Mar 2, 2016 · Streptococci are facultatively anaerobic, Gram-positive organisms that often occur as chains or pairs (figures 1 and 2) and are catalase -negative (in contrast, staphylococci are catalase positive) (figure 3). Streptococci are subdivided into groups by antibodies that recognize surface antigens (figure 4).

Diagnosis is based on a sputum Gram stain and culture; blood or cerebrospinal fluid may also be cultured. Capsular antigen can be detected serologically. Pneumococci are distinguished from viridans streptococci by the quellung (capsular swelling) reaction, bile …

Gram Stain. In addition to Optochin test, bile solubility test, and catalase test, Gram staining is one of the methods used to determine the presence of Streptococcus bacteria in a sample. In this section, S. pneumoniae will be used as the representative of the group.

Mar 16, 2022 · Gram-positive organisms include: Staphylococcus species. Streptococcus species. Corynebacterium species. Clostridium species. Listeria species. Gram-negative bacteria have cell walls with thin layers of peptidoglycan (10% of the cell wall) and high lipid (fatty acid) content. This causes them to appear red to pink under a Gram stain.

3 days ago · Discover the key differences between Staph and Strep bacteria using Gram stain techniques. This quick guide explains their distinct characteristics, morphology, and staining results, helping you accurately identify these pathogens. Learn essential LSI keywords like bacterial identification, Gram-positive vs. Gram-negative, and clinical microbiology for precise …

We now know that those organisms that stained blue/violet with Gram’s stain are gram-positive bacteria and include Streptococcus pneumoniae (found in the lungs of those with pneumonia) and Streptococcus pyogenes (from patients with Scarlet fever) while those that were decolorized are gram-negativebacteria such as the Salmonella Typhi that is ass...

May 30, 2023 · Gram-positive cocci include Staphylococcus (catalase-positive), which grows clusters, and Streptococcus (catalase-negative), which grows in chains. The staphylococci further subdivide into coagulase-positive (S. aureus) and coagulase-negative (S. epidermidis and S. saprophyticus) species.

Mar 17, 2025 · Gram staining is a differential bacterial staining technique used to differentiate bacteria into Gram Positive and Gram Negative types according to their cell wall composition. It is the most widely used and the most important staining technique in bacteriology, especially in medical bacteriology.

This image is a light micrograph of Gram-stained S. pneumoniae (also known as S. pneumococcus), rounded bacteria (cocci) that usually occur in pairs and sometimes short chains. Their blue color indicates they are Gram-positive. Magnification is …

Aug 10, 2022 · Gram Staining is the common, important, and most used differential staining techniques in microbiology, which was introduced by Danish Bacteriologist Hans Christian Gram in 1884. This test differentiate the bacteria into Gram Positive and Gram Negative Bacteria, which helps in the classification and differentiations of microorganisms.