Classification of medically important bacteria

There are several systems of classifications available. But the classifications based on the morphology and the biochemical characteristics of the bacteria. One of the most comprehensive classifications is as follows;

Characteristics	Genus	Representative diseases
Rigid, thick-walled cells
A) Free-living
1. Gram-positive
a) Cocci	Streptococcus	Pneumonia, pharyngitis, cellulitis
	Staphylococcus	Abscess
b)Spore-forming rods
i) Aerobic	Bacillus	Anthrax
ii)Anaerobic	Clostridium	Tetanus, gas gangrene, botulism
c)Non-spore-forming rods
i)Nonfilamentous	Corynebacterium	Diphtheria
	Listeria	Meningitis
ii)filamentous	Actinomyces	Actinomycosis
	nocardia	Nocardiosis
2)Gram-negative
a) Cocci	Neisseria	Gonorrhea, meningitis
b) Rods
i)facultative
Respiratory organisms	haemophilus	Meningitis
	Bordetella	Whooping cough
	Legionella	Pneumonia
Zoonotic organisms	Brucella	Brucellosis
	Francisella	Tularemia
	Pasteurella	Cellulites
	Yersinia	Plague
Enteric-related organisms	Escherichia	UTI, diarrhea
	Enterobacter	UTI
	Serratia	Pneumonia
	Klebsiella	Pneumonia, UTI
	Salmonella	Enterocolitis, typhoid fever
	Shigella	Enterocolitis
	Proteus	UTI
	Campylobacter	Enterocolitis
	Helicobacter	Gastritis, peptic ulcers
	Vibrio	Cholera
ii)Aerobic	Pseudomonas	Pneumonia, UTI
iii)Anaerobic	Bacteroides	Peritonitis
3) Acid fast	Mycobacterium	Tuberculosis, leprosy
B)Non-free-living	Rickettsia	Spotted fever, typhus, Q fever
	Chlamydia	Urethritis, trachoma, psittacosis
Flexible thin-walled	Treponema	Syphilis
	Borrelia	Lyme disease
	Leptospira	Leptospirosis
Wall-less cell	Mycoplasma	pneumonia