Mixed infection in adult bacterial meningitis

adult patients suffering from bacterial meningitis caused by mixed infectio n were identified at Kaohsiung Chang Gung Memorial Hospital over a period o f 13 years (1986-1998), and they accounted for 6.5% (12/184) of our culture -proven adult bacterial meningitis. The 12 cases included seven males and f ive females, aged 17-74 years. Six of the 12 cases had community-acquired i nfections and the other six had nosocomially-acquired infections. Ten of th e 12 cases had associated underlying diseases, with head trauma and/or neur osurgical procedure being the most frequent. Both gram-negative and gram-po sitive pathogens were identified in these 12 cases with gram-negative patho gens outnumbering the gram-positive ones. The implicated pathogens, startin g with the most frequent, included Enterobacter species (Enterobacter cloac ae, Enterobacter aerogenes); Klebsiella species (Klebsiella pneumoniae, Kle bsiella oxytoca), Escherichia coli, Staphylococcus species (Staphylococcus aureus, Staphylococcus haemolyticus), Pseudomonas aeruginosa, Acinetobacter baumannii, Enterococcus, Serratia marcescens, Citrobacter diversus, Proteu s mirabilis, Streptococcus viridans and Neisseria meningitidis. Six of the 12 cases were found to have multi-antibiotic-resistant strains, which inclu ded E. cloacae in one, A. baumannii in one, K. pneumoniae in one and S. aur eus in three. The management of these 12 cases included appropriate antibio tics and neurosurgical procedures including shunt revision. Despite the com plexity of implicated pathogens and the high incidence of emergence of resi stant strains, the overall mortality rate (8.3%, 1/2) was not higher than t hat in adult bacterial:meningitis. However, complete recuperation was diffi cult in adult patients with mixed bacterial meningitis.