What is an important characteristic of Gram negative bacteria?

Gram negative bacteria are characterized by the presence of an outer membrane that is rich in lipopolysaccharides (LPS). This outer membrane is a distinguishing feature of Gram negative bacteria and plays a critical role in their biology and pathogenicity. The lipopolysaccharides contribute to the structural integrity of the bacterial cell wall and also serve as an important component of the immune response, as they can elicit strong responses in the host organism.

The presence of this outer membrane makes Gram negative bacteria more impermeable to certain antibiotics and detergents compared to their Gram positive counterparts, which have a thicker peptidoglycan layer and lack this outer membrane. Understanding this characteristic is crucial for laboratory diagnosis and treatment strategies because it influences the effectiveness of many antimicrobial agents. The outer membrane can also be a factor in the virulence of Gram negative pathogens, as the lipopolysaccharides can act as endotoxins.