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M C Rubio

Publications and source records attributed to M C Rubio.

At least 19 recordsLinked to original sources
PubMed2006

Genetic relatedness and antimicrobial resistance determinants among clinical isolates of enterococci from Cuba.

This study describes the genetic relationships and antimicrobial resistance determinants found among 99 clinical isolates of enterococci from 15 different hospitals in Cuba. Pulsed-field gel electrophoresis SmaI analysis demonstrated a high degree of genetic diversity. A limited number of multiresistant Enterococcus faecalis clones, showing resistance to three or more families of antimicrobial agents, were detected simultaneously in different institutions, suggesting inter-hospital circulation of selected clones, and/or selection of particular clones following their introduction into the hospital environment. Antimicrobial resistance determinants, including erm(B), aac(6')-aph(2'), aph(3'), ant(6), vanB (E. faecalis) and vanA (Enterococcus faecium) were detected by PCR in various isolates.

Aminoglycosides↗
PubMed2005

Smoking habits of parents and male: female ratio in spermatozoa and preimplantation embryos.

BACKGROUND: Previous observations have addressed a decreased male:female ratio associated with smoking. Our aim was to assess whether this effect is observed at the spermatozoa or at the early embryo development. METHODS: We retrospectively assessed smoking intake habits of 56 couples included in our preimplantation genetic diagnosis (PGD) program. Three groups were established according to male or female cigarette consumption per day: non-smokers, smokers (1-19 cigarettes per day) and heavy smokers (> or =20 cigarettes per day). Fluorescence in-situ hybridization (FISH) was performed on ejaculated sperm samples to analyse chromosomes X and Y. On day 3, embryos were also analysed. Additionally, sperm samples from four heavy smoking and four non-smoking donors were prospectively analysed before and after capacitation. RESULTS: FISH on spermatozoa revealed no statistical differences in the Y:X ratio between the three groups. However, in the PGD study, in male heavy smokers, the XY:XX embryo ratio was decreased compared with non-smokers (22:47 versus 80:71; P = 0.0057). The smoking condition of the female partner had no significant effect on embryo XY:XX ratio, but for non-smoking females with a heavy smoking partner, the ratio was decreased (P = 0.0018) compared with non-smoking males. In heavy smoking donors a decreased of Y:X ratio was observed after swim-up with a statistically significant difference of ratios (P = 0.021). CONCLUSIONS: Smoking habits of males do not have an effect on the percentage of X- and Y-bearing spermatozoa on ejaculated samples. However, male heavy smokers produce an increased incidence of female embryos that could be related to an enrichment of X spermatozoa after swim-up in patients with high tobacco consumption.

Adult↗
PubMed2004

Characterization of the molecular mechanisms of quinolone resistance in Yersinia enterocolitica O:3 clinical isolates.

OBJECTIVES: The aim of this study was to determine the roles of mutations in the gyrA and parC genes and the overexpression of efflux pump(s) as mechanisms of resistance to quinolones. Forty-five Yersinia enterocolitica O:3 clinical isolates (41 nalidixic acid-resistant, three nalidixic acid-susceptible and one nalidixic acid-resistant strain obtained in vitro) were analysed. RESULTS: All the nalidixic acid-resistant strains showed mutations in the gyrA gene and none in the parC gene. The presence of the inhibitor produced decreases in the MIC values of nalidixic acid by two to six serial dilution steps in 37 of the 41 nalidixic acid-resistant strains. Meanwhile, the MIC value of ciprofloxacin was affected in two strains whose values diminished three serial dilution steps. The nalidixic acid-resistant mutant obtained in vitro was also affected by the inhibitor decreasing the MIC value of nalidixic acid three serial dilutions steps whereas the MICs for the nalidixic acid-susceptible strains were not affected. CONCLUSIONS: Our results show that the high level of resistance to nalidixic acid is likely due to an overexpression of an efflux pump plus a mutation in the gyrA gene, whereas decreased susceptibility to ciprofloxacin is only associated with the presence of a mutation in the gyrA gene.

Anti-Infective Agents↗
PubMed2004

Tinea capitis in infants in their first year of life.

