Publicaciones científicas 2000

Prevalence of vancomycin-resistant Enterococcus faecium (VREF) in pig faeces from slaughterhouses in Spain

Preventive Veterinary Medicine 47(4):255-62.

     A study to estimate the prevalence of vancomycin-resistant Enterococcus faecium in faecal samples from pigs at slaughterhouses in Spain was carried out between November 1998 and January 1999 with 900 samples taken from four abattoirs representing 9.7% of all pig slaughtered in 1998. Using a selective enrichment broth with vancomycin (8microg/ml), 64 samples (7.1%; 95% CI: 5.5, 9.0%) had E. faecium vancomycin-resistant strains that showed minimal inhibitory concentrations of 256microg/ml (62 strains) and 512microg/ml (two strains). Results by farm showed that 43 of the 240 pig farms represented in the sampling had at least one faecal sample with vancomycin-resistant E. faecium… Leer más

Herrero IA., Teshager T., Garde J., Moreno MA. y Dominguez L..

Isolation of an SHV-12 beta-lactamase-producing Escherichia coli strain from a dog with recurrent urinary tract infections

Antimicrobial Agents And Chemotherapy 44(12):3483-4.

     An Escherichia coli strain (EC98/4153-2) was isolated in 1998 (by the Microbiology and Parasitology Service, Complutense University, Veterinary Hospital, Madrid, Spain) from a urine specimen from a dog with a recurrent urinary tract infection, and this strain was submitted to the Network of Veterinary Antimicrobial Resistance Surveillance (VAV). This strain showed resistance (8) to amoxicillin, cephalothin, cefotaxime, ceftazidime, and aztreonam, but it was susceptible to cefoxitin, imipenem, and amoxicillin-clavulanic acid (Table 1). The same resistance phenotype was detected by the disk diffusion method. Extended-spectrum β-lactamase (ESBL) production was detected in this strain by double-disk synergy tests (with cefotaxime, amoxicil… Leer más

Teshager T., Dominguez L., Moreno MA., Saenz Y., Torres C. y Cardenosa S.

Intramammary Aspergillus fumigatus infection in dairy ewes associated with antibiotic dry therapy

The Veterinary Record 147(20):578-80.

Las Heras A., Dominguez L., Lopez I., Paya MJ., Pena L., Mazzucchelli F., Garcia LA. y Fernandez-Garayzabal JF..

Meningoencephalitis associated with Globicatella sanguinis infection in lambs

Journal Of Clinical Microbiology 38(11):4254-5.

     Thirty lambs displayed symptoms of meningoencephalitis. An unusual gram-positive coccus was isolated in pure culture from the blood and brain samples from one of the affected animals, and phenotypic and phylogenetic characterization showed this to be Globicatella sanguinis. This is the first report of the isolation of G. sanguinis in pure culture from an animal infection… Leer más

Vela AI., Fernandez E., Las Heras A., Lawson P., Dominguez L., Collins MD. y Fernandez-Garayzabal JF..

SmcL, a novel membrane-damaging virulence factor in Listeria

International Journal Of Medical Microbiology 290(4-5):369-74.

     We describe here the fourth listerial membrane-damaging virulence factor, a sphingomyelinase C (SMase) that is produced specifically by the ruminant pathogen Listeria ivanovii. Its coding gene, smcL, is a monocistron expressed independently of PrfA. The smcL product, SmcL, is highly similar to the staphylococcal beta-toxin and is responsible for the differential hemolytic properties of L. ivanovii (bizonal hemolysis and CAMP-like reaction with R. equi). The role of SmcL in virulence was assessed by gene disruption and complementation. Our data show that SmcL mediates disruption of the membrane of primary phagosomes, thereby promoting bacterial intracellular proliferation. They also suggest that SmcL may play a role in host tropism. smcL is … Leer más

Gonzalez-Zorn B., Dominguez-Bernal G., Suarez M., Ripio MT., Vega Y., Novella S., Rodriguez-Bertos A., Chico I., Tierrez A. y Vazquez-Boland JA.

