Reply to 'evaluation of mycobacterial interspersed repetitive-unit-variable-number tandem-repeat genotyping as performed in laboratories in Canada, France, and the United States'

摘要

With great interest, we have taken notice of the letter of Cowan et al. (1). Indeed, the very high degree of worldwide standardization in typing of Mycobacterium tuberculosis is unique compared to the variety of techniques used for typing of other bacteria. However, the quality of this variable-number tandem-repeat (VNTR) typing has hardly been studied in the international context. Thanks to the enthusiastic participation of 37 laboratories worldwide, the first external quality assessment has been conducted within the framework of an European Centre for Disease Prevention and Control (ECDC) project on the molecular surveillance of multidrug-resistant/extensively drug-resistant tuberculosis (MDR/XDR-TB) in the European Union (2). The main purpose of the initiation of this proficiency study was to identify the flaws in VNTR typing in international laboratories worldwide, and indeed, multiple structural aberrations were observed. This provided laboratories the opportunity to identify important problems in the use of the locally adapted typing technique.