BACKGROUND: Tinea capitis is the most common type of dermatophytosis in children, but is uncommon in the first year of life. OBJECTIVES: To review clinical, mycological and epidemiological data in a series of 10 infants aged under 1 year diagnosed as having tinea capitis in three Spanish hospitals between 1998 and 2002. METHODS: A retrospective case note study. RESULTS: There were six boys and four girls with a mean of age 7 months (range 1.5-12). All the children were born in Spain, but in five cases the parents were immigrants from Africa. In these cases the isolated dermatophytes were two Trichophyton tonsurans, one T. verrucosum and two Microsporum audouinii. Four autochthonous cases were caused by M. canis and one by M. audouinii (but this one was in contact with African immigrants). In two of the five cases produced by anthropophilic dermatophytes other family members were infected by the same fungus. Most cases were treated successfully with griseofulvin. CONCLUSIONS: Although tinea capitis is rare in infants in their first year of life, the condition should be investigated if scaling and/or alopecia are present. A thorough epidemiological study of other family members is mandatory.

Antifungal Agents↗
PubMed2004

In vitro activity of telithromycin, quinupristin/dalfopristin, linezolid and comparator antimicrobial agents against Staphylococcus aureus clinical isolates.

We have studied the prevalence of the different macrolide, lincosamide, streptograminB (MLS(B)) phenotypes among clinical Staphylococcus aureus isolates erythromycin- and/or oxacillin-resistant; and also the activity of other antimicrobial agents including telithromycin, quinupristin/dalfopristin, linezolid, aminoglycosides, chloramphenicol and vancomycin. We found that 64.86% of S. aureus were oxacillin-resistant. While the most prevalent MLS(B) phenotype among methicillin-resistant S. aureus (MRSA) was constitutive MLS(B) (cMLS) (83%), among methicillin-susceptible S. aureus (MSSA) it was inducible MLS(B) (iMLS(B)) (90%). Kanamycin resistance was more frequent than resistance to other aminoglycosides, being 100% for MRSA. Telithromycin was only active against iMLS(B), MS and erythromycin-susceptible isolates, although resistance rates were found among iMLS(B) MSSA (2.78%). Quinupristin/dalfopristin showed greater activity, with resistance rates of 2.5% for MRSA and 1.53% for MSSA. Both vancomycin and linezolid were fully active against all the isolates tested, with the highest MIC value being 2 microg/ml and 4 microg/ml, respectively. Among MRSA strains, 81.67% displayed resistance to five or more antimicrobials. This multiresistance was more frequently found among cMLS(B) strains (96.38% MRSA resistant to 6-9 agents).

Acetamides↗
PubMed2003

Epidemiological study of resistance to nalidixic acid and other antibiotics in clinical Yersinia enterocolitica O:3 isolates.

Forty-six Yersinia enterocolitica O:3 clinical isolates resistant to nalidixic acid were studied. The use of molecular typing techniques, other indicators of resistance patterns, the plasmid profile, and the presence of genes that encode aminoglycoside-modifying enzyme production suggested to us a clonal dissemination of the studied strains.

Anti-Infective Agents↗
PubMed2002

Evaluation of an immunochromatographic dip-strip test for the detection of Cryptosporidium oocysts in stool specimens.

The study presented here examined the efficacy of a commercially available qualitative immunochromatographic assay for detecting Cryptosporidium oocysts in stool samples. A total of 75 samples were tested, including 50 positive for Cryptosporidium spp. by acid-fast stain, 20 positive for other parasites ( Blastocystis hominis, Endolimax nana, Entamoeba coli, Giardia lamblia, Ascaris lumbricoides, Strongyloides stercoralis and Trichuris trichiura), and five negative samples. The observed sensitivity was 98%, while specificity was 100%; the detection threshold was near 1000 oocysts/ml. Correctly diagnosed positive samples included Cryptosporidium parvum genotypes 1 and 2, whereas the single false-negative sample corresponded to a Cryptosporidium meleagridis infection.

Animals↗
PubMed2002

Tolerance to the sedative effect of lorazepam correlates with a diminution in cortical release and affinity for glutamate.

