Publicaciones científicas SCI 1992
Applicability of an immunoblot technique combined with a semiautomated electrophoresis system for detection of staphylococcal enterotoxins in food extracts
Applied And Environmental Microbiology 58(12):4083-5.
We studied the usefulness of an immunoblot technique for the detection of staphylococcal enterotoxins (SEs) in strains and food extracts. Food samples (milk, yogurt, hot dog sausage, cheese, and mayonnaise) were artificially contaminated with SEA through SEE. Protein A did not interfere with the results; it appeared on electrophoresis gels as bands with molecular weights higher than those of the SEs. Other food proteins were not revealed by the technique. The immunoblot technique proved to be fast, specific, and sensitive for the detection of SEs in foods… Leer más
Orden JA., Goyache J., Hernandez J., Domenech A., Suarez G. y Gomez-Lucia E.
Aeromonas hydrophila conjunctivitis in a pet parrot (Amazona versicolor)
Avian Diseases 36(4):1110-1.
A bilateral conjunctivitis in a pet parrot (Amazona versicolor) is reported. Aeromonas hydrophila was isolated in pure culture from both eyes and considered of diagnostic significance. Biochemical characteristics and antimicrobial susceptibility of the strain were studied, as were the factors that could have contributed to the clinical conjunctivitis and the role of A. hydrophila as an opportunistic pathogen… Leer más
Garcia ME., Domenech A., Dominguez L., Ramiro F. y Fernandez-Garayzabal JF..
Diphasic dialysis: a new membrane method for a selective and efficient extraction of low molecular weight organic compounds from aqueous solutions
Journal Of AOAC International 75:854-857.
Dominguez L., Blanco JL., Moreno MA., Diaz S., Prieta J., Camara M., Bayo FJ. y Suarez G.
A Direct Plating Method for Monitoring the Contamination of Listeria monocytogenes in silage
Zentralblatt Für Veterinarmedizin. Reihe B. Journal Of Veterinary Medicine. Series B 39(7):513-8.
Twenty-two silage samples were analyzed for the presence of L. monocytogenes using five Listeria selective plating media, with and without previous selective enrichment step. L. monocytogenes was recovered from 3 samples by both procedures, but direct plating allowed the quantification of Listeria population. Two of these positive samples were implicated in outbreaks of listeriosis in sheep; the L. monocytogenes population in these samples was about 10(6) cells/g. The L. monocytogenes population in the other positive sample was 10(3) cells/g. Direct isolation of L. monocytogenes was only possible from LPM, PALCAM and LSAMm media. MOX and LSM media were not selective enough to allow direct Listeria isolation. In our hands, LSAMm was the most… Leer más
Fernandez-Garayzabal JF., Blanco MM., Vazquez-Boland JA., Briones V., Garcia JA., Delgado C., Domingo M., Marco J. y Dominguez L..
Choroiditis and meningitis in experimental murine infection with Listeria monocytogenes
European Journal Of Clinical Microbiology & Infectious Diseases : Official Publication Of The European Society Of Clinical Microbiology 11(8):744-7.
In a study of central nervous system involvement in experimental listeriosis 27 Swiss CD1 mice were inoculated subcutaneously with Listeria monocytogenes. Systemic infection developed, as shown by the isolation of Listeria monocytogenes and histopathological lesions in the spleen and liver. In the central nervous system a mixed inflammatory infiltration in the ventricular system, especially in the choroid plexus, and leptomeningitis were the most relevant lesions. Inflammatory lesions were associated with the presence of Listeria monocytogenes, as demonstrated by a positive anti-Listeria monocytogenes immunoperoxidase reaction within phagocytic cells. It is suggested that choroiditis and meningitis developed as a consequence of hematogenous… Leer más
Prats N., Briones V., Blanco MM., Altimira J., Ramos JA., Dominguez L. y Marco A.
Listeria monocytogenes CAMP reaction
Clinical Microbiology Reviews 5(3):343.
As highlighted by a Letter to the Editor recently published in Clinical Microbiology Reviews (8), there is controversy over reported results of the CAMP reaction of Listeria monocytogenes with Rhodococcus equi.
