Table 3.1.
Simplified classification of some cellular micro-organisms of medical importance
| Common group name | Normal genus names |
|---|---|
| Eukaryotes | |
| Protozoa | |
| Sporozoa | Plasmodium, Isospora, Toxoplasma, Cryptosporidium |
| Flagellates | Giardia, Trichomonas, Trypanosoma, Leishmania |
| Amoebae | Entamoeba, Naegleria, Acanthamoeba |
| Other | Babesia, Balantidium |
| Fungi | |
| Mould-like | Epidermophyton, Trichophyton, Microsporum, Aspergillus |
| Yeast-like | Candida |
| Dimorphic | Histoplasma, Blastomyces, Coccidioides |
| True yeast | Cryptococcus |
| Prokaryotes | |
| Bacteria | |
| Actinobacteria | (High G+C Gram positives) Actinomyces, Streptomyces, Corynebacterium, Nocardia, Mycobacterium, Micrococcus |
| Firmicutes | (Low G+C Gram positives) |
| Gram-positive bacilli | Listeria, Bacillus, Clostridium*, Lactobacillus*, Eubacterium* |
| Gram-positive cocci | Staphylococcus, Streptococcus, Enterococcus |
| Gram-negative cocci** | Veillonella*, Mycoplasma |
| Proteobacteria | (a very large group with 5 sub-divisions) |
| Gram-negative cocci | Neisseria, Moraxella |
| Gram-negative bacilli | Enterobacteria – Escherichia, Klebsiella, Proteus, Salmonella, Shigella, Yersinia |
| Pseudomonads – Pseudomonas, Burkholderia, Stenotrophomonas | |
|
Haemophilus, Bordetella, Brucella, Pasteurella Rickettsia, Coxiella | |
| Gram-negative curved and spiral bacilli | Vibrio, Spirillum, Campylobacter, Helicobacter |
| Bacteroidetetes | Bacteroides*, Prevotella* |
| Spirochaetes | Borrelia, Treponema, Brachyspira, Leptospira |
| Chlamydia | Chlamydia |
*
Anaerobic organism.
**
Exceptions in a predominantly Gram-positive group.