The following two studies (see summary here) demonstrate that Bb spirochetes can persist in the mouse after ceftriaxone therapy. This supports the claims of chronic Lyme sufferers who maintain that they still have the disease after antibiotic treatment – even IV antibiotics.
The Finish study was remarkable in that the culture and PCR were negative after ceftriaxone, but after additional treatment with anti-TNF-alpha, viable spirochetes were recovered.
TNF is a pro-inflammatory cytokine (cytokines signal molecules in our immune system) which, when blocked, typically results in a reduction in clinical inflammation; for this reason, such treatment is used for patients with rheumatoid arthritis.
To the surprise of the authors of the study, viable spirochetes were recovered in these PCR- and culture-negative mice after TNF blocking treatment was given.
Also interesting is that anti-TNF treatment did not result in the expected finding of a reduction of joint swelling.
The Finnish study was the first study to demonstrate that immuno-modulatory treatment of animals infected with Bb could convert them from culture negative to culture positive.
The California study was remarkable in that only tick-feeding was capable of extracting infectious but non-replicating attenuated spirochetes; without having done that step of xenodiagnosis of (xenodiagnosis refers to the process of exposing a sterile tick to the tissue suspected of infection and then examining the tick afterwards in this case finding the evidence of spirochetes which otherwise would not have been found) and then transferring the tick to feed on naive SCID mice, the authors conclusion would have been that infectious spirochetes do not persist in the mouse model as culture was negative. The authors further concluded that negative culture and PCR can not be relied upon as markers of treatment success.
We do not know the extent to which these findings can be translated to the human situation.
Nevertheless, the activation of infectious spirochetes after anti-TNF therapy in mice should alert clinicians to the possibility that anti-cytokine therapy may result in a similarly increased risk of activating latent infection among patients with a history of treated Lyme disease.
At this point, we do not know whether attenuated spirochetes are capable of inducing illness-symptoms in mice or humans; while it is possible that spirochetal mRNA may be producing surface lipoproteins that stimulate systemic symptoms, this hypothesis needs to be tested in the next phase of this important research.
SOURCE: Columbia University Lyme Research and letter from Dr. Brian Fallon the Director of the Lyme and Tick-Borne Disease Research center at Columbia University.