Gram-Positive vs Gram-Negative Bacteria- 31 Differences with Examples

Differences Between Gram Positive and Gram Negative Bacteria


Gram Positive vs Gram Negative Bacteria (31 Major Differences)

S.N.CharacterGram-Positive BacteriaGram-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
11.Lipopolysaccharide (LPS) ContentVirtually NoneHigh
12.Lipid and Lipoprotein ContentLow (acid-fast bacteria have lipids linked to peptidoglycan)High (because of the 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 the 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 render Gram -ve by increasing acidityThey can render Gram +ve by increasing alkalinity


Examples of Gram-positive cocci bacteria

Aerococcus species

Enterococcus faecalis

Enterococcus faecium

Gemella species

Lactococcus species

Leuconostoc species

Pediococcus species

Peptococcus niger

Peptostreptococcus species

Peptoniphilus species

Staphylococcus aureus

Staphylococcus epidermidis

Staphylococcus intermedius

Staphylococcus lugdunensis

Staphylococcus saprophyticus

Streptococcus agalactiae (Group B)

Streptococcus canis (Group G)

Streptococcus gallolyticus (Group D, formerly S. bovis)

Streptococcus infantarius (Group D, formerly S. bovis)

Streptococcus pneumoniae

Streptococcus pyogenes (Group A)

Streptococcus anginosus

Streptococcus constellatus

Streptococcus intermedius

Streptococcus mitis

Streptococcus mutans

Streptococcus salivarius

Streptococcus sanguis

Abiotrophia species (nutritionally variant streptococci)

Granulicatella species (nutritionally variant streptococci)

Examples of Gram-positive bacilli bacteria

Actinomyces israelii

Arcanobacterium species

Bacillus anthracis

Bacillus cereus

Bifidobacterium species

Clostridium botulinum

Clostridium difficile

Clostridium perfringens

Clostridium tetani

Corynebacterium diphtheriae

Corynebacterium jeikeium

Corynebacterium urealyticum

Eggerthella species

Erysipelothrix rhusiopathiae

Eubacterium species

Gardnerella vaginalis

Gordonia species

Lactobacillus species

Listeria monocytogenes

Mycobacterium abscessus

Mycobacterium avium

Mycobacterium bovis

Mycobacterium chelonae

Mycobacterium fortuitum

Mycobacterium intracellulare

Mycobacterium kansasii

Mycobacterium leprae

Mycobacterium marinum

Mycobacterium tuberculosis

Nocardia asteroides

Propionibacterium acnes

Rhodococcus equi

Tropheryma whippeli

Tsukamurella species

Examples of Gram-negative cocci bacteria

Moraxella catarrhalis

Neisseria gonorrhoeae

Neisseria meningitidis

Veillonella parvula

Examples of Gram-negative bacilli bacteria

Acinetobacter species

Aeromonas caviae

Aeromonas hydrophila

Aeromonas veronii biovar sobria

Alcaligenes species

Bacteroides ovatus

Bacteroides distasonis

Bacteroides thetaiotamicron

Bacteroides vulgatus

Brevundimonas species

Burkholderia cepacia

Burkholderia mallei

Burkholderia pseudomallei

Chryseobacterium species

Citrobacter freundii

Citrobacter koseri

Comamonas species

Cronobacter sakazakii

Edwardsiella tarda

Eikenella corrodens

Enterobacter aerogenes

Enterobacter cloacae

Escherichia coli

Fusobacterium necrophorum

Fusobacterium nucleatum

Klebsiella granulomatis

Klebsiella oxytoca

Klebsiella pneumoniae

Klebsiella pneumoniae subspecies rhinocscleromatis

Mobiluncus species

Moraxella species

Morganella morganii

Pasteurella multocida

Plesiomonas shigelloides

Porphyromonas species

Prevotella melaninogenica

Proteus mirabilis

Proteus vulgaris

Providencia alcalifaciens

Providencia rettgeri

Providencia stuartti

Pseudomonas aeruginosa

Pseudomonas fluorescens

Pseudomonas species

Ralstonia pickettii

Roseomonas species

Salmonella Choleraesuis

Salmonella Paratyphi A

Salmonella Paratyphi B

Salmonella Typhi

Serratia liquefaciens

Serratia marcescens

Shewanella putrefaciens

Shigella boydii

Shigella dysenteriae

Shigella flexneri

Shigella sonnei

Sphingobacterium species

Sphingomonas species

Stenotrophomonas maltophilia

Vibrio cholerae

Vibrio parahaemolyticus

Vibrio vulnificus

Yersinia enterocolitica

Yersinia pestis

Yersinia pseudotuberculosis

Examples of Gram-negative bacilli and coccobacilli bacteria

Aggregatibacter (Actinobacillus) actinomycetemcomitans

Aggregatibacter (Haemophilus) aphrophilus

Arcobacter species

Bartonella bacilliformis

Bartonella henselae

Bordetella bronchiseptica

Bordetella parapertussis

Bordetella pertussis

Brucella melitensis

Campylobacter fetus

Campylobacter jejuni

Capnocytophaga species

Cardiobacterium hominis

Chlamydia trachomatis

Chlamydophila pneumoniae

Chlamydophila psittaci

Ehrlichia chaffeensis

Francisella tularensis

Haemophilus aegyptius

Haemophilus ducreyi

Haemophilus influenzae

Haemophilus parainfluenzae

Helicobacter pylori

Kingella kingae

Legionella micdadei

Legionella pneumophila

Orientia tsutsugamushi

Streptobacillus moniliformis


Carroll K.C., & Hobden J.A., & Miller S, & Morse S.A., & Mietzner T.A., & Detrick B, & Mitchell T.G., & McKerrow J.H., & Sakanari J.A.(Eds.), (2019). Jawetz, Melnick, & Adelberg’s Medical Microbiology, 27e. McGraw Hill.

About Author

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Sagar Aryal

Sagar Aryal is a microbiologist and a scientific blogger. He is doing his Ph.D. at the Central Department of Microbiology, Tribhuvan University, Kathmandu, Nepal. He was awarded the DAAD Research Grant to conduct part of his Ph.D. research work for two years (2019-2021) at Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Saarbrucken, Germany. Sagar is interested in research on actinobacteria, myxobacteria, and natural products. He is the Research Head of the Department of Natural Products, Kathmandu Research Institute for Biological Sciences (KRIBS), Lalitpur, Nepal. Sagar has more than ten years of experience in blogging, content writing, and SEO. Sagar was awarded the SfAM Communications Award 2015: Professional Communicator Category from the Society for Applied Microbiology (Now: Applied Microbiology International), Cambridge, United Kingdom (UK).

9 thoughts on “Gram-Positive vs Gram-Negative Bacteria- 31 Differences with Examples”

  1. Mesosomes do not exist. Please stop using this term when it is proven to be not existing for about 40 years or more already.


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