Trends of Mycobacterium bovis Isolation and First-Line Anti-tuberculosis Drug Susceptibility Profile: A Fifteen-Year Laboratory-Based Surveillance

Abstract

Background Mycobacterium tuberculosis causes the majority of tuberculosis (TB) cases in humans; however, in developing countries, human TB caused by M. bovis may be frequent but undetected. Human TB caused by M. bovis is considered a zoonosis; transmission is mainly through consumption of unpasteurized dairy products, and it is less frequently attributed to animal-to-human or human-to-human contact. We describe the trends of M. bovis isolation from human samples and first-line drug susceptibility during a 15-year period in a referral laboratory located in a tertiary care hospital in Mexico City.Methodology/Principal FindingsData on mycobacterial isolates from human clinical samples were retrieved from the laboratory’s database for the 2000–2014 period. Susceptibility to first-line drugs: rifampin, isoniazid, streptomycin (STR) and ethambutol was determined. We identified 1,165 isolates, 73.7% were M. tuberculosis and 26.2%, M. bovis. Among pulmonary samples, 16.6% were M. bovis. The proportion of M. bovis isolates significantly increased from 7.8% in 2000 to 28.4% in 2014 (X 2 trend, p<0.001). Primary STR resistance was higher among M. bovis compared with M. tuberculosis isolates (10.9% vs.3.4%, p<0.001). Secondary multidrug resistance (MDR) rates were 38.5% and 34.4% for M. bovis and M. tuberculosis, respectively (p = 0.637). A rising trend of primary STR monoresistance was observed for both species (3.4% in 2000–2004 vs. 7.6% in 2010–2014; p = 0.02).Conclusions/SignificanceThere is a high prevalence and a rising trend of M. bovis isolates in our region. The proportion of pulmonary M. bovis isolates is higher than in previous reports. Additionally, we report high rates of primary anti-tuberculosis resistance and secondary MDR in both M. tuberculosis and M. bovis. This is one of the largest reports on drug susceptibility of M. bovis from human samples and shows a significant proportion of first-line anti-tuberculosis drug resistance.

Genetic diversity of Mycobacterium bovis in Jalisco, Mexico: Tracing back sources of infection

“…This agrees with previous reports (Cobos-Marín et al, 2005;Santillán-flores et al, 2006;Reyes et al, 2008;Pérez-Guerrero et al, 2008;Bobadilla-del Valle et al, 2015;Sandoval-Azuara et al, 2017), where in spite of studying samples from different and specific regions of Mexico, the diversity of strains has been evident, suggesting an intense and continuous exchange of animals, and new genetic lines emerging as a consequence of the high prevalence of bTB in dairy cattle. The spoligoforest demonstrates all possible relations of spoligotypes under the assumption of spoligotype mutation, with genetic instability ranging from 10 to 20 years (Brosch et al, 2002;Gutiérrez et al, 2005;Smith et al, 2006).…”

“…Spoligotype SB0140 has infected cattle, deer, badgers and people in Source: http://spoltools.emi.unsw.edu.au/ Ireland (de la McLernon et al, 2010), and cattle in the United Kingdom (de la RuaDomenech et al, 2006;McLernon et al, 2010). It has also been reported as the most frequent spoligotype in pigs (Barandiaran et al, 2011), cattle and cats in Argentina (Zumárraga et al, 2009), and humans in the United States (Rodwell et al, 2008) and Mexico (Bobadilla-del Valle et al, 2015). Spoligotype SB0140 has been studied profoundly in the United Kingdom (Smith et al, 2003).…”

Human tuberculosis caused by Mycobacterium bovis: a retrospective comparison with Mycobacterium tuberculosis in a Mexican tertiary care centre, 2000–2015

“…We previously reported this fact in a study encompassing local and referred samples from other hospitals in the region [3, 25, 26]. Also, we reported an uprising tendency in the proportion of M. bovis isolates through time.…”

“…The implementation of bovine TB (BTB) eradication programs and universal pasteurization of dairy products in developed countries has reduced the disease in these regions, and thus clinicians often overlook the possibility of human TB caused by M. bovis [1, 2]. Conversely, in developing countries, M. bovis disease is likely to be still frequent but underreported because of reliance on laboratory techniques that are insufficient to identify the different species within the M. tuberculosis complex (i.e., direct smear microscopy, GeneXpert molecular testing, or culture without species-level identification) [3]. …”

Mycobacterium bovis Prevalence in Humans Does Not Differ between Regions in Burkina Faso

“…The management of patients with M. bovis disease is critical because some strains of M. bovis are known to be less sensitive than M. tuberculosis to anti-tuberculosis drugs [8]: paraaminosalycilic acid, streptomycin, cycloserine and isoniazid; This last antibiotic is among the most important one in the drug regimen of human tuberculosis in Burkina Faso.…”