Cross-contamination of respiratory tract specimens by the avirulent M. tuberculosis H37Ra reference

Necrostatin-1 manufacturer strain has also been reported [21]. The MST method, which was used in this study in addition to the more commonly used VNTR/MIRU typing method [15, 16], requires a relatively small amount of sample DNA from the patient. In contrast to the conventional IS6110-RFLP method, which requires a relatively large amount of DNA, both the MST and GSK872 clinical trial the VNTR/MIRU typing methods require only small DNA samples as they are based on PCR amplification of selected genomic regions [22]. The fact that such a small amount of material is handled during these aforementioned procedures is an obvious advantage, since it limits the risk of exposure of laboratory personnel to a dangerous pathogen. Since the MST method is based on sequence

analysis, is reproducible and is easily exchangeable, we propose and offer a free and accessible M. tuberculosis MST database (at http://​ifr48.​timone.​univ-mrs.​fr/​MST_​MTuberculosis/​mst) so that microbiologists may compare the spacer sequence profiles they obtain with previously determined profiles for M. tuberculosis. The requirement for sequence analysis may limit the diffusion of MST to those laboratories that are equipped with an automatic sequencer, which is not a commonality in most laboratories, especially those in resource-limited countries. Since MST uses PCR amplification as the first experimental

step, it has the advantage of being P-type ATPase applicable this website to DNA extracts from inactivated mycobacterial cultures [23] shortly after they are shown to be positive. The MST results were obtained in four working days (from the moment the culture was obtained to the interpretation of MST analysis). A similar, yet slightly longer delay of 13 days (median value) between initial analysis and interpretation of results was recently reported when using the VNTR/MIRU method. In contrast, the conventional IS6110 technique provided results in a median time of 45 days [16]. The delay period required to complete the MST analysis is certainly short enough to contribute to the interpretation of laboratory data that may have a significant clinical impact on patients. Conclusion Our report confirms the importance of rapid identification of cross-contamination. Indeed, the misdiagnosed patient received unnecessary anti-tuberculosis therapy and the final correct diagnosis was slightly delayed. MST typing proved to be an efficient new tool for the detection of cross-contamination with M. tuberculosis. In addition, MST results may be obtained within a few days, which significantly improves the quality of laboratory processing and, therefore, the quality of medical care for the patient. Methods Epidemiological investigation We reviewed laboratory charts to identify mycobacterial isolates that were identified as M.