Person: Álvarez Sánchez, Julio
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First Name
Julio
Last Name
Álvarez Sánchez
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Veterinaria
Department
Sanidad Animal
Area
Identifiers
3 results
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Now showing 1 - 3 of 3
Item Interference of paratuberculosis with the diagnosis of tuberculosis in a goat flock with a natural mixed infection(Veterinary Microbiology, 2008) Álvarez Sánchez, Julio; Juan Ferré, Lucía De; Bezos Garrido, Javier; Romero Martínez, Beatriz; Sáez, Jose Luis; Reviriego Gordejo, F.J.; Briones Dieste, Víctor; Moreno Romo, Miguel Ángel; Mateos García, Ana Isabel; Domínguez Rodríguez, Lucas José; Aranaz Martín, AliciaDetection of infected animals is a key step in eradication programs of tuberculosis. Paratuberculosis infection has been demonstrated to compromise the specificity of the diagnostic tests. However, its effect on their sensitivity has not been clarified. In the present study, skin tests and the interferon-gamma (IFN-γ) assay were evaluated in a goat flock (n = 177) with a mixed tuberculosis–paratuberculosis infection in order to assess the possible effect of paratuberculosis on their sensitivity. Culture of mycobacteria was performed as the gold standard to determine the true infection status. All techniques showed lower sensitivities than previously described; the single intradermal tuberculin (SIT) test and the IFN-γ assay detected 71% (62.4–78.6, 95% C.I.) of the infected animals; the single intradermal cervical comparative tuberculin (SICCT) test detected only 42.7% (34.1–51.7, 95% C.I.) of infected animals. The highest level of sensitivity was obtained when SIT test and IFN-γ assay were combined in parallel (90.8%, 84.5–95.2, 95% C.I.). Sensitivities of the tests were also assessed by comparing animals suffering tuberculosis and animals with a mixed infection; tests were found to be more effective in the former group. Paratuberculosis seems to have a major effect in the sensitivity of the diagnostic tests under study, and therefore must be taken into account; in particular, the use of the SICCT test should be questioned when both tuberculosis and paratuberculosis are present.Item Identifying emerging trends in antimicrobial resistance using Salmonella surveillance data in poultry in Spain(Transboundary and Emerging Diseases, 2019) Álvarez Sánchez, Julio; Lopez, Gema; Muellner, Petra; Frutos, Cristina; Ahlstrom, Christina; Serrano, Tania; Moreno, Miguel A.; Duran, Manuel; Saez, Jose Luis; Domínguez Rodríguez, Lucas José; Ugarte Ruiz, MaríaDespite of controls and preventive measures implemented along the food chain, infection with non-typhoidal Salmonella (NTS) remains one of the major causes of foodborne disease worldwide. Poultry is considered one of the major sources of NTS. This has led to the implementation of monitoring and control programmes in many countries (including Spain) to ensure that in poultry flocks infection is kept to a minimum and to allow the identification and monitoring of circulating NTS strains and their antimicrobial resistance (AMR) phenotypes. Here, we investigated the information from the monitoring programme for AMR in Salmonella from poultry in Spain in 2011-2017 to assess the diversity in phenotypic resistance and to evaluate the programme's ability to detect multi-resistance patterns and emerging strains in the animal reservoir. Data on serotype and AMR to nine antimicrobials obtained from 3,047 NTS isolates from laying hens (n = 1,060), broiler (n = 765) and turkey (n = 1,222) recovered during controls performed by the official veterinary services and food business operators were analysed using univariate and multivariate methods in order to describe host and serotype specific profiles. Diversity and prevalence of phenotypic resistance to all but one of the antimicrobials (colistin) were higher in NTS from broiler and turkey compared with laying hen isolates. Certain combinations of serotype and AMR pattern (resistotype) were particularly linked with certain hosts (e.g. susceptible Enteritidis with laying hens, multi-drug resistant (MDR) Derby in turkey, MDR Kentucky in turkey and broiler). The widespread presence of certain serotype-resistotype combinations in certain hosts/years suggested the posible expansion of MDR strains in the animal reservoir. This study demonstrates the usefulness of the analysis of data from monitoring programmes at the isolate level to detect emerging threats and suggests aspects that should be subjected to further research to identify the forces driving the expansion/dominance of certain strains in the food chain.Item Effect of paratuberculosis on the diagnosis of bovine tuberculosis in a cattle herd with a mixed infection using interferon-gamma detection assay(Veterinary Microbiology, 2009) Álvarez Sánchez, Julio; Juan Ferré, Lucía De; Bezos Garrido, Javier; Romero Martínez, Beatriz; Sáez, Jose Luis; Marqués, Sergio; Domínguez, Concepción; Mínguez, Olga; Fernández-Mardomingo, Baudilio; Mateos García, Ana Isabel; Domínguez Rodríguez, Lucas José; Aranaz Martín, AliciaInterferon-gamma (IFN-gamma) detection assay is being applied as an ancillary test to tuberculin tests in the diagnosis of bovine tuberculosis to detect the maximum number of infected animals. Among possible factors influencing the performance of tuberculosis-diagnostic tests, paratuberculosis, a widespread disease in Spain and other European countries, has been pointed out as a cause of false positive reactions. Still, its effect on the sensitivity of these tests in cattle has yet to be fully characterized. The impact of paratuberculosis in the apparent sensitivity of IFN-gamma assay was studied in a bullfighting cattle herd with a mixed tuberculosis-paratuberculosis infection, using culture of Mycobacterium bovis and Mycobacterium avium paratuberculosis as the gold standard to determine the infection status of every animal. A total of 218 animals were slaughtered and sampled for bacteriology after blood sampling. IFN-gamma assay showed a lower apparent sensitivity in animals with a mixed infection (50%) compared to all animals suffering tuberculosis (78.3%). This finding indicates that the presence of paratuberculosis in tuberculosis-infected herds could imply a serious impairment in the sensitivity of IFN-gamma detection test.