Submitted to: Research in Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/1994
Publication Date: N/A
Interpretive Summary: Chlamydia psittaci is a bacterium that can cause disease and death in birds and mammals. The ability to determine the strain causing the disease is important for evaluating the prognosis of the disease in birds and the potential for spreading to other birds and mammals. Serotyping using monoclonal antibodies has been a useful method; however, a number of diagnostic laboratories are not equipped to do the testing. Genetic testing by polymerase chain reaction (PCR) was used for the differentiation C. trachomatis strains. Tests demonstrated that PCR produced different patterns which correlated with serological tests. This provides laboratories with an additional method of identifying C. psittaci isolates.
Technical Abstract: Sixty-five avian Chlamydia psittaci isolates collected worldwide were analyzed by restriction mapping of the major outer membrane protein gene (omp1) obtained after DNA amplification by PCR. They were compared to 2 ruminant isolates, a feline pneumonitis and a guinea pig inclusion conjunctivitis (GPIC) isolate. According to their omp1 restriction patterns, avian strains were heterogeneous in that they exhibited 6 and 4 distinct patterns using Alul and Mboll restriction enzymes, respectively, thus defining 7 groups. However, 84% of the studied strains belonged to groups 1 to 4, which share a specific fragment triplet of 411, 282, and 102 base pairs in their Alul digestion patterns. Comparisons with serological classifications showed a strict correlation and allowed further intra- serovar differentiation. The ruminant, feline pneumonitis and GPIC C. psittaci isolates were clearly distinguished from each other and the avian strains. Moreover, this method was clearly able to identify dubiously designated strains as well as mixtures of isolates within a single sample. In conclusion, this PCR approach based upon omp1 restriction mapping enables the differentiation of avian C. psittaci isolates and can be proposed as a taxonomic and epidemiologic tool.