Defense against antibiotic resistance- bacteria-eating bacteria- blog

In an attention-grabbing article published at NPR it is suggested to use bacteria-eating bacteria as a new mean to combat antibiotic-resistant bacteria. In a study funded by Defense Advanced Research Projects Agency (DARPA) Brad Ringeisen deputy director of the Biological Technologies Office at the DARPA claims that microbe-eating microbes are found in almost every ecosystem on Earth.

The study funded by DARPA showed that predatory bacteria will attack many disease-causing bacteria that have developed resistance to antibiotics. The main organism they worked with is Bdellovibrio (a small (0.3 to 0.4 micrometers wide, and 0.8-1.2 micrometers long), highly motile (with a single polar flagellum), vibrio shaped, mono flagellated, gram-negative bacteria).

Bdellovibrio life cycle is described as:

  1. Due to its high speed of movement, the Bdellovibriorams the target cell
  2. It quickly attaches to the host cell envelope by its non-flagellated end, presumably drilling into the host cell wall.
  3. A hole appears in the host’s cell wall at the site of attachment and the parasite invades the host periplasm. The flagellum is lost during penetration and remains outside the host.
  4. The Bdellovibriogrows with multiple copies of the genome.
  5. As the food supply becomes exhausted, the filament divides by multiple fission, splitting into several new Bdellovibrio bacteria.
  6. The host cell swells, ruptures and the Bdellovibrio new cells are liberated.

Bdellovibrio can attack common bacteria six times its size. The research found that Bdellovibrio attacked 145/168 tested human pathogens. Bdellovibrio actually bores into larger bacteria and eats them from the inside out.

According to Liz Sockett, a professor of bacterial genetics at Nottingham University in the UK, the Bdellovibrio uses it motility to get to it’s pray and then latches on, using tiny appendages “which are little grappling hooks on the surface.” Once attached to its pray, it kills the target pathogen. The attacked organisms do not appear to develop a resistance mechanism to Bdellovibrio.

Nancy Connell, a microbial geneticist from Rutgers University studied anthrax and all sorts of other deadly pathogens say that exploring these predatory bacteria is the most exciting work she’s done in her career. “This is the first time that I have felt we might have a way through many of these different infections.”

Connell and her lab studied the use of Bdellovibrio to help fight lung infections in rats. Bdellovibrio reduced significantly the disease-causing bacteria but did not totally eliminate it.  While not replacing antibiotics, it could be useful if given as a preventive in advance of an anticipated germ warfare attack, or it could also work in a patient who has an infection that simply doesn’t respond to antibiotics, Connell says. Of course, we won’t know whether it works at all in people until researchers can put it to the test.

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