Usefulness of a microarray method for the diagnosis of bone and joint infections directly on clinical samples: a new application of Proveit sepsis
Abstract number: P1808
Allais E., Boisset S., Freydière A.M., Ferry T., Lustig S., Etienne J., Tigaud S., Vandenesch F., Laurent F.
Objectives: We evaluate the performance of Prove-it Sepsis assay (PISA) (Mobidiag®) for rapid detection and identification of bacteria directly from bone and joint infections (BJIs) clinical samples, compared to conventional culture and universal 16S PCR. This microarray assay, targeted gyrB, parE and mecA genes, was initially developed to identify bacterial species (n > 50) in positive blood cultures in less than 3 hours.
Methods/Results: We selected 114 clinical BJI samples, for which microbiological diagnosis had been previously established either by culture (C+) or by PCR16S-sequencing (C-/PCR16S+). All these positive samples were chosen within the spectrum of bacteria included on the array. Sixteen negative clinical samples (C-/PCR16S-) were also included.
C-/PCR16S- (n = 16): 15 samples were negative; 1 sample was positive with S. epidermidis which has been confirmed by the tuf gene amplification and sequencing
C+/PCR16S+ (n = 32): 23 samples (71.9%) were positive with concordant identification, 3 samples were positive and concordant but revealed the presence of a second species; 6 samples remained negative
C+/PCR16S- (n = 20): 5 samples (25%) were positive and concordant; 15 samples remained negative as PCR16S
C-/PCR16S+ (n = 62): 36 samples (58%) were positive and concordant, 4 samples were positive with a mix of 2 to 4 species; 22 samples remained negative.
A new generation of PISA (StripArray) including specific probes for Kingella kingae and Propionibacterium acnes was also tested on culture-negative synovial fluids from children (n = 159):
C-/PCRKingella+ (n = 45): 35 were positive for K. kingae (77.8%). Ten samples remained negative, but seven revealed positive-Kingella probes in insufficient number to meet the strict positive identification criteria, deserving complementary studies.
C-/PCR16S- (n = 114): 110 samples were negative and 4 samples were found positive (K. kingae, P. acnes,S. aureus, S. pneumoniae).
Conclusions: The preliminary results of this rapid and cost-effective method are promising. Its advantages include: no sequencing step, detection of a large panel of bacterial species with a single multiplex PCR assay, detection of polymicrobial BJIs, detection of mecA. Currently, the new version of PISA is further evaluated with prospective BJI clinical samples as well as optimization of DNA extraction/amplification protocols is underway to improve the sensitivity of the test. The new version of PISA could eventually replace conventional 16S PCR for the diagnosis of BJIs.
|Session name:||Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases|
|Location:||Vienna, Austria, 10 - 13 April 2010|
|Back to top|