Samantha Harris

I chose to write my report on Vampirococcus namely due to the humorous name. I imagined a microbe prancing around with fangs and a cape, hissing at other microbes, “Let me suck your blood.” Alas, upon researching further into the microbe, I found the name to be rather appropriate and the bacterium intriguing.

Vampirococcus  is a predatory prokaryote found in fresh water sulfur lakes, especially in Spain.  It was first described in 1983 by Esteve, while studying bacterial communities in sulfuric lakes. The bacterium is ovoidal in shape (as coccus implies), Gram negative, and has no flagellum for movement. It is mainly aerobic, but can survive in anaerobic envirnoments, unlike its fellow predatory prokaryotic bacteria. Vampirococcus can not replicate via fission unless it’s attached to a prey cell. It’s prey of choice is the  much larger phototrophic purple sulfur bacteria Chromatium.

What does Vampirococcus do? As a predatory bacterium, it must feed off another organism. The steps of predation are finding a prey cell; associating with the cell; degrading the host macromolecules; and lastly, assimilting nutrients from the host in an efficent manner.  Vampirococcus strikes when conditions are poor for Chromatium growth. Most predatory bacterium feed off of prey from the inside.  Vampirococcus, however, is epibiont and remains on the external surface ; the bacterium adheres to the Chromatium attachment structures. Degradation forms an opening in the Chromatin membrane, and enzymes are released by the predator begins to break down the cytoplasm. Vampirococcus then ‘sucks’ the cytoplasm out of the host, until merely the husk is left. The cell wall, membrane, and organelles remain. Vampirococcus can only replicate while it feeds off of its ‘victims’.

Such a means of survival makes Vampirococcus seem like a parasite, and for quite sometime, that’s what it was considered. Now, the bacterium is seen as a primary consumer. The Chromatium that it feeds on won’t survive long in the unfavorable conditions. It is, in a way, putting its food out of it’s misery.  

Vampirococcus is one of few predatory prokaryotes. Being such, it helps explain the Endosymbiotic Theory. The Endosymbiotic Theory explains that the origins of organelles in eukaryotes could have been derived from relationships between bacteria. Predation may have established such evolution. For example, mitochondria, hydrogenosomes, kinetosomes, and nucleus in a double membrane could be due to the engulfing of or “eating” of bacterial species. Since Vampirococcus takes the cytoplasm from its prey, it may have early on taken organelles that later evolved into eukaryotic organelles in cells today.

There isn’t too much information available about Vampirococcus, though it is a fascinating microbe. Its ability to survive while waiting for its prey to reach unfavorable conditions so it can attack is incredible.  Also, the fact that it remains outside of its prey as it devours it separates it from other predatory bacteria.  Along with other predatory prokaryotes, Vampirococcus helps explain the Endosymbiotic Theory involving the possible explanation of the evolution of eukaryotic cells, making it very important to the science community. The entertaining name doesn’t hurt its popularity either.

Vampirococcus with Chromatium


Guerrero, Richard. “Predatory Prokaryotes: Predation and Primary Consumption Evolved in Bacteria.” 20 Feb 2009. <>

Microbe Zoo: Dirtland. 20 Feb 2009. <>

Esteve, Isabel. “Bacterial Symbiosis. Predation and Mutually beneficial associations.” 20 Feb 2009. <>


*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.


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