On the basis of previous reports (6, 7, 10, 11), Bergey`s Manual of Systematic Bacteriology (9) defined L. monocytogenes and Listeria ivanovii as CAMP negative and CAMP positive, respectively, with R. equi. This test was thereafter adopted as a fundamental criterion for the identification of the hemolytic Listeria species (5). The problem is that a number of investigators, including us, found that hemolytic
L. monocytogenes strains give a positive synergistic hemolysis reaction with R. equi (1-4, 12-14). We have observe… Leer más
Vazquez JA., Dominguez L., Fernandez-Garayzabal JF. y Suarez G.
Murine monoclonal antibodies against staphylococcal enterotoxin B: production and characterization
FEMS Microbiology Immunology 4(5):247-54.
A group of 14 monoclonal antibodies (mAbs) to staphylococcal enterotoxin B (SEB) were obtained by fusion of Sp2/O myeloma cells with spleen cells from female BALB/c mice immunized with commercial SEB. The antibodies belonged to IgG1 and IgG2b subclasses. We evaluated the anti-SEB titres, competition assays and sensitivity of detection by indirect ELISA. Reactivity and cross-reactivity were also studied by indirect ELISA and confirmed by immunoblotting. All the mAbs reacted with SEB and with a second band which had a different electrophoretic mobility and probably represents an aggregate of SEB or SEB bound to membranes. Three mAbs reacted only with SEB and the rest showed cross-reactions with SEC1. No reactions were observed against any oth… Leer más
Goyache J., Orden JA., Blanco JL., Hernandez FJ., Domenech A., Suarez G. y Gomez-Lucia E.
Lymphatic drainage of Listeria monocytogenes and Indian ink inoculated in the peritoneal cavity of the mouse
Laboratory Animals 26(3):200-5.
The lymphatic drainage of the peritoneal cavity has been investigated by intraperitoneal inoculation of an intracellular bacterium (Listeria monocytogenes) and an inert marker (Indian ink). The results reveal that both agents are transported, either after phagocytosis by intraperitoneal macrophages or in suspension in the lymph, towards the cranial sternal lymph nodes (Lymphonodi sternales craniales) of the ventral thoracic lymphocentrum (Lymphocentrum thoracicum ventrale) and to the lymph nodes of the mediastinal lymphocentrum (Lymphocentrum mediastinale), prior to systemic dissemination. This mechanism of peritoneal lymph drainage has relevance on experimental studies involving the inoculation of pathogens, and on the investigation of met… Leer más
Marco A., Domingo M., Ruberte J., Carretero A., Briones V. y Dominguez L..
A microbiological, histopathological and immunohistological study of the intragastric inoculation of Listeria monocytogenes in mice
Journal Of Comparative Pathology 107(1):1-9.
The course of murine infection after intragastric inoculation of L. monocytogenes was investigated by immunocytochemical, histopathological and microbiological techniques. L. monocytogenes antigen was observed in epithelial cells of intestinal mucosa overlying Peyer`s patches, but not in mucosa devoid of them. This suggests that penetration of L. monocytogenes into the host organism may take place through epithelium overlying Peyer`s patches. The efficiency of bacterial penetration appeared to be low, as shown by the small amounts of L. monocytogenes antigen detected and the low counts of bacteria in organs. Gross or histopathological lesions in the intestinal tract were not observed. The presence of L. monocytogenes in spleen, liver and in… Leer más
Marco A., Prats N., Ramos JA., Briones V., Blanco MM., Dominguez L. y Domingo M.
Detection of enterotoxins and TSST-1 secreted by Staphylococcus aureus isolated from ruminant mastitis. Comparison of ELISA and immunoblot
The Journal Of Applied Bacteriology 72(6):486-9.
