This study does a nice job of demonstrating that standard antibiotic treatment with accepted antichlamydials does not get rid of persistent Chlamydia pneumoniae in cells. Note the date. It's been around for a while, and yet "modern" researchers in cardiovascular disease "persist" in treating with 14-30 days of zith and pronouncing with medical authority that antibiotics have not effect on Cpn induced cardiovascular events. Duh! There's still infection. Note too, it's from our old friend Hammerschlag who also has argued strenously against Cpn in MS and Alzheimer's. Win one, loose one.Antimicrob Agents Chemother. 2002 Feb;46(2):409-12.Related Articles, Links Effect of prolonged treatment with azithromycin, clarithromycin, or levofloxacin on Chlamydia pneumoniae in a continuous-infection Model.Kutlin A, Roblin PM, Hammerschlag MR.Department of Pediatrics, State University of New York Health Science Center at Brooklyn, Brooklyn, New York 11203-2098, USA.Persistent infections with Chlamydia pneumoniae have been implicated in the development of chronic diseases, such as atherosclerosis and asthma. Although azithromycin, clarithromycin, and levofloxacin are frequently used for the treatment of respiratory C. pneumoniae infections, little is known about the dose and duration of therapy needed to treat a putative chronic C. pneumoniae infection. In this study, we investigated the effect of prolonged treatment with azithromycin, clarithromycin, or levofloxacin on the viability of C. pneumoniae and cytokine production in an in vitro model of continuous infection. We found that a 30-day treatment with azithromycin, clarithromycin, and levofloxacin at concentrations comparable to those achieved in the pulmonary epithelial lining fluid reduced but did not eliminate C. pneumoniae in continuously infected HEp-2 cells. All three antibiotics decreased levels of interleukin-6 (IL-6) and IL-8 in HEp-2 cells, but this effect appeared to be secondary to the antichlamydial activity, as the cytokine levels correlated with the concentrations of microorganisms. The levels of IL-1beta, IL-4, IL-10, tumor necrosis factor alpha, and gamma interferon were too low to assess the effect of antibiotics. These data suggest that the dosage and duration of antibiotic therapy currently being used may not be sufficient to eradicate a putative chronic C. pneumoniae infection.