Borrelia burgdorferi is the causative agent of Lyme borreliosis. Antibiotic therapy of early acute infection is effective for most patients, but 10-20% go on to develop Post-Treatment Lyme Disease Syndrome. The nature of PTLDS remains unknown, but currently approved antibiotics for treatment of Lyme disease do not appear to impact these symptoms after they have developed.
We reason that minimizing the time the pathogen interacts with the host will diminish the probability of developing PTLDS, irrespective of its nature. This calls for an efficient eradication of the pathogen during acute infection. In search of a superior killing antibiotic, we examined approved antibiotics for their ability to kill B. burgdorferi.
Vancomycin proved more effective in killing the pathogen in vitro than ceftriaxone, the standard of care for disseminated B. burgdorferi infection. Both compounds were also the most effective in killing stationary phase cells. This is surprising, given that inhibitors of cell wall biosynthesis are known to only kill growing bacteria. We found that peptidoglycan synthesis continues in stationary cells of B. burgdorferi, explaining this paradox. A combination of vancomycin and gemifloxacin sterilized a stationary phase culture of B. burgdorferi. Examination of the action of antibiotics in immune-deficient SCID mice showed that doxycycline, a standard of care for uncomplicated acute infection, did not clear the pathogen. By contrast, both ceftriaxone and vancomycin cleared the infection. A trial examining early use of more potent antibiotics on development of PTLDS may be warranted.
I like the initial thinking of the researchers regarding the need to treat acute infections thoroughly to hopefully prohibit later symptoms; however, vancomycin is often used IV which is more expensive and has its own risks. The oral route does not result in significant levels in the body which seems unwise since Bb can go anywhere in the body and typically does. https://www.medicinenet.com/vancomycin-oral/article.htm
It’s also active only on gram positive bacteria. While many claim Bb is gram-negative, it’s actually neither type and appears to be a monster complete with its own category: http://web.uconn.edu/mcbstaff/graf/Student%20presentations/Bburgdorferi/bburgdorferi.html
Doxycycline is far from a perfect drug but it’s a great front-line drug for many tick borne pathogens. The problem is it isn’t enough. Eva Sapi has shown it only works on two forms of Bb, the cell wall and spirochetal forms but actually increases the non cell wall form (she calls them round/cyst forms): https://www.dovepress.com/evaluation-of-in-vitro-antibiotic-susceptibility-of-different-morpholo-peer-reviewed-article-IDR
However, both metronidazole and tinidazole had far superior action:
Metronidazole led to reduction of spirochetal structures by ~90% and round body forms by ~80%. Tigecycline and tinidazole treatment reduced both spirochetal and round body forms by ~80%–90%.
In terms of qualitative effects, only tinidazole reduced viable organisms by ~90%. Following treatment with the other antibiotics, viable organisms were detected in 70%–85% of the biofilm-like colonies.
LLMD’s almost all use drug combinations due to the complexity of the organism as well as to ward off any potential resistance, and the fact coinfections are often involved. For examples: https://madisonarealymesupportgroup.com/2016/02/13/lyme-disease-treatment/
Things done in vitro (the lab) often do not play out in vivo (the body). It will be interesting to watch this develop.