Nontuberculous Mycobacteria – Clinical and Laboratory Diagnosis: Experiences from a TB Endemic Country

Figures & data

Table 1. Geographic distribution of the study population whose isolates were included in the study.

Geographic area	Number of cases, percentage
Tamil Nadu, India	25/90, 28%
West Bengal, India	23/90, 23%
Jharkhand, India	12/90, 13%
Andhra Pradesh, India	10/90, 11
Kerala, India	6/90, 7%
Bangladesh	5/90, 6%
Bihar, India	4/90, 4%
Chhattisgarh, India	2/90, 2%
Karnataka, India	2/90, 2%
Nepal	1/90, 1%

Table 2. Clinical presentations of rapidly growing nontuberculous mycobacteria.

Clinical presentation	Number of cases, percentage
Skin and soft tissue infections	16/41, 39
Blood stream/line associated infections	9/41, 21.9
Pulmonary infections	9/41, 21.9
Injection site abscesses	2/41, 4.8
Infections of the urinary system	2/41, 4.8
Breast abscess	1/41, 2.4
Skull base osteomyelitis	1/41, 2.4
Chemotherapy port site infection	1/41, 2.4

Table 3. Species identification of nontuberculous mycobacteria.

Species-based on 16S rRNA sequencing	ITS sequencing	MALDI-TOF ID
	Number of concordant isolates	Number of concordant isolates
M. intracellulare (n = 19)	19	14 (5 were not identified)
M. simiae (n = 8)	8	8
M. avium (n = 6)	6	5 (1 was not identified)
M. avium complex (n = 3)	3 (identified as M. intracellulare)	2 (1 was not identified)
M. kansasii (n = 2)	2	2
M. flavescens (n = 2)	2	2
M. europaeum (n = 2)	2	0 (1 was identified as M. gordonae, 1 was not identified as it was not included in the database)
M. szulgai (n = 1)	1	1
M. yongonense (n = 1)	1	Not identified as it was not included in the database
M. timonense (n = 1)	1	0 (M. avium complex)
M. novocastrense (n = 1)	0 (M. flavescens)	0 (M. flavescens)
M. scrofulaceum (n = 1)	0 (M. parascrofulaceum)	0 (no identification)
M. parascrofulaceum (n = 1)	1	Not included in the database
M. longobardum (n = 1)	0 (M. celatum)	Not included in the database
M. abscessus (n = 26)	^†	24 (2 were not identified)
M. fortuitum (n = 10)	^†	10 (M. fortuitum group)
M. farcinogenes (n = 1)	^†	1
M. bacteremicum (n = 1)	^†	0 (M. neoaurum)
M. mucogenicum (n = 1)	^†	1
M. phocaicum (n = 1)	^†	0 (Pseudomonas stutzeri)
M. goodii (n = 1)	^†	Not included in the database

† = not performed; results of discordant isolates given in the parenthesis.

ITS: Internal transcribed spacer; MALTI-TOF: Matrix-assisted laser desorption ionization-time of flight.

Table 4. Agreement between the results of 16S rRNA sequencing, ITS sequencing and MALDI-TOF.

Tests compared (Total tests, n = 90)	Statistical agreement	95% CI
Concordance of 16S rRNA sequencing and MALDI-TOF   • Rapidly growing NTM   • Slowly growing NTM	83% (cumulative) 94.5% 77.5%	74.00–90.4% 81.3–99.4% 63.9–81.4%
Concordance of ITS sequencing for slowly growing NTM and MALDI-TOF	76%	63.9–81.4%

ITS: Internal transcribed spacer; MALDI-TOF: Matrix assisted laser desorption ionization-time of flight; NTM: Non-tuberculous mycobacteria.