A child presents with infective skin lesion of the leg. Gram stain from the specimen shows pus cells with gram+ve cocci in chains and culture is done which shows hemolytic colonies. The test to confirm the organism is -
* Infective skin lesion with gram positive cocci in chains and hemolytic colonies suggest infection of Streptococcus pyogenes. Option 1, 2 Pneumococcus: Bile solubility Positive (Bile soluble) Optochin sensitivity Option 3 Streptococcus Pyogenes Transpo medium: Pike's medium Direct smear microscopy: Pus cells with gram-positive cocci in sho chains Culture: Blood agar: Pinpoint colony with a wide zone of b-hemolysis Selective media: Crystal violet blood agar and PNF (polymyxin B, neomycin, fusidic acid) media Liquid media: Granular turbidity with powdery deposit Biochemical: Catalase negative, Bacitracin sensitive (Maxted's observation) Pyrrolidonyl Arylamidase (PYR) test is positive. Option 4 Catalase +ve: Staphylococcus spp. Catalase -ve: Streptococcus spp.
Bile solubility
Optochin sensitivity
Bacitracin sensitivity
Catalase positive
Systemic Bacteriology Pa 1 (Gram Positive Cocci, Gram Negative Cocci)