Influence of third-generation cephalosporin resistance on adult in-hospital mortality from post-neurosurgical bacterial meningitis.

BACKGROUND/PURPOSE: To investigate the clinical features, etiology and predictors of in-hospital mortality in adults with post-neurosurgical bacterial meningitis.

METHODS: This retrospective analysis included 60 adult patients with culture-proven post-neurosurgical bacterial meningitis hospitalized between September 2006 and August 2008.

RESULTS: Of the 60 patients, 88.3% had monomicrobial infection and 11.7% had mixed infection. The mean duration from the first neurosurgical procedure to the diagnosis of meningitis was 21 days (range, 1-134 days). The median frequency of neurosurgical procedure before meningitis was 1 (range, 1-5). A total of 69 isolates were identified from the cerebrospinal fluid, the most common pathogens were Gram-negative bacilli (43, 62.3%), followed by Gram-positive bacteria (24, 34.8%). The three most common Gram-negative bacilli were Serratia marcescens (7, 10.1%), Klebsiella pneumoniae (6, 8.7%), and Enterobacter cloacae (4, 5.8%). Pseudomonas aeruginosa and Acinetobacter baumannii isolates comprised less than 3%. Notably, glucose non-fermenting Gram-negative bacilli other than Acinetobacter and Pseudomonas spp. accounted for 11.6% of the total. Of the Gram-negative bacilli, resistance rates to the third-generation cephalosporins, ceftriaxone and ceftazidime, were 58.1% and 34.9%, respectively. The two most common Gram-positive pathogens were Staphylococcus aureus (10, 14.5%) and coagulase-negative staphylococci (including S. epidermidis) (10, 14.5%). The in-hospital mortality rate was 15.0%, which was significantly related to Gram-negative bacilli resistant to third-generation cephalosporins in multivariate analysis (adjusted odds ratio = 33.65; p = 0.047).

CONCLUSION: These findings may portend the spread of serious resistance to third-generation cephalosporins in nosocomial Gram-negative bacilli throughout the neurosurgical units, suggestive of the need to reassess the empirical use of third-generation cephalosporins in post-neurosurgical bacterial meningitis.