Invasive infections caused by Streptococcus pneumoniae has been a nationally notifiable disease in Australia since 2001. A leading cause of meningitis, S. pneumoniae is a common coloniser of the upper respiratory tract, causing pneumonia, septicaemia and otitis media. The severity of the disease is pronounced in infants and the elderly. Laboratory diagnosis of invasive pneumococcal infections is hampered by often time consuming and unreliable classical methods. The provision of appropriate antimicrobial therapy is essential, requiring the clinical need for assays which are sensitive and specific to assist in early diagnosis.
The use of molecular biology techniques in order to detect critical infectious pathogens is regarded as a dependable and rapid means of diagnosis and epidemiological surveillance. The lytA target, part of the AusDiagnostics CSF 14Plex assay was evaluated for its utility in detecting the presence of S. pneumoniae from nucleic acid extracts obtained from CSF and EDTA Whole Blood. The primers employed in the assay have been designed to detect S. pneumoniae serotypes included in the 7V and 23V vaccines. Non-vaccine serotypes such as 6A will also be detected. Specimens with confirmed serotypes 15A and 15B have been detected by the assay in clinical practice. Serotyping was also possible by sequencing the product of capsular polysaccharide synthesis cpsA and cpsB genes from positive nucleic acid extracts.
The accurate diagnosis of invasive infections caused by S. pneumoniae is of significant importance for the continued surveillance of communicable diseases. The AusDiagnostics lytA target has demonstrated its clinical value to microbiology laboratories seeking for a means to rapidly diagnose or exclude invasive infections caused by S. pneumoniae directly from patient specimens.