RxPG - Classification of bacteria according to gram stain

Gram Positive Organisms

Aerobic, Gram-positive cocci
Staphylococcus aureus
Staphylococcus epidermidis
Staphylococcus sp. (Coagulase-negative)
Streptococcus pneumoniae (Viridans group)
Streptococcus agalactiae (group B)
Streptococcus pyogenes (group A)
Enterococcus sp.

Aerobic, Gram-positive rods
Bacillus anthracis
Bacillus cereus
Bifidobacterium bifidum
Lactobacillus sp.
Listeria monocytogenes
Nocardia sp.
Rhodococcus equi (coccobacillus)
Erysipelothrix rhusiopathiae
Corynebacterium diptheriae
Propionibacterium acnes

Anaerobic, Gram-positive rods
Actinomyces sp.
Clostridium botulinum
Clostridium difficile
Clostridium perfringens
Clostridium tetani

Anaerobic, Gram-positive cocci
Peptostreptococcus sp.

Gram Negative Organisms

Aerobic, Gram-negative cocci
Neisseria gonorrhoeae
Neisseria meningitidis
Moraxella catarrhalis

Anaerobic, Gram-negative cocci
Veillonella sp.

Aerobic, Gram-negative rods

Fastidious, Gram-negative rods
Actinobacillus actinomycetemcomitans
Acinetobacter baumannii
Bordetella pertussis
Brucella sp.
Campylobacter sp.
Capnocytophaga sp.
Cardiobacterium hominis
Eikenella corrodens
Francisella tularensis
Haemophilus ducreyi
Haemophilus influenzae
Helicobacter pylori
Kingella kingae
Legionella pneumophila
Pasteurella multocida
Enterobacteriaceae (glucose-fermenting Gram-negative rods)
Citrobacter sp.
Enterobacter sp.
Escherichia coli
Klebsiella pneumoniae
Proteus sp.
Salmonella enteriditis
Salmonella typhi
Serratia marcescens
Shigella sp.
Yersinia enterocolitica
Yersinia pestis

Oxidase-positive, glucose-fermenting Gram-negative rods
Aeromonas sp.
Plesiomonas shigelloides
Vibrio cholerae
Vibrio parahaemolyticus
Vibrio vulnificus

Glucose-nonfermenting, Gram-negative rods
Acinetobacter sp.
Flavobacterium sp.
Pseudomonas aeruginosa
Burkholderia cepacia
Burkholderia pseudomallei
Xanthomonas maltophilia or Stenotrophomonas maltophila

Anaerobic, Gram-negative rods
Bacteroides fragilis
Bacteroides sp.
Prevotella sp.
Fusobacterium sp.

Gram-negative spiral
Spirillum minus (minor)-

Bacteria which cannot or are difficult to Gram stain

Borrelia burgdorferi
Borrelia recurrentis
Bartonella henselae
Chlamydia trachomatis
Calymmatobacterium granulomatis (Gram negative rod)
Coxiella burnetii
Ehrlichia sp.
Legionella sp.
Leptospira sp.
Mycobacterium bovis
Mycobacterium tuberculosis
Mycobacterium avium, Mycobacterium intracellulare
Mycobacterium leprae
Rickettsia rickettsii
Treponema pallidum