Gramnegatiivista

Gramnegatiivista is a Finnish term that translates to "Gram-negative" in English, referring to a characteristic of bacteria. In microbiology, the Gram stain is a differential staining technique used to classify bacteria into two large groups based on their cell wall composition: Gram-positive and Gram-negative.

Gram-negative bacteria have a complex cell wall structure. This structure includes a thin peptidoglycan layer situated between the inner cytoplasmic membrane and an outer membrane. The outer membrane is a distinguishing feature and contains lipopolysaccharides (LPS), which are important for the bacteria's interaction with their environment and can elicit an immune response in host organisms.

When subjected to the Gram staining procedure, Gram-negative bacteria appear pink or red under a microscope. This is because they do not retain the crystal violet stain used in the initial step. Instead, they are decolorized by alcohol or acetone and subsequently counterstained with safranin, which imparts the pink/red color.

Many pathogenic bacteria are Gram-negative. Examples include Escherichia coli, Salmonella, and Pseudomonas aeruginosa. Their outer membrane provides a barrier against certain antibiotics and disinfectants, making them potentially more challenging to treat. Understanding whether a bacterium is Gram-positive or Gram-negative is crucial for diagnosis, treatment selection, and epidemiological studies in medicine and research.