Very few studies done on the effectiveness of various antibiotics on the cyst forms of spirochetes. Flagl is the only one observed so far that I know of that is effective. Tini (dinazol?) is used also but not approved in the US.

This is supposed to have limited effect when co-infections known and unknown are not addressed, specifically Babesia and WA-1.

1: APMIS 1999 Jun;107(6):566-76 Related Articles, Books, LinkOut

An in vitro study of the susceptibility of mobile and cystic forms of Borrelia burgdorferi to metronidazole.

Brorson O, Brorson SH.

Department of Microbiology, Vestfold Sentralsykehus, Tonsberg, Norway.

The aim of this study was to examine the susceptibility of mobile and cystic forms of Borrelia burgdorferi to metronidazole. Because B. burgdorferi is a microaerobic bacterium like Helicobacter pylori, metronidazole (MZ) was chosen in the susceptibility test. For both microaerobic and aerobic incubation the normal mobile spirochetes were resistant to this antibiotic with an MBC > or = 512 microg/ml. Conversion of mobile spirochetes to cystic forms was not observed when they were incubated with MZ. When they were incubated under microaerobic conditions, the biologically active cystic forms had an MBC > or = 4 microg/ml, but the MBC was > or = 32 microg/ml with aerobic incubation at 37 degrees C. Staining with acridine orange (AO), dark field microscopy (DFM), and transmission electron microscopy (TEM) revealed that the contents of the cysts were degraded when the concentration of MZ was > or = MBC. Some cysts were also ruptured. When incubated with a sufficient concentration of MZ, core structures did not develop inside the cysts, and AO revealed less RNA in the cysts. Our observations may help efforts to treat resistant infections caused by B. burgdorferi with a combination of MZ and other antibiotics in order to eradicate both cystic and mobile forms of B. burgdorferi.

PMID: 10379684 [PubMed - indexed for MEDLINE]

METRONIDAZOLE THERAPY IN THE TREATMENT OF CHRONIC LYME DISEASE
presented on the
12th INTERNATIONAL SCIENTIFIC CONFERENCE ON LYME DISEASE AND OTHER SPIROCHETAL & TICK-BORNE DISORDERS
April 1999, New York City/New Jersey, USADr. Martin Atkinson-Barr CPhys PhD (Calabasas, CA) and Dr. Vernon Padgett MD (Calabasas, CA) together with Dr. Richard Horowitz MD (Hyde Park, NY)

http://www.fit.fraunhofer.de/~roh/LymeInfo/Metronidazole.html