Phenotypic and genetic characterization of Lactococcus garvieae isolated in Spain from lactococcosis outbreaks and comparison with isolates of other countries and sources

Journal Of Clinical Microbiology 38(10):3791-5.

     The phenotypic and genetic analysis results for 84 isolates of Lactococcus garvieae (including 62 strains from trout with lactococcosis from four different countries, 7 strains from cows and water buffalos with subclinical mastitis, 3 from water, and 10 from human clinical samples) are presented. There was great phenotypic heterogeneity (13 different biotypes) based on the acidification of saccharose, tagatose, mannitol, and cyclodextrin and the presence of the enzymes pyroglutamic acid arylamidase and N-acetyl-beta-glucosaminidase. L. garvieae also exhibited high genetic diversity by pulsed-field gel electrophoresis (PFGE), with 19 different pulsotypes among the isolates of L. garvieae studied. Only epidemiologically related strains, like … Leer más

Vela AI., Vazquez J., Gibello A., Blanco MM., Moreno MA., Liebana P., Albendea C., Alcala B., Mendez A., Dominguez L. y Fernandez-Garayzabal JF..

Effect of selenium deficiency on the development of central nervous system lesions in murine listeriosis

Journal Of Comparative Pathology 123(2-3):104-9.

     The effect of selenium (Se) deficiency, produced by feeding a Se-deficient diet, on the development of central nervous system (CNS) lesions was studied in mice infected with Listeria monocytogenes, administered in drinking water for 1 or 7 days in a daily dose of 10(9)organisms, or for 7 days in a daily dose of 10(7). Se-deficient mice differed from Se-normal controls in developing CNS lesions significantly more frequently. Moreover, regardless of Se status, mice receiving repeated doses of 10(9)organisms differed from those receiving a single 10(9)dose in showing CNS lesions at least twice as often. The majority of animals with CNS lesions showed an inflammatory pattern of rhombencephalitis (17/24), while only two of 24 showed choroiditis-… Leer más

Altimira J., Prats N., Lopez S., Domingo M., Briones V., Dominguez L. y Marco A.

Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blot of nonspecific and specific viral proteins frequently detected in different antigen preparations of bovine leukemia virus

Journal Of Veterinary Diagnostic Investigation 12(4):337-44.

     Bovine leukemia virus (BLV) infection in cattle is seldom manifested clinically, and is routinely diagnosed by serologic tests such as enzyme-linked immunosorbent assay or Western blot (WB). Because of the difficulty in interpreting WB results, the aim of the present study was to determine which of the bands observed in WB were specifically produced by BLV and which corresponded to nonspecific proteins, either derived from medium components or of a cellular nature. Five different BLV antigen preparations from 2 cell lines (FLK-BLV and BLV-bat2) frequently used for the production of BLV antigen were compared. The protein profiles of these antigen preparations were analyzed using sodium dodecyl sulfate polyacrylamide gel electrophoresis and W… Leer más

Llames L., Gomez-Lucia E., Domenech A., Suarez G. y Goyache J..

Surveillance of antimicrobial resistance in Escherichia coli strains isolated from pigs at Spanish slaughterhouses

International Journal Of Antimicrobial Agents 15(2):137-42.

     Antimicrobial resistance can make the efficient treatment of bacterial infections in humans and animals more difficult. Antimicrobial use in food animals may be one of the factors contributing to resistance. The Spanish surveillance network VAV has established a baseline of antimicrobial resistance in Escherichia coli strains from healthy pigs. Minimum inhibitory concentration and patterns of resistance to antimicrobials used in animals and humans were determined for 205 faecal strains isolated in a sampling frame of four slaughterhouses in Spain from 220 pigs in 1998. Higher levels of resistance were seen against antimicrobial agents authorised for use in food animals especially tetracycline, sulphonamides, trimethoprim and amoxycillin. Al… Leer más

Teshager T., Herrero IA., Porrero MC., Garde J., Moreno MA. y Dominguez L..

Production and characterization of monoclonal antibodies against bovine leukaemia virus using various crude antigen preparations: a comparative study

Journal Of Veterinary Medicine. B, Infectious Diseases And Veterinary Public Health 47(5):387-97.

