Shape
Name
Example
of Shape
Bacteria
Examples
Coccus
(plural: cocci) - round or ball-shaped bacterium
Staphylococcus
aureus, agent of skin infection
Bacillus
(bacilli) - rod or cylindrical shaped bacterium
Bacillus
cereus, agent of food poisoning
Escherichia coli, agent of traveler's diarrhea, food poisoning
Vibrio
- curved, rod-shaped bacterium
Vibrio
cholerae, agent of cholera
Fusiform
--rod-shaped bacterium with tapered ends
Fusobacterium
periodonticum, agent of gingivitis and periodontitis
Spirillum
(spirilla) rigid spiral-shaped bacterium
Spirillum
minus, agent of rat bite fever
Spirochete
- flexible spiral-shaped bacterium
Treponema
pallidum, agent of syphilis
Pleomorphic
- Bacterium with varying shapes
Corynebacterium
diphtheriae, agent of diphtheria. They are rod-shaped bacteria, but in
culture, they exhibit different shapes: club-shaped, curved, filamentous
and coccoid.
Filamentous
- branch forming bacterium
Species
of Streptomyces, antibiotic producing bacteria
