Hello, all my lovely readers!
My apologies for not posting last week but it was my birthday on the 2nd February and so in true London style, I stretched it out to a week of celebration!
Amazing news also I am officially a ZSL Seasonal Presenter at London Zoo so come and visit me this summer and watch out for my twitter!
Now let's get our weekly dose of Science in the City!
Lurking in the very depths of wastewater is a predator that has bacterial infections running for the hills - Micavibrio aeruginosavorus. This predator is ‘the vampire’ bacteria. Micavibrio aeruginosavorus attaches to its prey externally and then leeches of the victim's nutrients. This parasitic predator could be our greatest biological weapon in the fight against antibiotic-resistant bacteria. Could this predatory species be our saving grace?
Micavibrio aeruginosavorus is a gram-negative obligate bacterial predator that feeds by being an ectoparasite (see image above: predator in yellow and bacteria in pink). Normally bacteria gain all their nutrients essential for survival and growth directly from their environment, however, this bacteria is unable to gain several proteins through either imports or their environment. Very similar to us in this manner, the only way to get the essential nutrients needed would be to consume others and gain it from them. M. aeruginosavorus kills its prey differently to other predatory bacteria such as Bdellovibrio bacterivorous. Bacteria from the Bdellovibrio genus bind to the surface of their victims and enter the periplasm of the bacteria, once inside Bdellovibrio consumes its prey’s nutrients and multiplies. When the preys nutrients have been exhausted, Bdellovibrio causes the bacteria to burst and moves onto its next victim. Micavibrio, on the other hand, kills its victims in a way that mirrors the sci-fi horrors of vampires. This predator attaches onto the surface of its victim and then ‘bleeds’ it dry! This results in the ectoparasite growing in size.
Predatory bacteria have been shown to attack a wide range of bacteria, however, Micavibrio aeruginosavorus shows a strong preference to Pseudomonas aeruginosa. Bacteria from the Pseudomonas genus are known to cause infections of the blood as well as trigger pneumonia, as such infection can prove to be fatal. With the rise in antibiotic resistant bacteria, novel treatments must be explored.
A group of researchers evaluated the ability of M. aeruginosavorus to locate and destroy different strains of pathogenic bacteria. In order to test the effectiveness for this bacteria, they planted the M. aeruginosavorus on a ‘lawn’ of prey cells and then measured the ‘lytic halo’, this is the area where pathogenic bacteria is absent. Results looked promising when carried out on Petri dishes, however, when this treatment was carried out in animal models with the bacteria injected either intravenously or delivered via the respiratory system the results were not as promising.
A predators potential for avoiding a medical armageddon:
Using a natural predator as a way of dealing with prey populations is not new, in fact, it is being carried out on a regular basis - just on a larger scale. Predatory bacteria such as M.aeruginosavorus comes with some potential advantages if we could get it to work with us:
They are fussy eaters. Initially, this came as a problem as scientists preferred a predator that would ‘eat’ a wide range of bacteria as opposed to a specific species of bacteria. However, this proves beneficial if these bacteria become a part of clinical practice. M. aeruginosavorus eats ‘pathogenic’ bacteria - bacteria that cause infections. Not all bacteria is bad, in fact, without our healthy gut bacteria, things would go very, very wrong. Being a fussy eater means that our healthy gut bacteria are safe from being eaten.
A low and concentrated dose of a bacterial killer. Because species belonging to Micavibrio go straight for their selected prey species, a low initial dose would be all that is needed to rid the body of its bacterial infection.
Resistance, not such a problem. The relationship displayed by M. aeruginosavorus and Pseudomonas aerguinosa, for instance, is a classic predatory-prey relationship. As a cause of this relationship resistance to being eaten is a lot trickier to evolve for the prey species because it is also in the predators best interest to evolve ways to get around it and eat them anyway!
Predators are determined to get to their food. In the case of Pseudomonas aeruginosa, this bacteria secretes a thick mucus that normally proves too great a barrier for antibiotics to penetrate, a barrier that is penetrated by M. aeruginosavorus.
In preparation for this post, I gathered sources of information from a range of sources and enjoyed reading through the comments left by other readers. One gentleman left a comment highlighting the similarities between using predatory bacteria and bacteriophages (image above). I remember my dad talking to me about this once before and decided to investigate further.
Bacteriophages are another type of bacterial predator but are not bacteria themselves they are actually viruses. These viruses invade a bacterial cell and disrupt the bacteria’s machinery eventually leading to cell death. These remarkable naturally occurring bacteria killers are able to penetrate much deeper to where the infection has spread and they stop replicating once they are no longer needed. Bacteriophages have been used in certain countries as a form of treatment since the Iron Curtain! As to why it is not available in the West could be due to things such as public reluctance to believe that a virus could be helpful, and there is actually no money to be made in pushing this forward.
Overall naturally occurring bacterial predators as a way of managing future bacterial infections is most definitely exciting. However, there is still a way to go before human trials could even be considered.
I hope you have all learned something today guys. Just to let you know keep an eye out for my post this Valentine's day! Next week's post will be published on Valentine's day and not Friday and I have a real treat for you romantics and bachelors!
Until next week you wonderful lot
Science in the City
