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Usefulness of PCR on normally sterile body fluids for the detection of fastidious bacteria

Abstract number: P1830

Jaton-Ogay K., Greub G., André C., Bille J.

Objectives: Molecular techniques to detect difficult to grow microorganisms in the clinical microbiology laboratory have become routine. Their contribution to patient care needs to be addressed. Thus, we assessed here the performance of PCR done on various types of normally sterile body fluids (i.e articular, pericardic, peritoneal and pleural fluids) for the detection of fastidious bacteria. These bacteria frequently remain undetected as they grow poorly or not at all on conventional culture media.

Methods: A total of 1247 samples (249 articular, 73 pericardic, 161 peritoneal and 764 pleural fluids) were investigated by PCR in our molecular diagnostic laboratory between 2000 and 2008. The different home-made molecular tests were 7 real-time TaqMan PCR detecting Chlamydia trachomatis, Neisseria gonorrhoeae, Mycobacterium tuberculosis complex, Borrelia burgdorferi, Chlamydophila pneumoniae, Mycoplasma pneumoniae, Legionella pneumophila, and 2 broad-range PCR with classic amplification of the 16S rDNA followed by sequencing of the amplified product i.e. a bacterial broad-range and a Mycobacterial spp. broad-range PCR.

Results: On the 1247 samples, 1370 PCR tests were performed. Eighty-three samples were positive for one of the PCR corresponding to 7% of the samples. Eleven samples (0.9%) contained inhibitors. In 4 to 14% of the various types of samples a positive PCR result could document the infection, with M. tuberculosis complex PCR (4%), bacterial broad-range PCR (14%), and C. trachomatis (12%), being the most productive tests (see Table).

For the other PCR results, 2/39 articular fluids were positive for B. burgdorferi, and 2/37 for N. gonorrhoeae; 1/38 peritoneal fluid was positive for N. gonorrhoeae; 1/13 pleural fluid was positive for L. pneumophila and 1/20 for M. pneumoniae. No specific samples were positive for C. pneumoniae nor for Mycobacteria spp other then M. tuberculosis complex.

Conclusion: Carefully indicated molecular methods could bring a positive added value over conventional testing especially for fastidious organisms. Here for 7% (83 out of 1247 normally sterile body fluids tested by various PCR) a difficult to grow bacteria has been detected and identified by specific PCR or broad-range PCR. The economical and clinical impact of such a diagnosis strategy need to be assessed.

FluidsSamplesa
 All (n = 1247)All + (n = 83)% of ++ for M. tuberculosis/total no. of samples tested% of ++ for bacterial broad-range PCR/total no. of samples tested% of ++ for C. trachomatis/total no. of samples tested% of +
Articular249218%5/915%12/9712%0/200%
Pericardic7368%5/677%1/119%0/0
Peritoneal1612214%0/210%2/633%19/13414%
Pleural764344%23/6993%9/6215%0/0
Total1247837%33/8784%24/17614%19/15412%
a+, positive.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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