PubMed Health⌕ Search

Biomedical subjects

A Doménech

Publications and source records attributed to A Doménech.

At least 19 recordsLinked to original sources
PubMed2006

Efficacy of high doses of levofloxacin in experimental foreign-body infection by methicillin-susceptible Staphylococcus aureus.

Antimicrobial efficacy in orthopedic device infections is diminished because of bacterial biofilms which express tolerance to antibiotics. Recently, the use of high doses of levofloxacin with rifampin has been recommended for staphylococcal infections. In the present study, we evaluated the efficacy of levofloxacin at doses of 50 mg/kg/day and 100 mg/kg/day (mimicking the usual and high human doses of 500 mg/day and 750 to 1,000 mg/day, respectively) and compared it to that of to linezolid, cloxacillin, vancomycin, and rifampin in a rat tissue cage model of experimental foreign-body infection by Staphylococcus aureus. The antimicrobial efficacy in vitro (by MIC, minimum bactericidal concentration, and kill curves) for logarithmic- and stationary-phase bacteria was compared with the in vivo efficacy. In vitro bactericidal activity at clinically relevant concentrations was reached by all drugs except rifampin and linezolid in the log-phase studies but only by levofloxacin in the stationary-phase studies. The bacterial count decreases from in vivo tissue cage fluids (means) for levofloxacin at 50 and 100 mg/kg/day, rifampin, cloxacillin, vancomycin, linezolid, and controls, respectively, were: -1.24, -2.26, -2.1, -1.56, -1.47, -1.15, and 0.33 (all groups versus controls, P < 0.05). Levofloxacin at 100 mg/kg/day (area under the concentration-time curve/MIC ratio, 234) was the most active therapy (P = 0.03 versus linezolid). Overall, in vivo efficacy was better predicted by stationary-phase studies, in which it reached a high correlation coefficient even if the rifampin group was excluded (r = 0.96; P < 0.05). Our results, including in vitro studies with nongrowing bacteria, pharmacodynamic parameters, and antimicrobial efficacy in experimental infection, provide good evidence to support the use of levofloxacin at high doses (750 to 1,000 mg/day), as recently recommended for treating patients with orthopedic prosthesis infections.

Acetamides↗
PubMed2004

Experimental study of teicoplanin, alone and in combination, in the therapy of cephalosporin-resistant pneumococcal meningitis.

OBJECTIVES: The aim of the study was to determine the efficacy of teicoplanin, alone and in combination with ceftriaxone, in a rabbit model of cephalosporin-resistant pneumococcal meningitis, and to assess the effect of concomitant therapy with dexamethasone. METHODS: In vitro killing curves of teicoplanin, with and without ceftriaxone, were performed. Groups of eight animals per treatment were inoculated with a cephalosporin-resistant pneumococcal strain (penicillin MIC, 4 mg/L; ceftriaxone MIC, 2 mg/L; teicoplanin MIC, 0.03 mg/L) and treated over a 26 h period. Teicoplanin was administered at a dose of 15 mg/kg, alone and in combination with ceftriaxone at 100 mg/kg with or without dexamethasone at 0.25 mg/kg. CSF samples were collected at different time-points, and bacterial titres, white blood cell counts, lactate and protein concentrations and bacteriostatic/bactericidal titres were determined. Blood and CSF teicoplanin pharmacokinetic and pharmacodynamic parameters were determined. RESULTS: Teicoplanin alone promoted a decrease in bacterial counts at 6 h of -2.66 log cfu/mL and was bactericidal at 24 h, without therapeutic failures. Similar good results were obtained when dexamethasone was used simultaneously, in spite of the penetration of teicoplanin into the CSF being significantly reduced, from 2.31% to 0.71%. Teicoplanin and ceftriaxone combinations were synergic in vitro, but not in the meningitis model. CONCLUSIONS: Teicoplanin alone was very effective in this model of cephalosporin-resistant pneumococcal meningitis. The use of concomitant dexamethasone resulted in lower CSF teicoplanin levels, but not in therapeutic failures. The combination of teicoplanin plus ceftriaxone and dexamethasone might be a good alternative for the empirical therapy of pneumococcal meningitis. Additional data should confirm our experiments, in advance of clinical trials to assess efficacy in humans.

