Differences Between Gram Positive and Gram Negative Bacteria 4.94/5 (17)

Differences Between Gram Positive and Gram Negative Bacteria


Differences Between Gram Positive and Gram Negative Bacteria

Differences Between Gram Positive and Gram Negative Bacteria


 S.N.

Character

Gram-Positive Bacteria

Gram-Negative Bacteria

1.   Gram ReactionRetain crystal violet dye and stain blue or purple on Gram’s staining.Accept safranin after



decolorization and stain pink or red on Gram’s staining.

2.   Cell wall thicknessThick (20-80 nm)Thin (8-10 nm)
3.   Peptidoglycan LayerThick (multilayered)Thin (single-layered)
4.   Rigidity and ElasticityRigid and less elasticLess rigid and more elastic
5.   Outer MembraneAbsentPresent
6. Variety of amino acid in cell wallFewSeveral
7. Aromatic and Sulfur-containing amino acid in cell wallAbsentPresent
8.   Periplasmic SpaceAbsentPresent
9.   Teichoic AcidsMostly presentAbsent
10.PorinsAbsentPresent
11.Lipopolysaccharide (LPS) ContentVirtually NoneHigh
12.Lipid and Lipoprotein ContentLow (acid-fast bacteria have lipids linked to peptidoglycan)High (because of presence of outer membrane
13.Ratio of RNA:DNA8:1Almost 1
14.MesosomesQuite ProminentLess Prominent
15.Flagellar Structure2 rings in basal body4 rings in basal body
16.MagnetosomesUsually absent.Sometimes present.
17.MorphologyUsually cocci or spore forming rods (exception : Lactobacillus and Corynebacterium)Usually non-spore forming rods (Exception : Neisseria)
18.Endospore formationSome produce endospores during unfavorable conditions.Usually not found to produce endospores.
19.Toxin ProducedExotoxinsEndotoxins or Exotoxins
20.PathogensFew pathogenic bacteria belong to Gram positive group.Most pathogens are Gram negative.
21.Nutritional RequirementsRelatively ComplexRelatively Simple
22.Resistance to Physical DisruptionHighLow
23.Cell Wall Disruption by LysozymeHighLow (requires pretreatment to destabilize outer membrane)
24.Susceptibility to Penicillin and SulfonamideHighLow
25.Susceptibility to Streptomycin, Chloramphenicol and TetracyclineLowHigh
26.Inhibition by Basic DyesHighLow
27.Susceptibility to Anionic DetergentsHighLow
28.   Resistance to Sodium AzideHighLow
29.Resistance to DryingHighLow
30.RenderingThey can rendered Gram -ve by increasing acidityThey can rendered Gram +ve by increasing alkalinity
31.ExamplesStaphylococcus

Streptococcus

Bacillus

Clostridium

Enterococcus

Escherichia

Salmonella

Klebsiella

Proteus

Helicobacter

Pseudomonas

Differences Between Gram Positive and Gram Negative Bacteria

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