Grampozitív

Grampozitív is a term used in microbiology, particularly in Hungarian, to refer to Gram-positive bacteria. These bacteria retain the crystal violet stain during the standard Gram staining procedure and appear purple under a light microscope after staining. The staining outcome is primarily due to a thick layer of peptidoglycan in the cell wall and the absence of an outer membrane, which in Gram-negative bacteria causes the dye to be washed away during decolorization. Gram-positive bacteria often contain teichoic acids in their cell walls, which can influence staining properties and interactions with the host.

Taxonomically, the Gram-positive group is diverse and mainly includes two large phyla: Firmicutes and Actinobacteria. Within Firmicutes are many Gram-positive cocci and rods, such as Staphylococcus, Streptococcus, Bacillus, and Clostridium. Actinobacteria encompass genera like Corynebacterium and Mycobacterium, the latter of which may stain variably due to their lipid-rich cell walls. Some Gram-positive lineages form endospores (notably Bacillus and Clostridium), giving them resilience in harsh environments.

Clinically, Gram staining is a rapid, first-line diagnostic tool used to distinguish Gram-positive from Gram-negative bacteria and to guide initial treatment decisions. Well-known Gram-positive pathogens include Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Listeria monocytogenes, and Corynebacterium diphtheriae. Antibiotic susceptibility among Gram-positive organisms varies; many respond to beta-lactams, glycopeptides, or other classes, though resistance mechanisms such as altered penicillin-binding proteins and antibiotic-degrading enzymes are present in some species.

Grampozitív signals a broad, clinically important group defined by cell-wall properties rather than a single taxonomic category.