Gram stain smear of sputum specimen, notice neutrophils and streptococcus pneumoniae diplococci

Streptococcus pneumoniae in sputum sample from patient with pneumonia, showing gram positive diplococci

 

Streptococcus pneumoniae colonies have a flattened and depressed center after 24-48 hours of growth on Blood Agar, whereas the viridans streptococci retain a raised center