Adult Citrobacter freundii meningitis: case report.

Citrobacter is a distinct group of Gram-negative bacilli belonging to the Enterobacteriaceae family. Central nervous system (CNS) infections due to Citrobacter are uncommon, though they occur more frequently in neonates and young children. In adults, Citrobacter meningitis is extremely unusual with only 6 cases reported in the literature before 1998. This rare CNS infection has been seen in patients with head trauma, following neurosurgical procedures, and in those who are immunocompromised. Of the patients in the 6 reported cases, only one developed multi-antibiotic resistant Citrobacter CNS infection. Adding to this small number of reported cases, we report an adult case of post-neurosurgical meningitis and subdural empyema caused by multi-antibiotic resistant Citrobacter freundii and also review the literature related to this infection. Antimicrobial therapy with imipenem and third-generation cephalosporins failed to result in cerebrospinal fluid sterilization in our patient. Because of the use of broad-spectrum antibiotics, multi-antibiotic resistant Citrobacter species have developed in this nosocomial CNS infection and now present a therapeutic challenge. Therefore, further clinical studies are needed to determine updated therapeutic modalities for treating this life-threatening infection.