     A total of 59 monoclonal antibodies (mAbs) specific against the bovine leukaemia virus (BLV) using different antigen preparations was produced. The five antigen preparations for immunizing BALB/c mice were: live cells (CEL), sonicated and ultracentrifuged cells (SOC), cell lysates (LYS), semi-purified BLV (PV), and formalin-treated cells (FOR) from two cell lines permanently infected with BLV (FLK-BLV and BLV-bat2). These viral component presentations were selected to obtain mAbs against specific BLV proteins: located on the cell surface (FOR and CEL), in free virus particles (PV) and intracellular viral proteins (SOC and LYS). Two antigen preparations (SOC and LYS) were lethal to the mice following the intravenous and intrasplenic routes. … Leer más

Llames L., Gomez-Lucia E., Domenech A., de Avila A., Suarez G. y Goyache J..

In vitro T-cell activation of monocyte-derived macrophages by soluble messengers or cell-to-cell contact in bovine tuberculosis

Immunology 100(2):194-202.

     The macrophage plays a dual role in tuberculosis, promoting not only protection against mycobacteria, but also survival of the pathogen. Macrophages inhibit multiplication of mycobacteria but also act in concert with lymphocytes through presentation of antigens to T cells. Studies in animal and human infections have suggested a correlation of in vitro growth rates of mycobacteria with in vivo virulence, using uracil uptake to assess mycobacterial metabolism. This study found that blood-derived, non-activated bovine macrophages were capable of controlling Mycobacterium bovis bacillus Calmette-Gurin growth for up to 96 hr, but were permissive to intracellular growth of virulent M. bovis. The present investigation compared the in vitro modulat… Leer más

Liebana E., Aranaz A., Welsh M., Neill SD. y Pollock JM.

Epidemiology and ecology of enterococci, with special reference to antibiotic resistant strains, in animals, humans and the environment. Example of an ongoing project within the European research programme

International Journal Of Antimicrobial Agents 14(4):337-42.

     The objectives of the present study are to generate knowledge of the ecology and epidemiology of enterococci in the food chain by studying the following: (1) the population structure (in measures of abundance, number of vancomycin resistant strains, antibiotic resistance patterns, diversity, and stability) among enterococcal populations in different geographical regions and in different links of the food chain (2) possible transmission of strains through the food chain and between hospital environments and the food chain (3) the association between vancomycin resistance and individual strains of enterococci and (4) the diversity of the drug resistance genes in enterococci. So far, 1578 samples have been collected from different countries wi… Leer más

Kuhn I., Iversen A., Burman LG., Olsson-Liljequist B., Franklin A., Finn M., Aarestrup F., Seyfarth AM., Blanch AR., Taylor H., Caplin J., Moreno MA., Dominguez L. y Mollby R.

Antibiotic resistance monitoring: the Spanish programme. The VAV Network. Red de Vigilancia de Resistencias Antibióticas en Bacterias de Origen Veterinario

International Journal Of Antimicrobial Agents 14(4):285-90.

     Antimicrobial resistance is a problem in modern public health and antimicrobial use and especially misuse, the most important selecting force for bacterial antibiotic resistance. As this resistance must be monitored we have designed the Spanish network `Red de Vigilancia de Resistencias Antibióticas en Bacterias de Origen Veterinario`. This network covers the three critical points of veterinary responsibility, bacteria from sick animals, bacteria from healthy animals and bacteria from food animals. Key bacteria, antimicrobials and animal species have been defined for each of these groups along with laboratory methods for testing antimicrobial susceptibility and for data analysis and reporting. Surveillance of sick animals was first implemen… Leer más

Moreno MA., Dominguez L., Teshager T., Herrero IA. y Porrero MC.

Risk factors for brucellosis seroprevalence of sheep and goat flocks in Spain

Preventive Veterinary Medicine 44(3-4):167-73.

