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Bovine tuberculosis (bTB) is mainly caused by Mycobacterium bovis. In Mexico, dairy cattle play an important role in the persistence and spread of the bacillus. In order to describe M. bovis genetic diversity, we genotyped a total of 132 strains isolated from slaughtered cattle with bTB suggestive lesions between 2009 and 2010 in Hidalgo, Mexico, using a panel of 9-loci mycobacterial interspersed repetitive unit-variable number of tandem repeats (MIRU-VNTR) and spoligotyping. We found 21 spoligotypes, and 124 isolates were grouped in 13 clusters. The most frequent spoligotypes were SB0121 (49, 37.1%) and SB0673 (27, 20.5%); three new spoligotypes were reported SB02703, SB02704 and SB02705. We observed 37 MIRU-VNTR patterns, 107 isolates were grouped in 12 clusters and 25 isolates were unique. Spoligotypes SB0121, SB0673, SB0140, SB0145 and SB0120 showed marked subdivision applying MIRU-VNTR method; meanwhile, spoligotypes SB0971 and SB0327 showed single MIRU-VNTR profiles. The Hunter-Gaston discriminatory index (HGDI) was 0.88, 0.78 and 0.90 for 9-loci MIRU-VNTR, spoligotyping and both methods, respectively. Additionally, allelic diversity (h) analysis showed high diversity for QUB3232, QUB26 and QUB11b with h = 0.79, 0.66 and 0.63, respectively. Overall, high genetic variability was observed among M. bovis isolates. Thus, the use of 9-loci MIRU-VNTR panel is enough to describe genetic diversity, evolution and distribution of M. bovis. This study supports the use of these tools for subsequent epidemiological studies in high incidence areas.

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ABSTRACT Introduction: Nontuberculous mycobacteria (NTM) comprise several pathogens with a complex profile of virulence, diverse epidemiological and clinical patterns as well as host specificity. Recently, an increase in the number of NTM infections has been observed; therefore, the objective of this study was to evaluate the clinical characteristics and outcomes of these infections. Methods: We included patients with NTM infections between 2001-2017 and obtained risk factors, clinical features and outcomes; finally, we compared this data between slowly growing (SGM) and rapidly growing mycobacteria (RGM). Results: A total of 230 patients were evaluated, 158 (69%) infected and 72 (31%) colonized/pseudoinfected. The average annual incidence in the first 11 years of the study was 0.5 cases per 1000 admissions and increased to 2.0 cases per 1000 admissions later on. The distribution of NTM infections was as follows: bloodstream and disseminated disease 72 (45%), lung infection 67 (42%), skin and soft tissue infection 19 (12%). Mycobacterium avium complex was the most common isolate within SGM infections, and HIV-infected patients were the most affected. Within RGM infections, M. fortuitum was the most common isolate from patients with underlying conditions such as cancer, type-2 diabetes mellitus, presence of invasive devices, and use of immunosuppressive therapy. We did not find significant differences in deaths and persistent infections between disseminated SGM infection when compared to disseminated RGM infection (42% vs. 24%, p = 0.22). However, disseminated SGM infection required a longer duration of therapy than disseminated RGM infection (median, 210 vs. 42 days, p = 0.01). NTM lung disease showed no significant differences in outcomes among treated versus non-treated patients (p = 0.27). Conclusions: Our results show a significant increase in the number of Non-tuberculosis-mycobacteria infections in our setting. Patients with slow-growing-mycobacteria infections were mainly persons living with human immunodeficiency virus . Older patients with chronic diseases were common among those with rapidly-growing-mycobacteria infections. For non-tuberculosis-mycobacteria lung infection, antibiotic therapy should be carefully individualized.