Benzodiazepines are anxiolytic, anticonvulsant, sedative and hypnotic compounds usually prescribed on a long-term basis. Chronic treatment with these compounds induces tolerance, which has been extensively attributed to modifications in the GABAergic neurotransmission. However, a compensatory increase in the excitatory response, named as an oppositional response, has also been put forward as a means for explaining such tolerance. Changes in the excitatory neurotransmission have been found in withdrawn rats after a long treatment with benzodiazepines but these modifications have not been conclusively studied during tolerance. In this work we studied several parameters of the glutamatergic neurotransmission in rats made tolerant to the sedative effect of 3 mg/kg (i.p.) of lorazepam (LZ). We found a decrease in the affinity of cortical NMDA receptors for (3)H-glutamate (K(D): 124.4 +/- 13.3 nM in tolerant rats, 71.6 +/- 10.4 nM in controls, P<0.05) together with a decrease in the in vitro 60 mM K(+)-stimulated cortical glutamate release (59+/- 12% vs. 153 +/- 38%, tolerant rats vs. controls, P<0.05). We conclude that tolerance to the sedative effect of LZ correlates with a decreased sensitivity for glutamate that may in turn diminish the cortical response to a chemical stimulus. Our findings constitute an evidence against the oppositional model of pharmacodynamic tolerance in this experimental condition.

Animals↗
PubMed2002

Baclofen prevents morphine withdrawal irrespective of seasonal variation.

In previous studies we have demonstrated a possible interaction between the gamma-aminobutyric acid (GABA)ergic and opioid systems involved in the antinociceptive effect of the GABAB agonist, baclofen (BAC). In addition, we have demonstrated that BAC was able to prevent the morphine (MOR) withdrawal syndrome in female, as well as male mice. On the other hand, seasonal variations have been observed in some MOR effects. In the present study, we analysed the effects of BAC on naloxone (NAL)-precipitated withdrawal, during two different seasons. The experiments were performed during two seasons: spring-summer (SS) and autumn-winter (AW) for two years, on male Swiss-Webster albino mice (27-33 g). Mice were rendered dependent by intraperitoneal (i.p.) injection of MOR (2mg/kg), twice daily for 9 days. On the tenth day the dependent animals were divided into two groups: one received NAL (6mg/kg, i.p.) 60 min after the last dose of MOR, to develop the NAL-precipitated withdrawal; the other group received BAC (2mg/kg, i.p.) followed by NAL (6mg/kg, i.p.), injected 30 and 60 min after the last dose of MOR, respectively. Behavioural signs were recorded in the open field for 30 min. Although there were seasonal variations in the MOR withdrawal syndrome, we found that BAC prevents MOR withdrawal irrespective of seasonal variation.

Animals↗
PubMed2002

[Antimicrobial resistance of clinical strains of Salmonella enterica isolated in Zaragoza].

In order to identify any changes in the incidence of Salmonella enterica serotypes and their resistance to a variety of antimicrobial agents, we conducted a retrospective study of all the strains isolated from stool samples at Hospital Clínico Universitario Lozano Blesa in Zaragoza from 1997 to 2000. We observed an increase in the number of isolates of Salmonella and Campylobacter and a decrease in other enteropathogens. Enteritidis was the most frequently isolated serotype (55.2%), showing an increasing tendency (from 44.1% in 1997 to 60.6% in 2000). Hadar, glostrup and virchow showed the highest rate of resistance to nalidixic acid. Enteritidis also showed an important increase in resistance to nalidixic acid (from 17.6% in 1997 to 41.4% in 2000). Typhimurium showed the highest resistance levels to ampicillin, chloramphenicol and cotrimoxazole. No resistance to fluoroquinolones or to cefotaxime was detected, with the exception of 0.5% of the S. enteritidis strains, which showed resistance to fluoroquinolones.

Drug Resistance, Bacterial↗
PubMed2002

[In vitro activity of posaconazole against yeasts isolated in blood cultures].

The in vitro activity of posaconazole against Candida species isolated from blood cultures and the influence of incubation time was studied and compared with that of fluconazole. A total of 112 isolates were studied: 32 Candida albicans, 33 C. parapsilosis, 17 C. tropicalis, 8 C. glabrata, 8 C. guilliermondii, 3 C. famata, 2 C. lusitaniae, 1 C. lipolytica, 1 C. inconspicua, 1 C. lambica, 3 Saccharomyces cerevisiae, 1 Blastoschizomyces capitatus, 1 Geotricum spp. and 1 Pichia omheri. The MIC was obtained using the M27-A microdilution method described by the NCCLS for Candida spp. and Cryptococcus neoformans. The species most susceptible to posaconazole were C. parapsilosis (MCI90 0.016 mg/l), C. guilliermondii (MIC90 0.12 mg/l), C. glabrata (MCI90 0.5 mg/l) and Candida spp. (MCI90 0.25 mg/l). However, this azole did not improve the activity of fluconazole against C. tropicalis (MIC90 8 mg/l) and C. albicans (MCI90 mg/l). The time of reading was important in the detection of resistance, as the number of strains resistant to fluconazole or posaconazole was higher at 48 hours than at 24 hours for C. albicans and C. tropicalis. All the other species of Candida were susceptible at both reading times.

