I have no first hand experience with it. en.wikipedia.org/wiki/Imipenem
B.B. is not classified as gram negative OR positive, but....here's a quote about
" When Borrelia burgdorferi is Gram-stained, the cells stain a weak Gram-negative by default, as safranin is the last dye used. Borrelia, like most spirochetes, does have an outer membrane that contains an LPS-like substance, an inner membrane, and a periplasmic space which contains a layer of peptidoglycan. Therefore, it has a Gram-negative bacterial type cell wall, despite its staining characteristics."
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Fibro diagnosed '85 Lyme (false?)positive '92,Osteoporosis, COPD, Hypertension, degen. disc disease, RMSF pos. Spring 2015, CHF, osteoarthritis. No LLMD. Used Doxy, Zithro and Flagyl since June '15, mono each time. Useless. Current treatment JK, Milk Thistle, kudzu for head fullness/pressure, avena sativa for nerves. Bragg's ACV, lemon water, Herbal de-tox tea.