Prevalence of nontuberculous mycobacteria among extrapulmonary tuberculosis cases in tertiary care centers in Northern India.

A K Maurya,S Kant,R A S Kushwaha,A K Singh,T N Dhole,M Kumar,V L Nag

doi:10.1155/2015/465403

Abstract

The reports of nontuberculous mycobacteria (NTM) associated with extrapulmonary diseases are increasing in tertiary care hospitals. Despite a significant increase in knowledge about NTM infections, they still represent a diagnostic and therapeutic challenge. The aim of this study is to know the prevalence of NTN among extrapulmonary tuberculosis cases in tertiary care centers in Northern India. A total of 227 culture positive isolates from 756 cases were tested for niacin production and catalase assay. BIO-LINE SD Ag MPT64 TB test and final identification and differentiation between MTBC and different species of NTM were further confirmed by GenoType Mycobacterium CM/AS assay. 71 cases (9.3%) were positive for AFB by ZN staining and 227 cases (30.1%) were positive for mycobacteria by culture. Niacin production and catalase activity were negative in 62/227 (27.4%) strains and after using a panel of different biochemicals and final confirmation by GenoType Mycobacterium CM assay. Out of 227 cultures tested, 165 (72.6%) strains were confirmed as M. tuberculosis complex, and 62 (27.4%) were confirmed as NTM. The most common NTM species identified were M. fortuitum 17 (27.5%) and M. intracellulare 13 (20.9%). The rapid identification of NTM species may help in targeted therapy and management of the diseases.

Highlights

Nontuberculous mycobacterium (NTM) has been observed for 100 years, but the trend of increasing prevalence of NTM is great concern for clinician as well as microbiologist
After using a panel of different biochemicals and again testing by rapid BIO-LINE SD Ag MPT64 TB test for rapid differentiation between Mycobacterium tuberculosis complex (MTBC) and NTM and using confirmatory test by GenoType Mycobacterium common mycobacteria/additional species (CM/AS) assay, 165 (72.6%) isolates were M. tuberculosis complex and the remaining 62 (27.4%) isolates were identified as different species of NTM by GenoType Mycobacterium CM/AS assay
In present study the rapidly growing mycobacteria were prominently isolated from extrapulmonary samples; M. fortuitum (27.4%) and M. abscessus (14.4%) were the most frequently isolated species

Summary

Introduction

Nontuberculous mycobacterium (NTM) has been observed for 100 years, but the trend of increasing prevalence of NTM is great concern for clinician as well as microbiologist. More than 125 species of NTM have been catalogued and available out of which at least 42 species related with diseases in NTM [2]. Several species of NTM caused pulmonary and extrapulmonary diseases such as skin/softtissue infections and lymphatic, disseminated, and nosocomial infections after surgery of varying severity in both sporadic and epidemic form [5, 6]. Disseminated disease due to NTM is mostly related with AIDS and other forms of severe immunosuppression [3]. World Health Organization (WHO) recommended use of line probe assay to reduce the time for culture, identification, and drug resistance detection to as short as 2 days [7]. DNA strip technology (line probe assays) based on the reverse hybridization of PCR products to their complementary probes has been used for the simultaneous detection and identification of mycobacteria.

Objectives

Methods

Results

Discussion

Conclusion