The causes of post-operative meningitis: the comparison of gram-negative and gram-positive pathogens

2015, Çeşme, Turkey The Causes of Postoperative Meningitis: The Comparison of Gram-Negative and Gram-Positive Pathogens ABSTRACT ment.Neurosurgical interventions for trauma or tumors, invasive procedures of the central nervous system, or implants for cerebrospinal fluid (CSF) drainage could end up with POM with an incidence of 0.34%-3.1% (6,8,22,27).The etiology of POM includes a wide spectrum of microorganisms from Gram-positive cocci to Gram-negative bacilli.Although still █ INTRODUCTION In spite of new antimicrobials and surgical techniques, postoperative meningitis (POM) results in considerable morbidity and mortality, necessitating an organized and thoughtful approach for prevention, diagnosis, and manage-AIM: To determine the microbiological etiology in critically ill neurosurgical patients with nosocomial meningitis (NM) and to show the impact of Gram-negative rods and the differences between patient characteristics and the clinical and prognostic measures in Gram-negative and Gram-positive meningitis. MATERIAL and METHODS:In this prospective, single-center study, we reviewed all adult patients hospitalized during a 12-year period and identified pathogens isolated from post-neurosurgical cases of NM.Demographic, clinical, and treatment characteristics were noted from the medical records. RESULTS:Of the 134 bacterial NM patients, 78 were male and 56 were female, with a mean age of 46±15.9 and a median age of 50 (18-80) years.One hundred and forty-one strains were isolated; 82 (58.2%) were Gram-negative, 59 (41.8%) were Grampositive.The most commonly isolated microorganism was Acinetobacter baumannii (34.8%).Comparison of mortality data shows that the patients who have meningitis with Gram-negative pathogens have higher mortality than with Gram-positives (p=0.034).The duration between surgery and meningitis was shorter in Gram-negative meningitis cases compared to others (p=0.045)but the duration between the diagnosis and death was shorter in Gram-positive meningitis cases compared to Gram-negatives (p=0.017).Cerebrospinal fluid protein and lactate levels were higher and glucose level was lower in cases of NM with Gram-negatives (p values were respectively, 0.022, 0.039 and 0.049). CONCLUSION:In NM, Gram-negative pathogens were seen more frequently; A. baumanni was the predominant pathogen; and NM caused by Gram-negatives had worse clinical and laboratory characteristic and prognostic outcome than Gram-positives.