Animals↗
PubMed2002

2,4,6-triphenylpyrylium ion encapsulated into zeolite Y as a selective electrode for the electrochemical determination of dopamine in the presence of ascorbic acid.

2,4,6-Triphenylpyrylium ion immobilized inside the supercages of zeolite Y enhances by 1-2 orders of magnitude the response of electrochemical oxidation of dopamine in neutral aqueous media accompanied by a remarkable inhibition of post-electron-transfer reactions. The negative charge of the zeolite framework in which the 2,4,6-triphenylpyrylium ion is incorporated blocks the electrochemical oxidation of the negative ascorbate ion, enabling the determination of micromolar concentrations of dopamine in the presence of a large excess (10(3)-10(4) times) of ascorbate in phosphate buffer (pH 7.4). Under optimized conditions, linear calibration plots were obtained for a differential pulse detection mode over the range 250-1 microM dopamine with a sensitivity of 62 nA/microM and a detection limit (S/N = 3) of 0.2 microM in the presence of 1.0 mM ascorbate.

Ascorbic Acid↗
PubMed2002

Efficacy of colistin versus beta-lactams, aminoglycosides, and rifampin as monotherapy in a mouse model of pneumonia caused by multiresistant Acinetobacter baumannii.

The treatment of life-threatening infections due to carbapenem-resistant Acinetobacter baumannii has become a serious challenge for physicians worldwide. Often, only colistin shows in general good in vitro activity against these carbapenem-resistant strains, but its antibacterial efficacy in comparison with the antibiotics most used in clinical practice is not well known. We studied the efficacy of colistin versus those of imipenem, sulbactam, tobramycin, and rifampin in an experimental pneumonia model with immunocompetent mice. We used three strains of A. baumannii corresponding to the main clones (A, D, and E) involved in the outbreaks of our hospital, with different grades of resistance to imipenem (imipenem MICs of 1, 8, and 512 microg/ml, respectively) and to the other antibiotics. The MIC of colistin was 0.5 microg/ml for the three strains. Reduction of log(10) CFU/g in lung bacterial counts, clearance of bacteremia, and survival versus results with controls were used as parameters of efficacy. Imipenem and sulbactam (Deltalung counts: -5.38 and -4.64 log(10) CFU/ml) showed the highest level of bactericidal efficacy in infections by susceptible and even intermediate strains. Tobramycin and rifampin (-4.16 and -5.15 log(10) CFU/ml) provided good results against intermediate or moderately resistant strains, in agreement with killing curves and pharmacodynamics. On the contrary, colistin showed the weakest antibacterial effect among the antibiotics tested, both in killing curves and in the in vivo model (-2.39 log(10) CFU/ml; P < 0.05). We conclude that colistin did not appear as a good option for treatment of patients with pneumonia due to carbapenem-resistant A. baumannii strains. Other alternatives, including combinations with rifampin, may offer better therapeutic profiles and thus should be studied.

Acinetobacter↗
PubMed2001

Isolation of salmon pancreas disease virus (SPDV) in cell culture and its ability to protect against infection by the 'wild-type' agent.

