What is the arrangement of Streptococcus pneumoniae?
What is the arrangement of Streptococcus pneumoniae?
Streptococcus pneumoniae bacteria are gram-positive cocci arranged in chains and pairs (diplococci) on microscopic examination. A green, α-hemolytic, zone surrounds S. pneumoniae colonies on blood-agar plates.
What is the cell shape of Streptococcus pneumoniae?
Streptococcus pneumoniae are lancet-shaped, gram-positive, facultative anaerobic bacteria with 100 known serotypes. Most S. pneumoniae serotypes can cause disease, but only a minority of serotypes produce the majority of pneumococcal infections.
What is the microscopic difference between R and S strains of Streptococcus pneumoniae?
The bacteriologists were interested in the difference between two strains of Streptococci that Frederick Griffith had identified in 1923: one, the S (smooth) strain, has a polysaccharide coat and produces smooth, shiny colonies on a lab plate; the other, the R (rough) strain, lacks the coat and produces colonies that …
Is Streptococcus pneumoniae coagulase positive or negative?
Streptococcus pneumoniae is a gram-positive, encapsulated, lancet-shaped diplococci, most commonly causing otitis media, pneumonia, sinusitis, and meningitis.
What is the morphology of S. pneumoniae?
Morphology. Streptococcus pneumoniae is a Gram-positive, non-motile, non-spore-forming bacterium [2]. S. pneumoniae cells appear as lance-shaped cocci and typically form in pairs (diplococci) but can also appear as single cocci or cocci chains [2,3].
What is a capsular serotype?
In invasive pneumococcal disease the capsular serotype is assumed to be more important than the genotype, because individual serotypes vary in their invasive disease potential (4, 13). Serogroups 1, 4, 5, 7, and 14 are strongly associated with invasive disease, whereas serotype 23F is associated with carriage (5).
Is Streptococcus A eubacteria or archaebacteria?
Streptococcus pneumoniae, abbreviated to S. pneumoniae is another common eubacteria. It belongs to the Firmicutes phylum. It has a spherical shape and is Gram-positive.
What is S strain and R strain?
The R strain is non-pathogenic (does not cause disease). The S strain is pathogenic (disease-causing), and has a capsule outside its cell wall. The capsule allows the cell to escape the immune responses of the host mouse. When Griffith injected the living S strain into mice, they died from pneumonia.
Is Streptococcus pneumoniae Gram-positive Diplococci?
Streptococcus pneumoniae is a gram-positive, α-hemolytic, lancet-shaped diplococcus and is bile soluble and optochin sensitive.
Is S epidermidis catalase positive?
Excerpt. Staphylococcus epidermidis is a coagulase-negative, gram-positive cocci bacteria that form clusters. It is also a catalase-positive and facultative anaerobe. They are the most common coagulase-negative Staphylococcus species that live on the human skin.
Is Streptococcus Gram positive or negative?
Streptococci are Gram-positive, nonmotile, nonsporeforming, catalase-negative cocci that occur in pairs or chains. Older cultures may lose their Gram-positive character.
What type of hemolysis is produced by S. pneumoniae?
pneumoniae appear as small, grey, moist (sometimes mucoidal), colonies and characteristically produce a zone of alpha-hemolysis (green) (Figure 1). The alpha-hemolytic property differentiates this organism from many species, but not from the commensal alpha-hemolytic (viridans) streptococci.
How are the cells of Streptococcus pneumoniae arranged?
Size – The size of Streptococcus pneumoniae is about 1 mm (micrometer). Arrangement Of Cells – Streptococcus pneumoniae is arranged in pairs (diplococci), with a broad end in apposition and the long axis of the coccus parallel to the line joining the two cocci.
What is the motility of Streptococcus pneumoniae?
Motility – Streptococcus pneumoniae is a Non-motile bacterium. Flagella – Streptococcus pneumoniae is a Non-flagellated bacterium. Spores – Streptococcus pneumoniae is a Non-sporing Bacterium. Capsule – S. pneumoniae is a capsulated bacterium and is present in such a way that a capsule encloses each pair of cocci.
What is the inhibition zone for Streptococcus pneumoniae?
An inhibition zone of 14 mm or more, around a 6-mm disk, allows for identification of the viridans streptococcus in question as Streptococcus pneumoniae. If the inhibition zone is less than 14 mm, further testing (bile solubility or serology) is indicated for the identification of S. pneumoniae.
What is the opacity variance of Streptococcus pneumoniae?
The opacity variance of S. pneumoniaecolonies appears to reflect differences in the organism’s pathogenesis and virulence. Animal model studies showed that transparent variants are more able to colonize the nasopharynx of infant rats, while opaque variants are more virulent in the intraperitoneal model of infection.
