Abstract
Extra-pulmonary mycobacterial infections are characterized by a paucibacillary nature and extra-pulmonary samples consist of different matrices; the processing of these samples requires a high level of manual skills and non-standardized procedures. The aim of this study was to compare the performance of MYCO-TB with MycoPrep on extra-pulmonary samples in terms of Mycobacteria detection, culture contamination and suitability for molecular assay. This prospective study was conducted on 201 extra-pulmonary samples from suspected cases of mycobacterial infection. Specimens were divided into two equal aliquots; one was decontaminated with MYCO-TB the other with MycoPrep. The contamination rate of liquid cultures was significantly different: 2.5% (5/201) for MYCO-TB and 7.5% (15/201) for MycoPrep (p = 0.036). At least 1 Mycobacterium tuberculosis complex (MTBc) positive culture was detected in 6 specimens treated with MYCO-TB and 8with MycoPrep, without significant differences in times to positivity (TTP) in liquid culture. No Xpert MTB/RIF Ultra invalid results were obtained with samples decontaminated with MYCO-TB. The MYCO-TB kit had greater activity than MycoPrep in the digestion and decontamination of extra-pulmonary specimens for the detection of Mycobacteria, supporting the use of MYCO-TB in this type of sample. Ready-to use reagents, rapid protocol and single-sample formulation of MYCO-TB reduced the level of manual skills required as well as the risk of sample contamination.
Highlights
Extra-pulmonary mycobacterial infections are characterized by a paucibacillary nature and extrapulmonary samples consist of different matrices; the processing of these samples requires a high level of manual skills and non-standardized procedures
Mycobacterial infections, caused by Mycobacterium tuberculosis complex (MTBc) and Non-tuberculous Mycobacteria (NTM), are frequently associated with lung disease and most commercial IVD products intended for the detection of Mycobacteria have been designed for respiratory specimens
Liquid culture of 10 samples (5 urine and 5 purulent samples) were negative with MYCO-TB, whereas treatment with MycoPrep did not prevent contamination; in these samples Gramnegative bacteria were isolated in 7 cases and Gram-positive in 3
Summary
Extra-pulmonary mycobacterial infections are characterized by a paucibacillary nature and extrapulmonary samples consist of different matrices; the processing of these samples requires a high level of manual skills and non-standardized procedures. The aim of this study was to compare the performance of MYCO-TB with MycoPrep on extra-pulmonary samples in terms of Mycobacteria detection, culture contamination and suitability for molecular assay. This prospective study was conducted on 201 extra-pulmonary samples from suspected cases of mycobacterial infection. The process of digesting and decontaminating extra-pulmonary samples requires a high level of manual skill to prepare reagents, which are often not available in bulk, as well as to process samples with non-standardized procedures
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