The production of staphylococcal enterotoxins (SE) and toxic shock syndrome toxin-1 (TSST-1) was studied in 81 strains of Staphylococcus aureus isolated from cases of mastitis in cattle, goats and sheep. SE and TSST-1 were detected by two techniques: ELISA double antibody sandwich, and an immunoblot technique combined with a semiautomated electrophoresis system. More Staph. aureus strains isolated from sheep produced enterotoxins than those from goats and cattle. SEC was the predominant type in all isolates from these animal species. The highest proportion of strains producing TSST-1 were obtained from sheep, twice as many as those from goats or cows. The two techniques gave similar results, as all the strains positive by immunoblot were al… Leer más
Orden JA., Goyache J., Hernandez FJ., Domenech A., Suarez G. y Gomez-Lucia E.
Determination of the reactivities and cross-reactivities of monoclonal antibodies against staphylococcal enterotoxin A by indirect ELISA and immunoblot including a semiautomated electrophoresis system
Letters In Applied Microbiology 14(5):217-20.
Eight murine monoclonal antibodies (Mabs) to staphylococcal enterotoxin A (SEA) were produced using standard hybridoma techniques. We studied reactivities and cross-reactivities by indirect ELISA and immunoblotting. Two of these Mabs (A5 and A7) reacted with five serovars (A-E) of SE in both systems. Only Mab A1 reacted specifically with the homologous toxin, while four Mabs reacted with SEA and SEE. Mabs A5 and A7 could be used to detect all five serovars of SEs in a single assay… Leer más
Goyache J., Orden JA., Blanco JL., Domenech A., Hernandez J., Suarez G. y Gomez-Lucia E.
Epidemiologic investigation of a silage-associated epizootic of ovine listeric encephalitis, using a new Listeria-selective enumeration medium and phage typing
American Journal Of Veterinary Research 53(3):368-71.
The role of silage feeding in the origin of an epizootic of encephalitic listeriosis in a sheep flock was investigated by use of a new direct Listeria-selective isolation and enumeration medium, in combination with serotyping and phage typing. The silage contained high numbers (about 10(6) cells/g) of a L monocytogenes strain indistinguishable with respect to serovar and phagovar from that isolated from the brains of sick sheep. These results provided unambiguous bacteriologic evidence of the epidemiologic link between silage consumption and listeriosis in ruminants… Leer más
Vazquez-Boland JA., Dominguez L., Blanco M., Rocourt J., Fernandez-Garayzabal JF., Gutierrez CB., Tascon RI. y Rodriguez EF.
Production of staphylococcal enterotoxins and TSST-1 by coagulase negative staphylococci isolated from ruminant mastitis
Journal Of Veterinary Medicine. B, Infectious Diseases And Veterinary Public Health 39(2):144-8.
The production of staphylococcal enterotoxins (SE) and toxic shock syndrome toxin-1 by 40 coagulase negative staphylococci isolated from sheep, goat and cow mastitis was studied. Both ELISA double sandwich and Western blot were used to detect the production of these toxins. Only two strains of S. xylosus were enterotoxigenic, producing SEC. TSST-1 was seen to be produced by 5 strains of S. xylosus, 1 S. sciuri and 2 S. epidermidis. Results obtained by ELISA and by Western blot agreed in all cases except in one strain of S. epidermidis which was only positive using ELISA… Leer más
Orden JA., Goyache J., Hernandez FJ., Domenech A., Suarez G. y Gomez-Lucia E.
Lack of growth of heat-shocked Staphylococcus aureus surviving cells in common media and enterotoxin release
Journal Of Veterinary Medicine. B, Infectious Diseases And Veterinary Public Health 39(1):65-8.
The ratio of the different types of S. aureus surviving cells immediately after sub-lethal heat treatment (52 degrees C for 15 min) was studied. A high ratio of cells which are unable to form colonies even in a common medium such as TSA was observed. This fact has not been reported previously for common media through recovery after heat shock has been widely studied. After the treatment, staphylococcal protein A, but no enterotoxin, was seen to be released into the extracellular environment… Leer más
Hernandez FJ., Gomez-Lucia E., Orden JA., Goyache J., Domenech A. y Suarez G.
Effect of six organic acids on staphylococcal growth and enterotoxin production
Zeitschrift Für Lebensmittel-Untersuchung Und -Forschung 194(2):124-8.
