Intrathecal colistin for treatment of multidrug resistant (MDR) Pseudomonas aeruginosa after neurosurgical ventriculitis Colistina intratecale nel trattamento di un caso di ventricolite post-chirurgica da Pseudomonas aeruginosa multi resistente

C erebrospinal fluid (CSF) shunts significantly improve the quality of life in patients with acute hydrocephalus. However, CSF infection associated with shunts is a severe complication with high morbidity and mortality [1]. The incidence of shunt-associated infection has a range of 1%-18%, and several independent risk factors have been identified [2-5]. Organisms causing shunt-associated infections typically adhere to the device surface and form biofilms, which makes clinical and laboratory diagnosis difficult and treatment challenging. Clinical symptoms are often non-specific, especially when shunt-associated infections are caused by low-virulence organisms. Often, only signs of intracranial hypertension attributable to shunt malfunction are present, but these are difficult to evaluate in patients with a poor Glasgow Coma Scale (GCS) [6]. It is therefore crucial to diagnose shunt-associated infection both early on and accurately so as to be able to plan appropriate medical and/or surgical intervention. The fluid is usually colonized by Gram-positive bacteria, but long stays in Intensive Care Units (ICU) permit colonization by Gram-negative bacteria. Gram-negative infections are normally treated with carbapenems which are usually considered the treatment of choice for severe infection due to their high penetration through the cerebral blood barrier [7]. However, the increasing resistance of carbapenems worldwide has led to the revival of old antibiotics: polymyxin E (or colistin) and B which are active against Gram-negative bacteria like Acinetobacter spp, Pseudomonas aeruginosa, Klebsiella spp and Enterobacter spp. The antibacterial action of these drugs targets the cell membrane.