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Biomedical subjects

M T Blanco

Publications and source records attributed to M T Blanco.

At least 19 recordsLinked to original sources
PubMed2006

Modification of adherence to plastic and to human buccal cells of Candida albicans and Candida dubliniensis by a subinhibitory concentration of itraconazole.

Exposure to subinhibitory concentrations of antifungal agents can influence the adherence of Candida spp. to the host cell. In this study the adherence of Candida albicans ATCC 10231 and Candida dubliniensis CECT 11455 to plastic and to human buccal epithelial cells was evaluated following pre-exposure to 0.5 x minimum inhibitory capacity (MIC) of itraconazole and compared with the corresponding cellular surface hydrophobicity. The yeasts were grown in Sabouraud broth or RPMI-1640 with itraconazole (0.5 x MIC) for 24-26 h at 37 degrees C and the drug was then removed. The adhesion capacity to plastic was studied by turbidimetry in a polystyrene microtiter plate. The adhesion of the yeast to buccal epithelial cells was determined using microscopy techniques. The cellular surface hydrophobicity levels were determined by the microbial adhesion hydrocarbons test. Pre-exposure to itraconazole decreased plastic adherence and cellular surface hydrophobicity in both species when grown in RPMI. When C. albicans was grown in Sabouraud broth, it was nonhydrophobic and did not adhere and therefore no change was detected with the antibiotic. Itraconazole increased adherence to buccal epithelial cells in both species and media studied, as compared to controls without antifungal agents. To study the effects of these antifungal agents on pathogenicity mechanisms, it will be necessary to standardize the methodology for evaluation to determine their in vivo therapeutic efficacy.

Adhesiveness↗
PubMed2005

Exposure to therapeutic concentrations of ritonavir, but not saquinavir, reduces secreted aspartyl proteinase of Candida parapsilosis.

The effect of ritonavir and saquinavir, HIV proteinase inhibitors, on the secreted aspartyl proteinase (Sap) activity of Candida parapsilosis was studied. In a proteinase-inducing medium (yeast carbon base-bovine serum albumin), Sap activity in all clinical isolates of C. parapsilosis (n = 20) was observed at 37 degrees C but not at 22 degrees C. The presence of ritonavir at a concentration of 8 microg/ml produced an inhibition close to 50% albumin consumption and also delayed yeast growth; however, saquinavir did not have any effect on growth or on Sap activity. In Sabouraud broth, which does not induce Sap production, no effect was shown on yeast growth by either of the two HIV proteinase inhibitors studied.

Aspartic Acid Endopeptidases↗
PubMed2004

Moxifloxacin and biofilm production by coagulase-negative staphylococci.

The in vitro activity of moxifloxacin against 41 strains of coagulase-negative staphylococci was determined. A relationship between the activity of moxifloxacin and biofilm formation was detected. Biofilm-producing strains were more resistant to moxifloxacin than biofilm-negative strains. Our global results obtained with six strains of Staphylococcus epidermidis showed that subinhibitory concentrations of moxifloxacin did not significantly modify biofilm formation. On the other hand, moxifloxacin concentrations of 2, 10, 50 and 100 x MIC produced a log decrease in viable count (included in a biofilm) of 0.20, 0.37, 1.10 and 1.69, respectively.

Anti-Bacterial Agents↗
PubMed2003

National prevalence of larval echinococcosis in sheep in slaughtering plants Ovis aries as an indicator in control programmes in Uruguay.