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INTRODUCTION: Nontuberculous mycobacteria (NTM) comprise several pathogens with a complex profile of virulence, diverse epidemiological and clinical patterns as well as host specificity. Recently, an increase in the number of NTM infections has been observed; therefore, the objective of this study was to evaluate the clinical characteristics and outcomes of these infections. METHODS: We included patients with NTM infections between 2001-2017 and obtained risk factors, clinical features and outcomes; finally, we compared this data between slowly growing (SGM) and rapidly growing mycobacteria (RGM). RESULTS: A total of 230 patients were evaluated, 158 (69%) infected and 72 (31%) colonized/pseudoinfected. The average annual incidence in the first 11 years of the study was 0.5 cases per 1000 admissions and increased to 2.0 cases per 1000 admissions later on. The distribution of NTM infections was as follows: bloodstream and disseminated disease 72 (45%), lung infection 67 (42%), skin and soft tissue infection 19 (12%). Mycobacterium avium complex was the most common isolate within SGM infections, and HIV-infected patients were the most affected. Within RGM infections, M. fortuitum was the most common isolate from patients with underlying conditions such as cancer, type-2 diabetes mellitus, presence of invasive devices, and use of immunosuppressive therapy. We did not find significant differences in deaths and persistent infections between disseminated SGM infection when compared to disseminated RGM infection (42% vs. 24%, p=0.22). However, disseminated SGM infection required a longer duration of therapy than disseminated RGM infection (median, 210 vs. 42 days, p=0.01). NTM lung disease showed no significant differences in outcomes among treated versus non-treated patients (p=0.27). CONCLUSIONS: Our results show a significant increase in the number of Non-tuberculosis-mycobacteria infections in our setting. Patients with slow-growing-mycobacteria infections were mainly persons living with human immunodeficiency virus . Older patients with chronic diseases were common among those with rapidly-growing-mycobacteria infections. For non-tuberculosis-mycobacteria lung infection, antibiotic therapy should be carefully individualized.

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OBJECTIVES: To determine the factors associated with Mycobacterium tuberculosis complex-positive blood culture. METHODS: Case-control study. Sociodemographic, clinical and laboratory data were collected from 2000 to 2015. RESULTS: We reviewed medical records of 533 patients with culture-proven tuberculosis, of whom 27.2% (145/533) had blood culture available. Patients with mycobacteremia presented more frequently with abdominal tuberculosis, body mass index <18kg/m2, and had lower hemoglobin and albumin levels. No differences were observed regarding HIV status. CONCLUSIONS: Few studies have reported on the characteristics associated with Mycobacterium tuberculosis complex bacteremia, especially among Human Immunodeficiency Virus-negative patients. Out of 145 tuberculosis-infected patients with blood culture results available, 21 turned out positive. Anemia, hypoalbuminemia, and a body mass index<18kg/m2 were associated with mycobacteremia.

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ABSTRACT Objectives: To determine the factors associated with Mycobacterium tuberculosis complex-positive blood culture. Methods: Case-control study. Sociodemographic, clinical and laboratory data were collected from 2000 to 2015. Results: We reviewed medical records of 533 patients with culture-proven tuberculosis, of whom 27.2% (145/533) had blood culture available. Patients with mycobacteremia presented more frequently with abdominal tuberculosis, body mass index <18 kg/m2, and had lower hemoglobin and albumin levels. No differences were observed regarding HIV status. Conclusions: Few studies have reported on the characteristics associated with Mycobacterium tuberculosis complex bacteremia, especially among Human Immunodeficiency Virus-negative patients. Out of 145 tuberculosis-infected patients with blood culture results available, 21 turned out positive. Anemia, hypoalbuminemia, and a body mass index < 18 kg/m2 were associated with mycobacteremia.

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OBJECTIVE: To describe the seroprevalence and associated factors for brucellosis among dairy farm workers. MATERIALS AND METHODS: We performed a secondary analysis of a data set and sera from a previous cross-sectional study in a dairy farm. Sera were tested for Brucella spp. antibodies by the slide agglutination test. Seropositivity was defined as a titer ≥1:40; recent infection was titers ≥1:160. RESULTS: We tested 331 human sera. Seroprevalence of brucellosis was 18.1% (60/331; 95% CI 14.1-22.7); 13.3% of them (8/60; 95% CI 5.9 24.5) corresponded to recent infection. Highexposure occupation (calf caretaker; OR 3.3; 95%CI 1.1 - 9.7), daily hours in contact with cows (OR 1.1; 95%CI 1.03 - 1.2), and living on-site (OR 2.2; 95% CI 1.1 - 4.4) remained independently associated with seropositivity. CONCLUSIONS: We found a high seroprevalence of brucellosis among dairy farm workers, as well as a significant association among those with prolonged and close contact with cattle.

