It is traditionally thought that unlike human cells, bacteria do not contain specialized compartments called organelles where specific cellular functions are carried out. Rather, everything occurs in one giant compartment inside the bacterium, like a chaotic pot of soup where DNA, proteins, and RNA are synthesized, modulated, and degraded. Researchers have recently reported, however, that bacterial organelles actually exist and that one particular organelle may play a critical role during bacterial infections.

This team of researchers studied one pathogenic bacterial species—Clostridioides difficile, or C. diff—and found that these bacteria contained unique organelles called ferrosomes. During an infection, C. diff needs to collect iron from its host in order to replicate, and this collected iron is stored in its ferrosomes. The researchers also discovered that if they disrupted the formation of ferrosomes, or in other words, prevented C. diff from storing iron, the severity of the C. diff infection was reduced in mice. 

These findings suggest that ferrosome disruption could be a novel therapeutic treatment for people with C. diff infection. Currently, treatment options are limited to last-resort antibiotics, fecal transplants, or surgery, so a new antibiotic designed to disrupt ferrosome formation could significantly improve patient outcomes and reduce the need for more extreme treatment methods. And while C. diff is currently the only pathogenic bacterial species known to have ferrosomes, it is possible that there may be others that we have yet to discover.

We may not have traditionally thought of bacteria as having organelles, but it is clear that these tiny compartments do in fact exist and can play critical roles in human health. As technology improves and we can image tinier objects with more precision, we may discover the presence of even more unique bacterial organelles with significant structure and function.

This study was led by researchers at Vanderbilt University, including Hualiang Pi, Rong Sun, Qiangjun Zhou, and Eric P. Skaar.

Managing Correspondent: Jenny Kim

Press Article: Novel C. diff structures are required for infection, offer new therapeutic targets (VUMC Reporter)

Original Journal Article: Clostridioides difficile ferrosome organelles combat nutritional immunity (Nature)

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