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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. ResumenObjetivos. 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.

The lack of efficient and cost-effective diagnostic tools contributes to poor control of tuberculosis in endemic countries. Moreover, host biological processes influence susceptibility, and infection resolution. It is well known that comorbidities such as type 2 diabetes mellitus (DM2) affect the host immune response, making individuals more susceptible to Mycobacterium tuberculosis infection. Currently, there are no laboratory tools that can identify those subjects who have a higher risk of developing the disease. In this study, we used a whole blood mycobacterial growth inhibition assay to assess the immune response capacity to inhibit mycobacterial growth between healthy subjects and those living with DM2 with optimal and poor glycemic control. We also measured cytokine levels in the culture supernatant by cytokine bead arrays. We included 89 patients with DM2: 54 patients with optimal control (mean age 56.2 ± 11.75 years) and 35 patients with poor control (mean age 52.05 ± 9.94 years). We also included 44 healthy subjects as controls (mean age 42.12 ± 11.75 years). We compared the Δlog UFC (a value that represents the difference between mycobacterial growth in the control tube versus the subject’s blood) between each group. Our results demonstrate that patients with DM2 had a lower capacity to inhibit M. tuberculosis growth (Δlog UFC DM2 subjects 0.9581 (-0.3897 to 2.495) vs Δlog UFC healthy subjects 0.7190 (-0.2678 to 2.098); p=0.013). Comparing subjects living with DM2 (optimal and poor glycemic control) vs healthy subjects, we found only significant differences between healthy subjects and patients poorly controlled (Δlog UFC optimal control group 0.876 (-0.3897 to 2.495); Δlog UFC poor control group 1.078 (0.068 to 2.33); Δlog UFC healthy subjects 0.7190 (-0.2678 to 2.098); p= 0.022). Therefore, glycemic control assessed by glycosylated hemoglobin values influences the capacity of the host to control the infection. Our results confirm that the whole blood mycobacterial growth inhibition assay has potential utility as an in vitro marker of M. tuberculosis immunological control in vivo in subjects living with DM2. This assay can be used to evaluate the immune response of each individual against M. tuberculosis, allowing clinicians to choose a more specific host-directed therapy.

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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.