Gramnegatiivsetele

Gramnegatiivsetele refers to bacteria that do not retain the crystal violet stain used in the Gram staining procedure. This characteristic is due to their unique cell wall structure. Gram-negative bacteria possess a thin peptidoglycan layer that is surrounded by an outer membrane containing lipopolysaccharides (LPS). This outer membrane acts as a barrier, preventing the crystal violet-iodine complex from reaching the peptidoglycan layer and being retained during the decolorization step. Instead, they are counterstained by safranin, appearing pink or red under a microscope.

This distinction in cell wall composition has significant implications in medicine. Many common pathogens are gram-negative, including *Escherichia coli*, *Salmonella*, and *Pseudomonas aeruginosa*. Their outer membrane provides resistance to certain antibiotics and contributes to their virulence. Understanding the gram-negative classification is crucial for identifying bacteria, guiding antibiotic treatment choices, and developing strategies to combat infections. The presence and composition of the LPS layer, in particular, can trigger strong immune responses in the host. The study of gram-negative bacteria is a fundamental aspect of microbiology and infectious disease research.