Identification of Non-tuberculous Mycobacteria by Partial Gene Sequencing and Matrix Assisted Laser Desorption Ionisation Time of Flight at a Tertiary Care Hospital in Telangana, India DC01-DC05
Dr. Neelima Angaali,
Raja Residency, Flat-201, Street No. 7, Himayat Nagar, Hyderabad-500029, Telangana, India.
Introduction: Non-tuberculous Mycobacteria (NTM) pulmonary disease is often unrecognised or misdiagnosed as Mycobacterium tuberculosis (MTB), Multi-Drug Resistant Tuberculosis (MDRTB), because of similar clinical presentation in counties with high burden of Tuberculosis (TB) including India. In India due to lack of awareness among clinicians and lack of laboratory facilities to diagnose these infections, its prevalence is largely unknown.
Aim: To evaluate the efficacy of identification of NTM species by Matrix Assisted Laser Desorption Ionisation Time of Flight (MALDI-TOF) and Heat Shock Protein (hSP65) gene sequencing and to determine their Antimicrobial Susceptibility Testing (AST).
Materials and Methods: All the clinical specimens from pulmonary and extra-pulmonary TB suspects at Nizamâ€™s Institute of Medical Sciences, Hyderabad, Telangana, India, over a period of one year i.e., from June 2017 to May 2018 were included in the study. The specimens were subjected to microscopy, culture and GeneXpert. The NTMs isolated in the culture were further characterised genotypically by MALDI-TOF and hsp65 gene sequencing. The identified NTM isolates were subjected to AST. All the methods were followed as per the standard protocols. Data was analysed using SPSS 25.
Results: A total of 1085 samples were processed out of which Mycobacteria was detected in 201 cases (18.5%). Among the culture positives, MTB complex was detected in 146 cases (13.5%) and NTM in 55 (5.06%). Mycobacterium abscessus was the predominant isolate. The most common co-morbidities were bronchiectasis and Chronic Obstructive Pulmonary Disease (COPD). Linezolid, clarithromycin, moxifloxacin and amikacin showed high sensitivity.
Conclusion: Molecular assay helps in rapid identification which can lead to targeted therapy and can thus combat antimicrobial resistance. The MALDI-TOF and hsp65 gene sequencing also offers quick results at a low cost and is easy to perform hence it can be considered as an alternate diagnostic tool for identification.