     Risk factors for ovine and caprine brucellosis in the Avila region (center of Spain) were evaluated using data from a cross-sectional study of the most important diseases of small ruminants in this Spanish region between 1996 and 1997. Questionnaire data from 56 herds (35 ovine and 21 caprine) were used. Sixteen (29%) flocks (3 caprine and 13 ovine) were brucellosis-seropositive. Overall, 0.7% of sheep and 0.1% of goats were seropositive. Eleven risk factors were studied at the group level by logistic regression using flock brucellosis-status as outcome, and by linear regression using percentage of brucellosis-seropositivity as outcome. Both final models contained the same variables: contact with sheep and grazing in communal pastures as ri… Leer más

Reviriego FJ., Moreno MA. y Dominguez L..

Bovine tuberculosis and the endangered Iberian lynx

Emerging Infectious Diseases 6(2):189-91.

     We report the first case of bovine tuberculosis in a free-living Iberian lynx (Lynx pardina), an extremely endangered feline, from Doñana National Park in Spain. The isolate (Mycobacterium bovis) correlates by molecular characterization with other isolates from wild ungulates in the park, strongly suggesting an epidemiologic link. Mycobacterium bovis infects many animal species, with wild and free-ranging domestic ungulates being the main reservoirs in nature (1)… Leer más

Briones V., de Juan L., Sanchez C., Vela AI., Galka M., Montero N., Goyache J., Aranaz A., Mateos A. y Dominguez L..

Soil type as a putative risk factor of ovine and caprine paratuberculosis seropositivity in Spain

Preventive Veterinary Medicine 43(1):43-51.

     Relationships between soil type and ovine and caprine paratuberculosis in the Avila region (central Spain) were evaluated using data from a cross-sectional study of the most-important diseases of small ruminants in this Spanish region between 1996 and 1997. Questionnaire data from 61 herds (38 ovine and 23 caprine) and 1451 serum samples (1041 ovine and 410 caprine) were used. Herd paratuberculosis (herds were scored as positive to paratuberculosis if any of the serum samples was positive in an agar-gel immunodifussion) was the outcome of interest, whereas soil type in the municipality where farms were located was the predictor variable. Other variables related to soil and soil usage, and herd size, replacement, main food production and ani… Leer más

Reviriego FJ., Moreno MA. y Dominguez L..

In vitro infection of cells of the monocytic/macrophage lineage with bovine leukaemia virus

The Journal Of General Virology 81(Pt 1):109-18.

     The oncogenic retrovirus bovine leukaemia virus (BLV) primarily infects B cells. Most infected animals remain asymptomatic for long periods of time before an increase in circulating B cells or localized tumours can be observed. This long clinical latency period may be explained by cells of the monocyte/macrophage lineage (M/M) becoming infected and acting as a reservoir for the virus, as shown for other retroviruses (human immunodeficiency virus-1, feline immunodeficiency virus). M/M cells in different stages of differentiation (HL-60, THP-1, U-937, J774, BGM, PM2, primary macrophages of sheep and cows) were cultured with BLV produced by permanently infected donor cells (FLKBLV and BLV-bat(2)). Donor cells were inhibited from multiplying by… Leer más

Domenech A., Goyache J., Llames L., Paya MJ., Suarez G. y Gomez-Lucia E.

Cellular interactions in bovine tuberculosis: release of active mycobacteria from infected macrophages by antigen-stimulated T cells

Immunology 99(1):23-9.

     The outcome of Mycobacterium bovis infections depends on the interactions of infected macrophages with T lymphocytes. Several studies in humans and in mouse models have suggested an important role for cytotoxicity in the protective immune response to mycobacterial infections, and both CD4+ and CD8+ T cells have been shown to elicit appropriate cytolytic activity. The present study investigated in vitro interactions of T cells with M. bovis-infected macrophages in bovine tuberculosis. The results showed that following interaction with antigen-stimulated peripheral blood mononuclear cells (PBMC) from infected cattle, there was an increased presence of M. bovis in the extracellular compartment of infected macrophage cultures, as measured by in… Leer más

Liebana E., Aranaz A., Aldwell FE., McNair J., Neill SD., Smyth AJ. y Pollock JM.