VIASURE H. influenzae + N. meningitidis + S. pneumoniae Real Time PCR Detection Kit is designed for the specific identification and differentiation of Haemophilus influenzae, Neisseria meningitidis and/or Streptococcus pneumoniae in cerebrospinal fluid or blood samples from patients with signs and symptoms of meningitis.
This test is intended to be used as an aid in the diagnosis of H. influenzae, N. meningitidis and/or S. pneumoniae in combination with clinical and epidemiological risk factors.
DNA is extracted from specimens, multiplied using Real Time amplification and detected using fluorescent reporter dye probes specific for H. influenzae, N. meningitides and S. pneumoniae.
The most common causes of bacterial meningitis in adults are Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae. These organisms are spread from person to person by close contact with respiratory secretions. Once acquired, each species can colonize the mucosa of the nasopharynx and oropharynx, which is known as pharyngeal carriage. From there, they may cross the mucosa and enter the blood. Once in the blood, they can reach the meninges, causing meningitis, or other body sites causing other syndromes. The term “meningitis” describes inflammation of the membranes (meninges) that surrounds and protects the brain and spinal cord. Meningitis symptoms include sudden onset of fever, headache, and stiff neck. There are often other symptoms, such as nausea, vomiting, photophobia and altered mental status. Bacterial meningitis is a lifethreatening condition that requires prompt recognition and treatment.
Haemophilus influenzae, a pleomorphic gram-negative coccobacillus. Is a common commensal microorganism of the upper respiratory tract. It is a human-only pathogen that can cause severe invasive disease, including meningitis, pneumonia, and septicemia. H. influenzae strains are divided based on the presence or absence of a polysaccharide capsule; there are 6 encapsulated serotypes (Hia–Hif) and nonencapsulated, nontypeable H. influenzae (NTHi) strains. Among them, Hib strains are considered the most prevalent.
Neisseria meningitidis may either be encapsulated or unencapsulated. However, nearly all invasive N. meningitides organisms are encapsulated, or surrounded by a polysaccharide capsule. This capsular polysaccharide is used to classify N. meningitidis into 12 serogroups. Six of these serogroups cause the great majority of infections in people: A, B, C, W135, X, and Y. Meningitis epidemics are generally caused by serogroup A, although outbreaks have also been caused by serogroups C, W135, and X.
Streptococcus pneumoniae cause severe infections like meningitis, community-acquired pneumonia (CAP), bacteremia, bronchitis, sinusitis, and otitis media. More than 90 different serotypes of S. pneumoniae have been identified to date on the basis of the biochemical structure of the capsular polysaccharide that is a major virulence factor. The distribution of serotypes can vary with age, geography and time.
Cerebrospinal fluid culture is considered the diagnostic reference standard for bacterial meningitis, and bacterial isolation is important for antimicrobial susceptibility testing and molecular epidemiology. However, CSF culture requires at least a day or more, and has limited sensitivity. Real-Time Polymerase Chain Reaction (qPCR) of CSF and blood has been suggested as a rapid diagnostic test for bacterial meningitis, and amplification of DNA from non-viable bacteria could potentially facilitate diagnosis in culture negative cases. Using multiple analytic approaches, we found that qPCR assays on CSF and blood specimens were highly accurate for diagnosis of S. pneumoniae, N. meningitidis, and H. influenzae meningitis.