Diagnostic surveys carried out on ovine larval echinococcosis in slaughtering plants at a national level in 1998 made it possible to meet several objectives, i.e. to estimate the existing levels of prevalence, to evaluate the effectiveness of the control actions applied by the Programme against Hydatidosis and to contribute to the improvement of the health information systems for epidemiological surveillance. The work included sheep (Ovis aries), both lambs (2-4 teeth) and adults (6-8 teeth). A random sample was performed among sheep from the plants that slaughter the majority of animals in the country. The sample included 22 animals per herd, and it involved removing their offal (liver, lungs and heart) and processing serial sections at the laboratory. The histopathological studies were performed on the lesions that could not be adequately identified at gross examination, and those that were so small that had to be submitted for confirmation of the diagnosis. Of the 2035 animals that were examined, 1019 were lambs (2-4 teeth) and 1016 were adults (6-8 teeth). The prevalence of larval echinococcosis was 7.7% in lambs and 18.0% in adults. The overall prevalence in the liver was 8.5 and 8.0% in the lungs. As to the characteristics of the morphologic structures of the larvae, in younger animals 29% of the lesions were calcified, and 71.0% were hyaline, while in older animals the proportions were 34.4% calcified versus 65.6% hyaline. Other conditions found in the liver parenchyma included: white stain (0.8%), caseous lymphadenitis (3.0%), abscess (0.4%), larvae of Taenia hydatigena (5.1%), Fasciola hepatica (3.9%). And 1.7% of the animals presented larvae of Taenia ovis in the cardiac muscle. Previous surveys carried out in 1994 using the same methodology showed a prevalence of 15.2% in 2-4 teethed animals and 33.9% in 6-8 teethed animals, thus confirming that rates have decreased by 49.6 and 47.0%, respectively. The data obtained reflect the reduction of areas contaminated with eggs of Echinococcus granulosus, which would cause a loss in immunity against this parasite after a certain time. Prevalence of larvae T. hydatigena and T. ovis could change if more sites were considered, a fact that was confirmed in studies carried out in our country. The species O. aries must be used as an indicator in the control programmes, especially in the category of 2-4 teethed lambs. The fact they are not as frequent in our market must be considered; in 1998 they accounted for only 3.0% of the total numbers of animals.

Abattoirs↗
PubMed2003

In vitro activity of allicin against Staphylococcus epidermidis and influence of subinhibitory concentrations on biofilm formation.

AIMS: The aim of this study is to determine the in vitro activity of allicin against Staphylococcus epidermidis and to evaluate the influence of allicin on biofilm formation. METHODS AND RESULTS: In vitro activity of allicin (diallyl thiosulphinate) against 38 strains of S. epidermidis was investigated. The activity of allicin was similar against S. epidermidis methicillin susceptible and methicillin resistant strains [minimum inhibitory concentration (MIC)90=8 mg l(-1)]. In general, subinhibitory concentrations (sub-MIC) of allicin diminished biofilm formation in the five strains analysed. CONCLUSION: The results confirm the antibacterial effect of allicin. Sub-MICs of allicin also diminished the biofilm formations by S. epidermidis. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study shows that allicin is active in vitro against S. epidermidis and that sub-MICs of allicin may play a role in the prevention of adherence of this bacteria to medical devices.

Anti-Infective Agents↗
PubMed2003

Effect of ritonavir and saquinavir on Candida albicans growth rate and in vitro activity of aspartyl proteinases.

An in vitro study to evaluate the antifungal effect and activity of aspartyl proteinases of the HIV-proteinase inhibitors ritonavir and saquinavir was conducted. Ritonavir diminished the growth rate of Candida albicans as well as the activity of its secreted aspartyl proteinases (Saps) in a nitrogen-limited medium, yeast carbon base and bovine serum albumin (YCB-BSA). This inhibition occurred in a dose-dependent fashion; with 8 mg l(-1) of ritonavir a partial growth inhibition (44%) was produced. The growth rate of C. albicans in medium with saquinavir was similar to that seen in the control, and Sap activity was inhibited only at high concentrations. In conventional medium (RPMI-1640), which does not induce the production of yeast proteases, no inhibitory effect was detected with either HIV-protease inhibitor.

Aspartic Acid Endopeptidases↗
PubMed2001

Resistance to vancomycin, LY333328, ciprofloxacin and trovafloxacin of community-acquired and nosocomial strains of Enterococcus faecalis isolated in Badajoz (Spain) with and without high-level resistance to streptomycin and gentamicin.

