Genus |
Important species |
Gram staining |
Shape |
Capsulation |
Bonding tendency |
Motility |
Respiration |
Growth medium |
Intra/Extracellular |
Bordetella |
|
Gram-negative |
Small coccobacilli |
Encapsulated |
singly or in pairs |
|
aerobic |
Regan-Lowe agar |
extracellular |
Borrelia |
|
Gram-negative, but stains poorly |
|
|
Long, slender, flexible, spiral- or corkscrew-shaped rods |
highly motile |
|
(difficult to culture) |
extracellular |
Brucella |
|
Gram-negative |
Small coccobacilli |
Unencapsulated |
singly or in pairs |
|
aerobic |
Blood agar |
intracellular |
Campylobacter |
|
Gram-negative |
Curved, spiral, or S-shaped
with single, polar flagellum |
|
|
characteristic darting motion |
microaerophilic |
Blood agar inhibiting other fecal flora |
extracellular |
Chlamydia and Chlamydophila |
|
(not Gram-stained) |
Small, round, ovoid |
|
|
motile |
Facultative or strictly aerobic |
|
Obligate intracellular |
Clostridium |
|
Gram-positive |
Large, blunt-ended rods |
|
|
mostly motile |
Obligate anaerobic |
Anaerobic blood agar |
extracellular |
Corynebacterium |
|
Gram-positive (unevenly) |
Small, slender, pleomorphic rods |
unencapsulated |
clumps looking like Chinese characters or a picket fence |
nonmotile |
Mostly facultative anaerobic |
Aerobically on Tinsdale agar |
extracellular |
Enterococcus |
|
Gram-positive |
Round to ovoid |
|
pairs or chains |
|
Facultative Anaerobic |
6.5% NaCl, bile-esculin agar |
extracellular |
Escherichia |
|
Gram-negative |
Short rods |
|
|
|
Facultative anaerobic |
MacConkey agar |
extracellular |
Francisella |
|
Gram-negative |
Small, pleomorphic coccobacillus |
|
|
|
strictly aerobic |
(rarely cultured) |
Facultative intracellular |
Haemophilus |
|
Gram-negative |
Ranging from small coccobacillus to long, slender filaments |
|
|
|
|
Chocolate agar with hemin and NAD+ |
extracellular |
Helicobacter |
|
Gram-negative |
Curved or spiral rods
pultiple polar flagella |
|
|
rapid, corkscrew motility |
|
Medium containing antibiotics against other fecal flora |
extracellular |
Legionella |
|
Gram-negative, but stains poorly |
Slender rod in nature, cocobacillary in laboratory.
monotrichious flagella |
unencapsulated |
|
motile |
|
Specialized medium |
facultative intracellular |
Leptospira |
|
Gram-negative, but stains poorly |
Long, very slender, flexible, spiral- or corkscrew-shaped rods |
|
|
highly motile |
|
Specialized medium |
extracellular |
Listeria |
|
Gram-positive, darkly |
Slender, short rods |
|
diplobacilli or short chains |
Distinct tumbling motility in liquid medium |
|
enriched medium |
intracellular |
Mycobacterium |
|
(none) |
Long, slender rods |
|
|
nonmotile |
aerobic |
M. tuberculosis: Lowenstein-Jensen agar
M. leprae: (none) |
extracellular |
Mycoplasma |
|
(none) |
Plastic, pleomorphic |
|
singly or in pairs |
|
|
(rarely cultured) |
extracellular |
Neisseria |
|
Gram-negative |
Kidney bean-shaped |
|
diplococci |
|
aerobic |
Thayer-Martin agar |
Gonococcus: facultative intracellular
N. meningitidis: extracellular |
Pseudomonas |
|
Gram-negative |
rods |
encapsulated |
|
motile |
Obligate aerobic |
MacConkey agar |
extracellular |
Rickettsia |
|
Gram-negative, but stains poorly |
Small, rod-like coccobacillary |
|
|
|
|
(rarely cultured) |
Obligate intracellular |
Salmonella |
|
Gram-negative |
|
|
|
|
Facultative anaerobic |
MacConkey agar |
Facultative intracellular |
Shigella |
|
Gram-negative |
rods |
|
|
|
Facultative anaerobic |
Hektoen agar |
extracellular |
Staphylococcus |
|
Gram-positive, darkly |
Round cocci |
|
in bunches like grapes |
|
Facultative anaerobic |
enriched medium (broth and/or blood) |
extracellular |
Streptococcus |
|
Gram-positive |
ovoid to spherical |
|
pairs or chains |
nonmotile |
Facultative anaerobic |
blood agar |
extracellular |
Treponema |
|
Gram-negative, but stains poorly |
Long, slender, flexible, spiral- or corkscrew-shaped rods |
|
|
highly motile |
|
none |
extracellular |
Vibrio |
|
Gram-negative |
Short, curved, rod-shaped with single polar flagellum |
|
|
rapidly motile |
Facultative anaerobic |
blood- or MacConkey agar. Stimulated by NaCl |
extracellular |
Yersinia |
|
Gram-negative, stains bipolarly |
Small rods |
encapsulated |
|
nonmotile |
Facultative Anaerobe |
MacConkey or CIN agar |
extracellular |