Background and Objectives: Acute bacterial meningitis is one of the most
severe infectious diseases, affecting mainly infants and, secondarily,
older children and adolescents. Diagnosis in the early stages is often
difficult and despite treatment with appropriate antibiotic therapy, the
case fatality rate remains high. In the present study, the incidence of
bacterial meningitis was registered in a general pediatric hospital in
Athens, Greece, during a 9-year period (2000-2008), and the use of
molecular methods in the diagnosis of bacterial meningitis versus the
conventional cultural methods was evaluated. The impact of vaccination
against meningitis-causing bacteria on the incidence of bacterial
meningitis was also assessed.
Methods: From a total of 1833 children hospitalized with suspected
clinical symptoms and signs of meningitis, all cerebrospinal fluid (CSF)
and blood samples were analyzed by white blood cell (WBC) count,
measurement of glucose, protein, and C-reactive protein (CRP) levels, as
well as by conventional bacteriologic culture methods. If samples showed
altered CSF markers that were consistent with meningitis in general,
they were further investigated by PCR for bacterial pathogens.
Results: Of the 1833 patients, 289 (15.76%) were found to be positive
for meningitis after CSF examination, based on white blood cell count
and differentiation, glucose, protein, and CRP. Fifty-six of the 289
(19.37%) had confirmed bacterial meningitis, as diagnosed by either
culture and/or PCR. Of these 56 cases, 44(78.6%) were detected only by
PCR, and 12 cases (21.4%) were confirmed by PCR and culture. The
predominant microorganism was Neisseria meningitidis serogroup B (n =
40; 71.4%), followed by Streptococcus pneumoniae not typed [NT] (n =
7; 12.5%), Streptococcus spp. (n = 4; 7.1%), Haemophilus influenzae NT
(n = 2; 3.6%), and S. pneumoniae serotype 3, Streptococcus group B, and
S. pneumoniae serotype 18C (each n = 1; 1.8%).
Conclusion: In Greece, according to data from the National Meningitis
Reference Laboratory, vaccination against N. meningitidis serogroup C
since 2001 led to a 10-fold decrease in the incidence of meningitis
cases, vaccination against S. pneumoniae serotypes included in the
heptavalent conjugate vaccine since 2005 led to a 3.4-fold incidence
decrease, and vaccination against H. influenzae type b since 1992 led
almost to an absence of cases. In the population of the present study,
none of the cases were caused by the above-mentioned vaccine pathogens,
except for one S. pneumoniae serotype 18C case with no history of past
vaccination.
The introduction of vaccination against meningitis-causing bacteria has
drastically decreased the emergence of the infection. The improved
molecular amplification assays proved to be superior to conventional
bacteriologic methods and should be introduced into routine diagnosis,
as well as the epidemiologic surveillance of bacterial meningitis