Bacteriological Techniques↗
PubMed2001

Effects of optical isomers of clenbuterol on the relaxant response in rat uterus.

Previous works have shown that the administration of the racemic beta -adrenoceptor agent clenbuterol produces a desensitization of the relaxant response in rat uterus. The aim of this work was to study the effects of the optical isomers of clenbuterol on the relaxant response in rat uterus. The administration of (L)-clenbuterol (0.25 mg per kg per day) over 1 or 10 consecutive days, produced a reduction of the relaxant response to isoproterenol in uterine rings precontracted with 50 m m KCl from oestrogenic rats. The administration of (D)-clenbuterol (0.25 mg per kg per day) over 1 or 10 days did not affect the relaxant response of isoproterenol. (L)-clenbuterol also produced a concentration-dependent relaxant effect that was not observed with (D)-clenbuterol. These results show that the beta-adrenergic relaxant response and the desensitization of the relaxant effect to isoproterenol is due to the (L)-isomer and that the (D)-isomer is not involved in these effects.

Adrenergic beta-Agonists↗
PubMed2001

The eaeA gene is not found in Hafnia alvei from patients with diarrhea in Aragón, Spain.

A total of 102 Hafnia alvei clinical strains isolated from different patients with diarrhea has been tested, using polymerase chain reaction and dot-blot hybridization, for the enteropathogenic Escherichia coli attaching and effacing A (eaeA) gene to establish their role as a causative agent of diarrhea in our environment. None of them was positive for the eaeA gene. We cannot consider the eaeA gene as the virulence-associated factor implicated in the H. alvei strains isolated from diarrheal feces in our region.

Adhesins, Bacterial↗
PubMed2001

Diazepam fails to potentiate GABA-induced chloride uptake and to produce anxiolytic-like action in aged rats.

The pharmacological response to benzodiazepines has been demonstrated to be different in aged individuals in comparison to adults. We studied the age-dependent changes in some of the in vitro and behavioral effects of diazepam in aged (24 months old) rats, comparing them to adults (3 months old). We evaluated the in vitro gamma-aminobutyric acid (GABA)-induced 36Cl- uptake and the diazepam potentiation of GABA-stimulated 36Cl- uptake in microsacs from cerebral cortex of both groups of animals. We found no differences in the GABA-stimulated 36Cl- uptake between adult and aged animals, and diazepam failed to potentiate GABA-induced 36Cl- flux in the aged cortical microsacs. We also examined the effect of 0.03-10 mg of diazepam on locomotor activity in an open-field test and the anxiolytic-like action of diazepam in doses ranging from 0.03 to 1 in a dark-light transition test. We observed no anxiolytic-like action of the drug in the dark-light transition test in the aged rats, while there was a shift to the left in the diminution of locomotor activity evaluated by the open-field test. We conclude that the pharmacodynamic changes observed in cortical GABA(A) receptors in aged rats could partially explain the lack of anxiolytic-like action but not the oversedation evidenced in this group of animals.

Aging↗
PubMed2001

Comparative in vitro bacteriostatic and bactericidal activity of trovafloxacin, levofloxacin and moxifloxacin against clinical and environmental isolates of Legionella spp.

