capsulated

Differences Between Streptococcus Pneumoniae and Viridans Streptococci

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S.N   Streptococcus pneumoniae S.N   Viridans streptococci 1. Are capsulated. 1. Are non-capsulated. 2. Shape is lanceolate or flame shaped. 2. Shape is oval or round cells. 3. Give Positive quellung test. 3. Give negative quellung test. 4. On blood agar, dome-shaped initially, later on appear as draughtsman colonies. 4. On blood agar, dome-shaped. … Read more

Virulence factors of Bordetella pertussis

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Bordetella pertussis is a small non-motile, non-sporing ovoid. Gram negative cocco-bacillus. It measures about 1-1.5µm x 0.3µm and is haemolytic. Capsulated (fresh isolates from patients), strict aerobes and fastidious. On staining with toludine blue, metachromatic granules are seen. The genes coding for B. pertussis virulence factors are under the control of two sets of genes, which … Read more