A Scottish salmon pancreas disease virus (SPDV) has been isolated and its optimum growth conditions determined. Although several fish cell lines have been tested, successful culture was achieved only with CHSE-214 cells. Cytopathic effects were observed after 5 days. The highest virus titres, calculated by microtitration assay, were reached at 15 degrees C. After 7-9 days post-inoculation, CHSE-214 cell supernatants contained between 10(7)-10(5) TCID50 ml(-1) The cultured isolate is chloroform- and pH 3.0-sensitive, and virions are 50-60 nm in diameter. These characteristics are similar to the Irish SPDV isolates. The culture isolate induced typical pancreas disease (PD) lesions in experimentally infected Atlantic salmon and convalescent fish were resistant to experimental infection with PD-infective kidney homogenates obtained by serial in vivo passages from a PD-infected farmed salmon (termed wild-type SPDV). Furthermore, fish immunised with the inactivated cultured virus were protected against a cohabitation challenge with the wild-type virus. Immunised fish sera showed virus-neutralising activity before challenge (7 weeks post-immunisation) and from 3-6 weeks post-challenge, when sera from non-immunised fish did not neutralise the virus. At 6 weeks post-cohabitation challenge, previously immunised fish had neutralising titres of up to 1:65. Following intraperitoneal (i.p.) challenge, immunised fish showed neutralising titres as high as 1:226 at 8 weeks post-challenge. Non-immunised fish injected i.p. with the wild-type virus developed serum-neutralising activity against the cultured isolate when sampled 8 weeks after infection, confirming an antigenic relationship between the wild-type and cultured virus. The results demonstrate that the tissue culture-adapted isolate of SPDV could be successfully used to protect against challenge by the wild-type virus and could therefore have potential use as an inactivated vaccine against PD.

Alphavirus↗
PubMed2000

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

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 either irradiation or treatment with mitomycin C. In other experiments, supernatant from donor cells containing virus was used. In co-culture with the donor cells, the less differentiated monocytic cells showed severe cellular changes such as differentiation, vacuolization, cell lysis and membrane blebbing; apoptosis was a frequent phenomenon. Budding and extracellular viruses were also observed. The more differentiated macrophage cells, although they showed less signs of infection by microscopy, had a complete BLV protein profile, as seen by Western blotting; bands corresponding to p24CA (Gag) and its precursors were clearly seen. In addition, gp51SU was identified by syncytia formation assays. It is concluded that M/M cells may be infected by BLV, the consequences of the infection differing according to the type of cell.

Animals↗
PubMed2000

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.

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 WB. Fetal calf serum, required for cellular growth and important in induction of viral transcription in vitro, was identified as a source of irrelevant proteins. In this study, 15 nonspecific protein bands in the growth medium were observed. These bands interfered with the interpretation of results. A nonspecific protein (25 kD) that was highly reactive in cell lysate preparation from BLV-bat2 was also detected. The unequivocal identification of protein bands, both specific and nonspecific, seen in WB is important not for understanding the protein profile of antigen preparations but also for determining if an animal is BLV positive or negative.

Animals↗
PubMed1998

Comparison of four tests to evaluate the reactivity of rabbit sera against envelope or Gag-related proteins of bovine leukemia virus (BLV).

Bovine leukemia virus (BLV) has a long latency period during which animals are inapparently infected, may spread the disease, and are only detected by serological techniques or by the most cumbersome molecular biology techniques. We have compared techniques for detecting either total antibodies (ELISA), anti-p24 and Gag-related proteins (Western blot), or anti-gp51 (agar gel immunodiffusion, AGID, and syncytia inhibition, SI) in rabbits inoculated experimentally with inocula of variable immunogenicity. The two tests to detect antibodies to gp51 correlated well in sera clearly positive or clearly negative by either one, but correlation was poor in the intermediate groups. All sera positive by AGID were also positive by ELISA, but results did not agree in sera negative by AGID, ELISA proving to be more sensitive. Western blot was a good technique for detecting antibodies against Gag-related proteins. However, no band was identified to clearly correspond to anti-Env-related proteins. As for other retroviruses, testing of animals for infection with BLV should include the detection of antibodies anti-Gag and anti-Env proteins.

Animals↗
PubMed1997

Macrophages infected with bovine leukaemia virus (BLV) induce humoral response in rabbits.

BLV is a lymphotropic retrovirus which infects mainly B-cells. However, the possible infection of cells of the monocyte/macrophage lineage (M/M) might explain some aspects of the disease such as latency or disease progression. We infected sheep M/M with BLV either by culturing M/M with supernatant containing virus, or coculturing M/M with persistently infected cell lines. These BLV-infected M/M were inoculated into rabbits and the serological response was followed for two years. ELISA results using adsorbed sera showed a persistent production of specific antibodies from as early as the first week post inoculation. Two tests were used to detect the response against envelope glycoprotein gp51: Agar gel immunodiffusion (AGID) and a virus neutralization test read as syncytia inhibition (SI). Sera were positive by AGID after the second or third inoculation. Neutralizing titres (SI) were higher than those seen in control rabbits inoculated with persistently infected cell lines, suggesting that the virus may be expressed better in M/M. Gag-related proteins were analyzed by Western Blot (WB). Sera from rabbits inoculated with BLV-infected M/M recognized as many viral proteins as sera from BLV immunized control rabbits or infected cows, and this profile did not change with repeated inoculations. All these results suggest that BLV may infect M/M, where viral proteins are actively expressed to the point that they induce a humoral immune response in animals, and that animals get persistently infected.

