Fine Reading: Mycobacteria Grow and Divide Like Other Bacteria — Only Differently

Tubercle bacilli, scanning
EM. Source: Zimek Systems

I've been trying to find a simile for mycobacteria, those outliers in the world of bacterial pathogens (and saprobes). Maybe they are to other bacteria like cacti are to other plants. They’re not exactly spiny but they sure are different. (Come up with your own simile, if you wish.) They’re acid fast, resistant to drying, slow growing, and—to round out the picture—cause diseases like TB and leprosy that, if not unique, are not your ordinary infections. But, just as cactuses are green and have leaves, so do mycobacteria share a common physiological repertoire with other bacteria.

A recent review by Hett and Rubin tells much of what is known about the differences and similarities between mycobacteria and the rest of the bacteria with regard to cell structure, cell division, and growth. Also discussed are the particular challenges faced by mycobacteria, such as entering and escaping from dormancy. The writing features a string of refreshingly Socratic questions. Where else would you find queries such as: Are mycobacteria gram positive or gram negative? and Why are mycobacteria rods? and Does resuscitation involve normal homeostatic processes? Twenty-one pages of text and 463 references later, you will have found the answers to these and many other questions central to the mycobacterial way of life.

Comments

[Amin Talebi]

With thanks for writing this passage, I must assert that we cannot simplify the tubercle bacillus. I believe that it is more complicated that we thought. For instance, it has a Type VII secretion system, whereas we knew only of 5 or 6 secretion systems before. It must said that tubercle bacilli need more study .

[elio schaechter]

Thanks for pointing out that this is World TB Day. Given that TB is a "social" disease, its eradication, though difficult, is not out of the question.

Elio

[Mercè Piqueras]

I wonder whether you wrote about mycobacteria today because it is the World Tuberculosis Day. On March 24, 1882, at a meeting of the Physiological Society of Berlin, Robert Koch described the rod-shaped bacteria he had isolated from organs which had been altered by tuberculosis. I had not yet seen your post when I wrote about TB on my own blog (in Catalan) a few hours ago.

About the World TB Day, see
http://www.stoptb.org/events/world_tb_day/2008/