Molecular Epidemiology of Multidrug-ResistantMycobacterium bovisIsolates with the Same Spoligotyping Profile as Isolates from Animals

Abstract

PCR-based characterization techniques have been adopted in most laboratories for Mycobacterium bovis typing. We report a molecular characterization of human multidrug-resistant M. bovis isolates and three bovine isolates that share the spoligotyping profile. The analysis of the direct repeat region showed that both groups differed in the presence of spacers not included in the current membrane. They were also distinguished by two out of the nine mycobacterial interspersed repetitive unit variable-number tandem repeat loci tested, indicating that the human infection was not acquired from the cattle from which isolates were obtained. These results highlight that a combination of techniques is required for appropriate discrimination, even for those spoligotypes that have a low frequency.Mycobacterium bovis causes tuberculosis in cattle and other animals, and its implication in human tuberculosis has been recognized since the beginning of the twentieth century (21). In industrialized countries, human infection with M. bovis has been largely controlled through pasteurization of cow's milk, abattoir inspection, and culling of cattle reacting to compulsory diagnosis (tuberculin test). In spite of this, several cases of human tuberculosis caused by M. bovis have been described in recent years (6-8, 12, 17, 20), although some human M. bovis infections could be attributed to a possible endogenous reactivation of a historically acquired infection (11). On the other hand, some new cases of human M. bovis tuberculosis have also been associated with the consumption of dairy products, for instance, unpasteurized cheeses on the United States-Mexico border (7,17,35). Thereby, cases of human M. bovis have been related to immigrants or to people who have contracted the infection in countries where eradication programs are patchy or nonexistent (35). Moreover, several of these studies also found an association between human M. bovis disease and human immunodeficiency virus coinfection, showing tuberculosis to be an opportunistic disease in immunodepressed patients (5, 7).In Spain, less than 1% of clinically diagnosed cases of tuberculosis that are subsequently proven bacteriologically are attributed to M. bovis (28). From December 1993 to February 1995, 19 cases of primary M. bovis tuberculosis were detected in two big hospitals in central Spain (12). Afterwards, the outbreak spread to other cities and countries (18,23,27 Advances in molecular characterization have provided tools to enhance our knowledge of M. bovis dissemination and tuberculosis control. PCR-based characterization techniques such as spoligotyping (15) and mycobacterial interspersed repetitive unit (MIRU) variable-number tandem repeat (VNTR) typing (9, 31) have been adopted in most laboratories for M. bovis typing because they are faster, simpler, and cost-effective, with the added advantage that results are qualitative (present or absent or in the form of a number). The degree of differentiation and reproducibility is good, but spoligotyping has a lower discrimina...

Molecular Epidemiology of Mycobacterium bovis in Humans and Cattle

“…Mycobacterium bovis strains are, in contrast to M. tuberculosis, not transmitted effectively between humans (Runyon, 1959, CDC, 2011Gonzalo-Asensio et al, 2014) and are usually associated with extrapulmonary TB in humans (Malama et al, 2014;Han et al, 2015). However, the isolation of M. bovis from human sputum in some reports may indicate its potential for human-to-human infection, especially in closed populations such as prisons (Romero et al, 2006;Gumi et al, 2012). The human-to-human transmission can be differentiated from animal-to-human transmission by the application of fingerprinting tools (P erez-Lago et al, 2014).…”

Genotyping and rifampicin and isoniazid resistance in Mycobacterium bovis strains isolated from the lymph nodes of slaughtered cattle

“…Moreover, it will contribute to the success of programs for bTB control and eradication [18]. To address these questions, spoligotyping (Spacer Oligonucleotide Typing) and MIRU-VNTR (Mycobacterial Interspersed Repetitive UniteVariable-Number Tandem Repeat Typing) have been combined for the characterization of M. bovis in most laboratories, as these techniques are fast, costeffective, and have already been standardized [19,20]. More recently, whole genome sequencing (WGS) has gained a prominent role in answering research questions such as the rate of transmission within cattle herds and between hosts, the history of movement of M. bovis throughout the world, and routine surveillance activities [21].…”

Molecular typing of Mycobacterium bovis isolated in the south of Brazil

“…Genotyping techniques such as PCR-based spoligotyping and VNTR have been adopted in various laboratories for typing M. bovis with the advantage that the results are qualitative (presence or absence, or numerical form) (Romero et al , 2006). The approach used in this study for the genetic analysis of M. bovis isolates, combining spoligotyping and VNTR analysis, is still limited in Latin America.…”