Detection of Chlamydia trachomatis-DNA in synovial fluid: evaluation of the sensitivity of different DNA extraction methods and amplification systems

Table 3 Sensitivity of PCR for the detection of intracellular persisting Chlamydia trachomatis in synovial fluid depending on DNA extraction method

Number of serial dilution	1 Alkaline lysis	2 Qiaex II + CTAB gel extraction kit^®	3 Qiagen Tissue Kit^®	5 Qiagen Stool Kit^®
1	1	0.1	10	1
2	0.1	10	100	1
3	0.1	100	1	1
4	1	1	10	1
5	0.1	10	10	1
Sensitivity	0.1 M 0.1	10 M 10	10 M 10	1 M 1
Statistical analysis	* 2, 4	* 1	* 2, 5	* 4

Synovial fluid was spiked with C. trachomatis persistently infected peripheral blood monocytes (C. trachomatis PBMO) per ml synovial fluid (SF) ranging from 10,000 C. trachomatis PBMO/ml SF to 0.1 C. trachomatis PBMO/ml SF in 10-fold decreasing numbers. Five independent repeats of each serial dilution were performed (n = 5) for each DNA extraction method. Amplification was performed using system number 1 (C. trachomatis-omp1 directed PCR). The median (M) of serial dilutions is given below. Sensitivity was defined as reproducibly detected lowest number of detected C. trachomatis PBMO/ml SF. Statistical significant results are indicated by *, the method compared with is indicated by number (P < 0.05). omp-1 = major outer membrane protein.

ISSN: 1478-6362