In vitro resistance of community-acquired and nosocomial strains of Enterococcus faecalis isolated in Badajoz (Spain) were determined by a microdilution method. The isolates were identified with conventional MicroScan Pos Combo 4 I dehydrated panels. No resistance to glycopeptides was found, but LY333328 was 2-4 times more active than vancomycin. In the nosocomial strains, high-level resistance to streptomycin (HLRS) was 54.7%, and high-level resistance to gentamicin (HLRG) was 38.1%. Resistance to ciprofloxacin and trovafloxacin was 45.3 and 38.9%, respectively. In the community-acquired isolates, HLRS, HLRG, resistance to ciprofloxacin and resistance to trovafloxacin were 44.2, 17.3, 15.4 and 13.5%, respectively. Trovafloxacin was 2-4 times more active than ciprofloxacin against both groups of strains. An association between high-level resistance to aminoglycosides and resistance to fluoroquinolones was noted. The resistance to aminoglycosides did not influence the activity of vancomycin and LY333328.

Anti-Bacterial Agents↗
PubMed1998

Phagocytosis and killing of slime-producing Staphylococcus epidermidis bypolymorphonuclear leukocytes. Effects of sparfloxacin.

The interaction of slime-producing Staphylococcus epidermidis (S+ strain) with human polymorphonuclear leukocytes (PMNs) was analyzed. The phagocytosis index (PI) and the killing index (KI) were evaluated, and the effect of subinhibitory concentrations (sub-MICs) of sparfloxacin in this interaction was determined. The study was carried out in parallel with a non-slime-producing strain (S- strain). The MIC values of sparfloxacin against both strains was 0. 06 mg/ml. In the S- strain the mean values of PI and KI were 82% and 31%, respectively, whereas in the S+ strain these values diminished to 49% and 8%, respectively (p <0.05) when the inocula were prepared in aerobiosis. In a constant flow atmosphere of 5% CO2, the results were similar to the previous ones in the S- strain (PI = 79% and KI = 27%), whereas in the S+ strain a increase in the PI (59%) and a similar value to the KI (9%) were observed. Significant increases (p <0.05) in the PI were noted when PMNs were preincubated with 1/4 and 1/16 MIC of sparfloxacin, and S. epidermidis S+ grown in aerobiosis were used. In the other assays the variations in PI and KI were not statistically significant (p >0.05). Our results confirm that slime protects against phagocytosis and killing by PMNs, although they also suggest that the S+ strains possess additional properties which make them resistant to the action of the PMNs.

Aerobiosis↗
PubMed1997

Influence of N-acetylcysteine on the formation of biofilm by Staphylococcus epidermidis.

The influence of various concentrations (0.003-8 mg/mL) of N-acetylcysteine on the formation of biofilms by 15 strains of Staphylococcus epidermidis has been studied. A dose-related decrease in biofilm formation was observed, except with the lowest concentrations. The 'slime' index relative to the control was 63%, 55%, 46%, 34%, 26% and 26% in the presence of 0.25, 0.5, 1, 2, 4, and 8 mg/mL of N-acetylcysteine, respectively. These data are statistically significant. The inhibitory effect of 2 mg/mL of N-acetylcysteine on slime formation was also verified by electron microscopy.

Acetylcysteine↗
PubMed1997

Incubation temperatures affect adherence to plastic of Candida albicans by changing the cellular surface hydrophobicity.

The influence of cellular surface hydrophobicity on the adherence capacity to plastic of Candida albicans was investigated at two culture temperatures (37 and 22 degrees C). The majority of the 42 strains studied were hydrophobic at 22 degrees C and hydrophilic at 36 degrees C. The hydrophobic cells showed a consistent adherence capacity which was absent from the hydrophilic strains. The culture temperatures affect adherence to plastic of C. albicans by changing the cellular surface hydrophobicity.

Adhesiveness↗
PubMed1995

Influence of the incubation atmosphere on the production of slime by Staphylococcus epidermidis.

