Acute respiratory infection due to Chlamydia pneumoniae:: Current status of diagnostic methods

Chlamydia pneumoniae is an obligate, intracellular, gram-negative bacterium that has been associated with a wide variety of acute and chronic diseases. Respiratory infection with C. pneumoniae occurs worldwide and in all age groups. Serological testing remains the most commonly used method to diagnose C. pneumoniae infection. PCR holds promise as a rapid diagnostic test, but none of the currently available assays have been adequately validated against culture, which remains the reference standard despite its technical complexity and variable yield, depending on the specimens tested and the isolation protocols used. Different studies have used not only different diagnostic tools or combinations thereof, but also different diagnostic criteria for making a diagnosis of acute or chronic infection. Most importantly, none of the available methods have been standardized, which has resulted in a wide variation of interlaboratory test performance, even when using the same test and criteria. In an effort to standardize diagnostic assays for C. pneumoniae, the US Centers for Disease Control and Prevention (CDC) and the Canadian Laboratory Center for Disease Control published recommendations for diagnostic testing in 2001 [ 1]. We reviewed the epidemiology of C. pneumoniae-associated respiratory infections in studies performed all over the world for the purpose of examining the current state of knowledge of C. pneumoniae diagnostics since the publication of the above-mentioned guidelines.