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

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 findings: data 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 (x2 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/significance: there 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. © 2015 bobadilla-del valle et al.