Is Streptococcus pseudopneumoniae a neglected respiratory pathogen.

ABSTRACT

Streptococcus pseudopneumoniae is a member of Viridans streptococci, associated with chronic obstructive lung disease and lower respiratory infection. It is non-capsulated, bile insoluble and optochin susceptible in ambient air but intermediate or resistant in 5%CO2. But, its role as a pathogen is yet to be established. The objective of the study was to detect the prevalence and to determine the clinical significance of S.pseudopneumoniae in sputum samples. The study period was 5 months. Good quality sputum samples (>25 neutrophils and <10 epithelial cells/LPF) of patients suspected of LRTIs, were inoculated onto chocolate agar. Alpha haemolytic colonies were identified by testing for capsule by India ink preparation, bile solubility and optochin susceptibility in ambient air and 5%CO2. Antibiotic sensitivity testing was done by Kirby-Bauer's disc diffusion method. Out of 66 alpha haemolytic colonies, 4 were S.pseudopneumoniae, 17 were S.pneumoniae and 45 were other Viridans streptococci. Antibiotic sensitivity patterns of S.pseudopneumoniae and S.pneumoniae were analyzed. S.pseudopneumoniae is misinterpreted as S.pneumoniae unless specifically looked for. As there is scant information available, studies have to be encouraged for better determination of clinical importance of S.pseudopneumoniae. This will help in right diagnosis and successful treatment.