ME/CFS in the Department of Medicine

Chlamydia Pneumoniae


Jose Montoya, MDPhysician Perspective: Jose G. Montoya, MD

In patients thought to have chronic fatigue syndrome secondary to persisting Chlamydia spp infection, only select and long-term antibiotic regimens are likely to work.  Tetracycline, macrolide and quinolone antibiotics have been found to be effective in vitro, in animal models, as well as in acute disease in humans.  However, clinical information regarding dose and duration of these antimicrobial drugs for patients with CFS suspected to have Chlamydial spp. as single etiologic agent or as a co-pathogen, has not been published to date.

From Siewert et al. "Growth Cycle-Dependent Pharmacodynamics of Antichlamydial Drugs"
"Chlamydiae are obligate intracellular pathogens that exhibit an extensive intracellular developmental cycle in vivo. Clinical treatment of chlamydial infection is typically initiated upon occurrence of symptomatology and is directed against an asynchronous population of different chlamydial developmental forms. Pharmacodynamics of antichlamydial drugs are predominantly characterized by MICs; however, in vitro determinations of MIC may not reflect differential susceptibilities of the developmental cycle. In this study, we correlated the antichlamydial effect of erythromycin, rifampin, doxycycline, and ciprofloxacin with the developmental stage of a fast-replicating and a slow-replicating chlamydial species. In addition, we describe the influence of concentration on killing. Extracellular elementary bodies and very-early-phase and late-phase chlamydiae were refractory to all tested antibiotics except rifampin, which was very effective against early-cycle chlamydiae. Rifampin was the most effective antibiotic overall, killed in a dose dependent matter, and exhibited moderate synergism with erythromycin. These considerations provide important information on chlamydial biology and antimicrobial susceptibility. A combinational therapy of rifampin and a macrolide should be considered in therapy-refractory infections."


The information and opinions contained in this portion of the website are intended for educational and research purposes only. It is not intended for the medical management of patients and does not necessarily reflect the views of Stanford University or Stanford Hospital and Clinics.

Only a physician familiar with a patient's individual medical history can make medical judgments and give that patient specific medical advice.

Stanford Medicine Resources:

Footer Links: