|Everett, Karin - USDA/ARS/NADC, AMES, IA|
Submitted to: Journal of Clinical Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 8, 1998
Publication Date: N/A
Interpretive Summary: Chlamydiae are bacteria that live inside the cells of many different animals, ranging from humans and housecats to pigs and poultry. Chlamydiae are generally detected by using laborious and time-consuming culture methods or expensive assays. This study describes a new polymerase chain reaction (PCR) test that detects all known chlamydiae. This study also describes two simple and new PCR tests (multiplex and TaqMan) that specifically detect only strains belonging to the Chlamydiaceae family. The chlamydiae that belong to the Chlamydiaceae are often the cause of disease in animals and humans. Previously, easily detecting and distinguishing the Chlamydiaceae from other chlamydiae required the use of special antibodies or a "nested" PCR assay. These PCR tests will make it possible to detect all chlamydiae without culture, isolation, or complex reagents. This will assist veterinarians in the management of chlamydial diseases in livestock and poultry.
Technical Abstract: Few identification methods will rapidly or specifically detect all bacteria in the order Chlamydiales, family Chlamydiaceae. In this study, three PCR tests were developed for identification of these bacteria, based on sequence data from over 48 chlamydial strains. Two tests exclusively recognized the Chlamydiaceae: a multiplex test targeting the ompA gene and the rRNA intergenic spacer and a TaqMan test targeting the 23S rRNA. The multiplex test was able to detect as few as 200 IFU, while the TaqMan test could detect 2 IFU. The amplicons produced in these tests ranged from 132 to 320 bp in length. The third test produced a 600-bp amplicon from strains belonging to several families in the order Chlamydiales. Direct sequence analysis of this amplicon has facilitated the identification of new chlamydial strains. These three tests permit ready identification of chlamydiae for diagnostic and epidemiologic study. The specificity of these tests indicates that they might also be used to identify chlamydiae without culture or isolation.