“Satellidsm” in presence of streak of staphylococci is shown by
Correct Answer: Haemophilus influenzae
Description: Ans. c (Haemophilius influenzae) (Ref. Ananthanarayan Microbiology 7th ed., Fig. 36.2, p. 334)H. influenzae# Gram negative, nonmotile, non-sporing bacillus exhibiting considerable pleomorphism.# In sputum usually occurs as clusters of coccobacillary forms, while in the CSF from meningitis cases long, bacillary and filamentous forms predominate.# Strains isolated from acute infections are often capsulated.# They are relatively difficult to stain. Staining for 5-15 minutes with Loeffler's methylene blue or dilute carbol fuschin gives good results.# It is aerobic but grows anerobically also.# The optimum temp is 37degC. It does not grow below 20degC. Some strains require 10% CO2# It grows on blood agar but growth is scanty as the V factor is not freely available, being imprisoned inside the red blood cells.# Growth is therefore better if a source of factor V is also provided.# When Staph aureus is across a plate of blood agar on which a specimen containing H. influenzae has been inoculated, after' overnight incubation, the colonies of H. influenzae will be large and well developed alongside the streak of Staphylococcus, and smaller farther away. This phenomenon is called SATELLITISM.# It is however not very specific as it will also be positive with* other V factors requring hemophilli as well as occasional strains of Neisseriae and Diphtheroids.# Aerosol transmission.# Invasive disease caused by capsular type B.# Produces IgA protease.# Culture on chocolate agar requires factors V (NAD) and X (hematin) for growth.# Treat meningitis with ceftriaxone.# Rifampin prophylaxis in close contacts.# Vaccine contains type B capsular polysaccharide conjugated to diphtheria toxoid or other protein.# Given between 2 and 18 months age.
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