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Chinese Journal of Antituberculosis ›› 2025, Vol. 47 ›› Issue (8): 1031-1037.doi: 10.19982/j.issn.1000-6621.20250054

• Original Articles • Previous Articles     Next Articles

A study on the identification of Mycobacterium species using fluorescent PCR probe melting curve technique and DNA microarray chip technique

Fan Ruifang, Dai Xiaowei, Yang Xinyu, Chen Shuangshuang, Chen Hao, Yu Lan, Zhao Yanfeng, Li Chuanyou(), Wang Nenhan()   

  1. Tuberculosis Labroatory, Beijing Center for Disease Prevention and Control,Beijing 100035, China
  • Received:2025-02-12 Online:2025-08-10 Published:2025-08-01
  • Contact: Li Chuanyou, Email: lichuanyou@ccmu.edu.cn; Wang Nenhan, Email: hean_1983@126.com
  • Supported by:
    Beijing Center for Disease Prevention and Control Research and Cultivation Program(2023-KYJH-04)

Abstract:

Objective: To compare the clinical application value of fluorescent PCR probe melting curve assay (MeltPro) and DNA microarray chip technique for the Mycobacterium species identification. Methods: We collected the reference strains within the detection scope of both methods and the clinical isolates suspected to be nontuberculosis mycobacteria (NTM) stored in the Tuberculosis Laboratory the Beijing Center for Disease Control and Prevention from January 2016 to August 2023, and used the two methods for species identification. Strains yielding discrepant results underwent whole-genome sequencing analysis. Results: A total of 19 reference strains (one per species) were selected, with both the Melting Curve Method and the Gene Chip Method achieving a 100.00% concordance rate for their identification. A total of 180 clinical strains were collected, of which 8 strains were identified as Mycobacterium tuberculosis complex (MTBC), 1 strain showed the MTBC co-occuring with Mycobacterium fortuitum, and 171 strains were identified as NTM. The overall concordance rate between the two methods for clinical strains was 87.78% (158/180). The top four species by prevalence were Mycobacterium avium intracelluar complex (MAC)(38.26% (57/149)), Mycobacterium chelonae or Mycobacterium abscess (24.83% (37/149)), Mycobacterium kansas (17.45% (26/149)), and Mycobacterium fortuitum (12.75% (19/149)) in 149 NTM strains. Discrepant results occurred in 22 strains: 9 showed MAC discordance between two methods, 1 strain was identified as an Mycobacterium intracellulare using the DNA microarray chip technique, but as Mycobacterium lentiflavum by MeltPro,1 strain was identified as an Mycobacterium terrae using the DNA microarray chip, and as Mycobacterium nonchromogenicum by MeltPro, 10 strains had the identification results by DNA microarray chip, but yielded uninterpretable results by MeltPro, and 1 strain was uninterpretable by DNA microarray chip, but identified as Mycobacterium lentiflavum by MeltPro. Gordonia aichiensis (ANI=99.102),Mycobacterium wolinskyi (ANI=97.822),Mycobacterium monacense (ANI=97.365),Mycobacterium peregrinum (ANI=97.730/97.981/96.930) and Mycobacterium stomatepiae (ANI=96.277) were identified by WGS and calculation of Average Nucleotide Identity(ANI). Conclusion: Both the MeltPro assay and DNA microarray chip method demonstrate good clinical application value for the identification of Mycobacterium species; however, the MeltPro assay exhibits higher accuracy.

Key words: Mycobacterium infections, Mycobacterium tuberculosis, Molecular probe techniques, Diagnosis, differential

CLC Number: