In terms of sheer numbers, rod-shaped bacteria dominate the
field of pathogenic bacteriology. Included among the diseases
caused by bacilli are ancient, deadly, and fascinating ones such
as bubonic plague, typhoid fever, tetanus, and leprosy, as well as
newly emerging ones such as listeriosis and Legionnaires disease.
In chapters 19 and 20, we will characterize and differentiate genera
and medically important species using a simple modification of a
system presented in Bergey's Manual of Systematic Bacteriology.
This system divides the bacilli by Gram reaction and subgroups them
by morphological characteristics and oxygen utilization (see figure E,
page 542). Each section covers unique features of the pathogens
and the epidemiology, pathology, and control measures of the principal