Microbiology, 2021

148 4 • Prokaryotic Diversity
Figure 4.10
Myxobacteria form fruiting bodies. (credit: modification of work by Michiel Vos)
Table 4.5 summarizes the characteristics of several important genera of Deltaproteobacteria.
Class Deltaproteobacteria
Genus Microscopic Morphology Unique characteristics
Bdellovibrio
Gram-negative, commashaped
rod
Obligate aerobes; motile; parasitic (infecting other
bacteria)
Desulfovibrio
(formerly
Desufuromonas)
Gram-negative, commashaped
rod
Reduce sulfur; can be used for removal of toxic and
radioactive waste
Myxobacterium
Gram-negative, coccoid
bacteria forming colonies
(swarms)
Live in soil; can move by gliding; used as a model
organism for studies of intercellular communication
(signaling)
Table 4.5
CHECK YOUR UNDERSTANDING
• What type of Deltaproteobacteria forms fruiting bodies?
Epsilonproteobacteria
The smallest class of Proteobacteria is Epsilonproteobacteria, which are gram-negative microaerophilic
bacteria (meaning they only require small amounts of oxygen in their environment). Two clinically relevant
genera of Epsilonproteobacteria are Campylobacter and Helicobacter, both of which include human
pathogens. Campylobacter can cause food poisoning that manifests as severe enteritis (inflammation in the
small intestine). This condition, caused by the species C. jejuni, is rather common in developed countries,
usually because of eating contaminated poultry products. Chickens often harbor C. jejuni in their
gastrointestinal tract and feces, and their meat can become contaminated during processing.
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