Animals↗
PubMed1994

Double-sandwich enzyme-linked immunosorbent assay (ELISA) with murine monoclonal antibodies for detection of staphylococcal enterotoxin B.

Three monoclonal antibodies (MAbs) which react specifically with staphylococcal enterotoxin B (SEB) were studied for their suitability for use in ELISA. One of them (MAb B14) worked well as a coating antibody; MAb B12 was shown to be a good probing antibody (conjugated with peroxidase) when ELISA plates were coated with MAb B14. This effective pair of MAbs (B14-B12PO) is able to detect 0.625 ng SEB ml, and to distinguish between SEB and other proteins present in food extracts.

Animals↗
PubMed1993

Repair and enterotoxin synthesis by Staphylococcus aureus after thermal shock.

To study repair and enterotoxin synthesis, four staphylococcal strains (FRI-100, FRI-137, FRI-472, and S6) were subjected to sublethal heat treatment, transferred to four liquid repair media (1% powdered skim milk in distilled water, complex medium, M9 minimal salt medium, and saline solution), and then incubated at different temperatures. Powdered skim milk proved to be the most efficient medium for promoting the repair of injured cells, particularly at 37 degrees C. Minimal salt medium also gave good results. Salt tolerance also increased at 4 degrees C, although it did not reach normal values. After 6 h of incubation at 37 degrees C in powdered skim milk, strain FRI-100 synthesized detectable amounts of enterotoxin A. After 10 h of incubation in the same medium at the same temperature, enterotoxins were detected in all of the strains.

Culture Media↗
PubMed1993

Phenotypic and phylogenetic evidence for a close relationship between Lactococcus garvieae and Enterococcus seriolicida.

Cultural, biochemical and protein profiling studies were performed on L. garvieae strains isolated from diseased rainbow trout and on the fish pathogen Enterococcus seriolicida ATCC 49156. The results, confirmed by 16 rRNA sequence analyses, indicate that E. seriolicida ATCC 49156 should be reclassified in the genus Lactococcus. Contrary to previous reports, both L. garvieae and E. seriolicida were found to be beta-haemolytic.

Animals↗
PubMed1992

Detection of enterotoxins and TSST-1 secreted by Staphylococcus aureus isolated from ruminant mastitis. Comparison of ELISA and immunoblot.

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 also positive by ELISA, and only three were positive by ELISA but negative by immunoblot.

Animals↗
PubMed1992

Lack of growth of heat-shocked Staphylococcus aureus surviving cells in common media and enterotoxin release.

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.

Culture Media↗
PubMed1992

Murine monoclonal antibodies against staphylococcal enterotoxin B: production and characterization.

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 other serovar (SEA, SED and SEE) or other proteins.

Animals↗
PubMed1992

Applicability of an immunoblot technique combined with a semiautomated electrophoresis system for detection of staphylococcal enterotoxins in food extracts.

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.

Electrophoresis, Polyacrylamide Gel↗
PubMed1991

Detection of staphylococcal enterotoxin and toxic shock syndrome toxin-1 (TSST-1) by immunoblot combined with a semiautomated electrophoresis system.

An immunoblot technique combined with a semi-automated electrophoresis system has been developed for the detection of staphylococcal enterotoxins and toxic shock syndrome toxin-1 (TSST-1). The advantages of this method over other detection techniques include speed, sensitivity (10 ng/ml) and specificity. The use of semiautomated electrophoresis permits the routine detection of staphylococcal enterotoxins and TSST-1.

Bacterial Toxins↗