Living With Lyme | Persistent Lyme Infection After Antibiotic Treatment

Research: Persisting Lyme infection after antibiotic treatment

LINKING HUMAN ANIMAL BIOMEDICAL RESEARCH TO BENEFIT BOTH UC Davis Medicine Spring 2008 Feature No one knew what Lyme disease was when Stephen Barthold's daughter was diagnosed with it in 1978. At the time, Barthold and his family were living in Connecticut, the state where the cause of the tickborne disease would be identified four years later. While a course of antibiotics for an unrelated infection cured his daughter, the father remained intrigued. Today, with 30 years of research and more than 100 papers on Lyme disease under his belt, Barthold, a veterinary pathologist with a joint appointment in the schools of Medicine and Veterinary Medicine, is recognized as one of the leading authorities on how the Lyme bacterium interacts with the hosts it infects. When he arrived at UC Davis in 1997, Barthold lost no time in creating an ideal home for the kind of interdisciplinary work his research program requires: UC Davis Center for Comparative Medicine. Housed on the west side of the Davis campus, the unique teaching and research complex draws faculty from the schools of Medicine and Veterinary Medicine to focus on infectious disease and cancer research. Photo: UC Davis Medical School Center for Comparative Medicine Director Stephen Barthold is a leading expert in Lyme disease. "We take advantage of the concept of ‘one medicine.' That is, since nearly every human disease has an animal counterpart, what we learn from one benefits the other," explains Barthold, who was recruited from Yale School of Medicine to become the center's founding director. With 23,305 human cases reported to the CDC in 2005, Lyme disease is now the most common vector-borne disease in the United States. Infection is very common among domestic animals, as well. When treated with antibiotics early, it can usually be eradicated. But, says Barthold, "our work has shown that in the absence of antibiotic treatment, 100 percent of animals infected with Lyme bacteria remain infected even though they have a perfectly functional immune response." Working with mice, Barthold has found that the bacteria, Borrelia burgdorferi, "literally integrate themselves into collagen tissue. They colonize little spots here and there: one joint, but not another; nervous tissue; the heart. It varies from individual to ... individual, which explains the disease's highly variable clinical manifestations." In a study to be published later this year, Barthold outlines his discovery that even after long-term antibiotic treatment, bacteria hidden in collagen tissue are still viable and infectious. "We're trying to be careful in what we claim," he says, "but these findings will be controversial." http://aac.asm.org/cgi/content/abstract/AAC.01050-07v1 Persistence of Borrelia burgdorferi Following Antibiotic Treatment in Mice Emir Hodzic, Sunlian Feng, Kevin Holden, Kimberly J. Freet, and Stephen W. Barthold* Center for Comparative Medicine, Schools of Medicine and Veterinary Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616   Abstract The effectiveness of antibiotic treatment was examined in a mouse model of Lyme borreliosis. Mice were treated with ceftriaxone or saline for one month, commencing during the early (3 weeks) or chronic (4 months) stages of infection with Borrelia burgdorferi. Tissues from mice were tested for infection by culture, polymerase chain reaction (PCR), xenodiagnosis, and transplantation of allografts at 1 and 3 months after completion of treatment. In addition, tissues were examined for spirochetes by immunohistochemistry. In contrast to saline-treated mice, mice treated with antibiotic were consistently culture-negative, but tissues from some of the mice remained PCR-positive, and spirochetes could be visualized in collagen-rich tissues. Furthermore, when some of the antibiotic treated mice were fed upon by Ixodes scapularis ticks (xenodiagnosis), spirochetes were acquired by the ticks, based upon PCR, and ticks from those cohorts transmitted spirochetes to naïve SCID mice, which became PCR-positive, but culture-negative. Results indicated that following antibiotic treatment, mice remained infected with non-dividing but infectious spirochetes, particularly when antibiotic treatment was commenced during the chronic stage of infection. Article May Be Viewed in Full at LYME BLOG www.LymeBlog.com If you want to be kept up to the minute on Lyme News, Lyme Blog is the best resource I've found...  http://lymeblog.com/modules.php?name=News&file=article&sid=1345