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Abstract: Objective: To describe the seroprevalence and associated factors for brucellosis among dairy farm workers. Materials and methods: We performed a secondary analysis of a data set and sera from a previous cross-sectional study in a dairy farm. Sera were tested for Brucella spp. antibodies by the slide agglutination test. Seropositivity was defined as a titer ≥1:40; recent infection was titers ≥1:160. Results: We tested 331 human sera. Seroprevalence of brucellosis was 18.1% (60/331; 95% CI 14.1-22.7); 13.3% of them (8/60; 95% CI 5.9 24.5) corresponded to recent infection. Highexposure occupation (calf caretaker; OR 3.3; 95%CI 1.1 - 9.7), daily hours in contact with cows (OR 1.1; 95%CI 1.03 - 1.2), and living on-site (OR 2.2; 95% CI 1.1 - 4.4) remained independently associated with seropositivity. Conclusions: We found a high seroprevalence of brucellosis among dairy farm workers, as well as a significant association among those with prolonged and close contact with cattle.

Resumen: Objetivos: Describir la seroprevalencia y factores asociados con la brucelosis en los trabajadores de una cuenca lechera. Material y métodos: Se realizó un análisis secundario de datos y sueros obtenidos en una cuenca lechera. Se buscaron anticuerpos contra Brucella spp. en los sueros por medio de la prueba de aglutinación en placa. Se definió seropositividad a partir de un título ≥1:40, e infección reciente con títulos ≥1:160. Resultados: Se analizaron 331 sueros humanos. La seroprevalencia de brucelosis fue de 18.1% (60/331; IC 95% 14.1-22.7); el 13.3% (8/60; IC 95% 5.9 24.5) correspondieron a infección reciente. Alta exposición (becerrero; RM 3.3; IC 95% 1.1 - 9.7), horas diarias en contacto con vacas (RM 1.1; IC 95% 1.03 - 1.2), y vivir en el establo (RM 2.2; IC 95% 1.1 - 4.4) estuvieron asociadas independientemente con seropositividad. Conclusiones: Se encontró alta seroprevalencia de brucelosis en trabajadores de una cuenca lechera, y asociación en aquellos con contacto cercano y prolongado con vacas.

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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 (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/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.

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BACKGROUND: Human tuberculosis caused by M. bovis is a zoonosis presently considered sporadic in developed countries, but remains a poorly studied problem in low and middle resource countries. The disease in humans is mainly attributed to unpasteurized dairy products consumption. However, transmission due to exposure of humans to infected animals has been also recognized. The prevalence of tuberculosis infection and associated risk factors have been insufficiently characterized among dairy farm workers (DFW) exposed in settings with poor control of bovine tuberculosis. METHODOLOGY/PRINCIPAL FINDINGS: Tuberculin skin test (TST) and Interferon-gamma release assay (IGRA) were administered to 311 dairy farm and abattoir workers and their household contacts linked to a dairy production and livestock facility in Mexico. Sputa of individuals with respiratory symptoms and samples from routine cattle necropsies were cultured for M. bovis and resulting spoligotypes were compared. The overall prevalence of latent tuberculosis infection (LTBI) was 76.2% (95% CI, 71.4-80.9%) by TST and 58.5% (95% CI, 53.0-64.0%) by IGRA. Occupational exposure was associated to TST (OR 2.72; 95% CI, 1.31-5.64) and IGRA (OR 2.38; 95% CI, 1.31-4.30) adjusting for relevant variables. Two subjects were diagnosed with pulmonary tuberculosis, both caused by M. bovis. In one case, the spoligotype was identical to a strain isolated from bovines. CONCLUSIONS: We documented a high prevalence of latent and pulmonary TB among workers exposed to cattle infected with M. bovis, and increased risk among those occupationally exposed in non-ventilated spaces. Interspecies transmission is frequent and represents an occupational hazard in this setting.

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