Streptococcus pneumonia is a \ \ \ \ \ \ type of bacteria. - RRB Nsg Superintendent -29 April 2025 (Shift-1st)

RRB Nsg Superintendent -29 April 2025 (Shift-1st)

Microbiology

Easy

Appeared in: RRB Nsg Superintendent -29 April 2025 (Shift-1st)

Explanation

Streptococcus pneumoniae is classified as a Gram-positive coccus.
The term 'Gram-positive' indicates that its cell wall retains the crystal violet stain during the Gram staining procedure, causing it to appear purple under a microscope.
The term 'coccus' refers to its spherical shape. These bacteria characteristically arrange in pairs (diplococci) and are often described as being lancet-shaped.

Option A: This is incorrect. Gram-negative bacilli are rod-shaped bacteria that do not retain the crystal violet stain, appearing pink/red. An example is Escherichia coli.
Option B: This is incorrect. While Gram-positive, bacilli are rod-shaped, not spherical like cocci. An example is Clostridium tetani.
Option D: This is incorrect. While these bacteria are spherical (cocci), they are Gram-negative, meaning they do not retain the purple stain. An example is Neisseria meningitidis.

Visual 1: Diagram: The Gram staining procedure, illustrating how Gram-positive bacteria retain the purple crystal violet stain while Gram-negative bacteria are decolorized and then counterstained pink.
Visual 2: Micrograph: A high-magnification image of a Gram stain of S. pneumoniae, clearly showing the purple, lancet-shaped diplococci (pairs of cocci).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Bacterial classification based on Gram stain and morphology as background academic context rather than a clinical decision trigger.
Correctly identifying S. pneumoniae as a Gram-positive coccus is the first step in choosing effective antibiotic therapy. Penicillins and macrolides are often used, but resistance patterns must be considered.
As a leading cause of pneumonia, meningitis, and otitis media, rapid identification of S. pneumoniae from clinical samples (like sputum or cerebrospinal fluid) is critical for patient outcomes.
Vaccination with the pneumococcal conjugate vaccine (PCV) and pneumococcal polysaccharide vaccine (PPSV) is a key public health strategy to prevent invasive disease, especially in young children and the elderly.

How to Approach the Question

This is a factual recall question testing fundamental knowledge in microbiology.
First, break down the options into their two components: Gram stain reaction (positive vs. negative) and cell shape (cocci vs. bacilli).
Recall the classic examples for each category. The genus 'Streptococcus' is a textbook example of Gram-positive cocci.
Associate 'coccus' with a spherical or berry-like shape and 'bacillus' with a rod shape.
Eliminate the 'bacilli' options (A and B) because Streptococcus species are spherical.
Between the remaining 'cocci' options (C and D), recall that Streptococcus is Gram-positive. This eliminates the Gram-negative option (D), leaving Gram-positive cocci as the correct answer.

Concept Tested & Keywords

Q61CtlEGuovDFxqK-WjG6l