GENETIC SURVEY OF INVASIVE S. PNEUMONIAE SEROTYPES IN BULGARIA FOR A 5-YEAR PERIOD

Streptococcus pneumoniae colonises the mucosal lining of the upper respiratory tract and is an important cause of invasive infections affecting young children, adults over 65 years of age, the immunocompromised and individuals with chronic diseases. Recent studies have shown variations in virulence based on the high rate of pneumococcal recombination. PCR-based molecular methods are highly sensitive, specific and are becoming the preferred tool for quick and accurate diagnosis of bacterial meningitis which is required to be defined within 2-3 hours. During the 5-year survey period (2013-2017), 202 materials received as cerebrospinal fluid samples and pneumococcal strains isolated from patients diagnosed with meningitis, were examined by Real-time PCR in the reference laboratory at NCIPD. Serotyping of S. pneumoniae-positive materials was performed with conventional multiplex PCR and Real-time PCR with primers for 41serotypes/serogroups. There is a high incidence of S. pneumoniae serotypes not covered by the pneumococcal conjugate vaccine (PCV10) currently used in Bulgaria. It was found that all cases of meningitis caused by S. pneumoniae vaccine serotypes occurred in patients that were not vaccinated.