P095
Preliminary study on STANDARD™ M10 MTB/NTM, a RT-PCR multiplex test for management of TB and NTM patients
F Sorella(1) F Bisognin(2) V Ferraro(1,2) C M Crovara Pesce(1,2) P Dal Monte(1,2)
1:Microbiology Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Italy; 2:Alma Mater Studiorum University of Bologna, Italy
Background
The STANDARD™ M10 MTB/NTM (SD BIOSENSOR, KR) is a new cartridge-based RT-PCR multiplex able to detect M. tuberculosis complex (MTB) and Nontuberculous Mycobacteria (NTM) positive pulmonary samples.
The aim of this preliminary study is to evaluate the performance of this test on selected Xpert® MTB/RIF Ultra (Cepheid, USA) positive respiratory specimens.
Materials and Methods
Forty-five decontaminated frozen respiratory samples, which had previously resulted MTB-positive on GeneXpert® system were included in the study: 10 were detected with “high” DNA load, 10 “medium” and 10 “low”, all with MTB culture-positive. In addiction we included 15 MTB culture-negative specimens, of which 10 were detected as “very low” and 5 “trace” on GeneXpert®. All samples were mixed in a 2:1 ratio with a “sputum pretreatment solution” and loaded into the cartridge according to the manufacturer’s instruction.
Results
All samples obtained “High”, “Medium” and “Low” load on GeneXpert® were confirmed MTB-positive on STANDARD™ M10 system.
Among the 15 MTB culture-negative specimens with “very low” and “trace” load on GeneXpert®, two of them were detected MTB-positive on STANDARD™ M10.
Conclusions
In this preliminary study we observed a full agreement between GeneXpert® and STANDARD™ M10 system in samples with MTB culture-positive pulmonary samples, while among culture-negative and MTB DNA poor load samples, only 13% were detected positive by STANDARD™ M10 MTB/NTM test. These data should be confirmed in a study with a larger sample size and NTM positive samples, however this new device appears to be suitable in the diagnosis of TB cases.