BackgroundHuman 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 FindingsTuberculin 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.ConclusionsWe 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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BackgroundCarbapenem-resistant Enterobacteriaceae (CRE) infections have emerged as a serious threat to health worldwide. They are associated with increased morbidity and mortality and are capable of silently colonizing the gastrointestinal tract. Because of this, there is great interest to characterize the epidemiology of CRE carriage and acquisition in healthcare facilities. The aim of this study was to determine the prevalence and factors associated with CRE fecal carriage (CRE-fc), and risk factors for incident cases.Methods/ResultsA cohort study was conducted at a tertiary care hospital from January 1st to April 30th, 2014 during a CRE outbreak. Weekly rectal swabs were performed in patients considered at risk until discharge. CRE-fc prevalence was 10.9% (CI 95% 7.7–14.7) among 330 patients. Treatment with carbapenems (OR 2.54, CI 95% 1.15–5.62); transfer from an institution (OR 2.16, CI 95% 1.02–4.59); multi-drug resistant infection within the previous six months (OR 2.81, CI 95% 1.47–5.36); intensive care unit admission (OR 0.42, CI 95% 0.20–0.88); hematologic malignancy (OR 4.02, CI 95% 1.88–8.06); invasive procedures (OR 2.18, CI 95% 1.10–4.32); and sharing a room with a known CRE carrier (OR 3.0, CI 95% 1.43–6.31) were independently associated factors for CRE-fc. Risk factors associated with CRE-fc incidence were determined for 87 patients initially negative and with subsequent screening; the incidence rate was 2.5 cases, per 1000 person-years (CI 95% 1.5–3.9). Independently associated risk factors were carbapenem treatment (HR 2.68, CI 95% 1.03–6.98), hematologic malignancy (HR 5.74, 95% CI 2.46–13.4) and a mean daily colonization pressure ≥10% (HR 5.03, IC 95% 1.77–14.28). OXA-48-like (OXA-232) and CTX-M-15 were the predominantly identified mechanisms of resistance.ConclusionsWe found an elevated incidence and prevalence of CRE-fc in our hospital. Hematologic patients need to be considered a population at risk, and antibiotic stewardship along with infection control programs need to be improved to avoid nosocomial spread.

BackgroundHuman tuberculosis caused by Mycobacterium bovis is believed to be frequent in developing countries. Transmission is usually through ingestion of unpasteurized dairy products, although airborne contagion is possible. Disease caused by M. tuberculosis or M. bovis is clinically indistinguishable from each other. The aim of this study was to determine the factors associated with M. bovis disease.MethodsRetrospective analysis of all culture-positive cases of M. bovis and M. tuberculosis from 2000 to 2015, in a Mexican tertiary-care centre. Sociodemographic, clinical, and radiographic data from medical records were compared. Disease site was classified as pulmonary, extrapulmonary, or pulmonary and extrapulmonary, based on cultures.ResultsWe evaluated 533 cases, 372 (69.7 %) of which were caused by M. tuberculosis and 161 (30.2 %) by M. bovis. Characteristics associated with M. bovis disease were: younger age (aOR 0.97, 95 % CI 0.95–0.98), glucocorticoid use (aOR 2.27, 95 % CI 1.42–3.63), and extrapulmonary disease (aOR 1.80, 95 % CI 1.21–2.69). M. tuberculosis was associated with lower socioeconomic status (aOR 0.52, 95 % CI 0.28–0.97). When we analysed only pulmonary cases, younger age (aOR 0.97, 95 % CI 0.96–0.99), glucocorticoid use (aOR 2.41, 95 % CI 1.30–4.46), and smoking (aOR 1.94, CI 95 % 1.15–3.27) were associated with M. bovis. Both groups showed similar proportions of direct microscopy smear results (respiratory samples) and chest X-ray cavitations.ConclusionsYounger age, glucocorticoid use, and extrapulmonary disease were associated with M. bovis as the causative agent of tuberculosis in a group of patients from a tertiary care centre in a country where bovine tuberculosis is endemic. Further studies must be conducted in the general population to determine pathogen-specific associated factors and outcomes.

Carbapenem-resistant Enterobacteriaceae carrying New Delhi metallo-␤-lactamase 1 (NDM-1) have rarely been reported in Latin America. We report of an outbreak caused by a bla NDM-1 -harboring plasmid spread through different bacterial species, including Escherichia coli (ST617) and Enterobacter cloacae (ST182) isolates from the same patient and three Klebsiella pneumoniae isolates (ST22) derived from three epidemiologically related patients. IncFII plasmids were found in all strains. Measures to control the outbreak were applied successfully. The spread of carbapenem-resistant Enterobacteriaceae (CRE) is a global concern. The most common mechanism of CRE is the acquisition of plasmid-borne ␤-lactamases that can hydrolyze carbapenems. The New Delhi metallo-␤-lactamase (MBL) 1 (NDM-1) has been reported in several regions of the world, mostly in patients with a history of travel to areas where it is endemic but scarcely in Latin America (1-4). We report an outbreak caused by NDM-1-harboring Enterobacteriaceae, where horizontal gene transfer likely occurred between different species with further clonal expansion.Hospital setting and bacterial strains. Ours is a 230-bed tertiary care hospital in Mexico City with a 14-bed intensive care unit (ICU) to which adult patients from the all of Mexico are referred for medical treatment. The first case of CRE carrying an MBL was detected on 5 November 2013 in a patient transferred from a southwestern city in Mexico who was admitted to the ICU. A second case was identified on 14 December 2013 in the ICU. After this, we established active screening of CRE carriers via rectal swab cultures. Rectal swabs were cultured using a 10-g ertapenem disk in 5 ml Trypticase soy broth (6). Other clinical samples were collected from the patients according to the usual protocol.Antimicrobial susceptibility tests and molecular detection of ␤-lactamases. Identification and antimicrobial susceptibility of the isolates were done with the Vitek 2 (bioMérieux, Durham, NC) and interpreted according to CLSI standards (7). Additionally, the EDTA double-disc synergy phenotypic test was performed to detect metallo-␤-lactamases (8). Presence of ␤-lactamases was determined by PCR (bla IMI , bla VIM , bla NDM , bla GES bla CTX-M-15 , bla , bla SHV , bla TEM ), as described elsewhere (8, 9). PCR-generated fragments were purified by Qiaquick PCR purification spin columns (Qiagen, Venlo, Netherlands), and sequenced with a 3130xl genetic analyzer (AB Applied Biosystems, Hitachi, San Francisco, CA). The nucleotide sequences were analyzed through the National Center for Biotechnology Information website (http://www.ncbi.nlm.nih.gov). Five isolates (1 Escherichia coli, 1 Enterobacter cloacae, and 3 Klebsiella pneumoniae) from four patients were evaluated. All isolates showing resistance to third-generation cephalosporins, quinolones, monobactams, carbapenems, and PCR were positive for NDM-1 and CTX-M-15 (Table 1).Genotyping. Pulsed-field gel electrophoresis (PFGE) was performed for all K. pneumoniae clinical (n ϭ ...