Four Staphylococcus aureus strains were incubated at 37 degrees C for 24 h in broth progressively acidified with lactic, citric, ascorbic, acetic, pyruvic and propionic acids, and their survival rate and enterotoxin producing ability was studied. Acids were chosen based on their frequent use by the food industry. Periodically, samples were withdrawn to determine counts, pH and the presence of enterotoxins A, B, C, and D. For a given acid, the effect on growth and enterotoxin synthesis was different. The most inhibitory acid for the growth of strains FRI-100 and FRI-472 was pyruvic acid, for strain FRI-137 was lactic acid, all six acids were equally effective on strain S6. Lactic acid was very inhibitory to enterotoxin synthesis, but the eff… Leer más
Domenech A., Hernandez FJ., Orden JA., Goyache J., Lopez B., Suarez G. y Gomez-Lucia E.
Biliary excretion as possible origin of Listeria monocytogenes in fecal carriers
American Journal Of Veterinary Research 53(2):191-3.
The presence of Listeria monocytogenes in feces of animals has been related with ingestion of contaminated foods. In the study reported here, healthy mice inoculated SC with L monocytogenes excreted the organism in their feces, regardless of whether they developed clinical signs of infection. Listeria monocytogenes was isolated simultaneously from liver, feces, and bile of inoculated mice, which strongly suggested that the microorganism reached the gastrointestinal tract by biliary excretion… Leer más
Briones V., Blanco MM., Marco A., Prats N., Fernandez-Garayzabal JF., Suarez G., Domingo M. y Dominguez L..
Growth of Staphylococcus aureus and synthesis of enterotoxin during ripening of experimental Manchego-type cheese
Journal Of Dairy Science 75(1):19-26.
To study the possible presence of staphylococcal enterotoxins in Manchego-type cheese, milk was inoculated with the enterotoxigenic Staphylococcus aureus collection strains FRI-100, S6, FRI-137, and FRI-472 to a final concentration of 10,000 to 25,000 cfu/ml. Cheese was prepared following the industrial specifications and ripened for 60 d. Batches were prepared with 1 and .1% lactic acid culture and labeled with the abbreviated name of the strain and the concentration of lactic acid culture. Mean staphylococcal counts in .1% lactic bacteria cheeses were usually more than 1 log higher than the corresponding 1% ones. Staphylococcal counts declined markedly after d 35 to 42, and, by the end of ripening, they had disappeared from some cheeses. … Leer más
Gomez-Lucia E., Goyache J., Orden JA., Domenech A., Hernandez FJ., Ruiz JA., Lopez B. y Suarez G.
Determination of patulin by diphasic dialysis extraction and thin-layer chromatography
Journal Of Food Protection 55:1001-1002.
A quick, simple, and economical semiquantitative method has been devised for the detection of patulin in apple juice. The mycotoxin is extracted from the sample using ethyl acetate in a diphasic dialysis system. No purification or cleanup stages are required. Patulin is detected by thin-layer chromatography using a 3-methyl-2-benzothiazolinone-hydrazone solution as spray reagent. The limit of detection is 50 micrograms/L and recovery is 65% at 100 micrograms/L.… Leer más
Prieta J., Moreno MA., Blanco JL., Suarez G. y Dominguez L..
Role of potassium tellurite and brain heart infusion in expression of the hemolytic phenotype of Listeria spp. on agar plates
Applied And Environmental Microbiology 58(1):434-8.
The influence of potassium tellurite (PT) and brain heart infusion agar (Difco), two components of modified Listeria selective agar medium (LSAMm), on the hemolytic phenotype of Listeria spp. was studied. L. monocytogenes and L. ivanovii displayed bigger zones of hemolysis on brain heart intusion agar compared with on Columbia agar base. The addition of PT increased the sizes of zones of hemolysis displayed by L. monocytogenes. This effect seemed to be produced by the enhancement of the cytolytic effect of listeriolysin O. PT decreased the hemolysis produced by L. ivanovii, and this effect seemed to be due to an inhibition of the sphingomyelinase C produced by this species… Leer más
Fernandez-Garayzabal JF., Delgado C., Blanco MM., Vazquez-Boland JA., Briones V., Suarez G. y Dominguez L..
