Non-Tuberculosis mycobacterium speciation using HPLC under Revised National TB Control Programme (RNTCP) in India

Area of Science:

• Microbiology
• Clinical Diagnostics
• Public Health

Background:

• Non-Tuberculous Mycobacteria (NTM) are environmental bacteria with growing clinical relevance.
• Data on NTM prevalence within the Revised Tuberculosis Control Programme (RNTCP) is limited.
• Accurate identification and speciation of NTM are crucial due to their potential to cause disease.

Purpose of the Study:

• To determine the prevalence and speciation of NTM isolates from samples processed under the RNTCP.
• To evaluate the utility of High-Performance Liquid Chromatography (HPLC) for NTM identification and speciation.

Main Methods:

• A cross-sectional study was conducted at five RNTCP-accredited culture and drug susceptibility testing laboratories.
• AFB-positive, ICT-negative samples were analyzed for NTM identification and speciation using HPLC.
• A total of 266 isolates were initially processed, with 164 having a second sample available for speciation.

Main Results:

• HPLC identified NTM species in 95% of the 164 isolates analyzed.
• The most common NTM identified were Mycobacterium chelonae (26.8%) and Mycobacterium fortuitum (12.8%).
• Mycobacterium tuberculosis complex was identified in 9% of isolates, alongside other NTM species.

Conclusions:

• NTM identification and speciation are not routinely performed within the current TB control program.
• HPLC demonstrated high efficacy in identifying NTM to the species level, identifying 10 different species.
• The speciation of NTM using HPLC should be prioritized in TB reference laboratories for accurate diagnosis and management of NTM-related diseases.