colistin in Gram-negative ventriculoperitoneal shunt infection in two pediatric patients.

Abstract

Dear Editor, The treatment of post-neurosurgical meningitis, ventriculitis, or central nervous system (CNS) shunt infections is a difficult clinical problem and is associated with a high morbimortality rate [5]. The widespread use of antibiotics led to the emergence of Gram-negative bacteria on these infections [2]. In adults, there are numerous reported methods for the treatment of CNS shunts infections, although no randomized, prospective studies have ever been performed [6]. In pediatric patients, there are only a few case reports in the literature. We report two cases of pediatric neurosurgical patients and the clinical data are summarized in Table 1. A 15-month-old boy, submitted to ventricular-peritoneal shunt (VPS) valve replacement 1 month before, with Escherichia coli and Klebsiella pneumoniae, both extended spectrumβ-lactamases (ESBL) isolated on cerebrospinal fluid (CSF) cultures. On the eighth day of meropenem, after VPS removal, CSF cultures remained positive; an 11-month-old boy with hydrocephalus secondary to neonatal group B streptococcal meningitis was brought to the hospital 16 days after VPS placement and Acinetobacter baumannii was identified in CSF culture. After 6 days of meropenem and amikacin, CSF cultures remained positive. Since our patients did not improve after adequate intravenous antibiotic therapy, we considered the administration of colistin, an old class of cationic, cyclic polypeptide antibiotic. Colistin CSF penetration after intravenous administration appears to be minimal and, although it increases with meningitis, the concentrations achieved may be inadequate [1]. Therefore we considered intraventricular administration. There is a dose discrepancy recommended to intraventricular use in the reviewed studies. In children the daily dose range from 2000 IU/kg (0.16 mg/kg) up to 125,000 IU (10 mg) [4]. For our 15and 11 month-old patients, we decided to dilute colistin with preservative-free NaCl 0.9 % to a concentration of 2 mg/ml and extrapolated the dose to administer based among all the published cases in children: on the first day, a single dose of 1 mg, 2 mg on the second day followed by 4 mg continued 10 days in patient 1 and 9 days on patient 2. The direct instillation of colistin was achieved through external ventricular devices after the removal of a greater or equal volume of CSF used for daily cultures and cytochemistry, in a mean speed of 0.5 ml/min. Whenever a higher volume of CSF was removed, normosaline sterile solution was instilled. The catheter was closed for at least 1 h. The decision to stop should be based on the clinical and microbiological response but we consider that a 10-day period after the first CSF-negative culture is a safe option considering the antimicrobial properties of colistin and the risk for toxicity. Both patients were submitted to simultaneous intraventricular colistin administration and intravenous therapy with a different antimicrobial class, reported susceptible. Removal of all components of the infected shunt in combination with appropriate antimicrobial therapy is the most effective treatment for CNS shunt infections. Success rates are lower when the shunt is treated in situ because of the ability of many of these microorganisms to adhere to prostheses and survive antimicrobial therapy [6] through the * Ana Sofia Santos asfaustino@gmail.com