The influence of various incubation atmospheres on the growth and slime production of 23 Staphylococcus epidermidis strains was studied. The atmospheres evaluated were aerobiosis (control), anaerobiosis, candle jar, 5% CO2 and 10% CO2. As compared to the aerobic control, growth was 55.7 +/- 19% (p < 0.01) in anaerobic incubation, 113.7 +/- 12% (p < 0.01) in 5% CO2, 112.8 +/- 13% (p < 0.01) in 10% CO2 and 106.4 +/- 7% (p > 0.1) in the candle jar. The slime production in relation to the aerobic control was 20.3 +/- 19% in anaerobiosis (p < 0.01), 22.3 +/- 27% (p < 0.01) in 5% CO2, 29.4 +/- 39% (p < 0.01) in 10% CO2 and 68.3 +/- 26% (p > 0.1) in the candle jar. The results of this study may explain the discrepancies which have been noted on occasion between slime formation data and pathogenicity.

Aerobiosis↗
PubMed1994

Effects of cefpirome in comparison with cefuroxime against human polymorphonuclear leucocytes in vitro.

The interaction of cefpirome and cefuroxime, with human polymorphonuclear leucocytes (PMNs) was examined. The effects of therapeutic concentration (1, 10, and 50 mg/L) of both antimicrobial agents on the adherence, spontaneous mobility, chemotaxis, chemokinesis, phagocytosis and candidacidal capacity were studied in vitro. No statistically significant variations, in relation to the control, were observed in the ability of PMNs to adhere to nylon fibre at the concentrations of cefuroxime and cefpirome used. With both antimicrobial agents, PMN mobility increased as the antibiotic concentration was increased. A statistically significant increase (P < 0.05) in spontaneous mobility, chemotaxis and chemokinesis was observed with cefpirome at only 10 mg/L. However, only spontaneous mobility was increased significantly with cefuroxime at 10 mg/L. The strongest effects were observed with cefpirome at 50 mg/L with variations of about 70% (P < 0.01), in chemotaxis and chemokinesis. In general, cefpirome had a positive effect on phagocytosis and candidacidal power, which was significant at a concentration of 50 mg/L (P < 0.01). Cefuroxime, in general, produced no modifications in either phagocytosis or candidacidal power.

Candida albicans↗
PubMed1992

In vitro studies of activities of some antifungal agents against Candida albicans ATCC 10231 by the turbidimetric method.

Different criteria (the drug concentration which inhibited 50% of growth [IC1/2], the lowest drug concentration at which growth was just less than 30% of that in a positive control well [IC30], the visual inhibitory concentration [ICv], and the minimum fungicidal concentration [MFC]) were applied to study the effects of some antifungal agents against Candida albicans. Amphotericin B, flucytosine, and bifonazole produced total growth inhibition. Clotrimazole, itraconazole, ketoconazole, and miconazole produced partial growth inhibition. The values of IC1/2 and IC30 were similar for all agents and avoided the problems of partial inhibition; the values of ICv and MFC were higher than those of IC1/2 and IC30.

Antifungal Agents↗
PubMed1991

Activity of vancomycin and teicoplanin against human polymorphonuclear leucocytes: a comparative study.

The in-vitro effects of therapeutic concentrations of teicoplanin and vancomycin on the adherence, spontaneous mobility, chemotaxis, phagocytic and candidacidal capacity of human polymorphonuclear leukocytes (PMNs) were studied. Adherence was not affected by the tested concentrations of teicoplanin. A progressive diminishing of adherence was observed in relation to the control, which reached 30% with the maximum concentration of vancomycin (50 mg/L), although this was not statistically significant. An increase in spontaneous mobility was noted after 30 min incubation in the presence of any one of the tested concentrations of both antibiotics, although the results were only significant (P less than 0.05) for 50 mg/L of teicoplanin. Chemotaxis increased, although not significantly (P greater than 0.05) in the presence of 10 and 50 mg/L of teicoplanin, and diminished with respect to the control very significantly (P less than 0.019) when 1 and 50 mg/L of vancomycin were tested. The study of the phagocytic and candidacidal capacity of the PMNs on Candida albicans showed that teicoplanin had a favourable effect on both functions, even though the differences were not statistically significant.

Anti-Bacterial Agents↗