Diagnosis of Streptococcus pneumoniae meningitis by polymerase chain reaction amplification of the gene for pneumolysin

Healthy adults with Streptococcus pneumoniae meningitis and Streptococcus pneumoniae subdural abscess: two case reports and a literature review

We present the cases of two otherwise healthy adults, one with meningitis and another with a subdural abscess, with both conditions attributable to Streptococcus pneumoniae. A 31-year-old man was admitted with a 3-day history of fever, headache, and vomiting. Physical examination revealed intermittent confusion, irritability, and neck stiffness. Cerebrospinal fluid (CSF) culture was positive for S. pneumoniae. Contrast-enhanced magnetic resonance imaging (C-MRI) revealed multiple small lesions on the bilateral frontal lobes. Intravenous ceftriaxone and vancomycin were administered, followed by intravenous moxifloxacin. His symptoms resolved within 3 months. Additionally, a 66-year-old man was admitted for acute fever with confusion, abnormal behavior, and a recent history of acute respiratory infection. Physical examination revealed confusion, neck stiffness, and a positive right Babinski sign. CSF metagenomic analysis detected S. pneumoniae. C-MRI disclosed left occipitotemporal meningoencephalitis with subdural abscesses. Intravenous ceftriaxone was administered for 3 weeks. His condition gradually improved, with resorbed lesions detected on repeat MRI. This study expanded the clinical and imaging spectra of S. pneumoniae meningitis. In healthy adults, S. pneumoniae can invade the brain, but subdural abscess is a rare neuroimaging manifestation. Early diagnosis of S. pneumoniae meningitis by high-throughput sequencing and flexible treatment strategies are necessary for satisfactory outcomes.

Detection and serotyping of lyophilized nonculturable pneumococcal isolates

One hundred fifty-two nonculturable lyophilized carriage pneumococcal isolates from a vaccine trial were subjected to PCR for serotyping, and 149 (98%) were successfully classified as vaccine or nonvaccine types, which were similar to viable isolates. The methodology will be useful for analysis of this and other studies where stored pneumococcal isolates fail to grow.

Acute bacterial meningitis cases diagnosed by culture and PCR in a children's hospital throughout a 9-Year period (2000-2008) in Athens, Greece

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.

Medical microbiology: laboratory diagnosis of invasive pneumococcal disease

The laboratory diagnosis of invasive pneumococcal disease (IPD) continues to rely on culture-based methods that have been used for many decades. The most significant recent developments have occurred with antigen detection assays, whereas the role of nucleic acid amplification tests has yet to be fully clarified. Despite developments in laboratory diagnostics, a microbiological diagnosis is still not made in most cases of IPD, particularly for pneumococcal pneumonia. The limitations of existing diagnostic tests impact the ability to obtain accurate IPD burden data and to assess the effectiveness of control measures, such as vaccination, in addition to the ability to diagnose IPD in individual patients. There is an urgent need for improved diagnostic tests for pneumococcal disease--especially tests that are suitable for use in underresourced countries.