Isolation and analysis of the molecular epidemiology and zoonotic significance of Mycobacterium tuberculosis in domestic and wildlife ruminants from three states in India

Abstract

The majority of tuberculosis cases in ruminants are caused by Mycobacterium bovis (MB). However, in this study, the authors reported the isolation of Mycobacterium tuberculosis (MT) from bovine milk, nasal swabs and post-mortem tissue samples (n = 841) collected from cattle and buffaloes in the states of Telangana, Maharashtra and Gujarat in India in the period from 2010 to 2015. The isolates (n = 7) were confirmed as Mycobacterium due to their growth characteristics and colony morphology in a commercial liquid medium Mycobacteria Growth Indicator Tube (MGIT)™ employing the BD BACTEC™ MGIT™ 960 system and the Lowenstein Jensen (LJ) medium supplemented with glycerol but not with sodium pyruvate, and BD-DIFCO™ Middlebrook 7H10 agar containing oleic albumin dextrose catalase (OADC). These isolates were initially identified as members of the Mycobacterium tuberculosis complex (MTC) using a commercial nested polymerase chain reaction (PCR) kit based on the IS6110 MTC specific nucleotide sequence. The isolates were confirmed as MT using three commercial line probe assay kits, were further genotyped, and the spoligotypes identified were of East African Indian (EAI) 3_IND, EAI5, Central-Asian (CAS) 1_DELHI, U and T1 lineages. Two MT isolates from one antelope (Antelope cervipara) and one gazelle (Gazelle bennettii) from Gujarat, which were identified previously, were spoligotyped during this study and identified as belonging to EAI3_IND and EAI5 lineages, respectively. The epidemiological significance and zoonotic implications of regional presence and documentation of the same or two different spoligotypes in different species within the family Bovidae as well as humans is discussed.

Zoonotic Tuberculosis – The Changing Landscape

“…However, this may be partially explained by insufficient laboratory facilities and lack of accurate identification of the causative agent of zTB ( M. orygis seems to be the major pathogen in Indian cattle, Bos indicus ) ( Brites et al, 2018 ). The region possesses multiple risk factors for zTB including high human-animal density, close and frequent physical contact with infected animals, inadequate disease control measures, as well as consumption of unpasteurized milk and milk products ( Bapat et al, 2017 , Mukherjee et al, 2018 ). For example India has an estimated 21.8 million (95% CI: 16.6, 28.4) infected cattle in a rapidly growing dairy sector ( Srinivasan et al, 2018 )…”

“…In India, M tuberculosis (MANU strain) was found to be more prevalent in cattle than M. bovis ( Sweetline Anne et al, 2017 ). M. tuberculosis MANU1 strain infection in cattle is likely due to spillover from humans in TB endemic areas ( Sweetline Anne et al, 2017 , Mukherjee et al, 2018 ) and demonstrates the potential for MDR-TB strains to acquire an animal reservoir that could then pose a future risk to human TB control. Reverse zoonoses with M. tuberculosis has also been reported in zoo animals especially in elephants, primates and felines ( Montali et al, 2001 ).…”

Tuberculosis caused by Mycobacterium orygis in wild ungulates in Chennai, South India

“…They have been isolated from antelopes, gazelles, white tailed deer, red deer, fallow deer and roe deer (García-Bocanegra et al, 2012;Martín-Hernando et al, 2010;Mukherjee et al, 2018;Schmitt et al, 1997). It is possible that TB can spread among wild animals because of mycobacterial shedding into the environment by the infected animals (Dorn-In et al, 2020;Lugton et al, 1998;Santos et al, 2015).…”

“…Several studies have reported the isolation of MTBC from wildlife around the globe (Lekko et al., 2020; Thapa et al., 2017), especially those belonging to the Cervidae family. They have been isolated from antelopes, gazelles, white tailed deer, red deer, fallow deer and roe deer (García‐Bocanegra et al., 2012; Martín‐Hernando et al., 2010; Mukherjee et al., 2018; Schmitt et al., 1997). It is possible that TB can spread among wild animals because of mycobacterial shedding into the environment by the infected animals (Dorn‐In et al., 2020; Lugton et al., 1998; Santos et al., 2015).…”

Role of abattoir monitoring in determining the prevalence of bovine tuberculosis: A systematic review and meta‐analysis

“…The possibility of the infection being transmitted to cattle by humans cannot be ignored (WHO End TB Strategy, 2015). In 2018, Mukherjee et al identified the same spoligotypes of M. tuberculosis in humans and animals living in close proximity indicating the presence of an active ‘spill over’ mechanism from human to cattle (Mukherjee et al., 2018).…”