Question

How are colony descriptions used in research and/or clinical microbiology?

Answer 1

Colony descriptions are quite useful. For example, several Porphyromonas species autofluorescence under long-wavelength ultraviolet and Proteus species swarm on appropriate media. A primary distinguishing characteristic is whether an organism grows aerobically, anaerobically, facultatively (i.e., in either the presence or absence of oxygen), or microaerobically (i.e., in the presence of a less than atmospheric partial pressure of oxygen). The proper atmospheric conditions are essential for isolating and identifying bacteria. Other important growth assessments include the incubation temperature, pH, nutrients required, and resistance to antibiotics. For example, one diarrheal disease agent, Campylobacter jejuni, grows well at 42° C in the presence of several antibiotics; another, Y. enterocolitica, grows better than most other bacteria at 4° C. Legionella, Haemophilus, and some other pathogens require specific growth factors, whereas E. coli and most other Enterobacteriaceae can grow on minimal media.