The susceptibility of 140 Legionella spp isolates (106 clinical and 34 environmental isolates) to trovafloxacin (TRFX), levofloxacin (LEVX), moxifloxacin (MOFX), ciprofloxacin (CIPX), ofloxacin (OFLX), erythromycin (ERY), azithromycin (AZI) and rifampicin (RIF) was studied using a standard microdilution method and buffered yeast extract broth (BYE) supplemented with 0.1% alpha-ketoglutarate. The post-antibiotic effects (PAEs) of the study drugs against 10 clinical isolates of Legionella pneumophila sg.1 were compared. The MIC inhibiting 90% of strains tested on BYEalpha broth were 0.008, 0.016, 0.016, 0.06, 0.125, 0.5, 0.5, and 0.004 mg/l for TRFX, LEVX, MOXX, CIP, OFLX, ERY, AZI, and RIF, respectively. The MBC/MIC ratios ranged from one to eight depending on the antibiotic tested: TRFX [1x-2 x MIC], LEVX, MOFX, CIPX and OFLX [1x-4 x MIC], RIF [2x-4 x MIC], ERY and AZI [2x-8 x MIC]. TRFX, RIF, LEVX, MOFX, CIPX, OFLX, ERY and AZI showed similar activity against Legionella species other than L. pneumophila. One-hour exposures to the study antimicrobial agents at a concentration of 4 x MIC resulted in PAEs as follows (average in hours): TRFX: 2.68 h; RIF: 2.63 h; CIPX: 2.62 h; MOFX: 2.56 h; LEVX: 2.41 h; OFLX: 2.25 h; AZI: 1.65 h; and ERY: 1.54 h. In conclusion, our in vitro data confirm that trovafloxacin, levofloxacin, moxifloxacin and rifampicin have excellent bacteriostatic and bactericidal activity against Legionella spp and show significant post-antibiotic effect.

Anti-Bacterial Agents↗
PubMed2001

Expression studies of superoxide dismutases in nodules and leaves of transgenic alfalfa reveal abundance of iron-containing isozymes, posttranslational regulation, and compensation of isozyme activities.

The composition of antioxidant enzymes, especially superoxide dismutase (SOD), was studied in one nontransgenic and three transgenic lines of nodulated alfalfa plants. Transgenic lines overproduced MnSOD in the mitochondria of nodules and leaves (line 1-10), MnSOD in the chloroplasts (line 4-6), and FeSOD in the chloroplasts (line 10-7). In nodules of line 10-7, the absence of transgene-encoded FeSOD activity was due to a lack of mRNA, whereas in nodules of line 4-6 the absence of transgene-encoded MnSOD activity was due to enzyme inactivation or degradation. Transgenic alfalfa showed a novel compensatory effect in the activities of MnSOD (mitochondrial) and FeSOD (plastidic) in the leaves, which was not caused by changes in the mRNA levels. These findings imply that SOD activity in plant tissues and organelles is regulated, at least partially, at the posttranslational level. All four lines had low CuZnSOD activities and an abundant FeSOD isozyme, especially in nodules, indicating that FeSOD performs important antioxidant functions other than the scavenging of superoxide radicals generated in photosynthesis. This was confirmed by the detection of FeSOD cDNAs and proteins in nodules of other legumes such as cowpea, pea, and soybean. The cDNA encoding alfalfa nodule FeSOD was characterized and the deduced protein found to contain a plastid transit peptide. A comparison of sequences and other properties reveals that there are two types of FeSODs in nodules.

Amino Acid Sequence↗
PubMed2001

The antioxidants of legume nodule mitochondria.

The mitochondria of legume root nodules are critical to sustain the energy-intensive process of nitrogen fixation. They also generate reactive oxygen species at high rates and thus require the protection of antioxidant enzymes and metabolites. We show here that highly purified mitochondria from bean nodules (Phaseolus vulgaris L. cv. Contender x Rhizobium leguminosarum bv. phaseoli strain 3622) contain ascorbate peroxidase primarily in the inner membrane (with lesser amounts detected occasionally in the matrix), guaiacol peroxidases in the outer membrane and matrix, and manganese superoxide dismutase (MnSOD) and an ascorbate-regenerating system in the matrix. This regenerating system relies on homoglutathione (instead of glutathione) and pyridine nucleotides as electron donors and involves the enzymes monodehydroascorbate reductase, dehydroascorbate reductase, and homoglutathione reductase. Homoglutathione is synthesized in the cytosol and taken up by the mitochondria and bacteroids. Although bacteroids synthesize glutathione, it is not exported to the plant in significant amounts. We propose a model for the detoxification of peroxides in nodule mitochondria in which membrane-bound ascorbate peroxidase scavenges the peroxide formed by the electron transport chain using ascorbate provided by L-galactono-1,4-lactone dehydrogenase in the inner membrane. The resulting monodehydroascorbate and dehydroascorbate can be recycled in the matrix or cytosol. In the matrix, the peroxides formed by oxidative reactions and by MnSOD may be scavenged by specific isozymes of guaiacol peroxidase, ascorbate peroxidase, and catalase.

Antioxidants↗